Summary Dextroversion of the heart is an uncommon congenital anomaly characterized by situs solitus (normal position) of thoracic and abdominal viscera with right cardiac apex. Isolated dextroversion, i.e., without associated congenital heart disease, is rare, but its occurrence permits adult survival, setting the stage for late development of acquired heart disease. The patient herein reported was known since childhood to have a right thoracic heart that represented isolated uncomplicated dextroversion. He presented in the sixth decade with a new murmur that proved to be due to asymmetric septal hypertrophy (ASH) with obstruction. This combination of anomalies is possible only if dextroversion exists without ventricular inversion, since aortic-anterior mitral leaflet continuity is obligatory for obstructive ASH. This paper presented clinical, phonocardiographic, vectorcardiographic, echocardiographic, hemodynamic, angiocardiographic, and intracardiac electrophysiologic information on the unique combination of isolated dextroversion of the heart with obstructive asymmetric septal hypertrophy.