Made by DATEXIS (Data Science and Text-based Information Systems) at Beuth University of Applied Sciences Berlin
Deep Learning Technology: Sebastian Arnold, Betty van Aken, Paul Grundmann, Felix A. Gers and Alexander Löser. Learning Contextualized Document Representations for Healthcare Answer Retrieval. The Web Conference 2020 (WWW'20)
Funded by The Federal Ministry for Economic Affairs and Energy; Grant: 01MD19013D, Smart-MD Project, Digital Technologies
Canadian genetic testing guidelines and recommendations for individuals diagnosed with HCM are as follows:
- The main purpose of genetic testing is for screening family members.
- According to the results, at-risk relatives may be encouraged to undergo extensive testing.
- Genetic testing is not meant for confirming a diagnosis.
- If the diagnosed individual has no relatives that are at risk, then genetic testing is not required.
- Genetic testing is not intended for risk assessment or treatment decisions.
- Evidence only supports clinical testing in predicting the progression and risk of developing complications of HCM.
For individuals "suspected" of having HCM:
- Genetic testing is not recommended for determining other causes of left ventricular hypertrophy (such as "athlete's heart", hypertension, and cardiac amyloidosis).
- HCM may be differentiated from other hypertrophy-causing conditions using clinical history and clinical testing.
Although HCM may be asymptomatic, affected individuals may present with symptoms ranging from mild to critical heart failure and sudden cardiac death at any point from early childhood to seniority. HCM is the leading cause of sudden cardiac death in young athletes in the United States, and the most common genetic cardiovascular disorder. One study found that the incidence of sudden cardiac death in young competitive athletes declined in the Veneto region of Italy by 89% since the 1982 introduction of routine cardiac screening for athletes, from an unusually high starting rate. As of 2010, however, studies have shown that the incidence of sudden cardiac death, among all people with HCM, has declined to one percent or less. Screen-positive individuals who are diagnosed with cardiac disease are usually told to avoid competitive athletics.
HCM can be detected with an echocardiogram (ECHO) with 80%+ accuracy, which can be preceded by screening with an electrocardiogram (ECG) to test for heart abnormalities. Cardiac magnetic resonance imaging (CMR), considered the gold standard for determining the physical properties of the left ventricular wall, can serve as an alternative screening tool when an echocardiogram provides inconclusive results. For example, the identification of segmental lateral ventricular hypertrophy cannot be accomplished with echocardiography alone. Also, left ventricular hypertrophy may be absent in children under thirteen years of age. This undermines the results of pre-adolescents’ echocardiograms. Researchers, however, have studied asymptomatic carriers of an HCM-causing mutation through the use of CMR and have been able to identify crypts in the interventricular septal tissue in these people. It has been proposed that the formation of these crypts is an indication of myocyte disarray and altered vessel walls that may later result in the clinical expression of HCM. A possible explanation for this is that the typical gathering of family history only focuses on whether sudden death occurred or not. It fails to acknowledge the age at which relatives suffered sudden cardiac death, as well as the frequency of the cardiac events. Furthermore, given the several factors necessary to be considered at risk for sudden cardiac death, while most of the factors do not have strong predictive value individually, there exists ambiguity regarding when to implement special treatment.
The principal method to diagnose LVH is echocardiography, with which the thickness of the muscle of the heart can be measured. The electrocardiogram (ECG) often shows signs of increased voltage from the heart in individuals with LVH, so this is often used as a screening test to determine who should undergo further testing.
The enlargement is not permanent in all cases, and in some cases the growth can regress with the reduction of blood pressure.
LVH may be a factor in determining treatment or diagnosis for other conditions. For example, LVH causes a patient to have an irregular ECG. Patients with LVH may have to participate in more complicated and precise diagnostic procedures, such as imaging, in situations in which a physician could otherwise give advice based on an ECG.
Hypertrophy of the ventricle can be measured with a number of techniques.
