Cardiac Disease

A wide variety of cardiac abnormalities have been reported in HIV-infected patients, including ventricular dysfunction myocarditis, pericarditis, endocarditis, and arrhythmias. Most often, cardiac involvement is clinically silent and is noted as an incidental finding at autopsy. When clinical symptoms are present, however, disease manifestations can be debilitating, and, in many cases, life threatening. Unlike HIV-associated renal disease, no specific cardiac syndrome or disease state has been described.

Epidemiology

Cardiac abnormalities have been observed in 25 to 75% of HIV-infected patients studied at autopsy. Myocardial disease is noted most frequently, occurring in >90% of subjects with cardiac findings. Pericardial disease, often with adjacent myocardial involvement, is observed in >20% of cases with cardiac abnormalities. Endocarditis is evident histologically in 3 to 5% of cases reported in autopsy series. No characteristic epidemiologic factor, such as age, gender, race, or means of acquiring HIV infection, has been identified which predisposes patients to cardiac disease. Although cardiac abnormalities are observed more frequently in AIDS patients, up to 30% of patients with early symptomatic HIV disease are noted to have abnormal findings on echocardiograms and electrocardiograms.

Pathology and Pathogenesis

HIV-related heart disease may result from metastatic extension of a concomitant opportunistic infection or malignancy but most often is seen as lymphocytic infiltration of the myocardium or as an unspecified myocarditis. The mechanism responsible for the myocarditis remains unknown, although many investigators believe that HIV itself may be directly responsible. Other viruses, such as CMV, may be responsible for the development of myocarditis, although the typical "owl's eye" inclusion bodies are rarely seen in patients with HIV-associated cardiomyopathy. Additional mechanisms, such as postviral myocarditis or catecholamine-induced myocarditis, have been postulated, but little evidence exists to support their role.

A broad range of opportunistic infections and malignant diseases has been described in cardiac tissue examined at autopsy. Among the infectious disorders, fungal and viral pathogens are identified most often, followed by bacterial and protozoal infections (Table 417-2). Although the invading pathogen is frequently diagnosed at another primary site antemortem, cardiac involvement is rarely (<2%) identified before autopsy. This is largely due to the clinically silent nature of cardiac disease in HIV infection and a low index of suspicion by clinicians. Kaposi's sarcoma and metastatic lymphoma are the most common neoplastic diseases reported that invade the heart. Primary cardiac lymphoma has been reported rarely.

Pericardial disease is almost invariably associated with adjacent myocardial involvement. Pericarditis is usually nonspecific in origin, but when an etiologic process is identified, Kaposi's sarcoma or a pathogen, such as Mycobacterium tuberculosis or Cryptococcus neoformans, is responsible most often. Drugs used to treat HIV-associated disorders, such as doxorubicin for Kaposi's sarcoma, may cause myocardial damage. Other toxins, vitamin deficiencies, or metabolic abnormalities (e.g., hypothyroidism) may also result in myocardial dysfunction or pericardial disease.