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Dilated Cardiomyopathy

Familial Dilated Cardiomyopathy

Dilated cardiomyopathy is characterized by increased ventricular size and impaired ventricular function. It is the most common form of non-ischemic cardiomyopathy.


Presentation

Symptoms are a good indicator of the severity of dilated cardiomyopathy. The following are the symptoms with which the patient may present and based on how severe the symptoms are, it suggests how advanced the diseased condition may be. The following are the symptoms with which a patient may present: fatigue, orthopnea, dyspnea on exertion, paroxysmal nocturnal dyspnea, increasing edema, weight gain, or an increase in the abdominal girth. Vital signs must be assessed with special attention to the following: tachypnea, tachycardia and hypertension. Other findings which are of importance include: cyanosis, clubbing, jugular venous distension, pulmonary edema, S 3 gallop, enlarged liver and peripheral edema.

On examination of the heart, the following findings must be paid attention to: cardiomegaly, murmurs, S 2 at the base S 3, and S 4, tachycardia, irregularly regular rhythm and gallops [3]. Symptoms of left- and right-sided congestive failure develop gradually in most patients. Some patients have left ventricular dilatation for months or even years before becoming symptomatic. Vague chest pain may be occasionally present, but typical angina pectoris is rare and suggests presence of concomitant coronary heart disease. Syncope may occur due to arrhythmias and systemic embolism (often emanating from a ventricular thrombus).