Electrocardiogram (EKG), a non-invasive assessment of the electrical system of the heart, can be useful in determining the degree of hypertrophy, as well as subsequent dysfunction it may precipitate. Specifically, increase in Q wave size, abnormalities in the P wave as well as giant inverted T waves are indicative of significant concentric hypertrophy. Specific changes in repolarization and depolarization events are indicative of different underlying causes of hypertrophy and can assist in appropriate management of the condition. Changes are common in both eccentric and concentric hypertrophy, though are substantially different from one another. In either condition fewer than 10% of patients with significant hypertrophy display a normal EKG.
Transthoracic echocardiography, a similarly non invasive assessment of cardiac morphology, is also important in determining both the degree of hypertrophy, underlying pathologies (such as aortic coarction), and degree of cardiac dysfunction. Important considerations in echocardiography of the hypertrophied heart include lateral and septal wall thickness, degree of outflow tract obstruction, and systolic anterior wall motion (SAM) of the mitral valve, which can exacerbate outflow obstruction.
It is not uncommon to undergo cardiopulmonary exercise testing (CPET), which measures the heart's response to exercise, to assess the functional impairment caused by hypertrophy and to prognosticate outcomes.
HFpEF is typically diagnosed with echocardiography. Techniques such as catheterization are invasive procedures and thus reserved for patients with co-morbid conditions or those who are suspected to have HFpEF but lack clear non-invasive findings. Catheterization does represent are more definitive diagnostic assessment as pressure and volume measurements are taken simultaneously and directly. In either technique the heart is evaluated for left ventricular diastolic function. Important parameters include, rate of isovolumic relaxation, rate of ventricular filling, and stiffness.
Frequently patients are subjected to stress echocardiography, which involves the above assessment of diastolic function during exercise. This is undertaken because perturbations in diastole are exaggerated during the increased demands of exercise. Exercise requires increased left ventricular filling and subsequent output. Typically the heart responds by increasing heart rate and relaxation time. However, in patients with HFpEF both responses are diminished due to increased ventricular stiffness. Testing during this demanding state may reveal abnormalities that are not as discernible at rest.
In most situations, described above, the increase in ventricular wall thickness is a slow process. However, in some instances hypertrophy may be "dramatic and rapid." In the Burmese python, consumption of a large meal is associated with an increase in metabolic work by a factor of seven and a 40% increase in ventricular mass within 48 hours, both of which return to normal within 28 days.
Remodeling of the heart is evaluated by performing an echocardiogram. The size and function of the atria and ventricles can be characterized using this test.
Athlete's heart is not dangerous for athletes (though if a nonathlete has symptoms of bradycardia, cardiomegaly, and cardiac hypertrophy, another illness may be present). Athlete's heart is not the cause of sudden cardiac death during or shortly after a workout, which mainly occurs due to hypertrophic cardiomyopathy, a genetic disorder.
No treatment is required for people with athletic heart syndrome; it does not pose any physical threats to the athlete, and despite some theoretical concerns that the ventricular remodeling might conceivably predispose for serious arrhythmias, no evidence has been found of any increased risk of long-term events. Athletes should see a physician and receive a clearance to be sure their symptoms are due to athlete’s heart and not another heart disease, such as cardiomyopathy. If the athlete is uncomfortable with having athlete's heart or if a differential diagnosis is difficult, deconditioning from exercise for a period of three months allows the heart to return to its regular size. However, one long-term study of elite-trained athletes found that dilation of the left ventricle was only partially reversible after a long period of deconditioning. This deconditioning is often met with resistance to the accompanying lifestyle changes. The real risk attached to athlete's heart is if athletes or nonathletes simply assume they have the condition, instead of making sure they do not have a life-threatening heart illness.
