Left Heart Ventricular Function

By Jan Masila

United States

What is the LV Function? This is a question that is heard often with cardiac imaging due to many important diagnostic, prognostic, and treatment decisions resting upon left ventricle (LV) morphology/function analysis. “Many echocardiographic departments perform “eyeball” analysis of global and regional LV function and provide visual estimates of ejection fraction because existing M Mode and 2D Echo quantification methods can be both time consuming and difficult to perform.”(1) Visual estimation of global and regional ventricular function are termed qualitative. Quantitative measures to evaluate ventricular function include things such as stroke volumes (SV) and ejection fraction (EF). Two-dimensional Echo and M Mode echocardiography provide the ability to quantitatively evaluate ventricular function through the use of endocardial border tracing and Doppler but geometric assumptions can limit the accuracy. “Advances in 3D echocardiography instrument technology and computer processing power have led to a potentially powerful clinically applicable technique to evaluate LV function. Three dimensional echocardiography has shown to be an accurate and reproducible method for LV quantitation, mainly, by avoiding the use of geometric assumptions which are inherent in 2D and M Mode.” (2) Currently, there are several tools and methods available to assist in providing the answer to this commonly asked question – “What is the LV function?”.

To begin with, the “function” or “job” of the LV should be understood. The hearts basic function is that of a pump. The LV is the largest pumping chamber of the heart and is muscular and thick as compared to the right ventricle. Literally the LV’s job is to pump oxygenated blood systemically throughout the body and as mentioned previously, this function is integral in diagnosing and making treatment decisions. The question of, “What is the LV function?” that is often asked, refers to how well the LV is doing it’s job. A normal left ventricle should squeeze or contract (systole) forcibly enough to eject blood to open the aorta and pump blood systemically. Typically, a normal, healthy adult hearts pump volume is 5 ml/min resting. A normal heart should also relax quickly after each systolic contraction so that it can fill properly (diastole) with blood from the pulmonary veins. “Left ventricular function and pump performance depend on contractility (the basic ability of the myocardium to contract), preload (initial ventricular volume or pressure), afterload (aortic resistance or end systolic wall stress) and ventricular geometry.”(3)

Qualitative evaluation is a fast answer that is subjective person to person. The parasternal long-axis, parasternal short axis, apical four chamber, two chamber and three chamber view offer views of the various walls. The parasternal long-axis shows the anterior septum and posterior wall; parasternal short-axis the inferior, medial, anterior septum and anterior, lateral, posterior and inferior wall; apical four chamber the lateral and septum; two chamber the anterior and inferior wall; the three chamber the posterior and antero-septal wall. Also, keep in mind that the shape is important. The normal shape of the LV is symmetrically conal shaped or “bullet shaped”. These views together help provide a more complete picture of the LV for an experienced eye to determine a qualitative estimate of the LV function. Emergency rooms are a good example of when a quick evaluation of LV function may be needed, either to eliminate heart dysfunction or initiate a more in depth quantitative investigation. In other words use a qualitative approach to determine if there is primary cardiac dysfunction versus non-primary cardiac dysfunction. Qualitative functions can be classified as normal, mildly impaired, moderately impaired and severely impaired. Quantitative evaluation of ventricular function utilizes linear dimension measurements, ventricular volumes, LV mass and wall stress as parameters of ventricular function.

LV internal dimensions and wall thickness are measured routinely in 2D echocardiography. Most often this is done in the TTE parasternal long-axis view, at the level of the mitral valve leaflet tips. These measurements can also be made in M-Mode. “M-mode is most helpful and used for timing of rapid cardiac motions, precise measurement of cardiac dimensions, or further evaluation of structures seen on 2D images (such as suspected vegetations) to aid in their identification.”(3) Transesophageal Echocardiography (TEE) measurement of LV internal dimensions are made in a transgastric two-chamber view a the junction between the basal third and apical third of the ventricle. TEE Wall thickness is measured in the transgastric short-axis.(3) The TEE process involves guiding a prove down the throat into the esophagus which provides a clearer image due to the closer proximity to the heart. Wall thickness is measured using leading-edge to leading-edge technique. Chamber size is measured in end-diastole and end-systole. These measurements provide an evaluation of contractility of the myocardium.

Various assumptions about LV shape have been used to derive formulas for calculating ventricular volumes, linear dimensions, cross-sectional areas, (2D) or 3D volumes. Some of the common formulas used are listed below:

• LV Imaging: SV = EDV(end diastolic volume) – ESV (end systolic volume) (3)

• Doppler: SV = CSA * VTI (3)

• Cardiac Output (Q) = SV * heart rate (3)

• Cardiac Index (CI) = Q / Body Surface Area (BSA) = SV × HR/BS

• EF = {(EDV-ESV) / EDV] * 100 (4) or EF = (SV/EDV) * 100% (3)

Stroke volume is a measure of the amount of blood pumped from a ventricle of the heart in one beat. Cardiac output is the volume of blood pumped by the heart per minute.(3) EF is a measurement of the fraction of blood leaving your heart each time it contracts. Specifically, when referring to the left ventricular ejection fraction it is termed LVEF. The normal for the above quantifications are listed below:

• Stroke Volume : 75-100 ml

• Cardiac Output: 4-8 L/min

• Cardiac Index: 2.4 – 4.2L/min/m2

• Ejection Fraction: ≥ 55% (4)

