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Biomedical subjects

F Khaja

Publications and source records attributed to F Khaja.

At least 37 records · Page 2Linked to original sources
PubMed1990

Practical value of echo Doppler evaluation of aortic and mitral stenosis: a comparative study with cardiac catheterization.

This retrospective analysis compares data derived by echocardiography and cardiac catheterization in the evaluation of aortic and mitral valve stenosis. Sixty-seven patients, aged 69 +/- 12 years, underwent 76 catheterization procedures. In all studies the Doppler recording was technically adequate. In 64 studies of patients with aortic stenosis, correlation was good between the gradient obtained at catheterization (peak 51 +/- 28 mm Hg, mean 48 +/- 24 mm Hg) and the Doppler gradient (peak 73 +/- 29 mm Hg, mean 41 +/- 17 mm Hg) (R = 0.78 peak, 0.77 mean). In 15 studies the aortic valve area, 0.8 +/- 0.2 cm2, calculated by the simplified continuity equation, correlated well with the catheterization valve area, 0.7 +/- 0.3 cm2, calculated by the Gorlin equation (R = 0.80). In 14 studies in mitral stenosis patients, the mean gradient at catheterization was 11 +/- 5 mm Hg compared to the Doppler gradient of 8 +/- 4 mm Hg (R = 0.58). The mitral valve area was 1.1 +/- 0.3 cm2 by the Gorlin equation and 1.2 +/- 0.3 cm2 by echo Doppler, using pressure half-time. When cardiac rhythm, the presence and severity of regurgitation, and the cardiac index were analyzed, none was shown to have demonstrable influence on the accuracy of the Doppler study. Doppler echocardiography can be used reliably to assess valvular stenosis in a clinical, noninvasive laboratory where routine tests are performed and interpreted by more than one individual.

Aged↗
PubMed1989

Cardiac event rate after non-Q-wave acute myocardial infarction and the significance of its anterior location.

To correlate cardiac event rate with infarct location on the electrocardiogram in patients recovering from a non-Q-wave acute myocardial infarction (AMI), 135 consecutive patients with enzymatically proven non-Q-wave AMI were followed prospectively for a median of 9.9 months. Of these, 65 patients were classified as having had an anterior non-Q-wave AMI, defined as new ST- or T-wave changes, or both, in leads V1 through V4 (group 1). The remaining 70 patients were classified as having had inferior or lateral non-Q-wave AMI, or both, defined as ST- or T-wave changes in 2 consecutive leads (II, II aVF; II and aVL or V5 and V6) (group 2). At baseline group I was older and had a higher incidence of previous AMI than group 2. After adjusting for baseline variables, the patients in group I had a 29% reinfarction and 32% mortality rate, which was significantly higher (p less than 0.002 for both) when compared to group 2, which had a reinfarction and mortality rate of 8 and 9%, respectively. Patients with anterior non-Q-wave AMI are at very high risk for developing a major cardiac event very soon after the index AMI. This high risk is probably related to a larger area of residual ischemic but viable myocardium in the infarct-related artery when compared to inferolateral non-Q-wave AMI.

Electrocardiography↗
PubMed1988

Left ventricular function after successful percutaneous transluminal coronary angioplasty for postinfarction angina pectoris.

The purpose of this study was to determine if coronary revascularization by balloon angioplasty (PTCA) in patients with postinfarction angina can elicit an improvement of global systolic left ventricular (LV) function. LV function was evaluated in 18 patients with postinfarction angina based on peak aortic blood acceleration measured noninvasively with a continuous wave Doppler velocimeter. Initial Doppler measurements were made 4 +/- 1 days after infarction and just before PTCA and were repeated 24 to 48 hours after PTCA. Patients were divided into 2 groups. Group I (n = 10) had successful PTCA (reperfusion). Group II (n = 8) either had an unsuccessful PTCA or did not undergo PTCA or thrombolytic therapy (no reperfusion). In group I patients, peak acceleration increased from 16 +/- 1 m/s/s just before PTCA to 24 +/- 2 m/s/s 24 to 48 hours after successful PTCA (p less than 0.001). In group II patients, peak acceleration was 17 +/- 2 m/s/s just before PTCA and remained relatively unchanged (18 +/- 2 m/s/s) 24 to 48 hours later. These data indicate that revascularization of coronary arteries in patients with postinfarction angina can elicit considerable improvement of global LV systolic function.