General ECG features include:
- Right axis deviation (>90 degrees)
- Tall R-waves in RV leads; deep S-waves in LV leads
- Slight increase in QRS duration
- ST-T changes directed opposite to QRS direction (i.e., wide QRS/T angle)
- May see incomplete RBBB pattern or qR pattern in V1
- Evidence of right atrial enlargement (RAE)
Specific ECG features (assumes normal calibration of 1 mV = 10 mm):
- Any one or more of the following (if QRS duration <0.12 sec):
- Right axis deviation (>90 degrees) in presence of disease capable of causing RVH
- R in aVR > 5 mm, or
- R in aVR > Q in aVR
- Any one of the following in lead V1:
- R/S ratio > 1 and negative T wave
- qR pattern
- R > 6 mm, or S 10 mm
Other chest lead criteria:
- R in V1 + S in V5 (or V6) 10 mm
- R/S ratio in V5 or V6 < 1
- R in V5 or V6 < 5 mm
- S in V5 or V6 > 7 mm
ST segment depression and T wave inversion in right precordial leads is usually seen in severe RVH such as in pulmonary stenosis and pulmonary hypertension.
Many factors influence the time course and extent of remodeling, including the severity of the injury, secondary events (recurrent ischemia or infarction), neurohormonal activation, genetic factors and gene expression, and treatment. Medications may attenuate remodeling. Angiotensin-converting enzyme (ACE) inhibitors have been consistently shown to decrease remodeling in animal models or transmural infarction and chronic pressure overload. Clinical trials have shown that ACE inhibitor therapy after myocardial infarction leads to improved myocardial performance, improved ejection fraction, and decreased mortality compared to patients treated with placebo. Likewise, inhibition of aldosterone, either directly or indirectly, leads to improvement in remodeling. Carvedilol, a 3rd generation beta blocker, may actually reverse the remodeling process by reducing left ventricular volumes and improving systolic function. Early correction of congenital heart defects, if appropriate, may prevent remodeling, as will treatment of chronic hypertension or valvular heart disease. Often, reverse remodeling, or improvement in left ventricular function, will also be seen.
Diastolic dysfunction must be differentiated from diastolic heart failure. Diastolic dysfunction can be found in elderly and apparently quite healthy patients. If diastolic dysfunction describes an abnormal mechanical property, diastolic heart failure describes a clinical syndrome. Mathematics describing the relationship between the ratio of Systole to Diastole in accepted terms of End Systolic Volume to End Diastolic Volume implies many mathematical solutions to forward and backward heart failure.
Criteria for diagnosis of diastolic dysfunction or diastolic heart failure remain imprecise. This has made it difficult to conduct valid clinical trials of treatments for diastolic heart failure. The problem is compounded by the fact that systolic and diastolic heart failure commonly coexist when patients present with many ischemic and nonischemic etiologies of heart failure. Narrowly defined, diastolic failure has often been defined as "heart failure with normal systolic function" (i.e. left ventricular ejection fraction of 60% or more). Chagasic heart disease may represent an optimal academic model of diastolic heart failure that spares systolic function.
A patient is said to have diastolic dysfunction if he has signs and symptoms of heart failure but the left ventricular ejection fraction is normal. A second approach is to use an elevated BNP level in the presence of normal ejection fraction to diagnose diastolic heart failure. Concordance of both volumetric and biochemical measurements and markers lends to even stronger terminology regarding scientific/mathematical expression of diastolic heart failure. These are both probably too broad a definition for diastolic heart failure, and this group of patients is more precisely described as having heart failure with normal systolic function. Echocardiography can be used to diagnose diastolic dysfunction but is a limited modality unless it is supplemented by stress imaging. MUGA imaging is an earlier mathematical attempt to distinguish systolic from diastolic heart failure.
No one single echocardiographic parameter can confirm a diagnosis of diastolic heart failure. Multiple echocardiographic parameters have been proposed as sufficiently sensitive and specific, including mitral inflow velocity patterns, pulmonary vein flow patterns, E:A reversal, tissue Doppler measurements, and M-mode echo measurements (i.e. of left atrial size). Algorithms have also been developed which combine multiple echocardiographic parameters to diagnose diastolic heart failure.
There are four basic Echocardiographic patterns of diastolic heart failure, which are graded I to IV:
- The mildest form is called an "abnormal relaxation pattern", or grade I diastolic dysfunction. On the mitral inflow Doppler echocardiogram, there is reversal of the normal E/A ratio. This pattern may develop normally with age in some patients, and many grade I patients will not have any clinical signs or symptoms of heart failure.
