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Biomedical subjects

A H Hakki

Publications and source records attributed to A H Hakki.

At least 55 records · Page 3Linked to original sources
PubMed1985

Forward ejection fraction: a new index of left ventricular function in mitral regurgitation.

Previous studies have shown that a normal LVEF is not a reliable index of LV function in MR. We hypothesized that the forward EF, which is the forward stroke volume (measured by Fick or thermodilution) divided by end-diastolic volume (measured by contrast ventriculography) may be a useful index of LV function, since it represents LV emptying into the aorta. This index was examined in 54 patients with chronic MR who had normal EF (greater than or equal to 50%). There were significant correlations between the forward EF and the end-diastolic volume index (r = -0.69, p less than 0.001), end-systolic volume index (r = -0.64, p less than 0.001), cardiac index (r = 0.43, p less than 0.01), and the ratio of systolic pressure-to-end-systolic volume (r = 0.65, p less than 0.001). Patients were divided into two groups according to the forward EF: group I (n = 34) had forward EF less than or equal to 35%; and group II (n = 20) had forward EF greater than 35%. Of the 32 patients who subsequently underwent mitral valve replacement, 24 patients were in group I and eight patients were in group II. At a mean follow-up of 35 months, four patients died; all of them were in group I. Improvement in functional class occurred in 75% of surgical survivors (80% in group I and 63% in group II, p = NS). These preliminary data suggest that forward EF may be a useful index of LV performance in patients with MR who have normal EF.

Adolescent↗
PubMed1985

Left ventricular pressure/volume relationship in aortic regurgitation.

In this study we examined the left ventricular pressure/volume relationship in 39 patients with moderate or severe aortic regurgitation (AR) and 15 normal subjects. The patients with AR were divided into two groups; patients with normal resting ejection fraction (EF greater than or equal to 50%, group I, n = 21) and patients with abnormal EF (group II, n = 18). The patients in group I were younger (p less than 0.005), exercised to a higher workload, and had better exercise tolerance than patients in group II (p less than 0.01). The patients' exercise heart rate and blood pressure were not significantly different between the two groups. During exercise tests nine patients in group I and seven patients in group II had normal EF response (greater than or equal to 5% increase) (p = NS). The peak systolic blood pressure to end-systolic volume index ratio (SBP/ESVI) was higher in normal subjects than in patients in groups I and II, at rest it was (4.3 +/- 1.0 vs 2.6 +/- 1.2 vs 1.6 +/- 0.8, respectively, p less than 0.0001) and during exercise it was (7.6 +/- 1.8 vs 4.2 +/- 1.4 vs 2.6 +/- 1.3, respectively, p less than 0.0001). The resting SBP/ESVI ratio was below the lower normal limit in 12 patients (57%) in group I and in 16 patients (89%) in group II. Also, the exercise SBP/ESVI ratio was below the lower normal limit in 17 patients (81%) in group I and all of the patients (100%) in group II. Multivariate discriminant analysis identified the change in SBP/ESVI (F = 34.8) and resting end-diastolic volume (F = 6.7) as independent predictors of the EF response to exercise. Thus, most patients with AR, including those with normal resting EF or normal EF response to exercise, have abnormal SBP/ESVI at rest or during exercise.

Adult↗
PubMed1985

The relation between myocardial ischemia and the ejection fraction response to exercise in patients with normal or abnormal resting left ventricular function.

This study examines the relation between myocardial ischemia and the left ventricular (LV) ejection fraction (EF) response to exercise in patients with normal or abnormal resting EF. We studied 69 patients aged 25 to 78 years (mean 52 years) by radionuclide ventriculography (at rest and during peak upright exercise) and by exercise thallium-201 imaging. In 27 patients with resting EF less than 50%, the EF response to exercise was normal (greater than or equal to 5% increase) in 13 patients and abnormal in 14. The thallium scans showed reversible defects in 11 of the 14 patients (79%) with abnormal response but none in any of the patients with normal responses (p = 0.0001). In the 42 patients with resting EF greater than or equal to 50%, the EF response to exercise was normal in 23 and abnormal in 19. Reversible defects were present in 13 of the 19 patients (68%) with abnormal response and in only 3 of 23 patients (13%) with normal response (p = 0.0001). Therefore, an abnormal EF response to exercise was seen in 11 of 11 patients with resting EF less than 50% and in 13 of 16 patients (81%) with resting EF greater than or equal to 50% who had reversible thallium defects; normal EF responses were seen in 13 of the 16 patients (81%) with resting EF less than 50% and in 20 of 26 patients (77%) with resting EF greater than or equal to 50% who had no reversible thallium defects. Thus, in patients with abnormal resting LV function an abnormal EF response to exercise suggests the presence of myocardial ischemia rather than a nonspecific response to stress.