Adult↗
PubMed1988

Influence of coronary collaterals on left ventricular function in patients undergoing coronary angioplasty.

The purpose of this study was to determine the role of coronary collaterals on global left ventricular function during transient coronary occlusion. Left ventricular systolic function was evaluated noninvasively in 37 patients undergoing percutaneous transluminal coronary angioplasty (PTCA) by means of peak aortic blood acceleration measured with a continuous-wave Doppler velocity meter placed suprasternally. Doppler measurements were made before, during, and immediately after balloon inflation. Nineteen patients underwent PTCA of the left anterior descending coronary artery, 15 of the right coronary artery, and three of the circumflex coronary artery. All patients had a subtotal coronary occlusion. Among the 37 patients 23 had no angiographic evidence of collaterals supplying the vessel undergoing PTCA and 14 had collaterals. In patients without collaterals peak acceleration was 16.0 +/- 3.0 m/sec/sec before balloon occlusion and decreased to 11.8 /+- 3.6 m/sec/sec within 30 to 40 seconds of coronary occlusion (p less than 0.001). After 30 to 40 seconds of reperfusion (balloon deflated), peak acceleration returned to near- preocclusion levels (17.3 +/- 7.5 m/sec/sec). Among patients with collaterals peak acceleration remained unchanged during balloon occlusion and reperfusion relative to preocclusion levels (NS). These data indicate that collaterals can preserve left ventricular function during transient coronary occlusion in humans.

Angioplasty, Balloon↗
PubMed1987

Efficacy of propranolol therapy after acute myocardial infarction related to coronary arterial anatomy and left ventricular function.

The effect of the beta-adrenergic blocking agent propranolol on morbidity and mortality risk after acute myocardial infarction was studied relative to coronary anatomy and left ventricular (LV) ejection fraction in a subset of 406 patients participating in a randomized study of 3,837 patients in the Beta Blocker Heart Attack Trial (BHAT). Median follow-up for this subset of patients was 28 months. The mortality rate was 2% (2 of 100) in patients with 2- and 3-vessel coronary artery disease taking propranolol and 10% (12 of 126) in those taking placebo (p less than 0.02). In patients with 2- and 3-vessel coronary artery disease with decreased LV function (defined as ejection fraction less than 50%), no patient taking propranolol died, whereas 17% (7 of 42) taking placebo died (p less than 0.04). The salutary effect of propranolol on mortality in the larger BHAT after acute myocardial infarction also was evident in this population studied in regard to their coronary and LV anatomy and function.

Coronary Vessels↗
PubMed1987

Doppler and echocardiographic features of normal and dysfunctioning bioprosthetic valves.

Echocardiographic and Doppler studies were performed on 183 clinically normal and 58 severely dysfunctioning bioprosthetic mitral, aortic and tricuspid valves. The valve dysfunction resulted from spontaneous cusp degeneration in 49 instances and from paravalvular regurgitation in 9. The pulsed Doppler study demonstrated regurgitant flow in 36 (92%) of 39 regurgitant valves and 8 (90%) of 9 paravalvular regurgitant valves. Diagnostic echocardiographic features were present in only 51 and 10% of the patients, respectively. Although the Doppler regurgitant jet was peripheral in seven of the nine patients with paravalvular regurgitation, it was not possible to differentiate these patients from those who had valve degeneration and cusp tear at the periphery of the valve ring. Eight patients presented with a musical holosystolic murmur of mitral insufficiency. In all eight there was a characteristic honking intonation on the audio signal and a striated shuddering appearance on the video Doppler signal. Ten stenotic mitral bioprosthetic valves (less than or equal to 1.1 cm2 valve orifice) were identified by Doppler study. Diagnostic echocardiographic features were present in only two of these patients. The Doppler-derived valve orifice dimension correlated well (r = 0.83) with cardiac catheterization values. Fourteen asymptomatic or minimally symptomatic patients had echocardiographically thickened mitral cusps (greater than or equal to 3 mm). These patients had a significantly (p less than 0.0001) smaller valve area as compared with normal control valves, and during 4 to 24 months of follow-up, five of these patients developed severe valve regurgitation or stenosis. Doppler ultrasound is more sensitive than echocardiography in diagnosing bioprosthetic valve stenosis and regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Echocardiographic evaluation of left ventricular function during coronary artery angioplasty.