- Grade II diastolic dysfunction is called "pseudonormal filling dynamics". This is considered moderate diastolic dysfunction and is associated with elevated left atrial filling pressures. These patients more commonly have symptoms of heart failure, and many have left atrial enlargement due to the elevated pressures in the left heart.
Grade III and IV diastolic dysfunction are called "restrictive filling dynamics". These are both severe forms of diastolic dysfunction, and patients tend to have advanced heart failure symptoms:
- Class III diastolic dysfunction patients will demonstrate reversal of their diastolic abnormalities on echocardiogram when they perform the Valsalva maneuver. This is referred to as "reversible restrictive diastolic dysfunction".
- Class IV diastolic dysfunction patients will not demonstrate reversibility of their echocardiogram abnormalities, and are therefore said to suffer from "fixed restrictive diastolic dysfunction".
The presence of either class III and IV diastolic dysfunction is associated with a significantly worse prognosis. These patients will have left atrial enlargement, and many will have a reduced left ventricular ejection fraction that indicates a combination of systolic and diastolic dysfunction.
Imaged volumetric definition of systolic heart performance is commonly accepted as ejection fraction. Volumetric definition of the heart in systole was first described by Adolph Fick as cardiac output. Fick may be readily and inexpensively inverted to cardiac input and injection fraction to mathematically describe diastole. Decline of injection fraction paired with decline of E/A ratio seems a stronger argument in support of a mathematical definition of diastolic heart failure.
Another parameter to assess diastolic function is the , which is the ratio of mitral peak velocity of early filling (E) to early diastolic mitral annular velocity (E'). Diastolic dysfunction is assumed when the E/E' ratio exceed 15.
Athlete's heart is usually an incidental finding during a routine screening or during tests for other medical issues. An enlarged heart can be seen at echocardiography or sometimes on a chest X-ray. Similarities at presentation between athlete's heart and clinically relevant cardiac problems may prompt electrocardiography (ECG) and exercise cardiac stress tests. The ECG can detect sinus bradycardia, a resting heart rate of fewer than 60 beats per minute. This is often accompanied by sinus arrhythmia. The pulse of a person with athlete's heart can sometimes be irregular while at rest, but usually returns to normal after exercise begins.
Regarding differential diagnosis, left ventricular hypertrophy is usually indistinguishable from athlete's heart and at ECG, but can usually be discounted in the young and fit.
It is important to distinguish between athlete's heart and hypertrophic cardiomyopathy, a serious cardiovascular disease characterised by thickening of the heart's walls, which produces a similar ECG pattern at rest. This genetic disorder is found in one of 500 Americans and is a leading cause of sudden cardiac death in young athletes (although only about 8% of all cases of sudden death are actually exercise-related). The following table shows some key distinguishing characteristics of the two conditions.
The medical history of the patient (endurance sports) and physical examination (bradycardia, and maybe a third or fourth heart sound), can give important hints.
- ECG - typical findings in resting position are, for example, sinus bradycardia, atrioventricular block (primary and secondary) and right bundle branch block - all those findings normalize during exercise.
- Echocardiography - differentiation between physiological and pathological increases of the heart's size is possible, especially by estimating the mass of the wall (not over 130 g/m) and its end diastolic diameter (not much less 60 mm) of the left ventricle.
- X-ray examination of the chest may show increased heart size (mimicking other possible causes of enlargement).
Previously, diagnosis was usually done through autopsy. Advances in imaging technologies allow for early detection and thus ample treatment and monitoring of the affected patient. A short-axis ultrasound of the aortic valve allows for the best view of the aortic valve, and gives a clear indication of the adduction pattern of the aortic valves.
If an “X” shape is seen, then the patient can be diagnosed with having a quadricuspid aortic valve. A transthoracic echocardiogram (TTE) indicates if there is an aortic regurgitation, but a 3-D transesophageal echocardiogram can give a better view of the aortic valve.
