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Biomedical subjects

A H Hakki

Publications and source records attributed to A H Hakki.

At least 19 recordsLinked to original sources
PubMed1991

Failure of adjuvant heparin to reduce myocardial ischemia in the early treatment of patients with unstable angina.

Although the efficacy of long-term administration of antithrombotic agents in unstable angina has been established, short-term effects on myocardial ischemia are unknown. A retrospective analysis was performed in 47 patients undergoing three-channel continuous ST segment monitoring as part of a multicenter trial using esmolol in unstable angina, in which 20 patients received a continuous heparin infusion during the initial assessment of chest pain. Concomitant medications included calcium channel blockers, beta-adrenergic blockers, nitrates, and aspirin in the majority of patients. Clinical variables between the heparin and no heparin groups were similar, except for fewer males and fewer total artery occlusions in the heparin group. No significant differences in the incidence or duration of ischemia were found in a 36 +/- 16 hour monitoring period. Forty percent of the heparin group had 35 episodes of ischemia with a mean of 11 +/- 10 minutes per episode and a total ischemic time of 48 +/- 39 minutes per patient with ischemia. Forty-four percent of the no heparin group had 47 episodes of ischemia with a mean of 13 +/- 13 minutes per episode and a total ischemic time of 58 +/- 47 minutes per patient with ischemia. Multiple linear regression analysis to adjust for intergroup differences did not alter the results. Eighty-five percent of all episodes were asymptomatic. Clinical events, such as episodes of chest pain, emergency coronary arteriography, or coronary revascularization, were also similar between groups. Thus the short-term administration of heparin did not alter the incidence or duration of ischemia in patients with unstable angina.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1989

Relation between myocardial thallium-201 kinetics during exercise and quantitative coronary angiography in patients with one vessel coronary artery disease.

This study examined the relation between the kinetics of thallium-201 and coronary stenosis in 30 patients with one vessel coronary artery disease; 25 patients had no visible collateral vessels. The myocardial thallium concentration in the postexercise images and percent washout were determined in the distribution of the diseased vessel and a normal vessel, and each was expressed as a ratio. Coronary stenosis was assessed as minimal diameter stenosis, minimal area stenosis and percent diameter stenosis. The correlations between the myocardial concentration ratio or washout ratio and the descriptors of coronary stenosis improved when the patients with collateral vessels were excluded. There were significant correlations between the myocardial thallium concentration ratio and minimal diameter stenosis (r = 0.73, p less than 0.001), minimal area stenosis (r = 0.72, p less than 0.001) and, to a lesser degree, percent diameter stenosis (r = -0.51, p less than 0.01). Similarly, there were significant correlations between washout ratio and minimal diameter stenosis (r = 0.50, p less than 0.01) and minimal area stenosis (r = 0.45, p less than 0.02) but not percent diameter stenosis (r = 0.37, p = 0.06). Thus, variation in thallium kinetics in relation to the severity of coronary stenosis can be demonstrated with conventional imaging in patients with one vessel disease. The myocardial thallium concentration and washout are physiologic expressions of the severity of perfusion deficit and are dependent on collateral flow. The myocardial thallium concentration ratio and washout ratio correlate better with minimal diameter and area stenosis than with percent diameter stenosis.

Aged↗
PubMed1987

Effects of beta blockade on systolic and diastolic left ventricular function at rest and during exercise in patients with chronic stable angina pectoris.

This study examined the effects of beta blockade with betaxolol, a cardioselective, lipid-soluble, beta-adrenergic-blocking agent, on rest and exercise systolic and diastolic left ventricular function in 15 patients, aged 40 to 70 years (mean = 52), with chronic stable angina pectoris. Each patient underwent three upright exercise studies at identical workloads; the first was a baseline study, the second was done 3 hours after a single oral dose, and the third was obtained after chronic therapy for 2 weeks. Beta blockade was evident by significant decreases in heart rate, systolic blood pressure, and diastolic blood pressure at rest and during exercise (p less than 0.04). Although there were no significant changes (at rest or during exercise) in mean left ventricular ejection fraction and peak filling rate, individual variations were seen after 3 hours and 2 weeks of therapy. During chronic therapy, the peak filling rate increased in three patients, decreased in five, and remained unchanged in seven. Also, discordant changes in systolic and diastolic functions were seen at rest and during exercise during both acute and chronic therapy. Thus, although acute and chronic beta blockade produces no significant changes in mean measurements of diastolic and systolic left ventricular performance, individual variations and discordant results are seen in many patients. The acute effects are generally consistent with the chronic effects, but exceptions are present.