Fatigue
  • CASE PRESENTATION: A 52-year old Cameroonian male patient with human immunodeficiency virus infection since 4 years, longstanding heavy alcohol consumption and cigarette smoking presented with gradually worsening shortness of breath, fatigue, persistent[ncbi.nlm.nih.gov]
  • Shortness of breath and fatigue are often the first symptoms. Electrocardiography, echocardiography, magnetic resonance imaging, and blood tests are used to diagnose dilated cardiomyopathy.[msdmanuals.com]
  • Symptoms of DCM can occur at any age and may include: Heart failure symptoms ( shortness of breath and fatigue ). Swelling of the lower extremities. Fatigue (feeling overly tired). Weight gain .[medicinenet.com]
  • For those who have heart failure, symptoms can include: Older children and adults Shortness of breath and fatigue Feeling dizzy or light-headed Fainting or passing out (syncope) Persistent cough Feeling abnormal heart beats (palpitations) Unexplained[cincinnatichildrens.org]
Congestive Heart Failure
  • Congestive heart failure and malignant arrhythmias are the most widespread complications. The incidence of idiopathic dilated cardiomyopathy in the general population is 5-8/100.000.[ncbi.nlm.nih.gov]
  • heart failure (see pathophysiology section).[healio.com]
  • The most common presenting symptoms relate to congestive heart failure, but can also include circulatory collapse, arrhythmias, and thromboembolic events. Secondary neurohormonal changes contribute to reverse remodelling and ongoing myocyte damage.[ncbi.nlm.nih.gov]
  • However it should be suspected as a cause of congestive heart failure in any patient with features suggestive of TB.[doi.org]
Renal Artery Stenosis
  • Computed tomography angiogram confirmed the diagnosis of TA and revealed the presence of bilateral renal artery stenosis.[ncbi.nlm.nih.gov]
Severe Clinical Course
  • After a severe clinical course, the baby had external left ventricular assist as a bridge to heart transplantation. 1.5 months after transplantation, the baby suffered sudden cardiac death (SCD) despite maximal treatment in the pediatric intensive care[ncbi.nlm.nih.gov]
Heart Disease
  • Experimental murine models of enterovirus-induced heart disease provide a framework for examining the pathogenic mechanisms.[ncbi.nlm.nih.gov]
  • However, how this pathway is involved in the progression of cardiac dysfunction in different heart diseases remains unclear.[ncbi.nlm.nih.gov]
  • Understand Your Risk for Cardiomyopathy Symptoms and Diagnosis of Cardiomyopathy Prevention and Treatment of Cardiomyopathy Cardiomyopathy in Children Learn more: Family History and Heart Disease Alcohol and Heart Disease Cocaine, Marijuana and Other[heart.org]
  • Many previously unreported genes that may contribute to the pathophysiologic aspects of heart disease were identified.[ncbi.nlm.nih.gov]
Tachycardia
  • The treatment is of a dilated cardiomyopathy is aimed at the cause if potentially reversible (i.e. selenium deficiency or tachycardia mediated) and towards blockage of the neurohormonal response as discussed in the systolic congestive heart failure review[healio.com]
  • The diagnosis of TIC remains difficult since cardiomyopathy and tachycardia are often identified simultaneously [ 5 ]. In up to 70 % of the cases, a tachycardia is the symptom and not the cause of an underlying cardiomyopathy.[ncbi.nlm.nih.gov]
  • Other causes include prolonged tachycardia, toxoplasmosis, thyrotoxicosis, and beriberi.[merckmanuals.com]
  • Vital signs must be assessed with special attention to the following: tachypnea, tachycardia and hypertension.[symptoma.com]
Heart Murmur
  • There may also be a fast or slow heart beat and the doctor may hear an abnormal heart sound (heart murmur) through a stethoscope, or a large heart may be visible on an x- ray.[chfed.org.uk]
  • There may be a heart murmur (made by abnormal backward flow through the mitral valve) or other extra heart sounds and the liver is often enlarged.[mottchildren.org]
  • murmurs) When to see a doctor If you're short of breath or have other symptoms of dilated cardiomyopathy, see your doctor as soon as possible.[mayoclinic.org]
  • Lung crackles (a sign of fluid buildup), heart murmur, or other abnormal sounds. The liver is possibly enlarged. Neck veins may be bulging.[medlineplus.gov]
Cardiomegaly
  • Chest radiograph showed cardiomegaly; electrocardiogram showed left ventricular hypertrophy and echocardiography revealed dilated cardiomyopathy.[ncbi.nlm.nih.gov]
  • Most cases of dilated cardiomyopathy present as congestive heart failure: dyspnoea, weakness, fatigue, oedema, raised JVP, pulmonary congestion, cardiomegaly, loud third and/or fourth heart sound.[patient.info]
  • The chest X-ray demonstrates enlargement of the cardiac silhouette due to left ventricular dilatation, although generalized cardiomegaly is seen easily too.[symptoma.com]
  • A chest radiograph (Figure 2 ) performed at admission revealed cardiomegaly and bilateral alveolar opacities. Electrocardiogram revealed sinus tachycardia and non-specific ST-T changes in the lateral leads.[doi.org]
  • Cardiomegaly with marked biventricular dilation and fibrosis were noticeable histopathological findings. The affected males had tested negative on a 46-gene pancardiomyopathy panel.[ncbi.nlm.nih.gov]
Pulsus Alternans
  • Evaluation noted pulsus alternans, with beat-to-beat alternations in aortic pulse wave amplitude, both clinically and on diagnostic studies. Pulsus alternans is an infrequent, complex pathophysiologic sign often associated with severe heart failure.[ncbi.nlm.nih.gov]
Auditory Hallucination
  • CASE PRESENTATION: We report on the case of a 25 year-old patient, who was admitted for the evaluation of a potential electroconvulsive therapy due to persistent auditory hallucinations under clozapine.[ncbi.nlm.nih.gov]

Workup

TThe workup must include the following: a complete blood count, metabolic panel, thyroid function tests, cardiac biomarkers, B-type natriuretic peptide assay, chest radiography, echocardiography, cardiac magnetic resonance imaging (MRI), electrocardiography (ECG) [1].

The chest X-ray demonstrates enlargement of the cardiac silhouette due to left ventricular dilatation, although generalized cardiomegaly is seen easily too. The lung fields may demonstrate evidence of pulmonary venous hypertension and interstitial or alveolar edema. The electrocardiogram often shows sinus tachycardiaatrial fibrillation, premature ventricular complexes, nonspecific ST-T-wave abnormalities, Q waves, left ventricular hypertrophy, ventricular arrhythmias, and conduction defects. Echocardiography and radionuclide ventriculography may show dilatation, with thinned walls and systolic dysfunction [6].