“One method for determination of ventricular volumes (EDV and ESV) is based on endocardial border tracing at end diastole and end systole in one or more tomographic planes on TTE or TEE images.” (3)  In order to accomplish this, the image needs to include the apex and show adequate and accurate visualization of the endocardial borders. The best accuracy is obtained from multiple view tracing and with the fewest geometric assumptions. The Biplane Simpson’s is an example of a method used in acquiring LV volumes. Tracing is done during end diastole and end systole in the apical 4 and 2 chamber view. “The greatest accuracy would be expected with 3D reconstructions that use data from multiple tomographic images of known orientation and make no geometric assumptions. Real time data sets provide the promise of rapid measurement of LV volumes, without geometric assumptions.” (3) “The latest generation of advanced quantification tools available with the iE33 offer the possibility to use voxel data instead of interpolated slice data to generate a full surface mesh for a more assumption free echocardiograph analysis of global volume and ejection fraction.” (2) The Live 3D image is a pyramid-shaped volume of information, allowing you to visualize anatomy in three dimensions: lateral, elevation, depth.“Other useful parameters to evaluate LV function include wall stress and LV mass.”(3) “LV mass is the total weight of the myocardium, derived by multiplying the volume of myocardium by the specific density of cardiac muscle.” (3) LV mass = 1.05(total volume-chamber volume). Endocardial border tracing is used for this method but has limitations in that epicardial definition is often not adequate. Via 3D echocardiography, LV mass can potentially be better identified through the use of analysis software to calculate an epicardial cast of the ventricle. The volume of this cast can be subtracted from an endocardial cast to give the volume of the LV myocardium. By multiplying this by the specific gravity of myocardium, LV mass is derived. 3D echo can provide direct and assumption-free analysis of LV mass and volume with the possibility to accurately assess volumes in other cardiac chambers.

Afterload can be thought of as the "load" that the heart must eject blood against. In simple terms, the afterload is closely related to the aortic pressure. “More precisely, afterload is related to ventricular wall stress (σ), where σ = P (pressure) * R (radius)/2Th (wall thickness). LV wall stress is the force per unit area exerted on the myocardium.” (5) In other words wall stress is wall tension divided by wall thickness. This relationship is similar to the Law of LaPlace, which states that wall tension is proportionate to the pressure times radius for thin-walled spheres or cylinders. Over stressed walls lead to hypertrophy, which can eventually lead to dilation of the ventricular chamber.

Tissue Doppler imaging (TDI) provides the ability to quantitatively measure the velocity of the myocardium lengthening in systole and shortening in diastole. It is a useful echocardiographic tool for quantitative assessment of LV systolic and diastolic function. Tissue Doppler is a method that is independent of volume to measure diastolic function. Often myocardial velocities are recorded from the apical four chamber view with a PW sample at the basal portion and/or mitral annulus of the LV. Pulse wave samples are taken from the basal septal side and/or the lateral wall side. Relaxation abnormalities, restrictive physiology and pseudo-normalization can be determined via tissue Doppler imaging. TDI is able to determine the percent change in the length of cardiac muscle, which can be use in evaluation regional systolic function. Tissue Doppler imaging is a reproducible echocardiographic tool which provides a quantitative assessment of both global and regional function and timing of myocardial events.

The left ventricle global and segmental systolic function can be evaluated with stress echocardiography. There are several contraindication for performing a stress echo such as pregnancy, acute myocardial infarction within two days, uncontrolled cardiac arrhythmias, etc. Exercise and pharmacologic stress testing are the two common methods. The response to exercise is an increase in left ventricular contractility, which can highlight myocardial ischemia. “This shows as a decrease/cessation of contractility in the myocardial region supplied by the stenosed vessel.” (4) The process of stress echo is to take resting images and then post exercise images after achievement of a predicted heart rate. A sonographer has only 60 second to take the post exercise images. With 3D Echo, it is possible to acquire volumetric images of the LV from the apical approach, with display of simultaneous apical four, two and long axis views. This approach may be particularly useful for evaluation for regional LV function during stress echocardiography. Stress echo is another option for a more in depth look into the LV function for patients who are suspected of having LV dysfunction but resting evaluations are not conclusive. This is another tool to add to our LV function evaluation toolbox.

There are several methods other than echocardiography used to evaluate LV function. “Cardiac magnetic resonance (CMR) also known as MRI, provides precise and accurate measure of LV volumes, mass, EF and cardiac output.”(3) CMR is noninvasive and utilizes a powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures. MRI doesn't use ionizing radiation or carry any risk of causing cancer. It should be noted that a 3-D CMR also is becoming available. An MRI can be considered the gold standard but cost/benefits are usually taken into consideration. The cost of an MRI itself, time and equipment trends higher than the standard echocardiography with reasonably comparable results. Angiography is also used and is a imaging technique that is done by injecting a radiopaque contrast agent into the blood vessel and imaging using x-ray based techniques such as fluouroscopy. Radionuclide ventriculography is also available but it has largely been replaced by echocardiography because it is less expensive and does not require radiation. The choice of which technique to use is steered by cost/benefit, availability, and other clinical questions that may be present.

There are numerous methods available to address the evaluation of LV function, both globally and regionally. As a summarization, global function is typically described as normal, depressed, or hyperdynamic. Depressed systolic function may be characterized both in severity (mild, moderate, severe) and focality (global or regional). Systolic function in general can be a major prognostic factor in acute cardiac disease. Hyperdynamic function is frequently associated with high-output syndromes (e.g. anemia, thyrotoxicosis), hypertrophic cardiomyopathies, or in response to exercise or pharmacologic stress (e.g. dobutamine). Regional function refers to the specific regions of the LV wall. It can be used to narrow down a specific area of wall motion abnormality. The LV is divided into segments, which correlate to coronary artery territories, which aids in determining which artery may have a problem. It is important to know which coronary arteries supply blood to which wall segments. Qualitative evaluations tend to be global in nature and regional evaluation more quantitative.

