Cardiomyopathy Disease

BASICS

DESCRIPTION

Cardiomyopathy can be divided into two types:

Systolic failure: low cardiac output, decreased left ventricular ejection, tendency to accumulate salt and water causing increased intravascular volume, peripheral edema, and left and right heart failure symptoms. Idiopathic, viral, postpartum, alcoholic, and many ischemic cardiomyopathies may produce systolic failure. An imbalance of the neurohormonal system in norepinephrine causes fluid retention, peripheral vasoconstriction, and overstimulation of cardiac beta-receptors. These changes initially allow the heart to maintain a normal blood flow, but later cause progressive heart enlargement, lung congestion, and failure of the right side of the heart from fluid overload. This imbalance of the neuroendocrine system has led to changes in medical therapy; angiotensin converting enzyme (ACE) inhibitors are an important part of therapy.
Diastolic failure: normal or super normal systolic function, non-compliant (stiff) left ventricle with increased filling pressures. Scarring (eg, post MI), amyloidosis, and hypertrophic cardiomyopathy may result in diastolic failure. Generally, the heart is not as enlarged as in the systolic failure group.
System(s) affected: Cardiovascular
Genetics: Idiopathic hypertrophic subaortic stenosis has a familial distribution
Incidence/Prevalence in USA:
- 60,000 patients, under 65, die each year with end-stage heart disease.
- 35,000 to 70,000 of the population might benefit from cardiac replacement or chronic support
- Heart failure is the most rapidly growing form of heart disease
Predominant age:
- Ischemic cardiomyopathy is seen predominately in patients > 50
- Idiopathic and familial cardiomyopathies are seen at an earlier age, as are those related to congenital heart disease, viral cardiomyopathy, alcoholic cardiomyopathy and post partum cardiomyopathy
Predominant sex: Male > Female (ischemic cardiomyopathy)

SIGNS AND SYMPTOMS

Shortness of breath at rest
Dyspnea on minimal exertion
Paroxysmal nocturnal dyspnea/orthopnea
Postprandial dyspnea
Fatigue
Syncope
Tachypnea
Cyanosis, pallor
Cool vasoconstricted extremities
Diaphoresis
Jugular venous distention
Bi-basilar inspiratory rales
S3 cardiac gallop
Liver and spleen enlargement
Ascites, edema
Chest pain

CAUSES

Infectious
- Viral (e.g., Coxsackie virus)
- Poliomyelitis
- Diphtheria
- Toxoplasmosis
- Trichinosis
- Trypanosomiasis
- Acute rheumatic fever
Congenital
- Congenital heart disease
- Glycogen storage disease
- Pompe's disease
- Hurler's syndrome
- Hunter's syndrome
- Fabry's disease
- Duchenne's muscular dystrophy
- Friedreich's ataxia
- Familial cardiomyopathies, such as "asymmetric septal hypertrophy"
Toxic/metabolic
- Alcoholism
- Radiation
- Beriberi
- Kwashiorkor
- Potassium deficiency
- Cobalt
- Hemosiderosis
Drugs
- Adriamycin
Inflammatory
- Giant cell myocarditis
- Loeffler's eosinophilia
- Sarcoidosis
Idiopathic
Others
- Coronary artery disease
- Peripartum and postpartum
- Amyloidosis
- Idiopathic hypertrophic subaortic stenosis
- Endomyocardial fibrosis

RISK FACTORS

Hypertension
Hyperlipidemia
Obesity
Diabetes mellitus
Smoking
Stress
Sedentary lifestyle
Cardiac surgery

DIAGNOSIS

LABORATORY

Hyponatremia
Pre-renal azotemia
Mild hyperbilirubinemia
ECG: left ventricular hypertrophy, left bundle branch block (LBBB) ventricular strain pattern, left and right atrial enlargement are often seen. In ischemic cardiomyopathies evidence of previous myocardial infarctions (Q-waves and poor R-wave progression in the precordial leads).