The detection of elevated circulating levels of brain natriuretic peptide may help clarify which patients with dyspnea of uncertain etiology actually have heart failure rather than pulmonary disease as the cause of their symptoms, and identifies patients at increased risk of sudden death. Cardiac catheterization and coronary angiography are often performed to exclude ischemic heart disease, and bedside hemodynamic monitoring is helpful in managing acutely decompensated patients. Angiography reveals a dilated, diffusely hypokinetic left ventricle, with mild grade mitral regurgitation. Transvenous endomyocardial biopsy is usually not necessary in idiopathic or familial dilated cardiomyopathy. However, it may be helpful in the recognition of secondary cardiomyopathies, like acute myocarditis and amyloidosis [3].

Non Specific ST-T Changes
  • Electrocardiogram revealed sinus tachycardia and non-specific ST-T changes in the lateral leads.[doi.org]
T Wave Inversion
  • BACKGROUND: Takotsubo cardiomyopathy is characterized by the basal hypercontractility and apical ballooning of the left ventriculum and T-wave inversion in the electrocardiogram.[ncbi.nlm.nih.gov]
Left Ventricular Hypertrophy
  • Chest radiograph showed cardiomegaly; electrocardiogram showed left ventricular hypertrophy and echocardiography revealed dilated cardiomyopathy.[ncbi.nlm.nih.gov]
  • Example 3 Dilated cardiomyopathy: There is marked left ventricular hypertrophy with repolarisation abnormality (LV “strain” pattern) in V5-6.[lifeinthefastlane.com]
  • Left ventricular hypertrophy is calculated as the ratio of LV mass to cavity size; this ratio is decreased in persons with dilated cardiomyopathies. Dilated cardiomyopathies may have both systolic and diastolic dysfunction.[symptoma.com]

Treatment

Treatment and management of dilated cardiomyopathy is usually the same as that of congestive heart failure. Some therapeutic interventions treat symptoms whereas others treat factors that affect survival. The drug classes used include the following: Angiotensin-converting enzyme (ACE) inhibitors, vasodilators, angiotensin II receptor blockers (ARBs), aldosterone antagonists, diuretics, antiarrhythmics, beta-blockers, human B-type natriuretic peptide, cardiac glycosides, and inotropic agents. Anticoagulants may be used in certain cases [7]. Surgical options include the following: cardiac resynchroniztion, ventricular restoration surgery, left ventricular assist devices, automatic implantable cardioverter defibrillators and heart transplantation [7].

Most patients pursue an inexorably downhill course, and the majority, particularly those >55 years, die within 3 years of the onset of symptoms. African Americans are more likely to suffer progressive heart failure and death than Caucasians. Spontaneous stabilization occurs in about a quarter of patients. Death is due to either CHF or ventricular tachy- or bradyarrhythmia; sudden death is a constant threat. Systemic embolization is a possible complication and should be considered for chronic anticoagulation. Standard therapy of heart failure is following a salt restricted diet. Angiotensin-converting enzyme (ACE) inhibitors, diuretics, and digitalis produce symptomatic improvement [8]. An angiotensin II receptor blocker may be substituted in ACE-intolerant patients. Most patients should be treated with a β-adrenergic blocker. Spironolactone should be added for most patients with recent or current advanced heart failure [9].

Some patients with dilated cardiomyopathy who have biopsy evidence of myocardial inflammation have been treated with immunosuppressive therapy, but long-term evidence of efficacy is lacking. Alcohol should be avoided because of its cardiac toxic effects, as should calcium channel blockers and non-steroidal anti-inflammatory drugs. Anti-arrhythmic agents are best avoided for fear of pro-arrhythmia, unless they are needed to treat symptomatic or serious arrhythmias. For one in three patients with an intraventricular conduction delay, biventricular pacing improves symptoms, reduces hospitalizations and mortality. Insertion of an implantable cardioverter-defibrillator is useful in patients with symptomatic ventricular arrhythmias [10]. In patients with advanced disease who are refractory to medical therapy, cardiac transplantation should be considered.

Prognosis

Although a few cases of dilated cardiomyopathy are reversible with treatment of the underlying disease, many progress to heart failure. Continued decompensation might necessitate heart transplantation. The prognosis depends on many factors with etiology of the disease being the primary factor. Other factors which play an important role are the patient's age, sex, ability to follow medical advice, access to optimal medical therapy, and presence of severe congestive heart failure (CHF). The Framingham heart study found that approximately 50% of patients diagnosed with CHF died within 5 years [5]. Patients with severe heart failure have a mortality rate of more than 50% yearly. Patients having mild heart failure benefit tremendously with optimal medical therapy.