In conclusion, assessment of left ventricular function is one of the most valuable assessments in cardiac evaluation which is why the question, “What is the LV function?” is so commonly requested. There are two ways to answer the question; qualitatively and quantitatively. Both are common practice and can go hand in hand. Qualitative answers are subjective and can vary from person to person and/or from echo to echo. The LV function is that first look in the investigation in evaluation of the hearts function. It points the way and provides guidance to diagnosing and determining treatment plans. There are different paths and technology that are available to put together a complete picture of the LV function. With existing and advancing technology, the picture is on the way to becoming more clear, dynamic and precise for both qualitative and quantitative answers for LV function.

References

(1) “Role of Real Time 3D Echocardiography in Evaluating the Left Ventricle”, Mark J. Monaghan, BMJ Publishing Group and British Cardiac Society, Department of Cardiology, King's College Hospital, Denmark Hill, London, © 2006,

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1861009/

(2) “Why 3D Echo”

(3) “Left and Right Ventricular Systolic Function”, p126-154, Clinical Echocardiography 4th Edition, Catherine M. Otto, MD, ©2004, ISBN 978-1-4160-5559-4

(4) “Evaluation of Left Ventricular Systolic and Diastolic Function”, p176 – 190, The Echocardiographer’s Pocket Reference 3rd Edition, Terry Reynolds, BS RDCS, ©2010

(5) “Cardiac Afterload”, Cardiovascular Physiology Concepts, Richard E. Klabunde, Ph.D., Ohio University Athens, Revised 08/07/07, http://www.cvphysiology.com

Hypoplastic Left Heart Syndrome (HLHS)

By Jan Masila

United States

Introduction

Hypoplastic Left Heart Syndrome is one of the most complicated congenital cardiac defects. It can easily be diagnosed at the fetal stage with the use of Echocardiography. Surprisingly, fetuses do well even with the presence of this condition as long as they are confined to the womb. It becomes very fatal after birth when babies have to survive on their own without depending on fetal circulation.

Hypoplasia is underdevelopment or incomplete development of a tissue or organ. It is descriptive of many medical conditions such as chambers of the heart in hypoplastic left heart syndrome. Hypoplastic left heart syndrome is a collection of diverse congenital heart anomalies in which a diminutive left ventricle is incapable of providing adequate systemic perfusion.

Historical Background

Commonly abbreviated HLHS, Hypoplastic left heart syndrome was first reported in 1952 by Lev but was first described by Noonan and Nadas. According to Goldberg and Rychik, it may include abnormalities such as mitral stenosis or atresia, left ventricular hypoplasia, aortic valve stenosis or atresia, and ascending aortic hypoplasia.

Prevalence and Associated Anomalies

Based upon recent literature reports, the prevalence of HLHS in the population ranges from 0.02% to 0.08% or 0.21 and 0.28 per 1000 live births. These figures are currently on the increase because of increasing survival of patients owing to accurate diagnosis and successful management strategies. The syndrome comprises 8 percent of all cases of congenital heart disease. It is one of the top three heart abnormalities to cause problems in the newborn. HLHS occurs slightly more often in boys than in girls.

The prevalence of extra cardiac anomalies or chromosomal syndromes has been described in autopsy series with HLHS. Numerous syndromes have also been reported in association with HLHS including Holt Oram, Jacobsen and Smith-Lemli-Opitz. Turner syndrome is equally included in this category and has notably been well described in association with HLHS. It is imperative that this particular disease be investigated in every female infant with Hypoplastic Left Heart Syndrome.

The association of HLHS with Developmental brain anomalies has been the focus of much research. Details of the type, frequency, and clinical presentation of developmental brain anomalies in 41 infants with the hypoplastic left heart syndrome encountered during a 52-month interval have been published following a joint study by the Divisions of Neurology, Pathology, and Cardiology, the Children's Hospital of Philadelphia, and the Departments of Neurology, Pathology, and Pediatrics, the University of Pennsylvania School of Medicine. Brain anomalies ranging from agenesis of the corpus callosum, holoprosencephaly to micrencephaly have been associated with HLHS. The study indicated that the occurrence of developmental neuropathology was elevated in those infants with hypoplastic left heart syndrome who did not have a recognizable pattern of malformation but who were small for gestational age, microcephalic, or had ocular abnormalities. This study suggested that infants with hypoplastic left heart syndrome undergo careful genetic, ophthalmologic, and neurologic evaluations which should include imaging of their intracranial anatomy, and long-term neurologic follow-up.

Etiology

Due to the phenotypic differences evident in HLHS, the exact cause is unknown. Some of the developmental origins of HLHS which have been hypothesized include fetal aortic stenosis, altered flow into the developing left ventricle owing to aortic or mitral stenosis/ atresia, obstruction of right-to-left flow early in gestation because of abnormalities of the atrial septum and abnormalities of left ventricular myocardium. HLHS is obviously a heritable disorder with a strong genetic association. It is one of many congenital heart defects with a genetic link, either occurring due to a defect in a gene, a chromosome abnormality, or environmental exposure. This may probably explain why heart problems occur more often in certain families. There have been reports of mutations associated with HLHS in genes NKX2-5, connexin 43 and NOTCHI.

