Ali Dabestani

Pulsed Doppler echocardiographic study of left ventricular filling in dilated cardiomyopathy

Patients with dilated cardiomyopathy (DC) have been reported to have abnormal left ventricular (LV) diastolic properties. To evaluate LV diastolic filling characteristics in patients with DC, pulsed Doppler echocardiography was used to study mitral flow velocity in 21 patients with DC and mitral regurgitation (MR), 12 patients with DC but no MR and 19 age-matched normal subjects. Diagnosis of MR was based on the Doppler echocardiographic finding of holosystolic turbulent flow in the left atrium. Peak mitral flow velocity in early diastole (PFVE) and during atrial systole (PFVA), PFVA/PFVE and deceleration half-time of early diastolic flow were measured from Doppler mitral flow velocity recordings. In 21 patients with DC and MR, PFVE (61 +/- 13 cm/s), PFVA (37 +/- 19 cm/s) and PFVA/PFVE (0.6 +/- 0.4) were not significantly different from PFVE (53 +/- 10 cm/s), PFVA (47 +/- 12 cm/s) and PFVA/PFVE (1.0 +/- 0.4) in normal subjects (p greater than 0.05). Deceleration half-time in DC patients with MR (62 +/- 32 ms) was shorter than normal (87 +/- 25 ms) (p less than 0.05). In contrast, PFVE (31 +/- 11 cm/s) was lower and PFVA/PFVE (1.7 +/- 0.8) was higher in the 12 DC patients without MR than in normal subjects and DC patients with MR (p less than 0.005). PFVA (46 +/- 8 cm/s) and deceleration half-time (88 +/- 33 ms) in patients without MR were not significantly different from normal mean values. Thus, abnormalities of peak diastolic mitral flow velocity were detected in DC patients without MR but not in DC patients with MR, suggesting that MR masks LV filling abnormalities in patients with DC.

Left ventricular filling in hypertrophic cardiomyopathy: A pulsed Doppler echocardiographic study

Abnormal left ventricular diastolic properties have been described in patients with hypertrophic cardiomyopathy. To evaluate the diastolic filling characteristics of the left ventricle in patients with this disease, pulsed Doppler echocardiography was used to study mitral flow velocity in 17 patients with hypertrophic cardiomyopathy (11 with and 6 without systolic anterior motion of the mitral valve) and 16 age-matched normal subjects. There were no statistically significant differences between patients with hypertrophic cardiomyopathy with and without systolic anterior motion with regard to ventricular septal thickness, left ventricular posterior wall thickness, left ventricular internal dimensions or the extent of hypertrophy evaluated by two-dimensional echocardiography. Mitral regurgitation was detected by Doppler echocardiography in all 11 patients with and in 2 (33%) of the 6 patients without systolic anterior motion of the mitral valve. Early and late diastolic peak flow velocity, the ratio of late to early diastolic peak flow velocity and deceleration of early diastolic flow were measured from Doppler mitral flow velocity recordings. There were no statistically significant differences in these four indexes between the patients with systolic anterior motion and normal subjects. In contrast, the patients with hypertrophic cardiomyopathy without systolic anterior motion showed lower early diastolic peak flow velocity, higher ratio of late to early diastolic peak flow velocity and lower deceleration of early diastolic flow compared with the patients with systolic anterior motion and normal subjects, suggesting impaired left ventricular diastolic filling.(ABSTRACT TRUNCATED AT 250 WORDS)

Reproducibility of doppler aortic blood flow measurements: Studies on intraobserver, interobserver and day-to-day variability in normal subjects

