Denise Mrosek

Influence of alteration in preload on the pattern of left ventricular diastolic filling as assessed by Doppler echocardiography in humans.

We examined the influence of alterations in preload on pulsed Doppler indexes of left ventricular diastolic function in 50 patients including 12 without cardiovascular disease, 29 with coronary artery disease, and nine with critical aortic stenosis. Micromanometer left ventricular pressure was recorded simultaneously with pulsed Doppler echocardiography of left ventricular inflow and M-mode echocardiography of left ventricular diameter. Chamber stiffness constants, kd and kv, were obtained from the diastolic pressure-diameter and pressure-volume relations, respectively. Relaxation was measured by the isovolumic relaxation time constants, TL and TD, derived from the exponential left ventricular pressure decay and maximum negative dP/dt. In 41 patients after nitroglycerin treatment, left ventricular end-diastolic pressure decreased from 18 +/- 5 to 13 +/- 4 mm Hg (p less than 0.001). The ratio of peak early to peak atrial filling velocities and time-velocity integral ratios decreased from 1.08 +/- 0.57 to 0.90 +/- 0.42 (p less than 0.001) and from 1.77 +/- 0.95 to 1.41 +/- 0.71 (p less than 0.001), respectively. The peak early filling velocity and time-velocity integral decreased from 56.1 +/- 15.7 to 49.9 +/- 14.5 cm/sec (p less than 0.001) and from 7.9 +/- 2.7 to 6.8 +/- 2.8 cm (p less than 0.001), respectively. Relaxation (TL, TD, and maximum negative dP/dt) and chamber stiffness (kd and kv) were not impaired after nitroglycerin administration. In 48 patients after ventriculography, left ventricular end-diastolic pressure increased from 18 +/- 6 to 22 +/- 8 mm Hg (p less than 0.001). The peak early and peak atrial filling velocities increased from 57.4 +/- 15.2 to 68.3 +/- 19.7 cm/sec (p less than 0.001) and from 61.0 +/- 22.7 to 69.4 +/- 23.2 cm/sec (p less than 0.01), respectively. As a result, the ratio of peak early to peak atrial filling velocity was unchanged. However, in the aortic stenosis group, the ratio of peak early to peak atrial filling velocity increased from 0.95 +/- 0.64 to 1.10 +/- 0.72 (p less than 0.02). Relaxation and chamber stiffness were unchanged. Thus, a reduction or increase in preload may induce a diastolic filling pattern that mimics or masks diastolic dysfunction, respectively. Preload conditions need to be accounted for when the status of diastolic function is extrapolated from the pulsed Doppler mitral inflow velocity profile.

Left ventricular diastolic function: Comparison of pulsed doppler echocardiographic and hemodynamic indexes in subjects with and without coronary artery disease

To evaluate the influence of left ventricular chamber stiffness and relaxation on Doppler echocardiographic indexes of diastolic function, 35 patients (mean age 60 +/- 12 years) were examined; 24 had coronary artery disease and 11 (Group I) had no cardiovascular disease. Micromanometer left ventricular pressure was recorded simultaneously with Doppler echocardiograms of mitral valve inflow and M-mode echocardiograms of left ventricular diameter. The chamber stiffness constant (k) was derived from the pressure-diameter relation. Relaxation was assessed by the isovolumic relaxation time constant (tau) derived from the exponential left ventricular pressure decay. The patients with coronary artery disease were classified into two groups on the basis of complete (Group II; n = 10) and incomplete (Group III; n = 14) relaxation. In Group I (no coronary disease), significant correlations were demonstrated between the chamber stiffness constant and the peak early filling velocity (r = 0.73; p less than 0.02), peak early to atrial filling velocity ratio (r = 0.82; p less than 0.005), atrial time-velocity integral (r = -0.73; p less than 0.02), early to atrial time-velocity integral ratio (r = 0.70; p less than 0.05), percent atrial contribution to filling (r = -0.64; p less than 0.05) and one-half filling fraction (r = 0.73; p less than 0.02). In Group II (coronary disease with complete relaxation), the chamber stiffness constant correlated with peak early filling velocity (r = 0.68; p less than 0.05), early filling time-velocity integral (r = 0.65; p less than 0.05) and early to atrial time-velocity integral ratio (r = 0.74; p less than 0.02). No correlations between k and Doppler indexes were found in Group III (coronary disease with incomplete relaxation). However, Group III demonstrated significant correlations between tau and the peak early filling velocity (r = -0.71; p less than 0.005), percent atrial contribution to filling (r = 0.56; p less than 0.05) and mean acceleration rate of early filling (r = -0.79; p less than 0.002). Thus, in subjects with normal relaxation, increasing chamber stiffness was associated with an enhanced peak early filling velocity and volume and decreased filling during atrial systole. This finding differs strikingly from the proposed influence of chamber stiffness on diastolic filling postulated by several researchers.(ABSTRACT TRUNCATED AT 400 WORDS)

