Improvement in forward cardiac output without a change in ejection fraction during nitroglycerin therapy in patients with functional mitral regurgitation.

Left ventricular volumes and forward aortic flow were measured using combined two-dimensional echocardiography and doppler cardiography in seven patients with decompensated congestive heart failure and functional mitral regurgitation prior to and during intravenous administration of nitroglycerin. Total stroke volume was calculated from the difference between end-diastolic and end-systolic volumes, and regurgitant mitral volume from the difference between total stroke volume and forward aortic flow. Regurgitant mitral volume fell from 19 +/- 9 to 3 +/- 3 mL/beat (p less than 0.001), while forward stroke volume increased from 35 +/- 8 to 45 +/- 9 mL/beat (p less than 0.001). The changes were well correlated (r = 0.8, p less than 0.001). Total stroke volume decreased from 54 +/- 12 to 48 +/- 6 mL/beat (p less than 0.05), and ventricular end-diastolic volume from 173 +/- 66 to 158 +/- 66 mL (p less than 0.05). Left ventricular ejection fraction did not change significantly: 33 +/- 9% vs 32 +/- 9% (NS). Thus, in patients with severe congestive heart failure and functional mitral regurgitation, intravenous nitroglycerin redistributes blood flow within the heart by decreasing mitral regurgitation and increasing forward aortic flow, without affecting left ventricular ejection fraction.