Adrenergic beta-Antagonists↗
PubMed1987

Merits and limitations of quantitative treadmill exercise score.

This study examined the ability of the treadmill exercise score (TES) in determining the presence and extent of coronary artery disease (CAD). The score was derived from the integrated area of ST segment depression and ST slope in two leads (V5 and a VF), corrected for R wave amplitude, exercise time, and percent of maximum predicted heart rate. The ST segment depression was measured at 80 msec after the J point. There were 34 patients with no significant CAD, 38 patients with one-vessel CAD (greater than or equal to 50% diameter stenosis), and 58 patients with multivessel CAD. The TES showed a considerable scatter in patients with and without CAD. A receiver operating characteristic curve showed different levels of sensitivity and specificity, depending on the cut-point. The TES was similar to ST segment depression in detecting CAD (predictive accuracy, 77% vs 78%, p = NS). A markedly abnormal score (less than -1.0) was seen in 41 patients, of whom 32 (78%) had multivessel CAD. On the other hand, a score greater than 0 was seen in 49 patients, of whom 40 (82%) had no or one-vessel CAD. In 40 patients with TES between -1.0 and 0, 17 (43%) had multivessel CAD and 23 (57%) had no or one-vessel CAD. In 51 patients with nondiagnostic ST changes, the TES correctly classified the extent of CAD in 20 patients (40%). Thus, the TES has a similar accuracy to the ST segment depression criteria in detecting CAD. The extent of CAD can, however, be ascertained in 80% of the patients with very high or very low TES.

Adult↗
PubMed1987

Relative prognostic value of rest thallium-201 imaging, radionuclide ventriculography and 24 hour ambulatory electrocardiographic monitoring after acute myocardial infarction.

Rest thallium-201 scintigraphy, radionuclide ventriculography and 24 hour Holter monitoring are acceptable methods to assess myocardial necrosis, performance and electrical instability. This study examined the relative value of the three tests, when obtained a mean of 7 days after acute myocardial infarction, in predicting 1 year mortality in 93 patients. Planar thallium-201 images were obtained in three projections and were scored on a scale of 0 to 4 in 15 segments (normal score = 60). Patients were classified as having high risk test results as follows: thallium score less than or equal to 45 (33 patients), left ventricular ejection fraction less than or equal to 40% (51 patients) and complex ventricular arrhythmias on Holter monitoring (36 patients). During the follow-up of 6.4 +/- 3.4 months (mean +/- SD), 15 patients died of cardiac causes. All three tests were important predictors of survival by univariate Cox survival analysis; the thallium score, however, was the only important predictor by multivariate analysis. The predictive power of the thallium score was comparable with that of combined ejection fraction and Holter monitoring (chi-square = 21 versus chi-square = 22). Thus, rest thallium-201 imaging performed before hospital discharge provides important prognostic information in survivors of acute myocardial infarction which is comparable with that provided by left ventricular ejection fraction and Holter monitoring. Patients with a lower thallium score (large perfusion defects) are at high risk of cardiac death during the first year after infarction.

Adult↗
PubMed1987

Exercise thallium imaging in patients with diabetes mellitus. Prognostic implications.

We used exercise thallium 201 imaging in 123 patients with diabetes mellitus (77 men and 46 women, aged 56 +/- 8 years), 75% of whom had angina pectoris (typical or atypical). During exercise testing, 18 patients (15%) had angina pectoris, 28 (23%) had ischemic ST changes, and 69 (56%) had abnormal thallium images. During follow-up (up to 36 months), there were 12 cardiac events; four patients died of cardiac causes and eight had nonfatal acute myocardial infarction. Univariate and multivariate survival analysis identified two independent predictors of cardiac events: the event rate was significantly less in patients with normal images and exercise heart rate over 120 beats per minute than in patients with abnormal images and exercise heart rate of 120 beats per minute or less (0% vs 22%). The patients with abnormal images or exercise heart rate of 120 beats per minute or less had an intermediate event rate (11.5%). Furthermore, two of the 54 patients with normal images and ten of 69 patients with abnormal images had subsequent cardiac events. Thus, exercise thallium imaging is useful in risk stratification in patients with diabetes mellitus.