Assessment of diastolic function in normal and hypertrophied hearts: comparison of Doppler echocardiography and M-mode echocardiography

Left ventricular (LV) filling was examined by Doppler and M-mode echocardiography in 24 patients with LV hypertrophy (five with aortic stenosis, six with hypertrophic cardiomyopathy, and 13 with LV hypertrophy secondary to systemic hypertension) and in 18 normal subjects. Patients with LV hypertrophy had significantly lower Doppler-determined peak filling rates (218 +/- 17 vs 288 +/- 66 cc/sec, p less than 0.01), but M-mode determined peak rate of chamber enlargement and normalized peak rate of chamber enlargement did not differ significantly between groups. Doppler measures of the ratio between early and late filling were significantly depressed in patients with LV hypertrophy and correlated inversely with age in the normal subjects. The M-mode derived normalized peak rate of chamber enlargement and the Doppler-derived normalized peak filling rate correlated weakly, but significantly, when both groups were combined (r = 0.56, p less than 0.01). Thus Doppler measurements can detect abnormalities of LV filling in patients with LV hypertrophy. These abnormalities are present when M-mode filling indices and systolic function are still normal.

Left ventricular diastolic function in weight lifters

Concentric left ventricular (LV) hypertrophy and asymmetric septal hypertrophy have both been described in weight lifters, but diastolic filling, which is abnormal in pathologically hypertrophied ventricles, has not been investigated in such subjects. Accordingly, pulsed Doppler examination of LV inflow, M-mode and 2-dimensional echocardiography were performed in 16 competitive weight lifters and 10 age-matched male control subjects. Peak and mean filling rates were determined in milliliters per second as the product of the cross-sectional area of the mitral anulus and the Doppler-derived peak early and mean transmitral inflow velocities, respectively. Rapid filling index was defined as peak filling rate divided by mean filling rate. Flow velocity integrals of the early and atrial diastolic filling phases were also measured. LV end-diastolic volume and ejection fraction were measured using 2-dimensional echocardiography. Weight lifters had significantly higher LV end-diastolic volume (181 +/- 50 vs 136 +/- 40 ml, p less than 0.05) and dimension (5.6 +/- 0.6 vs 5.1 +/- 0.5 cm, p less than 0.05), and posterior wall thickness (0.9 +/- 0.2 vs 0.8 +/- 0.1, p less than 0.05); however, after correction for body surface area there was no significant difference in these values. Weight lifters had significantly higher LV mass (241 +/- 70 vs 165 +/- 29, p less than 0.02) and LV mass index (114 +/- 29 vs 87 +/- 15 g/m2, p less than 0.05). There was no significant difference between the weight lifters and control subjects in rapid filling index, early to late integral ratio or ejection fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative evaluation of aortic insufficiency by continuous wave Doppler echocardiography

To assess the usefulness of continuous wave Doppler echocardiography in the evaluation of aortic insufficiency, the aortic regurgitant flow velocity pattern obtained with continuous wave Doppler examination was compared with the results of aortography and conventional pulsed Doppler techniques in 25 individuals with aortic insufficiency. The diastolic deceleration slope as measured from the continuous wave tracing was significantly different among subgroups of patients with mild (1.6 +/- 0.5 m/s2), moderate (2.7 +/- 0.5 m/s2) and severe (4.7 +/- 1.5 m/s2) aortic insufficiency as determined from aortography. Deceleration slopes greater than 2 m/s2 separated individuals with moderate and severe insufficiency from those with mild insufficiency. Similar findings were seen when comparing the pressure half-time method of diastolic velocity decay with the more severe grades of aortic insufficiency exhibiting the shortest pressure half-times. There was also a high correlation (r = 0.85) between the deceleration slope measured by continuous wave Doppler recordings and the grade of insufficiency as assessed by pulsed Doppler echocardiography. End-diastolic velocities correlated poorly (r = 0.28) with catheter-measured end-diastolic pressure difference between the aorta and the left ventricle. These findings demonstrate that the aortic regurgitant flow pattern by continuous wave Doppler echocardiography may be useful in quantitating the degree of aortic insufficiency by assessing the rate with which aortic and left ventricular pressures equilibrate during diastole.