Etiology

DCM is one of the cardiomyopathies that affect mainly the myocardium. Various cardiomyopathies have differing causes and may affect the heart in many ways. In DCM, a portion of the myocardium is enlarged, often without any obvious cause. Obesity increases the risk of developing heart failure, and so does sleep apnea. Probably 20% to 40% of affected individuals have familial forms of the disorder, with possible mutations and chromosomal aberrations in more than 30 genes yet identified [2]. The disease is genetically heterogeneous, but most commonly autosomal dominant in transmission, but autosomal recessive, mitochondrial (especially in children), and X-linked inheritance is found as well [2].

DCM may occur secondary to other cardiovascular disease, ischemia, hypertension, valvular disease and tachycardia. Whipple disease and Lyme disease are probable infectious causes. Viral, bacterial, fungal, rickettsial, metazoal and protozoal infections can also cause DCM. Endocrine diseases such as hyperthyroidism and hypothyroidism or diabetes mellitus, are also a contributing factors. The other causes of DCM include nutritional imbalances such as beriberi and protein deficiency, collagen vascular disease, sarcoidosis, physical agents such as electric shock, ionizing radiation and extreme temperatures. A primary cardiac tumor (myxoma) and transplant rejection are also causes for DCM. Toxins are a significant cause. Almost one third of the cases may occur from severe ethanol abuse. However, often in dilated cardiomyopathy, the cause remains unexplained. Some idiopathic cases may be occurring from failure to identify known causes such as infections or toxins or familial forms.

Epidemiology

It is difficult to assess the prevalence of cardiomyopathy. Dilated cardiomyopathy may be the late sequel of acute viral myocarditis, mediated via immunologic mechanisms. Although it may occur in any patient population, it is most commonly a disease of middle aged men and is more common in African Americans than in whites [3]. The most common ages of developing DCM is between the ages of 20 and 60 years. Dilated cardiomyopathy also occurs in children. The prevalence of this condition is increasing. Patients with the condition often go undiagnosed and may present directly with sudden cardiac arrest. The estimated prevalence of idiopathic dilated cardiomyopathy is 0.4 per 1,000 of population. In the future, as more causes are elucidated and more patients diagnosed with genetic or familial cardiomyopathy, the number of cases with idiopathic disease, a diagnosis of exclusion, are bound to decrease.

Sex distribution
Age distribution

Pathophysiology

DCM is primarily a failure of systolic function with inadequate contractility (pump failure). Left ventricular hypertrophy is calculated as the ratio of LV mass to cavity size; this ratio is decreased in persons with dilated cardiomyopathies [1]. Dilated cardiomyopathies may have both systolic and diastolic dysfunction. The decrease in systolic function is the primary abnormality which leads to an increase in end-diastolic and end-systolic volumes.

Continuous and progressive dilatation may cause significant regurgitation at the mitral and tricuspid orifices, which may further diminish the cardiac output and increase end-systolic volumes and ventricular wall stress. This further leads to dilatation and myocardial dysfunction [4]. Thus, the affected myocardium is unable to generate the pressures required to maintain cardiac output. As a result the ventricles become stretched and overloaded. The poor cardiac output can be explained by applying the Frank-Starling Law. The law states that the myocardial force increases at end-diastole compared to the end-systole as the muscle length increases, thereby generating a greater force as the muscle is stretched. Overstretching produces failure of myocardial contractile unit. These compensatory mechanisms are dysfunctional in persons with dilated cardiomyopathies, compared to patients with normal LV function. These compensatory methods lead to further damage to myocaridum, cardiac dysfunction, and geometric remodelling [1][4].

Decreased cardiac output leads to reductions in organ perfusion which results in neurohormonal activation, and stimulation of adrenergic nervous system and the renin-angiotensin-aldosterone system (RAAS). Additional factors important to compensatory neurohormonal activation include the release of arginine vasopressin and the secretion of natriuretic peptides [4]. These compensatory responses worsen the cardiomyopathy gradually.