Adult↗
PubMed1985

Radionuclide evaluation of exercise left ventricular performance in patients with coronary artery disease.

Rest and exercise radionuclide angiography is a useful technique to study the cardiac adaptation during exercise in patients with coronary artery disease. Most patients with coronary artery disease have an abnormal EF response to exercise, although the magnitude of the change in EF may not correlate with the extent of coronary artery disease. The resting end-diastolic volume maybe the most important determinant of the presence and degree of left ventricular dilation during exercise in such patients. The exercise left ventricular EF improves after revascularization, but the EF response to exercise often remains abnormal. Evaluation of the regional and global left ventricular performance and the pressure-volume relationship during systole and diastole, as well as changes in these parameters after revascularization are possible. The exercise EF is also an important prognosticator in patients with known or suspected coronary artery disease.

Blood Pressure↗
PubMed1985

The use of rest and exercise radionuclide ventriculography in risk stratification in patients with suspected coronary artery disease.

The study examined the value of rest and exercise radionuclide ventriculography in risk stratification in patients with suspected coronary artery disease. There were 604 patients, 474 men and 130 women, aged 55 +/- 11 years (mean +/- standard deviation). At a follow-up of 18 +/- 10 months, there were 43 hard cardiac events: 27 patients died of cardiac causes and 16 had nonfatal acute myocardial infarctions. Univariate and multivariate survival analysis of the 10 most important clinical and exercise variables identified the exercise left ventricular ejection fraction as the most important predictor of death and total cardiac events (chi 2 = 18.1 and 29.6, respectively). The exercise heart rate was a significant, independent, but much weaker predictor of cardiac death and total events (chi 2 = 8.4 and 3.9, respectively), while exercise tolerance was a significant independent predictor of cardiac death only (chi 2 = 6.4). Actuarial life table analysis showed that the risk for future cardiac events increased in stepwise fashion as the exercise ejection fraction decreased. Thus, the exercise left ventricular ejection fraction is a useful prognosticator in patients with suspected coronary artery disease. This finding has important implications in patient management.

Actuarial Analysis↗
PubMed1985

Age-related changes in cardiovascular performance in mitral regurgitation: analysis of 61 patients.

This study examines the cardiovascular performance in relation to age in 61 patients with moderate or severe chronic mitral regurgitation (MR). Coronary artery disease (CAD) (50% or more diameter narrowing of one or more major coronary arteries) was present in 20 patients (33%). Patients less than 60 years (n = 33) had lower pulmonary artery pressure, systolic arterial pressure, left ventricular (LV) end-diastolic pressure, and pulmonary artery wedge pressure than the patients greater than or equal to 60 years (n = 28) (p less than 0.05). In the 41 patients without associated CAD, the LV end-diastolic pressure and systemic arterial pressure were higher in patients greater than or equal to 60 years (n = 14) than patients less than 60 years (n = 27) (p less than 0.05). The LV end-diastolic pressure showed an age-related increase in the presence or absence of CAD. Thus, older patients with MR have higher LV end-diastolic pressure, probably because of an increase in myocardial stiffness.

Adult↗
PubMed1985

Scintigraphic characterization of Q wave and non-Q-wave acute myocardial infarction.

This study examines the scintigraphic features of patients in Killip class I or II after acute myocardial infarction (AMI) with relation to ECG changes. The 41 consecutively studied patients (23 men and 18 women) with first AMI were divided into two groups: group 1 (n = 25) had Q wave AMI, and group 2 (n = 16) had non-Q wave AMI. Rest thallium-201 myocardial scintigrams and radionuclide ventriculograms were obtained 10 days (mean) after AMI. The thallium images were divided into 15 segments in three projections and assessed qualitatively and quantitatively. Fixed perfusion defects were present in at least one segment in 23 patients (92%) in group 1 and in eight patients (50%) in group 2 (p = 0.007). All but one patient in group 1 (4%) and three patients in group 2 (19%) had perfusion defects (fixed or reversible). The number of segments with perfusion defects was 5.6 +/- 2.6 in group 1 and 2.9 +/- 2.3 in group 2 (p = 0.002); the peak creatine kinase was 1280 +/- 880 Units/L in group 1 and 360 +/- 340 Units/L in group 2 (p less than 0.001); the left ventricular ejection fraction was 38 +/- 14% in group 1 vs 43 +/- 15% in group 2 (p = NS). Thus fixed perfusion defects are present in 92% of patients with Q waves and in 50% of patients with no Q waves.