The hemodynamic benefit of differential atrioventricular delay intervals for sensed and paced atrial events during physiologic pacing

The ability to program different atrioventricular (AV) delay intervals for paced and sensed atrial events is incorporated in the design of some newer dual chamber pacemakers. However, little is known regarding the hemodynamic benefit of differential AV delay intervals or the magnitude of difference between optimal AV delay intervals for paced and sensed P waves in individual patients. In this study, Doppler-derived cardiac output was used to examine the optimal timing of paced and sensed atrial events in 24 patients with a permanent dual chamber pacemaker. The hemodynamic effect of utilizing separate optimal delay intervals for sensed and paced events compared with utilizing the same fixed AV delay interval for both was determined. The optimal delay interval during DVI (AV sequential) pacing and VDD (atrial triggered, ventricular inhibited) pacing at similar heart rates was 176 +/- 44 and 144 +/- 48 ms (p less than 0.002), respectively. The mean difference between the optimal AV delay intervals for sensed (VDD) and paced (DVI) P waves was 32 ms and was up to 100 ms in some individuals. The difference between optimal AV delay intervals for sensed and paced atrial events was similar in patients with complete heart block and those with intact AV node conduction. At the respective optimal AV delay intervals for sensed and paced P waves, there was no significant difference in the cardiac output during VDD compared with DVI pacing. However, cardiac output significant declined during VDD pacing at the optimal AV delay interval for a paced event and during DVI pacing at the optimal interval for a sensed event.(ABSTRACT TRUNCATED AT 250 WORDS)

Color Doppler echocardiographic evaluation of patients with a flail mitral leaflet

Chordal rupture with a subsequent flail mitral valve leaflet is now the most common cause of pure mitral regurgitation. To describe the Doppler color flow findings in flail mitral leaflet and the determinants of these findings, Doppler color flow mapping and conventional Doppler echocardiography were performed in 31 consecutive patients presenting with a flail mitral leaflet. In the 23 patients with a posterior flail leaflet, a distinctive highly eccentric and turbulent jet directed toward the posterior wall of the aorta was noted. In the eight patients with an anterior flail leaflet, a jet directed toward the posterolateral left atrial wall was noted. Maximal regurgitant jet area was significantly larger in patients with a flail anterior leaflet (13.1 +/- 3.0 cm2) than in those with a flail posterior leaflet (5.8 +/- 3.0 cm2, p = 0.0001). Maximal jet area to left atrial ratio was also significantly higher in those with a flail anterior leaflet (0.56 +/- 0.16) than in those with a flail posterior leaflet (0.27 +/- 0.17, p = 0.0006). When systolic left atrial velocities encoded as red were incorporated into the maximal jet area measurement, 7 of the 8 patients with an anterior flail leaflet had a jet area greater than 8 cm2, consistent with severe mitral regurgitation, compared with 13 of the 23 patients with a flail posterior leaflet. There was no correlation between jet area or jet area to left atrial ratio and any hemodynamic variable. Patients with acute mitral regurgitation exhibited a trend toward smaller jet areas, but this did not reach statistical significance. Regurgitant fraction calculated from pulsed Doppler recording of mitral and aortic flow was consistent with moderately severe or severe mitral regurgitation in all cases and averaged 70%. Thus, patients with a flail mitral valve leaflet have distinctive Doppler color flow findings. A highly eccentric and turbulent jet directed posteriorly to the aorta may contribute to a systematic underestimation of severe mitral regurgitation by conventional Doppler color flow criteria. The use of pulsed Doppler ultrasound to calculate regurgitant fraction in patients with a flail mitral valve leaflet may be helpful in reliably assessing the degree of mitral regurgitation.