Researchers at Cincinnati Children's Hospital Medical Center have shown in a study, a high heritability and likely genetic underpinnings of HLHS and recommend a direction for future research into its cause, development and possible therapeutic strategies.

“Our study demonstrates that HLHS has high heritability, suggesting it is caused almost entirely by genetic effects instead of environmental factors, and that families with a child with HLHS carry a significant recurrence risk of HLHS or related heart defects. This should be considered by physicians when counseling parents to ensure they are aware of potential risks,” said Robert B. Hinton, Jr., M.D., a physician and researcher at Cincinnati Children's and the study's lead author.

Types

For the purpose of clarity, HLHS can be divided into three main anatomic categories, namely;

 mitral and aortic stenosis

 mitral stenosis and aortic atresia

 mitral and aortic atresia

With respect to anatomy, a review of pathology specimens indicates that 5% of patients with HLHS had left superior vena cave. This can alter surgical technique during palliation. A small left atrium and abnormalities of the atrial septum are common features of HLHS. Inter-atrial communication is crucial for the survival of patients with this condition. An intact atrial septum poses a great risk for poor outcome. The pulmonary venous connections into the left atrium are an important consideration in the description of HLHS and particularly in planning for surgery. Great care must be taken to differentiate anomalous pulmonary drainage from anomalous pulmonary connection.

In hypoplastic left heart syndrome, most of the structures on the left side of the heart are small and underdeveloped. The degree of underdevelopment differs from child to child. The structures affected usually include the following: Mitral valve, Left ventricle, Aortic valve and Aorta. The risk of mortality is increased in patients who fall within the HLHS subcategory of mitral stenosis, aortic atresia, most especially in those patients with coronary connection to the left ventricle. Occurrences of abnormality in the morphology of the tricuspid valve are relatively common in HLHS and may play a big role in short-/long-time survival.

Systemic flow is predominantly through the PDA in the fetus with HLHS and very necessary for survival. The ductal arch therefore develops with a continuous, smooth transition into the descending aorta. Another common feature of HLHS is coarctation of the aorta. In extreme cases of coarctation, coronary perfusion and survival depend on sufficient antegrade flow across the aortic valve. According to Goldberg and Rychik, patients in the category of HLHS marked by mitral stenosis and aortic atresia, may be at risk of fistulous connections, with or without stenosis, from the left ventricle to the coronary arteries. They are at a higher risk for morbidity and mortality than the rest of the patient population with HLHS.

Pathophysiology

Infants with Hypoplastic Left Heart Syndrome can develop life-threatening shock when the ducutus arteriosus begins to close. In most cases, the ductus arteriosus is widely open at the time of birth, supplying the blood flow to the body and babies may not be diagnosed right away. The right ventricle must then do a "double duty" of pumping blood both to the lungs and out to the body via a patent ductus arteriosus (PDA). As the ductus arteriosus closes, the perfusion to the body is seriously diminished and shock rapidly ensues.

Peripheral pulses may be weak, with cool extremities due to poor perfusion. Blood flow to the body will severely diminish resulting in dangerously low blood flow to vital organs and leading to shock. Prostaglandin E1 infusion should be initiated immediately after HLHS is identified in order to maintain the PDA. Hypoplastic Left Heart Syndrome without treatment is fatal, often within the first hours or days of life.

Signs and Symptoms

 blue color of the skin, lips and nail beds (cyanosis)

 pale skin

 sweaty or clammy skin

 cool skin

 Fast breathing or working hard to breathe

 Trouble feeding

 Weak pulse

Diagnosis

HLHS is one of the most common cardiac defects picked up on obstetrical screening with ultrasounds and could most readily be diagnosed on fetal echocardiograms . Such early diagnosis of the anomaly allows for prompt intervention for stabilization at the time of birth so that severe shock may be avoided. Alternatively, a child's physician may have heard a heart murmur during a physical examination and then refer the child to a pediatric cardiologist for a diagnosis. Heart murmurs are fairly common and are caused by the turbulence of blood flowing through a narrow region. The pediatric cardiologist will perform a physical examination, listening to the heart and lungs, and make other observations that help in the diagnosis.

Other tests and/or procedures which are employed in the diagnosis of HLHS include; Chest X-ray, Cardiac Catheterization, Cardiac Magnetic Resonance Imaging (MRI) and most especially, Echocardiogram (echo). Due to its non-invasive nature and detailed information, Echo is the principal method of diagnosing Hypoplastic Left Heart Syndrome. It provides detailed information of the anatomy of the various cardiac structures affected in HLHS, as well as important information about the function of the right ventricle, the heart valves, the size of the atrial septal defect (important for blood mixing) and the size of the patent ductus arteriosus. Although Cardiac catheterization is the gold standard, it is rarely used as part of the initial evaluation, with this heart defect due to the high risks in an often unstable newborn.

Treatment

Neonates diagnosed with HLHS will be most likely admitted to the intensive care unit (ICU) or special care nursery once symptoms are noted. They may initially be placed on oxygen, or a ventilator to assist them with breathing. Management strategies can be divided into the initial stabilization period and the operative / post-operative period.

In situations where diagnosis took place before delivery, stabilization measures are started immediately so the newborn does not become unstable. In post natal diagnosis of HLHS, stabilization begins even while diagnostic tests are going on. Immediate infusion of prostaglandin to prevent the patent ductus arteriosus from closing is imperative. This will maintain the pathway for blood to reach the body from the right ventricle.