Aged↗
PubMed1985

The effects of aging after coronary arterial bypass grafting on the regulation of cardiac output during upright exercise.

We examined the effects of age on cardiac performance and the mechanisms that regulate cardiac output during upright exercise in patients free of myocardial ischemia after coronary revascularization. There were 90 subjects, aged 36 to 75 years, of whom 27 were greater than or equal to 60 years. There were no age-related changes in resting heart rate, systolic blood pressure, left ventricular end-diastolic volume index, left ventricular end-systolic volume index, stroke volume index, cardiac index and left ventricular ejection fraction. There were, however, age-related changes in exercise capacity (y = 20 - 0.21x, r = -0.52, P less than 0.001); exercise heart rate (y = 185 - 1x, r = -0.42, P less than 0.001); exercise end-systolic volume index (y = 11 + 0.46x, r = 0.28, P less than 0.01) and exercise ejection fraction (y = 81 - 0.31x, r = -0.28, P less than 0.01). In a subgroup of 54 patients with comparable exercise workload (27 aged less than 60 and 27 greater than or equal to 60 years), the age-related differences in exercise end-systolic volume index, exercise ejection fraction and exercise cardiac index were not observed, but the exercise heart rate was still higher in the younger patients (y = 168 - 0.76x, r = -0.34, P less than 0.01). Thus, age modifies the compensatory mechanisms that regulate the cardiac output during exercise. Young and old patients alike show increases in end-diastolic volume and ejection fraction to maintain exercise cardiac output. The higher exercise heart rate in the younger subjects suggests a decrease in cardiac responsiveness to adrenergic stimulation associated with aging.

Adult↗
PubMed1985

Exercise systolic blood pressure: a powerful determinant of increased left ventricular mass in patients with hypertension.

This study examines the relation between left ventricular mass determined by two-dimensional echocardiography and exercise blood pressure in patients with hypertension. Sixty-seven patients with hypertension and 19 normal subjects underwent treadmill exercise testing and two-dimensional echocardiography. The left ventricular mass index in the normal subjects was 80 +/- 10 g/m2 (mean +/- SD). Patients with hypertension were classified into two groups according to left ventricular mass: Group I (n = 42) had normal mass and Group II (n = 25) had increased mass (greater than 2 SD above the mean value in 19 normal subjects). There was a poor correlation between left ventricular mass and blood pressure at rest. However, a better correlation was found between left ventricular mass and exercise systolic blood pressure (r = 0.58, p less than 0.001) or the change in systolic blood pressure from rest to exercise (r = 0.48, p less than 0.001). Twenty-two (76%) of 29 patients with an exercise systolic blood pressure of 190 mm Hg or greater had an increased left ventricular mass index, whereas only 3 (8%) of 38 patients with an exercise systolic blood pressure of less than 190 mm Hg had an increased left ventricular mass index (p less than 0.0001). Thus, in patients with hypertension, left ventricular mass index is poorly related to blood pressure at rest, but is related to exercise systolic blood pressure. Patients with an exercise systolic blood pressure of 190 mm Hg or greater usually have an increased left ventricular mass. These findings may have therapeutic implications.

Adult↗
PubMed1985

Effect of collateral vessels on prognosis in patients with one vessel coronary artery disease.

