Comparison of atrial contribution to cardiac hemodynamics in patients with normal and severely compromised cardiac function.

The importance of atrial contribution to cardiac function in patients with congestive heart failure is controversial. Ten patients with severe congestive failure (Group A) and 10 patients with normal ventricular function (Group B) were studied during atrial and ventricular pacing. Left ventricular ejection fraction, baseline pulmonary capillary wedge pressure, and baseline cardiac index were different between Group A and Group B patients: 22 +/- 10 vs. 65 +/- 11 (p less than 0.01); 21 +/- 5 vs. 8 +/- 4, (p less than 0.01); and 2.8 +/- 0.5 vs. 3.5 +/- 1.0 (p = 0.05). Compared with atrial pacing, cardiac index decreased from 2.8 +/- 0.6 to 2.2 +/- 0.5 (p less than 0.01) in Group A and from 3.6 +/- 0.7 to 2.9 +/- 0.5 (p less than 0.01) in Group B, during ventricular pacing. Pulmonary capillary wedge pressure increased by similar amounts in both groups during ventricular pacing. The change in cardiac index, % change in cardiac index, and change in pulmonary capillary wedge pressure from atrial to ventricular pacing, were not different between Group A and Group B patients. By logistic regression analysis, no association was found between the % change in cardiac index and the following variables: left ventricular ejection fraction, left ventricular end-diastolic volume, baseline pulmonary capillary wedge pressure, change in pulmonary capillary wedge pressure, and baseline cardiac index. The atrial contribution to resting steady-state cardiac function is similar between patients with severe congestive failure and those with preserved ventricular function.

Diagnosis of aortic insufficiency: comparison of auscultation and M-mode echocardiography to angiography.

We compared auscultation and M-mode echocardiography to supravalvular aortography in 75 patients with chronic aortic insufficiency. Angiographic evidence of aortic insufficiency was present in 66 patients and absent in nine. Auscultation had a sensitivity of 72.7% (48/66) and a specificity of 77.8% (7/9). Echocardiography had a sensitivity of 75.8% (50/66) and specificity of 77.8% (7/9). When both methods were used in combination, their sensitivity for diagnosis of aortic insufficiency increased to 92.9% (61/66). The specificity did not change. Our data suggest that when used alone neither auscultation nor echocardiography is a sensitive method for detecting aortic insufficiency, but when used in combination they are excellent indicators for the presence or absence of aortic insufficiency.

Rapid estimation of echocardiographic peak velocity of circumferential fibre shortening (peak Vcf).

A transparent grid for estimating peak Vcf directly from the echocardiograph recording is described. Estimates so obtained were compared with peak Vcf measurements made by an echocardiographic digitising technique and with the angiographic ejection fraction in 13 patients with normal left ventricular function and 17 patients with impaired left ventricular function. No patient had angiographic segmental wall motion abnormalities. Significant linear correlations were found between peak Vcf derived by the simple manual technique and peak Vcf determined by the digitising technique and also between peak Vcf derived by the simple manual technique and the angiographic ejection fraction. Peak Vcf derived by the simple manual technique was found to be a reliable predictor of ventricular function, being more than 1.4 circumferences/s in 11 of 13 patients with angiographic ejection fractions greater than or equal to 55% and less than 1.4 in 14 of 17 patients with angiographic ejection fractions less than 55% (sensitivity 82%, specificity 85%). Thus, peak Vcf is an echocardiographic index that can be estimated rapidly and accurately without the need for digitising equipment and is well suited to general clinical use.

Ventricular response to isometric and isotonic exercise. Echocardiographic assessment.

The effects of supine isometric handgrip and graded isotonic bicycle ergometer exercise on left ventricular performance were studied echocardiographically in 20 normal subjects, aged 18 to 36. Measurements of the left ventricular minor axis diameter were taken from recordings performed at rest, during each form of exercise, and during recovery. At the completion of isometric exercise, the pressure-rate product increased significantly. There was no significant change in percentage of fractional shortening (%deltaD), while there was a small but significant fall in peak velocity of circumferential fibre shortening (peak Vcf). Isotonic exercise resulted in a significant increase in %deltaD and peak Vcf. The pressure-rate product also increased and showed a positive correlation with peak Vcf. Isotonic exercise produced a much greater stimulus to left ventricular contractility than isometric exercise and may be a useful means of detecting latent left ventricular dysfunction echocardiographically.