Because infants in HLHS are most likely to have low oxygen saturations, the tendency will be to administer supplemental oxygen. This should be avoided since it tends to promote more blood flow to the lungs which may steal blood flow from the body and place excessive demands on the already stressed single right ventricle.

The primary treatment options available to children with Hypoplastic Left Heart Syndrome include cardiac transplantation. With all its advantages, this treatment is limited by the scarcity of newborn organs available for transplantation as well as the life-long need for anti-rejection therapy. Even as outcomes for transplantation continue to improve along with decreasing incidence of rejection in patients transplanted as newborns, the average life span of the transplanted heart is still currently limited to less than 15 years.

"Staged reconstruction" is the most commonly pursued treatment for Hypoplastic Left Heart Syndrome. It is a palliative procedure in which three series of operations are performed to reconfigure the cardiovascular system to be as efficient as possible despite the lack of an adequate left ventricle. Due to continued improvement in outcome following reconstructive surgery, many cardiology centers have reserved transplantation exclusively for high-risk infants such as those with tricuspid dysplasia and severe regurgitation or marked Right Ventricular dysfunction.

Norwood operation is the first operation in the staged approach which is typically performed in the first week of life. The desired outcome is that the right ventricle becomes the systemic or main ventricle pumping to the body. From part of the pulmonary artery and the original, underdeveloped aorta a "new" or "neo" aorta is reconstructed to provide blood flow to the body. Finally, a small tube graft is placed either from an artery to the lung vessels (modified Blalock-Taussig shunt) or from the right ventricle to the lung vessels (Sano modification) to provide blood flow to the lungs. This operation is one of the most challenging heart surgeries in pediatrics hence, extensive reconstruction of the aorta that must be done. This is then followed by the bi-directional Glenn procedure and the Fontan operation, typically done at 3 to 6 months of age and 2 or 3 years respectively.

Mortality rate for neonatal Norwood reconstruction is relatively high and some investigators have moved toward the development of strategies that avoid a major surgical operation in the neonatal period. This is called the hybrid approach and it involves both a cardiac catheter-driven procedure and surgical technique. It achieves the same physiologic goals that are similar to the Norwood first-stage reconstruction while avoiding performing a challenging neonatal operation.

Prognosis/Follow-up

With current methods, the survival through the Glenn and Fontan operations exceeds 90 percent. Almost all children with hypoplastic left heart syndrome will continue to need some cardiac medications to optimize the function of their heart. They will need follow-up care throughout their life. Regular periodic follow-up visits with their cardiologist to evaluate their cardiac function and detect late complications is not just required but highly recommended.

Summary

2D-echocardiography and Doppler ultrasound are the diagnostic tools of choice in patients with HLHS. The use of Magnetic Resonance Imaging is complementary to Echocardiography and both provide unique information on cardiovascular anatomy, ventricular function and blood flow. A multidisciplinary team approach is important for successful outcome in the management of HLHS. Pediatric cardiac surgeons, neonatologists, social workers and other crucial medical personnel must be involved. Joining support groups and speaking to families with children living with HLHS should be part of the management strategy.

Innovations in Echocardiography

By Jan Masila

United States

Echocardiography is a non invasive cardiac diagnostic test performed using sound waves to create pictures of the heart for further interpretation by a cardiologist. The technique involves using an ultrasound machine which is used to send high-pitched sound waves through a device called a transducer which in turn picks up echoes of the sound waves as they bounce off the different parts of the heart. The echoes are converted into moving pictures of the heart which are displayed on a screen. The test is painless and safe since it poses no danger of exposure to radioactive elements to both the healthcare worker and the patient.

Application of this technology has been a test of choice for most cardiac anomalies in many leading hospitals not only here in the United States but also in other developed and developing nations across the globe. Cardiology departments in hospitals hire Cardiac Sonographers who are highly skilled individuals exclusively trained to operate echocardiography machines for the purpose of taking pictures of the hearts of patients with heart ailments in order to help in the diagnostic process.

Helpful information such as the size and shape of the heart, its pumping capacity, the location and extent of any damage to its tissues and the size of its chambers can be obtained easily using echocardiography therefore assisting cardiologists in their quest to evaluate heart functions. This test is applicable to adults as well as pediatric patients although there is a difference as pertains to the penetration power of the transducer used. Other alternative ways of performing echocardiography include transesophageal and transthoracic echocardiography.

The origin of this technology can be traced back to 1953 when Inge Edler a cardiologist practicing at Lund University in Sweden. Edler was in charge of the cardiology department of the medical clinic at the University and had a friend called Hertz a physicist with a long standing interest in using ultrasound for the measurement of distance. At that particular time, Edler used the M-Mode technique for a preoperative study of mitral stenosis and mitral regurgitation which marked the beginning of the use of ultrasound. He named the technique ultrasound cardiography.

This new discovery gained popularity and cardiologists around the world adopted it as a diagnostic tool and further research was done culminating into the discovery of Doppler, 2-dimensional echo, contrast, and transesophageal echocardiography. Regardless of any further discovery; Edler who lived between the years of 1911 and 2001 maintains his recognition and distinction as the father of echocardiography.

The machine used by Edler and Hertz to measure M-Mode was a bulky piece of equipment compared with the models available in the market today. Just like any other electronic equipment; echocardiography machines have evolved from bulky stationary machines to sleek and even portable machines.

Current echocardiography examination is based on real-time two dimensional images. M-mode technique is now relegated to a supplemental examination although it is still being used to make routine measurements which are better obtained directly from two-dimensional pictures. M-Mode has the advantage of having an enhanced temporal resolution which makes taking these measurements clear and easy.

