- Dilated Cmp
- Etiology
- Symptoms
- Physical Examination
- Laboratory ECG
- CXR
- Echocardiogram, CT, and Cardiac MRI
- B-Type Natriuretic Peptide (Bnp)
- Restrictive Cmp
- Symptoms
- Physical Examination
- Laboratory ECG
- CXR
- Echocardiogram, CT, Cardiac MRI, Nuclear Imaging
- Cardiac Catheterization
- Hypertrophic Cmp
- Symptoms
- Physical Examination
- Laboratory ECG
- Echocardiogram
- Myocarditis
- History
- Physical Examination
- Laboratory
- ECG
- CXR
- Echocardiogram, Cardiac MRI
Cardiomyopathies are primary diseases of heart muscle. Table 117-1 Presentation with Symptomatic Cardiomyopathy summarizes distinguishing presenting features of the three major types of cardiomyopathy (CMP). Table 117-2 Initial Evaluation of Cardiomyopathy details the comprehensive initial evaluation of suspected cardiomyopathies.
Dilated left ventricle (LV) with poor systolic contractile function; right ventricle (RV) often involved.
Over 30% of pts have a familial form; mutations in TTN (encodes large sarcomeric protein titin) are the most common. Additional causes include myocarditis (e.g., viral and other infections, sarcoidosis, giant cell, eosinophilic), toxins (e.g., ethanol, antineoplastic agents [e.g., doxorubicin, trastuzumab, imatinib], hydroxychloroquine, heavy metals), connective tissue disorders, hypothyroidism, hemochromatosis, muscular dystrophies, “peripartum,” transient stress “takotsubo” CMP. Impaired LV function owing to severe coronary disease/infarction or chronic aortic/mitral regurgitation may behave similarly.
Heart failure (Chap. 126 Heart Failure and Cor Pulmonale) often with secondary mitral and tricuspid regurgitation; tachyarrhythmias and peripheral emboli from LV mural thrombus occur.
Jugular venous distention (JVD), pulmonary crackles, diffuse and dyskinetic LV apex, S3, hepatomegaly, peripheral edema; murmurs of mitral and tricuspid regurgitation are common.
Echocardiogram, CT, and Cardiac MRI 
LV and RV enlargement with globally impaired contraction. Regional wall motion abnormalities suggest coronary artery disease rather than primary CMP.
B-Type Natriuretic Peptide (Bnp)
Level elevated in heart failure/CMP but not in pts with dyspnea due to lung disease.
| TREATMENT | ||
Dilated CMPPossible use of immunosuppressive drugs if specific forms active myocarditis present on RV biopsy (e.g., for sarcoidosis or giant cell myocarditis). Standard therapy of heart failure (Chap. 126 Heart Failure and Cor Pulmonale): Diuretic for volume overload, vasodilator therapy with ACE inhibitor (preferred), angiotensin receptor blocker or hydralazine-nitrate combination, and beta-blocker therapy (e.g., metoprolol succinate, carvedilol) limit disease progression and improve longevity. Consider aldosterone antagonist therapy for pts with class II-IV heart failure, and chronic anticoagulation if there is accompanying atrial fibrillation (AF), prior embolism, or recent large anterior MI. Antiarrhythmic drugs (e.g., amiodarone or dofetilide) may be useful to maintain sinus rhythm in pts with AF. Consider implanted cardioverter defibrillator (ICD) for class II-III pts with LVEF <35%. For those with class III-IV heart failure, LVEF <35%, and prolonged QRS duration, consider cardiac resynchronization therapy (CRT) using biventricular pacing; greatest benefit in pts with LBBB and QRS ≥150 msec (ICD and CRT functions can be provided by a single implanted device). In selected pts, consider cardiac transplantation. |
Characterized by abnormal diastolic relaxation, often with mildly reduced systolic function. Etiologies include infiltrative disease (e.g., amyloidosis, sarcoidosis), storage diseases (hemochromatosis, Fabry's disease), fibrotic disorders (radiation, scleroderma), endomyocardial disease (hypereosinophilic syndrome, endomyocardial fibrosis).
Especially signs of right-sided heart failure: JVD (Kussmaul sign may be present), hepatomegaly, peripheral edema. S4 is common.
Low limb lead voltage (e.g., in some forms of amyloidosis), sinus tachycardia, ST-T-wave abnormalities.
Echocardiogram, CT, Cardiac MRI, Nuclear Imaging
Bilateral atrial enlargement, often to a marked degree; increased ventricular thickness (“speckled pattern”) common in infiltrative disease, especially amyloidosis. Systolic function is usually normal or mildly reduced. Doppler analysis shows impaired diastolic function. Amyloid infiltration can be detected with MRI gadolinium enhancement. Technetium pyrophosphate nuclear imaging is sensitive for detection of transthyretin amyloidosis.