Balloon occlusion of a stenotic coronary artery during percutaneous coronary artery angioplasty provides a unique opportunity to study the effect of acute myocardial ischemia on left ventricular (LV) function. Simultaneous M-mode and 2-dimensional (2-D) echocardiograms and a 6-lead electrocardiogram were recorded during 20 episodes of coronary artery occlusion and release in 12 patients. No patient had previous myocardial infarction and all had normal LV function by angiography. All patients had isolated single coronary artery disease, with left anterior descending stenosis in 8 and right coronary stenosis in 4. In 18 of 20 episodes (90%), M-mode echocardiography during balloon occlusion revealed a significant (p less than 0.001) decrease in LV systolic, diastolic and percent systolic wall thickness; systolic excursion; systolic and diastolic endocardial velocities; and fractional shortening. These changes were observed in the area of the ventricular septum in patients with left anterior descending occlusion and posteroinferior wall in those with right coronary artery occlusion. Two-dimensional echocardiography revealed varying degrees of hypokinesia, akinesia and dyskinesia during balloon occlusion in 18 instances. The echocardiographic changes were observed within 15 to 20 seconds of balloon occlusion and resolved 10 to 20 seconds after balloon deflation. All patients who had echocardiographic changes during balloon occlusion also had concomitant electrocardiographic (ECG) ST-segment elevation, whereas 2 patients with normal LV function had no ECG changes. Both of these patients had profuse collateral blood supply to the stenotic coronary artery. The echocardiographic and ECG abnormalities increased proportionately to the length of balloon occlusion. This study confirms previous animal and recent human studies of transient LV dysfunction during coronary occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗
PubMed1986

Relation of atherosclerosis to arterial wall shear in the left anterior descending coronary artery of man.

Low fluid dynamic shear acting on the vascular endothelium has been suggested as a factor in atherogenesis. This study describes qualitatively differences of wall shear rate in the left anterior descending coronary artery (LAD) of man and relates the distribution of wall shear to that of atheromatous plaques. Selective coronary arteriograms of 21 patients without obstructive LAD diseases were reviewed. Blood velocity, and therefore wall shear in the LAD, was assessed qualitatively based upon the rate of clearance of contrast material. There was a rapid clearing of contrast material along the outer wall of the LAD as it curved around the border of the heart. A much slower clearing occurred along the inner wall, bordering the myocardium, which persisted two to six cardiac cycles after the outer wall had cleared. This suggests that velocity, and therefore shear rate, is lower along the inner wall of the LAD than along the outer wall. In 27 patients who died of noncardiac disease, an uneven distribution of atheromatous plaques in the LAD was observed histologically, with greater involvement of the inner wall. These observations demonstrate an association between the lower shear rate along the inner wall of the LAD and the site of higher concentration of atherosclerosis.

Adult↗
PubMed1986

Noninvasive evaluation of left ventricular performance based on peak aortic blood acceleration measured with a continuous-wave Doppler velocity meter.

Peak aortic blood acceleration is recognized to be a sensitive index of global left ventricular performance. In the present study peak acceleration was assessed noninvasively in patients with a continuous-wave Doppler velocity meter. Peak aortic blood velocity and peak blood acceleration were measured by placing the ultrasonic transducer at the suprasternal notch. Measurements were obtained in 36 patients undergoing diagnostic cardiac catheterization. Peak velocity and acceleration were measured at rest just before left ventriculography. In patients with ejection fractions greater than 60%, peak acceleration was 19 +/- 5 m/sec/sec. In patients with ejection fractions of 41% to 60%, peak acceleration was lower, at 12 +/- 2 m/sec/sec (p less than .001). In patients with ejection fractions of 40% or less, peak acceleration (8 +/- 2 m/sec/sec) was markedly lower than in patients with ejection fractions greater than 60% (p less than .001). Peak acceleration showed a good linear correlation with ejection fraction (r = .90), and a better power fit (r = .93). These results indicate that peak acceleration, measured noninvasively with a continuous-wave Doppler velocity meter, is a useful indicator of global left ventricular performance.