Multidetector coronary CT angiography has been indicated as a single competent diagnostic imaging tool capable of delineating valvular anatomy, severity of regurgitation, and high risk coronary problems. The typical method of treatment is through surgery such as aortic valve reconstruction surgery (AVRS) and aortic valve replacement, usually with a synthetic valve.
Despite increasing incidence of HFpEF effective inroads to therapeutics have been largely unsuccessful. Currently, recommendations for treatment are directed at symptom relief and co-morbid conditions. Frequently this involves administration of diuretics to relieve complications associated with volume overload, such as leg swelling and high blood pressure.
Commonly encountered conditions that must be treated for and have independent recommendations for standard of care include atrial fibrillation, coronary artery disease, hypertension, and hyperlipidemia. There are particular factors unique to HFpEF that must be accounted for with therapy. Unfortunately, currently available randomized clinical trials addressing the therapeutic adventure for these conditions in HFpEF present conflicting or limited evidence.
Specific aspects of therapeutics should be avoided in HFpEF to prevent the deterioration of the condition. Considerations that are generalizable to heart failure include avoidance of a fast heart rate, elevations in blood pressure, development of ischemia, and atrial fibrillation. More specific to HFpEF include avoidance of preload reduction. As patients display normal ejection fraction but reduced cardiac output they are especially sensitive to changes in preloading and may rapidly display signs of output failure. This means administration of diuretics and vasodilators must be monitored carefully.
HFrEF and HFpEF represent distinct entities in terms of development and effective therapeutic management. Specifically cardiac resynchronization, administration of beta blockers and angiotensin converting enzyme inhibitors are applied to good effect in HFrEF but are largely ineffective at reducing morbidity and mortality in HFpEF. Many of these therapies are effective in reducing the extent of cardiac dilation and increasing ejection fraction in HFrEF patients. It is unsurprising they fail to effect improvement in HFpEF patients, given their un-dilated phenotype and relative normal ejection fraction. Understanding and targeting mechanisms unique to HFpEF are thus essential to the development of therapeutics.
Randomized studies on HFpEF patients have shown that exercise improves left ventricular diastolic function, the heart's ability to relax, and is associated with improved aerobic exercise capacity. The benefit patients seem to derive from exercise does not seem to be a direct cardiac effect but rather is due to changes in peripheral vasculature and skeletal muscle, which show abnormalities in HFpEF patients.
Patients should be regularly assessed to determine progression of the condition, response to interventions, and need for alteration of therapy. Ability to perform daily tasks, hemodynamic status, kidney function, electrolyte balance, and serum natriuretic peptide levels are important parameters. Behavioral management is important in these patients and it is recommended that individuals with HFpEF avoid alcohol, smoking, and high sodium intake.
Congenital heart defects are now diagnosed with echocardiography, which is quick, involves no radiation, is very specific, and can be done prenatally.
Before more sophisticated techniques became available, chest x-ray was the definitive method of diagnosis. The abnormal "coeur-en-sabot" (boot-like) appearance of a heart with tetralogy of Fallot is classically visible via chest x-ray, although most infants with tetralogy may not show this finding. Absence of interstitial lung markings secondary to pulmonary oligaemia are another classic finding in tetralogy, as is the pulmonary bay sign.
Concentric hypertrophy is a hypertrophic growth of a hollow organ without overall enlargement, in which the walls of the organ are thickened and its capacity or volume is diminished.
Sarcomeres are added in parallel, as for example occurs in hypertrophic cardiomyopathy.
In the heart, concentric hypertrophy is related to increased pressure overload of the heart, often due to hypertension and/or aortic stenosis. The consequence is a decrease in ventricular compliance and diastolic dysfunction, followed eventually by ventricular failure and systolic dysfunction.
Laplace's law for a sphere states wall stress (T) is proportionate to the product of the transmural pressure (P) and cavitary radius (r) and inversely proportionate to wall thickness (W): In response to the pressure overload left ventricular wall thickness markedly increases—while the cavitary radius remains relatively unchanged. These compensatory changes, termed "concentric hypertrophy," reduce the increase in wall tension observed in aortic stenosis.