To back this technology up; some of the leading manufacturers of Ultrasound machines namely Philips, GE, HP, Sequoia and Acuson have been in the forefront making user friendly portable machines which make it possible to perform studies at the patient’s bedside. Philips specifically has been very successful with its iE33 which offers an interactive touch screen and a more user friendly operator panel. The machine has 3D technology capability but for the most part many institutions still continue to use its 2D package due to the fact that not very many sonographers are conversant with 3D and 4D which calls for further expenditure in training.

Lately, most of the medical imaging centers around the nation have adopted three dimensional displays and echocardiography is not to be left behind. Real time three dimension echo imaging is in its young stages and many sonographers and physicians are still learning its strengths and weaknesses. Interestingly though; the transthoracic three dimensions echo has shown value in accurately assessing the contractile function of the left ventricle and the transesophageal three dimensions approach has helped in improving the visualization of valve pathologies.

Echocardiography machines are now outfitted with the hardware and software to perform real time three dimensions echocardiography imaging. Beside 2D images; Color Doppler which is a component of the 2D technology is applied to shed light on further diagnostic facts. With color in place, a sonographer is able to show direction of blood flow as well as pinpoint with much accuracy the existence and position of cardiac shunts such as Ventricular Septal Defects (VSD’s), Atrial Septal Defects (ASD’s), or even muscular defects. Tricuspid and mitral regurgitations including pulmonic and aortic insufficiencies have been successfully diagnosed by the use of Color Doppler. This eliminates guess work and saves time that would have otherwise been used interrogating an area suspected to be having these shunts.

 Storage of echocardiography data is one area that is as important as the diagnostic process itself. Cardiologists always make follow up on treatment of their patients so it is important for them to be able to retrieve data for comparison or even simple reference. With the old technology, storage was done on bulky tapes which occupied large space and whose quality deteriorated with time especially when they are played many times. This deterioration led to the stored images losing their quality thereby becoming unreliable stored data.

Modern technology has ushered in digital storage called Digital Archiving which is more efficient and maintains pictures quality as they are stored in DVD’s which have a better resolution and can hold many files therefore making it possible to preserve filing space. They are easy to carry and can be used in different work stations hence providing convenience and easy retrieval of data whenever needed. Digital recordings can also be placed on a computer network and made available at numerous stations including satellite clinics. Examinations stored in this form are retrieved in less than 30 seconds and are available 24 hours a day 7 days a week.

Most clinical facilities operate in a networked system whereby a physician can view the pictures being taken as they stream in. This is a big milestone because it avoids the possibility of repeating a test because the physician is able to view and request for more pictures as he or she deems necessary. Another advantage of networked technology is that it saves time that would have otherwise been used entering information in the machine manually.

Post processing of imaged data is possible with 2D imaging technology. This ensures correction and maintenance of correct data for archiving. The flexibility that this maneuver comes with makes it possible for adjustments to be done without interfering with the quality of the data to be archived.

The companies involved in manufacturing of ultrasound machines have pumped a lot of money in research to outdo each other with innovative technologies and this has provided sonographers with variety of choices. GE and Philips have dominated the market although the competition is stiff from other competitors. As evidence of this unending competition, it is worth noting that the trend with which we continue to get a wide variety of transducers, frequencies, and many different and unique applications potentially available means that the ultimate echocardiography instrument and examination is not with us here yet. There has been a lot of jostling and fancy advertisements fronted by these leading manufacturers with each one of them trying to cut an edge for itself and stake a claim of the trophy of innovation in the ultrasound industry.

Information available on Philips website regarding their signature product iE33 suggests that it is the right machine to use to evaluate Cardiac Motion Quantification (CMQ) because it increases the accuracy of LV function and wall motion measurement. Further, Philips states that the new CMQ speckle tracking algorithm available in the machine makes strain analysis a useful tool in assessing presence and extent of LV disease including multiple strain and strain rate parameters and longitudinal strain.

On the other hand, GE without wanting to be left behind in this has staked a claim as the company holding the key to the future of ultrasound fronting its Vivid E9 as the ultrasound machine specifically made for 4D technology. Other advantages the company associates with this machine are that it is ergonomically easy, highly mobile, easy key board storage and convenient data management among others. It is also worth noting that GE has an array of other versions of ultrasound machines all of which it claims offer consumers the best bargain and quality.

It is not too early to predict but it is almost certain that the transducer technologies currently under development may change echocardiography drastically. Two-dimensional arrays of transducers provide the potential for real-time, three dimensional and four dimensional imaging. Made by the use of silicon chip technology; the new transducers will play an integral role in the development of the personal echocardiograph device.

Research and development in this sector has not been a preserve for the leading companies associated with the manufacture of ultrasound machines only as other players albeit small are emerging with even more sophisticated products some of which are hand held devices. In fact, we continue to me mesmerized by the frequency by which new devices are being made adding up to whatever the market has to offer at the moment. It was only last week that Apple Inc launched an application for echo testing which converts the iPhone to a mobile ultrasound machine. This is definitely technology of the cutting age which serves to make us see how advanced this technology has come to be.

Echocardiography has emerged as one of the most respected careers in the healthcare industry. Its popularity has grown due to its reputation as a painless yet very effective diagnostic test. The fact that this test does not expose a patient to radiation is a plus as many ailments are worsened by continued exposure to radiation while carrying out diagnostic tests.