Aorta↗
PubMed1985

Regional left ventricular systolic function in patients with segmental early relaxation and single-vessel coronary artery disease.

The purpose of this study was to determine whether systolic function is compromised in segments of the left ventricle that manifest early relaxation and are supplied by a diseased coronary artery. Regional fractional area of shortening (FAS) was evaluated from resting ventriculograms of 24 patients. Nine patients had no cardiac disease or segmental early relaxation (SER) and served as controls. Fifteen patients had single-vessel coronary artery disease (60% to 95% diameter stenosis of the left anterior descending coronary artery). Among these 15 patients, seven had no evidence of SER and eight had SER localized to the anterior wall. In patients with coronary disease and SER, and FAS of the anterolateral segment, 1.30 +/- 0.08, was greater than either controls, 1.07 +/- 0.12 (p less than 0.01) or patients with coronary disease but no SER, 1.03 +/- 0.19 (p less than 0.01). Among patients with coronary disease and SER, the FAS of the anterolateral segment was greater than the corresponding diaphragmatic segment (1.30 +/- 0.08 vs 0.97 +/- 0.12) (p less than 0.001). There was no difference in the FAS between these two segments in either controls or in patients with coronary disease, but without SER. These results indicate that SER of the anterior wall in patients with disease of the left anterior descending coronary artery is associated with enhanced systolic function of the anterolateral region. This observation is incompatible with the concept that ischemia is an underlying mechanism of SER.

Adult↗
PubMed1985

Idiopathic degeneration of the aortic valve: a common cause of isolated aortic regurgitation.

To establish the etiology of isolated aortic valvular regurgitation, histologic examination was carried out on 27 consecutive surgically removed aortic valves from patients with aortic regurgitation. In 12 patients, the regurgitation was due to rheumatic or syphilitic valvular disease or a congenital bicuspid aortic valve. In the remaining 15, no etiology was apparent. In the latter group, seven aortic valves were identified by the surgeon as redundant and eight as thickened and retracted. Despite these gross differences, the histologic features of the 15 valves were similar and consisted of increased and disorganized elastic and collagen fibers, with variable quantities of acid mucopolysaccharide and calcium. Although small foci of myxomatous stroma were present, they did not differ substantially from those observed in age-matched competent aortic valves removed at necropsy, nor were they as extensive as described in reports of floppy aortic valves. Idiopathic degeneration was the most common cause of aortic regurgitation, occurring in more than half of the surgically treated patients. An underlying defect in the synthesis of collagen or elastic fibers, similar to that described in mitral valve prolapse, may be an important feature in aortic valve degeneration.

Adult↗
PubMed1985

"Ischemia at a distance" during intermittent coronary artery occlusion: a coronary anatomic explanation.

The mechanism of electrocardiographic ST segment changes during acute coronary occlusion was evaluated in 28 consecutive patients with single vessel coronary artery disease undergoing coronary angioplasty. Patients were continuously monitored with a six lead electrocardiogram. Twenty-three patients showed ST changes in the primary zone of occlusion, and 13 of these had additional ST changes in a remote zone. Ten of these 13 had unusually extensive arteries supplying the remote zone. The balloon occluded two adjacent normal arteries in two patients, and no coronary anatomic explanation was evident in one patient. Ten patients with striking primary zone ST changes showed no remote change. Seven had nonextensive primary zone arteries, and three others had abundant collateral vessels. Five patients showed no electrocardiographic changes in primary or remote zones. Four had collateral vessels, and one had left ventricular hypertrophy on the baseline electrocardiogram. It was concluded that remote electrocardiographic changes are probably due to occlusion of unusually extensive coronary arteries and are not simply reciprocal.

Angioplasty, Balloon↗