Doppler aortic flow velocity measurements have been used to assess quantitatively left ventricular performance at rest and after pharmacologic and other hemodynamic interventions. To permit more meaningful interpretation of Doppler data, 10 normal subjects were studied to establish the intraobserver, interobserver and day-to-day variability in Doppler aortic flow velocity measurements. In each subject, pulsed Doppler recordings of ascending aortic flow velocity were obtained from the suprasternal notch on 2 different days (mean interval 6 days), with the same technician performing and same physician reading both Doppler studies to evaluate day-to-day variability of measurements. Interobserver variability was assessed by having 2 observers read each Doppler study. Both observers read the Doppler records from both days again at a second session to determine intraobserver variability. Intraobserver variability ranged from 1.9 +/- 1.8 to 3.2 +/- 2.9% for ejection time, peak flow velocity and flow velocity integral, but was higher for acceleration time (7.9 +/- 6.6%). Interobserver variability ranged from 3.5 +/- 2.2 to 5.4 + 3.4% for peak flow velocity, ejection time and flow velocity integral, but was notably higher for acceleration time (17 +/- 9%). Day-to-day variability was higher for acceleration time (7.0 +/- 5.2%) than for ejection time, peak flow velocity and flow velocity integral (range from 3.6 +/- 3.1 to 5.2 +/- 4.0%).(ABSTRACT TRUNCATED AT 250 WORDS)

Superiority of two-dimensional measurement of aortic vessel diameter in Doppler echocardiographic estimates of left ventricular stroke volume

Attempts to measure left ventricular stroke volume utilizing the Doppler aortic flow method have found varying correlations between invasive thermodilution and non-invasive Doppler methods. Because stroke volume is the product of the Doppler flow velocity integral (that is, the area under the flow velocity curve) and the cross-sectional area of the vessel through which blood flows, both variables are potential sources of error. Previous studies have shown that the Doppler flow velocity integral can be measured with acceptable reproducibility in the ascending aorta. Consequently, in this study an attempt was made to determine empirically the optimal method for measuring aortic diameter and area. The diameter of the ascending aorta was measured utilizing four M-mode and seven two-dimensional echocardiographic conventions. Doppler aortic flow velocity patterns were recorded with a 2.25 MHz M-mode echocardiographic transducer from the suprasternal notch by mapping the ascending aorta until aortic peak flow velocity was recorded. In 19 adult patients undergoing cardiac catheterization for clinical indications, Doppler stroke volume estimates utilizing the various echocardiographic conventions for measuring aortic root diameter and area were compared with simultaneous measurements of stroke volume by the thermodilution technique. The best correlation (r = 0.87) with thermodilution stroke volume was obtained by estimating aortic area from the two-dimensional parasternal long-axis images with the aortic dimension measured distal to the aortic sinuses from the inner to inner wall. The data were related by the equation: Thermodilution stroke volume = (0.73) X (two-dimensional Doppler stroke volume) + 17 cc.(ABSTRACT TRUNCATED AT 250 WORDS)

A simple Doppler echocardiographic method for estimating severity of aortic regurgitation

Doppler echocardiography is useful for detecting aortic regurgitation (AR). To determine if the presence of retrograde holodiastolic flow in the abdominal aorta can be used to assess the severity of AR, abdominal aortic flow velocity was examined by pulsed Doppler echocardiography in 33 patients with AR and 10 patients without AR confirmed by aortography, and in 15 normal subjects. Among the 33 patients with AR, 15 had mitral regurgitation, 11 had mitral stenosis, 8 had aortic stenosis, 5 had prosthetic mitral valves, 4 had prosthetic aortic valves and 2 had aorticopulmonary shunts. No retrograde holodiastolic flow was found in the abdominal aorta of 15 normal subjects or 10 patients without AR. Of the 22 patients with 1+ or 2+ AR independently determined by injection of iodinated contrast into the aortic root, 21 did not have retrograde holodiastolic abdominal aortic flow, whereas all 11 patients with 3+ or 4+ AR had retrograde holodiastolic flow in the abdominal aorta. One patient with 1+ AR and a left-to-right aorticopulmonary shunt had retrograde holodiastolic flow in the abdominal aorta. The finding of holodiastolic retrograde flow in the abdominal aorta is useful for distinguishing patients with severe AR from those with mild or absent AR. Moreover, the method is easy to perform and results appear to be independent of the presence of other cardiac diseases except significant aorticopulmonary shunt.