Regulation through a professional body called American Society of Echocardiography (ASE) has helped streamline echocardiography profession by setting standards and guidelines to be followed in performance of cardiograph tests. In addition to that, the American Registry for Diagnostic Medical Sonography (ARDMS) has taken up the task of ensuring regulation in terms of training for one to qualify as a registered cardiographer. Passage of a board examination set by ARDMS before being registered ensures that patients are placed in the safe hands of qualified professionals in the field. This comes with its own drawbacks though as going to school for sonography can be expensive and time consuming. Lack of many accredited colleges and inadequate facilities in the available colleges makes it hard for many people interested in pursuing a career in ultrasound to secure admission.

Overall; echo technology is here to stay and the future of this diagnostic technique is obviously very bright. The amount of money put in place by research companies and the continued supply of reference materials available in the market plus the continued demand for these services is a clear indication that this is definitely a growing field which has evolved over the years to claim a leading spot in terms of reliance and effectiveness in detecting and diagnosing heart diseases.

Transcript of a brief speech I gave on the role of the International Criminal Court (ICC) based in The Hague

By Jan Masila,

USA

THE ROLE OF THE INTERNATIONAL CRIMINAL COURT (ICC)

Introduction:

We tend to think it was all in the past. Hitler said that he was going to wipe out the Jews. We saw what happened in Yugoslavia during the reign of Slobodan Milosevic; we saw what happened in Rwanda not so long ago where the ruling Hutu tribe sought to wipe out the minority Tutsi tribe. These society evils continue to be perpetrated by selfish leaders who only think about their survival in power and that of their cronies. Look at what is happening right now in Darfur; this is enough evidence that these evils are not about to go away. Having said that, I urge you to ask yourself what kind of monster can want to wipe out a generation of people? And my submission is that any one who seeks to wipe out another is a monster who needs to go to the ICC.

Today, I will give a speech concerning the role of the International Criminal Court (ICC). As I discuss this, I am going to talk about genocide, crimes against humanity and war crimes which form the hallmark of the jurisdiction of the ICC.

Now, let me get to the main points

Crimes against humanity

Crimes against humanity are international crimes that cry out for justice.

What are crimes against humanity?

Crimes against humanity are crimes that are committed as part of a widespread or systematic attack directed against any civilian population.

They include acts such as:

• Murder

• Enslavement

• Deportation

• Forceful transfer of population

• Imprisonment

• Torture

• Rape

• Sexual slavery

• Enforced prostitution

• Forced pregnancy

• Enforced disappearance of persons

• The crime of apartheid

My next point will be war crimes

War crimes

War crimes are international crimes that cry out for justice; one would rightfully ask, what are war crimes?

War crimes are grave breaches of the Geneva Conventions of 12 August 1949 and other serious violations of the laws and customs applicable in armed conflicts.

The Geneva Conventions are international agreements defining the rules of war. They set international standards for the protection of the civilian population and the treatment of combatants in international and internal armed conflicts.

War crimes are committed in the context of armed conflict. Some war crimes are specifically linked to internal armed conflict – such as civil war – and others are linked to international armed conflict. But most war crimes can occur in both situations.

War crimes in international armed conflicts consist of acts such as:

• Willful killing

• Torture or inhuman treatment including biological experiments

• Willfully causing great suffering or serious injury to body or health

• Extensive destruction and appropriation of property, not justified by military necessity and carried out unlawfully and wantonly

• Compelling a prisoner of war or other protected person to serve in the forces of a hostile power

• Willfully depriving a prisoner of war or other protected person of the rights of fair and regular trial

• Unlawful deportation or transfer or unlawful confinement

• Taking of hostages.

War crimes in internal armed conflicts include acts such as

• Violence to life and person, in particular murder of all kinds

• Mutilation, cruel treatment and torture;

• Outrages upon personal dignity, in particular humiliating and degrading treatment

• taking of hostages

• conscripting and enlisting children under the age of fifteen years

In addition to the Geneva Conventions, other violations of the laws and customs of war can also be war crimes.

Examples include:

• Intentionally directing attacks against the civilian population;

• Intentionally directing attacks against civilian objects;

• Intentionally directing attacks against personnel, installations, material, units or vehicles involved in a humanitarian assistance or peacekeeping mission;

• Killing or wounding a combatant who, having laid down his arms or having no further means of defense, has surrendered..

Under international law, such acts can be war crimes even if they are not committed as part of a systematic or widespread attack on civilians.

However, if they are only rare or sporadic, the authority of the International Criminal Court is more limited.

My next point will be genocide

Genocide

Genocide is an international crime that cries out for justice; The question is, what is genocide?

This definition of genocide is based on the definition found in the 1948 U.N. Convention on the Prevention and Punishment of the Crime of Genocide, which confirmed genocide as a crime under international law in the aftermath of the Holocaust.

Genocide occurs when acts are committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group. Such acts of genocide can be carried out by:

• Killing members of the targeted group;

• Causing serious bodily or mental harm to members of the group;

• Deliberately inflicting on the group conditions of life calculated to bring about its physical destruction in whole or in part;

• Imposing measures intended to prevent births within the group;

• Forcefully transferring children of the group to another group.

Conclusion

In conclusion, I have talked about the scope and mandate of the ICC and its importance

Summary statement:

It is in this regard that I urge those of you who hold the view that the ICC is a court that does not serve the interests of the world community at large to change your attitude as it has been strongly in the fore front of trying and if found guilty punishing any one involved in crimes against humanity, war crimes and genocide. This important court goes for the culprits without regard to color, gender or position in society. Before the ICC, all are treated equally

Concluding remark:

If this court was not in place, the perpetrators of these heinous crimes most of whom are presidents of dictatorial regimes, rebel leaders and senior military officers would go scot free as they would have no one to account their actions to.