Prevention

It is a well-known fact that following a healthy lifestyle is one of the best ways to reduce the effects of heart related complaints. One must refrain from smoking; alcohol must be moderated [11]. Complete alcohol abstinence is ideal. One must refrain from using cocaine or other illegal drugs and must follow a healthy diet. Caffeine intake should be limited. It is also important to maintain a healthy weight, follow a recommended exercise regimen and get enough sleep and rest. At times, people who have cardiomyopathy but no signs or symptoms may not need treatment because sometimes dilated cardiomyopathy that comes up suddenly may even go on its own.

Summary

Dilated cardiomyopathy abbreviated as DCM is a progressive condition of the heart muscle which is characterized by dilation of one or both ventricles along with contractile dysfunction and normal left ventricular thickness [1]. Because of this, the enlarged heart cannot pump blood efficiently. Hence, this decreased function of the heart can affect the lungs, liver and other body systems. Statistics show that DCM is the third most common cause of heart failure as well as the most frequent cause for a cardiac transplantation. About one in three cases of congestive heart failure (CHF) is due to dilated cardiomyopathy, with the remainder the consequence of coronary artery disease [1] [2].

Patient Information

Dilated cardiomyopathy (DCM) is a heart condition in which there is enlargement of one of the chambers of the heart. This, results in the heart being over worked which is why a person comes up with symptoms of breathlessness, increase in weight and edema along with others. It is more common in males and a higher incidence is found among African-American people. However, DCM can be found amongst people in their 20’s or amongst children as well.

Mostly DCM is secondary to other heart diseases. At times viral and bacterial infections can also contribute to the same. The main goals of treating cardiomyopathy include controlling the signs and symptoms, manage other conditions which contribute to the disease, reduce complications of a sudden cardiac arrest. ACE inhibitors are usually prescribed to lower the blood pressure. It is important to maintain lifestyle changes which reduce the severity of the symptoms and thus the outcome of the disease. A healthy diet is a part of a healthy lifestyle. A healthy diet includes fruits, vegetables and grains. It is important to aim for a healthy weight.

References

Article

  1. Jameson JN, Kasper DL, Harrison TR, Braunwald E, et al (2005). Harrison’s principles of internal medicine (16thed). New York: McGraw-Hill Medical Publishing Division. ISBN 0-07-140235-7.
  2. Busko M. Genetic test helps spot familial cardiomyopathy. Heartwire [serial online]. October 22, 2013;Accessed October 25, 2013
  3. Hunt SA, Abraham WT, Chin MH, Feldman AM, et al. 2009 Focused update incorporated into the ACC/AHA 2005 Guidelines for the Diagnosis and Management of Heart Failure in Adults A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines Developed in Collaboration With the International Society for Heart and Lung Transplantation. J Am CollCardiol. Apr 14 2009;53(15):e1-e90.
  4. Martino TA, Liu P, Sole MJ (February 1994). Viral infection and the pathogenesis of dilated cardiomyopathy. Circ Res. 74 (2):182-8. doi 10.1161/01.res.74.2.182
  5. McKee PA, Castelli WP, McNamara PM, Kannel WB. The natural history of congestive heart failure: the Framingham study. N Engl J Med. Dec 23 1971;285(26):1441-6.
  6. Peacock WF, Emerman CE, Doleh M, Civic K, Butt S. Retrospective review: the incidence of non-ST segment elevation MI in emergency department patients presenting with decompensated heart failure. Congest Heart Fail. Nov-Dec 2003;9(6):303-8.
  7. Suma H. Partial left ventriculectomy. Circ J. Jun 2009;73Suppl A:A19-22.
  8. Packer M, Poole-Wilson PA, Armstrong PW, Cleland JG, et al. Comparative effects of low and high doses of the angiotensin-converting enzyme inhibitor, lisinopril, on morbidity and mortality in chronic heart failure. ATLAS Study Group. Circulation. Dec 7 1999;100(23):2312-8.
  9. Pitt B, Zannad F, Remme WJ, Cody R, et al. The effect of spironolactone on morbidity and mortality in patients with severe heart failure. Randomized Aldactone Evaluation Study Investigators. N Engl J Med. Sep 2 1999;341(10):709-17.
  10. Moss AJ. Implantable cardioverter defibrillator therapy: the sickest patients benefit the most. Circulation. Apr 11 2000;101(14):1638-40.
  11. Nicolas JM et al. The effect of controlled drinking in alcoholic cardiomyopathy. Ann Intern Med .2002;136:192-200.

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Last updated: 2018-06-22 00:02