Studies of doppler aortic flow velocity during supine bicycle exercise

Although Doppler echocardiography is useful in the assessment of left ventricular function at rest, little information is available on the application of this technique during exercise. Consequently, Doppler aortic flow studies were performed in 17 young normal subjects during and after supine bicycle exercise. The purposes of the study were to determine the feasibility of recording Doppler aortic flow velocity with a suprasternal notch transducer during exercise and to assess the changes in normal aortic flow velocity parameters during exercise and early recovery. Each subject exercised until fatigue; mean duration of exercise was 10 minutes. Heart rate increased from a mean of 69 beats/min at control to 159 beats/min at peak exercise. On average, aortic peak flow velocity increased by 45% from control, reaching its maximum at 2 minutes after exercise. Ejection time decreased by 34% during exercise, being shortest at peak exercise. Heart rate, peak flow velocity and ejection time had not returned to normal by 10 minutes after exercise. Aortic flow velocity integral (a relative measure of stroke volume) decreased by 10% at peak exercise (p less than 0.05) compared with control, but had returned to control at 2 minutes after exercise. Despite mild aliasing, increased spectral dispersion, faster heart rates and increased respiratory rate during maximal exercise, aortic flow velocity measurements could be recorded using the suprasternal technique. These baseline Doppler exercise data should be useful in further studies of exercise hemodynamic changes in patients with heart disease.

Effects of spontaneous respiration on diastolic left ventricular filling assessed by pulsed Doppler echocardiography

Abstract Left ventricular (LV) stroke volume decreases during spontaneous inspiration. 1–3 The explanations offered have been either decreased LV filling with a decrease in end-diastolic volume 2,3 or increased impedance to ejection by negative pleural pressure 4,5 resulting in an increased end-systolic volume. Meijboom et al 6 recently described variations in mitral mean temporal velocity during respiration. Because pulsed Doppler mitral flow velocity correlates with LV filling rate, 7 we used it to learn if, indeed, LV filling diminished during inspiration.

A pulsed Doppler echocardiographic study of the postnatal changes in pulmonary artery and ascending aortic flow in normal term newborn infants

Postnatal circulatory adaptations were studied with Doppler echocardiographic measures of flow velocity in the main pulmonary artery (PA) and ascending aorta (Ao) in 45 normal full-term neonates at 5 hours and at 27 hours after birth. PA flow velocity integral (FVI) was measured as the area under the systolic flow velocity curve and reflected total systemic flow in the presence of a left-to-right shunt through the ductus arteriosus. This index increased from 5 and 27 hours age, while Ao FVI, reflecting total pulmonary flow, remained unchanged. Evidence of a left-to-right ductal shunt demonstrated as diastolic retrograde flow in the main PA was detected in 42 neonates at 5 hours and in only four subjects after 27 hours of age, indicating a patent ductus arteriosus at 5 hours of age and its subsequent closure. In the PA, acceleration time (AT) increased while pre-ejection period to ejection time ratio (PEP/ET) decreased from 5 to 27 hours of age, reflecting the physiologic fall in PA pressure. In the Ao, FVI, AT, and PEP/ET remained unchanged, suggesting little change in left ventricular function.

Effect of left ventricular size on early diastolic left ventricular filling in neonates and in adults

Peak early diastolic left ventricular (LV) filling rate has been used as an index of LV diastolic function. However, it is known to be affected by LV size. Peak early diastolic transmitral flow velocity measured by pulsed Doppler echocardiography has also been proposed as a noninvasive method of assessing LV diastolic function. To determine if peak early diastolic mitral flow velocity also is influenced by LV size, 20 normal neonates (age 2 days) and 21 normal adults (mean age 38 years) were studied using pulsed Doppler echocardiography to measure mitral flow velocity and M-mode echocardiography to estimate LV end-diastolic volume and mitral valvular area. Peak early diastolic LV filling rate was calculated by multiplying peak early diastolic mitral flow velocity by mitral valvular area. Adults had significantly larger LV end-diastolic volumes (mean +/- standard deviation 108 +/- 25 vs 7 +/- 3 ml) and higher peak early diastolic LV filling rates (305 +/- 75 vs 29 +/- 10 ml/s) than neonates (both p less than 0.001). However, no significant difference was found in peak early diastolic mitral flow velocity between adults and neonates (61 +/- 10 vs 58 +/- 11 cm/s). These data suggest that peak early diastolic mitral flow velocity is independent of LV size. Since peak LV filling rate is equal to the product of peak mitral flow velocity and mitral valvular area, the correlation between peak early diastolic LV filling rate and LV size is probably due to differences in mitral valvular area rather than differences in peak mitral flow velocity.