Hemodynamic benefit of atrioventricular synchrony: Prediction from baseline Doppler-echocardiographic variables

The purpose of this study was to determine if baseline Doppler-echocardiographic variables of systolic or diastolic function could predict the hemodynamic benefit of atrioventricular (AV) synchronous pacing. Twenty-four patients with a dual chamber pacemaker were studied. Baseline M-mode and two-dimensional echocardiograms were obtained and Doppler-echocardiographic measurements of mitral inflow and left ventricular outflow were made in VVI mode (single rate demand) and in VDD (atrial synchronous, ventricular inhibited) and DVI (AV sequentially paced) modes at AV intervals ranging from 50 to 300 ms. Forward stroke volume and cardiac output were determined in each mode at each AV interval from the left ventricular outflow tract flow velocities, and the percent increase in cardiac output over VVI mode was determined. M-mode measurements, including left ventricular end-diastolic dimension, shortening fraction and left atrial size and Doppler measurement of diastolic filling, including peak early velocity and percent atrial contribution, did not correlate with the percent increase in cardiac output during physiologic pacing. The stroke volume in VVI mode correlated significantly with the percent increase in cardiac output during physiologic pacing (r = -0.61, p less than 0.005 for VDD mode and r = -0.55, p less than 0.05 for DVI mode). Five of the 15 patients with VVI stroke volume less than 50 ml but none of the 9 patients with stroke volume greater than 50 ml had ventriculoatrial (VA) conduction.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of successful PTCA on left ventricular function: Assessment by exercise echocardiography

To assess the usefulness of exercise echocardiography in the follow-up of patients after percutaneous transluminal coronary angioplasty (PTCA), we studied 56 patients at rest and immediately following exercise with two-dimensional echocardiography. Sixty-nine of 73 stress/echo studies (94%) were suitable for interpretation. Seventeen patients (group I) with significant coronary artery disease (CAD) were studied before and after PTCA. Sixteen patients with coronary disease not undergoing PTCA (group II) and 23 individuals without significant coronary disease (group III) served as age-matched controls. Left ventricular ejection fraction did not change significantly in group I patients prior to PTCA (56 +/- 7 versus 54 +/- 12, p = ns) or in group II patients (52 +/- 10 versus 56 +/- 15, p = ns), rest versus immediate after exercise measurements. Following angioplasty, left ventricular ejection fraction increased in group I patients from 55 +/- 7 to 65 +/- 8, p less than 0.001 from rest to exercise, and to a similar extent in group III individuals (55 +/- 6 to 66 +/- 8, p less than 0.001). Electrocardiographic (ECG) evidence of ischemia (greater than 1 mm ST segment depression) was found in 13 of 17 group I patients prior to PTCA and in 8 of 16 group II patients (CAD). None of the 25 normal patients and four of the group I patients following PTCA had abnormal ECG changes with exercise. New exercise-induced echocardiographic wall motion abnormalities were found in 12 of 17 group I patients prior to PTCA and in none of the group I patients following PTCA.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of pharmacologic coronary hyperemia on echocardiographic left ventricular function in patients with single vessel coronary artery disease

To assess whether pharmacologic coronary vasodilation could provoke new left ventricular wall motion abnormalities in patients with single vessel coronary artery disease, systemic hemodynamics, coronary blood flow velocity and left ventricular wall motion were measured by two-dimensional echocardiography during administration of 10 mg of intracoronary papaverine in 14 patients before and again immediately after left coronary angioplasty (group 1). As a comparison with an intravenous method, left ventricular wall motion was analyzed after 0.56 mg/kg body weight of intravenous dipyridamole in a separate group of 13 patients with single vessel coronary disease (group 2). Heart rate-blood pressure product increased 3% to 6% in papaverine-treated patients and 14 +/- 11% (p = NS) in dipyridamole-treated patients. No angiographic collateral vessels were present in either group. Although intracoronary mean flow velocity measured in the 14 group 1 patients and in 5 normal control subjects during papaverine treatment increased from 125% to 400% of basal flow velocity, papaverine induced new left ventricular wall motion abnormalities in only 5 of the 14 patients before coronary angioplasty. In three of five patients, left ventricular wall motion abnormalities persisted after successful coronary angioplasty. Four of the 14 patients demonstrated augmentation of left ventricular wall motion with papaverine. After intravenous dipyridamole, only 3 of the 13 group 2 patients developed new left ventricular regional asynergy. These data suggest that selective (papaverine) and, most likely, global (dipyridamole) augmentation of coronary flow alone does not reliably identify potential ischemic left ventricular regions affected by critical single vessel coronary artery disease.