Drugs that may alter lab results: Digoxin, furosemide, ACE inhibitors (by improving cardiac function)
Disorders that may alter lab results: N/A

PATHOLOGICAL FINDINGS

N/A

SPECIAL TESTS

Cardiac catheterization. Helps differentiate between ischemic and other types of cardiomyopathy, elucidates intracavitary pressures, cardiac output, left ventricular function and coronary anatomy. Also provides an opportunity to measure pulmonary artery pressures and pulmonary vascular resistance (mean pulmonary artery pressure minus the mean left atrial [wedge] pressure divided by the cardiac output [normal 1.2])
Maximal oxygen consumption. This treadmill exercise study provides the most prognostic information. Max-oxygen consumption 50% one year mortality, and >18 cc/kg/mm correlates with >90% one year survival.
For transplant candidates, the following are recommended: CT scans of the chest and abdomen; 24 hour creatinine clearance; routine pulmonary function studies (including blood gas determination); serologies for hepatitis A, B, C, HIV, Toxoplasma, CMV and EB virus; full panels of renal and liver function; complete blood count with differential; and Panorex dental x-ray. Additional studies indicated if any findings are suspicious for disease which would be a contraindication to transplantation. For instance, any undiagnosed roentgenographic abnormality of the lungs is a contraindication to transplantation.

IMAGING

Chest x-ray
- Cardiac enlargement (four chamber) in the dilated cardiomyopathies
- Increased vascular markings to the upper lobes: elevated pulmonary venous pressure
- Hazy diffuse densities in the hilar areas: pulmonary edema
- Pleural effusions and curly B-lines in the lung periphery: engorged pulmonary lymphatics
- In hypertrophic cardiomyopathies and cardiomyopathies with normal cardiac size, usually see pulmonary signs of cardiac failure
Echocardiogram:
- In the dilated cardiomyopathies, demonstrates four chamber enlargement and global hypokinesias
- In hypertrophic cardiomyopathies, severe left ventricular hypertrophy
- In ischemic cardiomyopathy, the heart may be normal or enlarged
- Usually segmental abnormalities in contraction of the left ventricle can be detected, indicative of previous localized myocardial infarction
MUGA: Best study to quantitate ejection fraction, often < 25%

DIAGNOSTIC PROCEDURES

N/A

TREATMENT

APPROPRIATE HEALTH CARE

Outpatient until time for myocardial transplant or for treatment of severe heart failure

GENERAL MEASURES

Treatment of heart failure
Treatment of electrolyte disturbances

SURGICAL MEASURES

Myocardial transplant

ACTIVITY

Limited by varying degrees. Bedrest may be necessary.

DIET

Low fat, low salt, fluid restriction

PATIENT EDUCATION

Careful instructions and precautions for all medications

FOLLOW UP

PREVENTION/AVOIDANCE

Reduce salt and water intake, home blood pressure measurement, daily weight check are helpful

POSSIBLE COMPLICATIONS

Worsening congestive heart failure, syncope, arrhythmias, sudden death

EXPECTED COURSE AND PROGNOSIS

20-40% of patients in New York functional class IV die within one year. With transplant, one year survival as high as 94%. Patients on ACE inhibitors have a longer survival due to afterload reduction and subsequent reduction in cardiac size and improved cardiac efficiency.
Expert medical therapy can significantly improve outcomes

MISCELLANEOUS

ASSOCIATED CONDITIONS

N/A

AGE-RELATED FACTORS

Pediatric: Idiopathic, viral, congenital heart disease, and familial cardiomyopathies more likely in children
Geriatric: N/A
Others: N/A

PREGNANCY

May occur postpartum

OTHER NOTES

N/A

ABBREVIATIONS

CMV = cytomegalic inclusion virus
EBV = Epstein-Barr virus
MUGA = Nuclear multiple gaited acquisition ventriculogram

Clinical Investigations

ROLE OF HOMOEOPATHY

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