PubMed1968
Left ventricular function was assessed in six patients with essentially normal cardiopulmonary function, in five patients with primary myocardial disease, and in 16 patients with chronic obstructive pulmonary disease by determining the response of the ventricle to an increased resistance to ejection. Studies were performed at the time of cardiac catheterization and increased resistance to left ventricular ejection was produced by the intravenous infusion of methoxamine. In the control patients, methoxamine produced an increase in stroke volume index (SVI), in stroke work index (SWI), and stroke power index (SPI), whereas left ventricular end-diastolic pressure (LVEDP) increased only moderately. In contrast SVI, SWI, and SPI fell, whereas LVEDP increased inordinately in the patients with myocardiopathy. The patients with chronic obstructive pulmonary disease responded to the infusion with an increase in SVI, SWI, SPI, and LVEDP comparable to the control patients. Furthermore, in this latter group of patients, a quantitatively similar response was observed in those with essentially normal resting hemodynamics, in those with resting pulmonary hypertension, and in those whose disease had progressed to the stage of right ventricular failure. This study provides no evidence that chronic obstructive pulmonary disease results in chronic impairment of left ventricular function, but on the contrary, has demonstrated that the left ventricle responds normally to an increased pressure load in these patients.