Increased LV and RV diastolic pressures with “dip and plateau” pattern; RV biopsy useful in detecting infiltrative disease.
Note: Must distinguish restrictive CMP from constrictive pericarditis, which is surgically correctable. Thickening of pericardium on CT or MR imaging is apparent in >80% of pts with constrictive pericarditis.
| TREATMENT | ||
Restrictive CMPSalt restriction and diuretics ameliorate pulmonary and systemic congestion. Note: Increased sensitivity to digitalis in amyloidosis. Anticoagulation often indicated, particularly in pts with eosinophilic endomyocarditis. For specific therapy of amyloidosis, hemochromatosis and sarcoidosis, see Chaps. 108, 407 and 360, respectively, in HPIM-20. |
Marked LV hypertrophy; often asymmetric, without underlying hypertension or valvular disease. Systolic function is usually normal; increased LV stiffness results in elevated diastolic filling pressures. Typically results from mutations in sarcomeric proteins (autosomal dominant transmission).
Secondary to elevated diastolic pressure, dynamic LV outflow obstruction (if present), and arrhythmias; dyspnea on exertion, angina, and presyncope; sudden death may occur.
Brisk carotid upstroke with pulsus bisferiens; S4, harsh systolic murmur along left sternal border, blowing murmur of mitral regurgitation at apex; murmur enhances with Valsalva and other maneuvers that decrease LV filling (Chap. 112 Physical Examination of the Heart).
LV hypertrophy with prominent “septal” Q waves in leads I, aVL, V5-6. Episodic AF or ventricular tachycardia (VT) may be found on ambulatory monitoring.
LV hypertrophy, often with asymmetric involvement, especially of the septum or apex; LV contractile function typically excellent with small end-systolic volume. If LV outflow tract obstruction is present, systolic anterior motion (SAM) of mitral valve and midsystolic partial closure of aortic valve are present. Doppler shows early systolic accelerated blood flow through LV outflow tract.
| TREATMENT | ||
Hypertrophic CMPStrenuous exercise should be avoided. Beta blockers, verapamil, or disopyramide used individually to reduce symptoms. Digoxin, other inotropes, diuretics, and vasodilators should generally be avoided. Endocarditis antibiotic prophylaxis (Chap. 83 Infective Endocarditis) is necessary only in pts with prior history of endocarditis. Antiarrhythmic agents, especially amiodarone, may suppress atrial and ventricular arrhythmias. However, consider ICD for pts with high-risk profile, e.g., history of syncope or aborted cardiac arrest, nonsustained VT, marked LVH (>3 cm), exertional hypotension, or family history of sudden death. In selected pts, LV outflow gradient can be reduced by controlled septal infarction by ethanol injection into the septal artery. Surgical myectomy may be useful in pts refractory to medical therapy. |
Inflammation of the myocardium that may progress to chronic dilated CMP, is most commonly related to acute viral infection (e.g., coxsackievirus, adenovirus, Epstein-Barr virus, parvovirus B19, human herpesvirus 6). Myocarditis may also develop in pts with HIV infection, hepatitis C, or Lyme disease. Chagas' disease (Trypanosoma cruzi) is a common cause of myocarditis in endemic areas, typically Central and South America. Noninfective causes of myocarditis include granulomatous disease (e.g., sarcoidosis, giant cell myocarditis), which should be considered if VT or conduction blocks dominate the presentation of heart failure in the absence of CAD. Rare etiologies include eosinophil myocarditis, hypersensitivity myocarditis, and systemic inflammatory diseases (e.g., polymyositis, dermatomyositis).
Fever, fatigue, palpitations; if LV dysfunction develops, symptoms of heart failure are present. Viral myocarditis may be preceded by URI.
Cardiac troponins and creatine kinase-MB isoenzyme may be elevated in absence of MI. Convalescent antiviral antibody titers may rise.
Depressed LV function; pericardial effusion if accompanying pericarditis present. MRI demonstrates mid-wall gadolinium enhancement. Endomyocardial biopsy is rarely indicated (e.g., in suspected sarcoidosis or giant cell myocarditis).
| TREATMENT | ||
MyocarditisTreat as heart failure (Chap. 126 Heart Failure and Cor Pulmonale); efficacy of immunosuppressive therapy (e.g., steroids) has not been demonstrated except in isolated conditions such as sarcoidosis and giant cell myocarditis. In fulminant cases, cardiac transplantation may be indicated. |