Doppler echocardiographic assessment of left ventricular systolic and diastolic function in mild hypertension.

Abnormalities in left ventricular (LV) wall thickness and mass have been demonstrated in patients with mild hypertension utilizing M-mode echocardiography. In addition, studies using radionuclide angiography have demonstrated abnormalities in early diastolic LV filling in asymptomatic hypertensive patients with normal ejection fraction and cardiac output. Recently, Doppler recordings of flow velocity in the ascending aorta and through the mitral valve have been shown to provide useful information about LV function. To determine whether flow abnormalities could be detected in patients with mild hypertension, we recorded Doppler aortic and mitral valve flow velocities in 21 men with mild hypertension. Casual systolic blood pressure was 147 +/- 18 mm Hg (mean +/- SD) and diastolic blood pressure was 96 +/- 9 mm Hg. LV mass (310 +/- 75 g) was elevated (i.e., above the 95% normal prediction interval) in 8 of 19 patients who underwent M-mode echocardiography; LV ejection fraction was normal in all patients (mean, 80%). As in previous studies in normal subjects, we found in these hypertensive patients an inverse correlation between age and both aortic peak flow velocity (r = -0.51, p less than 0.05) and transmitral early diastolic peak flow velocity (r = -0.44, p less than 0.05) and a positive relationship between age and mitral valve late diastolic peak flow velocity (r = 0.73, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of acute changes in heart rate on Doppler pulmonary artery acceleration time in a porcine model.

Doppler measurements of pulmonary artery (PA) acceleration time (AT) have been used clinically to estimate PA pressure. However, these studies have been performed primarily in patients without tachycardia. To determine the effect of acute changes in heart rate on PA AT, atrial pacing studies were performed in seven closed-chest pigs. Pulsed Doppler PA flow velocity recordings were obtained from a parasternal position at pacing rates from 100 to 140 beats/min. PA pressure remained constant (mean +/- SD = 14 +/- 5 mm Hg) over the entire range of paced rates. When PA Doppler measurements were compared at heart rates of 100 and 140 beats/min, there were decreases at the higher heart rate in both acceleration time (110 +/- 12 vs 83 +/- 11 ms, p less than 0.01) and ejection time (ET) (315 +/- 23 vs 237 +/- 21 ms, p less than 0.01). In contrast, there was no change in either PA peak flow velocity (69 +/- 15 vs 62 +/- 18 cm/s) or the ratio of AT/ET (0.35 +/- .02 vs. .36 +/- .03). Consequently, when estimating PA pressure in states of tachycardia, the PA AT/ET ratio may be a more useful measurement than PA acceleration time.

Assessment of left ventricular systolic and diastolic function with Doppler echocardiography in hypertensive patients receiving intravenous medroxalol.

Intravenous medroxalol, an alpha- and beta-adrenergic blocking agent, causes an immediate hypotensive effect. In 14 subjects with mild-to-moderate hypertension, cardiac output (CO) and cardiac index (CI) were significantly decreased without significant changes in stroke volume, reflecting the fact that a reduced CO and CI were related to decreases in heart rate. The vasodilator effect of intravenous medroxalol was not apparent with the dosages used in this study. Transient changes noted in two Doppler diastolic velocity indexes--mitral early diastolic peak flow velocity (PFVE) and the ratio of mitral late-to-early diastolic peak flow velocity (PFVA/E)--are suggestive of an improvement in left ventricular (LV) diastolic filling during medroxalol infusion, possibly related to changes in loading conditions. Systolic and diastolic blood pressure did not correlate with any of the Doppler diastolic and systolic indexes in our patient population. Reduced aortic peak flow velocity, rate of aortic flow acceleration, and the rate of mitral early diastolic deceleration were noted with increasing LV mass index, independent of age or blood pressure. Doppler echocardiography may be a useful tool in the assessment and follow-up of LV systolic and diastolic function in patients undergoing pharmacologic interventions.