Zuma driving South Africa to the dogs

By Jan Masila,
USA

On January 4th, the honorable president of the Republic of South Africa Jacob Zuma stunned the world by staging what his office called a private ceremony which was in effect a traditional event to solemnize his marriage to Tobeka Madiba.

Members of the press were barred from covering the event but this did not prevent them from accessing images of the president clad in his Zulu traditional regalia showing his dancing prowess. President Zuma like any other citizen of the world has a right to live his life the way he deems right, but he seems to have failed to realize that he is not any other villager in Kwazulu Natal but the president of South Africa.

When one runs for a public office and especially that of the presidency, they have a duty to the public and one of such duties is to live responsibly and account for their behaviors in private and public. If this be a test, then it is a test president Zuma has failed miserably for he has continued to be associated with bad behavior something many believed he would abandon after assuming the presidency.

President Zuma heads Africa’s most powerful nation with a leading economy and international respect. With such credentials, South Africa is always seen as the super power of Africa and that focuses a lot of attention to anything that happens to this great country within International media. It is no wonder that Zuma’s marriage has caused so much stir across the globe and in the continent to the effect that it brought the debate of polygamy back on the table.

The question is; was this genuine case of polygamy or was it a selfish act of self gratification? Analysts are divided as to what is the right answer but when reliable sources indicate that Mr. Zuma has engaged at least two more brides, the answer is obvious.

South Africa does not need a president like Zuma, the challenges of this African power need to be addressed by a leader who is ready to shed tribal loyalties for the sake of spearheading a unifying agenda for the nation the way Nelson Mandela did after assuming power straight from detention.

Presidents are role models for the young generation; they motivate and shape the views and ideals of the society. President Zuma has not been a good role model to the youth of South Africa, a country with one of the highest rates of HIV infection in the world. While many governments around the world and specifically their leaders have been in the fore front of fighting the AIDS pandemic president Zuma has been attracting the headlines with stories about his sexuality and morality. It would be right to say that he has not yet shed his populist image to embrace statesmanship a dubious distinction since he was elected on a platform of shaping the politics of South Africa and promoting national integration.

It is not clear what agenda Zuma has in store for South Africa, since taking office in May 2009, unemployment has been on the rise and tensions continue to build between indigenous South African and immigrants from the rest of the continent whom they accuse of taking their jobs. Animosity continues to grow between people of different races and there is a fear of blood bath if these concerns are not addressed. All these are vital national issues that require leadership and intervention which president Zuma has completely failed to provide.

It is a shame that instead of putting the interests of the struggling poor in South Africa as per his campaign manifesto, Zuma has been basking in the glory of occupying the presidency and high on his to do list is to marry all his girlfriends. This is shameful and despicable. A president of South Africa or any other nation should rise above cheap publicity, tribal affiliations and promote an agenda that addresses the needs of the whole country.

It is in this regard that I observe just like many other people that Zuma is dragging South Africa and the whole continent to the dark ages of primitive practices and it is a shame we can’t afford in the 21st century

China not good for Democracy

By, Jan Masila,
USA

The emergence of China as an economic power is a big credit to the hardworking people of the Peoples Republic of China; it is a culmination of efforts by the communist government to showcase its prudence in management of economic affairs in. There is no doubt that the Chinese deserve to be recognized and applauded for this rare achievement.

Thirty years ago, the economy of China was in tatters, the army poorly equipped with old fashioned hardware, poorly planned cities and bad infrastructure. Today the story is different; China has emerged as a world player with a lot of influence especially in the minerals rich Africa.

African leaders shunned by the west for undemocratic leadership have found solace in China. This emerging power had flooded the continent with no strings attached aid which has provided a lifeline to regimes which would have collapsed a case in point being the unpopular government of Zimbabwe led by Robert Mugabe who is known for his characteristic style of bashing the west at every opportunity.

A stable and economic stable China is a good thing not only for the world’s most populous nation but for the whole world as a whole. Problem comes in when this wealth is used to subvert democracy and propelling dictatorial regimes. It is no coincidence that China has continually associated itself with rogue governments like Sudan, Angola, Zimbabwe, Iran, North Korea and Myanmar. Looking at this list one will note that these are governments which have been associated with gross violation of human rights.

While western countries have for long attached demands to any aid they have provided to third world countries, China has virtually been providing them with blank checks with no demands for accountability in terms of democratic practices. This style has been hailed as a good gesture of not interfering with another country’s internal affairs but what those who hail this style have failed to notice is the fact that for the most part, these funds are used to suppress opposition and fatten the bank accounts of the ruling class.

Governments come and go but the citizens remain, it is only fair that any funds advanced to any government be used to uplift the standards of living for the citizens of the land. China has not been a good advocate of this cause and as such it has indirectly contributed to undemocratic practices around the world.

Unfortunately, the leadership of Communist China does not seem to be keen in changing this policy. They seem to be more interested in resources than governance and this is setting a bad trend around the world. In the twenty first century, the world should be getting rid of dictators but with a fat wallet, China seems to be dialing the clock backwards, reducing any gains in terms of democratic principles.

Corrupt regimes will always think they have a chance to survive as long as they know China will bail them out when shunned by the west. A world leader should lead by example and China is not living to this standard.