The prognostic implications of coronary collateral channels were examined in 359 medically treated patients with one vessel coronary artery disease and a normal left ventricular ejection fraction (greater than or equal to 50%). There were 149 patients with isolated left anterior descending coronary artery disease (group I) and 210 patients with isolated left circumflex or right coronary artery disease (group II). Collateral channels were present in 68 patients (46%) in group I and 115 patients (55%) in group II. During a follow-up period of up to 82 months (mean +/- SD 34 +/- 18), there were 23 cardiac events (4 patients died of cardiac causes and 19 patients had a nonfatal acute myocardial infarction). Actuarial survival analysis showed that the risk of cardiac events was not related to the presence of collateral channels in the two groups. Thus, the risk of cardiac events is not related to the presence or absence of collateral channels in patients with one vessel coronary artery disease. Further, the risks of cardiac death (0.3%/yr) and nonfatal myocardial infarction (1.9%/yr) are very low in medically treated patients with one vessel coronary artery disease and a normal left ventricular ejection fraction.

Adult↗
PubMed1985

Primary coronary artery dissection.

Three patients had angiographic appearance of chronic primary coronary artery dissection with features that differed from other patients with this entity studied at autopsy; they were men, greater than or equal to 40 years of age, had angina pectoris and severe coronary artery disease. The right coronary artery, which was the artery involved with dissection, had only mild atherosclerosis. Further studies are needed to determine the natural history of this angiographic finding.

Adult↗
PubMed1985

Left ventricular dilatation. Prognostic value in severe left ventricular dysfunction secondary to coronary artery disease.

This study determines the noninvasive prognostic predictors (using radionuclide angiography) in patients with severe left ventricular dysfunction (resting ejection fraction less than or equal to 35 percent) secondary to coronary artery disease. We retrospectively evaluated 94 such patients using rest and exercise radionuclide ventriculography. At a mean follow-up of 16 months, cardiac events occurred in 22 patients: ten patients died of cardiac causes, five patients sustained nonfatal myocardial infarction, and seven patients developed severe congestive heart failure (class 4). Results indicate that patients with severe left ventricular dysfunction may be stratified into different risk groups according to left ventricular size. Marked left ventricular dilatation identifies a subgroup at high risk.

Actuarial Analysis↗
PubMed1985

Prognostic implications of normal exercise thallium 201 images.

We studied 455 patients (mean age, 51 years) in whom exercise thallium 201 scintigrams performed for suspected coronary artery disease were normal. Of those, 322 (71%) had typical or atypical angina pectoris and 68% achieved 85% or more maximal predicted heart rate. The exercise ECGs were abnormal in 68 patients (15%), normal in 229 (50%), and inconclusive in 158 (35%). Ventricular arrhythmias occurred during exercise in 194 patients (43%). After a mean follow-up period of 14 months, four patients had had cardiac events, sudden cardiac death in one and nonfatal myocardial infarctions in three. None of the four patients had abnormal exercise ECGs. Two had typical and two had atypical angina pectoris. Normal exercise thallium 201 images identify patients at a low risk for future cardiac events (0.8% per year), patients with abnormal exercise ECGs but normal thallium images have good prognoses, and exercise thallium 201 imaging is a better prognostic predictor than treadmill exercise testing alone, because of the high incidence of inconclusive exercise ECGs and the good prognosis in patients with abnormal exercise ECGs.

Adult↗
PubMed1984

Relation between electrocardiographic and scintigraphic location of myocardial ischemia during exercise in one-vessel coronary artery disease.

The purpose of this study was to determine the usefulness of exercise electrocardiography in predicting the site of myocardial ischemia. Fifty-two patients were studied who had angiographically documented 1-vessel coronary artery disease (CAD) and exercise-induced reversible thallium-201 perfusion defects. The patients were divided into 2 groups: group I (28 patients) had left anterior descending CAD and group II (24 patients) had left circumflex or right CAD. There were no significant differences between the 2 groups in severity of coronary stenosis, heart rate and systolic blood pressure during exercise. The size of the perfusion defect was larger in group I than II (28 +/- 12% vs 19 +/- 10%, p less than 0.02). There was no significant difference between the 2 groups in the frequency of ST depression in the anterior, inferior or lateral electrocardiographic leads. ST depression occurred in 16 patients (57%) in group I and 11 patients (46%) in group II (difference not significant). The sensitivity of the exercise electrocardiogram was 52% using 12 leads, 50% using 3 leads (V3, V5 and aVF) and 50% using V5 alone (difference not significant). Thus, the site of ST depression during exercise is not a good predictor of the site of exercise-induced perfusion defect or anatomic site of CAD. The use of 12 leads does not improve the sensitivity of exercise electrocardiography in patients with CAD.

Adult↗