Among the clinical manifestations of ischemic heart disease, right coronary artery (RCA) disease offers a wide variety of right and left ventricular ischemic involvement, including prevalent right ventricular dysfunction and severe cardiac failure. Whether the right ventricular impairment is dependent primarily on ischemia of the right ventricle or requires a concomitant left ventricular dysfunction remains debatable. To assess the pathophysiology and clinical relevance of RCA-related ischemia, a systematic study of patients with single RCA disease (either vasospastic angina at rest or typical stable angina) was undertaken by radionuclide ventriculography. A high incidence of ischemia-induced right ventricular dysfunction was observed (93% and 95% in angina at rest and on effort, respectively), either alone or associated with left ventricular impairment. These results were compared with those obtained in a control population with isolated left anterior descending artery disease and either primary or secondary angina pectoris. We infer that the impairment of the right ventricle was related primarily to right ventricular ischemia and that left ventricular dysfunction alone did not cause an important depression of right ventricular systolic function. In conclusion, the clinical manifestations of RCA disease can be protean; the right ventricle can be the target of ischemia, and recognition of its impairment poses diagnostic problems. Radionuclide ventriculography and two-dimensional echocardiography, together with stressors of coronary flow reserve, are reliable techniques for assessing RCA-related ischemia.