Adult heterozygotes are also at significant risk for heart disease, including sudden death before the 5th decade as a result of asystole. Males complain of exertional fatigue and may be unable to perform hard labor. They may complain of palpitations and extra-systoles, and sometimes feel faint or may actually collapse temporarily. Females become symptomatic most notably in the later stages of pregnancy during the 4th decade. Diuretics and beta-blockers may relieve these symptoms but many women discontinue them following delivery and often deny significant symptoms thereafter. Echocardiography in symptomatic adults usually reveals hypertrophy of ventricular walls, especially the left, without dilation and outflow obstruction.
...Adult carriers should be monitored by a cardiologist. Many will never develop clinical heart disease
, but for those who have heart disease, appropriate medications for heart failure and implants for arrhythmias can be life-saving.
...Heterozygous adults may experience asystole and sudden death, or chronic low-grade heart failure unless appropriately treated. Arrhythmias and repeated syncopal episodes may benefit from pacemaker and defibrillator implantation. Importantly, the majority of adults never have cardiac symptoms and live otherwise healthy lives.