If untreated, severe symptomatic aortic stenosis carries a poor prognosis with a 2-year mortality rate of 50-60% and a 3-year survival rate of less than 30%. Prognosis after aortic valve replacement for people who are younger than 65 is about five years less than that of the general population; for people older than 65 it is about the same.
At present, there is no effective specific treatment available for diabetic cardiomyopathy. Treatment centers around intense glycemic control through diet, oral hypoglycemics and frequently insulin and management of heart failure symptoms. There is a clear correlation between increased glycemia and risk of developing diabetic cardiomyopathy, therefore, keeping glucose concentrations as controlled as possible is paramount. Thiazolidinediones are not recommended in patients with NYHA Class III or IV heart failure secondary to fluid retention.
As with most other heart diseases, ACE inhibitors can also be administered. An analysis of major clinical trials shows that diabetic patients with heart failure benefit from such a therapy to a similar degree as non-diabetics. Similarly, beta blockers are also common in the treatment of heart failure concurrently with ACE inhibitors.
The criteria to diagnose a left bundle branch block on the electrocardiogram:
- The heart rhythm must be supraventricular in origin
- The QRS duration must be ≥ 120 ms
- There should be a QS or rS complex in lead V1
- There should be a notched ('M'-shaped) R wave in lead V6.
The T wave should be deflected opposite the terminal deflection of the QRS complex. This is known as appropriate T wave discordance with bundle branch block. A concordant T wave may suggest ischemia or myocardial infarction.
There are also partial blocks of the left bundle branch: "left anterior fascicular block" (LAFB) and a "left posterior fascicular block" (LPFB). This refers to the bifurcation of the left bundle branch.
The risk of death in individuals with aortic insufficiency, dilated ventricle, normal ejection fraction who are asymptomatic is about 0.2 percent per year. Risk increases if the ejection fraction decreases or if the individual develops symptoms.
Individuals with chronic (severe) aortic regurgitation follow a course that once symptoms appear, surgical intervention is needed. AI is fatal in 10 to 20% of individuals who do not undergo surgery for this condition. Left ventricle dysfunction determines to an extent the outlook for severity of aortic regurgitation cases.
Hyperdynamic precordium is a condition where the precordium (the area of the chest over the heart) moves too much (is "hyper dynamic") due to some pathology of the heart. This problem can be hypertrophy of the ventricles, tachycardia, or some other heart problem.
Hyperdynamic precordium can also be due to hyperthyroidism, and thus indicates an increased cardiac contractility, with systolic hypertension. It may also be due to aortic coarctation, and most other congenital heart malformations.
Palpation of the chest wall can be done to assess volume changes within the heart. A hyperdynamic precordium reflects a large volume change.
In terms of treatment for pulmonary valve stenosis, valve replacement or surgical repair (depending upon whether the stenosis is in the valve or vessel) may be indicated. If the valve stenosis is of congenital origin, balloon valvuloplasty is another option, depending on the case.
Valves made from animal or human tissue (are used for valve replacement), in adults metal valves can be used.
Hypertrophy (, from Greek ὑπέρ "excess" + τροφή "nourishment") is the increase in the volume of an organ or tissue due to the enlargement of its component cells. It is distinguished from hyperplasia, in which the cells remain approximately the same size but increase in number. Although hypertrophy and hyperplasia are two distinct processes, they frequently occur together, such as in the case of the hormonally-induced proliferation and enlargement of the cells of the uterus during pregnancy.
Eccentric hypertrophy is a type of hypertrophy where the walls and chamber of a hollow organ undergo growth in which the overall size and volume are enlarged. It is applied especially to the left ventricle of heart. Sarcomeres are added in series, as for example in dilated cardiomyopathy (in contrast to hypertrophic cardiomyopathy, a type of concentric hypertrophy, where sarcomeres are added in parallel).
The presence of LBBB results in that electrocardiography (ECG) cannot be used to diagnose left ventricular hypertrophy or Q wave infarction, because LBBB in itself results in widened QRS complex, and changes in the ST-T segment consistent with ischemia or injury.