Adult↗
PubMed1986

Implications of abnormal right ventricular thallium uptake in acute myocardial infarction.

The correlates of abnormal right ventricular (RV) thallium uptake were examined in 116 patients with documented acute myocardial infarction (AMI) who underwent predischarge thallium-201 scintigraphy at rest, radionuclide angiography and 24-hour ambulatory electrocardiography. The patients were separated into 2 groups: patients group 1 (n = 31) had increased RV thallium uptake and those in group 2 (n = 85) had no such uptake. The 2 groups were comparable in age, type and site of AMI, peak creatine kinase level, systolic blood pressure and heart rate. However, compared with group 2, group 1 had a lower mean left ventricular (LV) ejection fraction (33 +/- 15% vs 39 +/- 14%, p less than 0.05), higher prevalence of increased lung thallium uptake (45% vs 22%, p less than 0.02), more extensive LV perfusion defects (4.4 +/- 2.9 vs 3.0 +/- 3.0 segments, p less than 0.03) and more complex ventricular arrhythmias (55% vs 35%, p less than 0.05). At a mean follow-up of 6 months, 17 patients (8 in group 1 and 9 in group 2) died from cardiac causes. Actuarial life-table analysis showed that the survival rate was better in group 2 than in group 1 (Mantel-Cox statistics = 4.62, p = 0.03). Thus, patients with AMI and abnormal RV thallium uptake have worse LV function, more complex ventricular arrhythmias and worse prognosis.

Adult↗
PubMed1986

Age- and gender-related changes in exercise left ventricular function in mitral valve prolapse.

The correlates of exercise left ventricular (LV) performance were examined in 45 patients with isolated mitral valve prolapse (no associated mitral regurgitation or coronary artery disease). There were 18 men and 27 women, aged 16 to 73 years; 20 patients were 40 years or younger and 25 were older than 40. The response of the LV ejection fraction (EF) to symptom-limited upright exercise was normal (at least a 5% increase) in 27 patients (60%) and abnormal in 18 (40%). There were no significant differences between patients with normal and abnormal EF response in clinical presentation, electrocardiographic findings (at rest or during exercise), medications, rest EF, heart rate (at rest or during exercise) and systemic arterial pressure (at rest and during exercise). A normal EF response was observed more frequently in patients 40 years or younger than in those older than 40 (80 vs 44%, p less than 0.01), and more often in men than in women (78 vs 48%, p less than 0.04). The change in EF from rest to exercise was 18 +/- 9% in men and 5 +/- 10% in women 40 years or younger (p less than 0.01), and 9 +/- 8% in men and 2 +/- 8% in women older than 40 (p less than 0.04). Thus, patients (especially women and those older than 40 years) with isolated mitral valve prolapse may have abnormal LV functional reserve. Genetic differences in the expression of the disease in both sexes and age-related irreversible myocardial changes may explain these observations.

Adolescent↗
PubMed1986

Determinants of abnormal blood pressure response to exercise in coronary artery disease.

This study assessed the determinants of exercise-induced abnormal systolic blood pressure (BP) response in 127 patients with documented coronary artery disease (CAD) who underwent exercise thallium-201 scintigraphy. Three types of systolic BP response to exercise were identified: an increase by more than 20 mm Hg (group I, n = 74); an increase by 20 mm Hg or less (group II, n = 36); and a decrease of at least 10 mm Hg (group III, n = 17). The 3 groups were not significantly different in age, gender or medications. The number of segments with perfusion defects was significantly higher in groups II and III than group I (group III, 2.9 +/- 1.5; group II, 2.9 +/- 2.1; and group I, 1.8 +/- 1.4, p = 0.009). Prior myocardial infarction, abnormal left ventricular ejection fraction, and multivessel CAD were more common in group III than in groups I and II. Stepwise discriminant analysis of 15 relevant clinical, angiographic and exercise scintigraphic descriptors showed that the number of thallium perfusion defects, abnormal LV ejection fraction at rest and multivessel CAD to be important predictors of hypotensive BP response. Multivariate analysis, however, showed that the number of thallium perfusion defects was the only important predictor of the hypotensive response. Thus, it is the functional significance of CAD assessed by the extent of thallium perfusion abnormalities rather than the extent of CAD or left ventricular dysfunction at rest that determines the systolic BP response to exercise.

Adult↗
PubMed1986

Relation between left ventricular diastolic function and exercise tolerance in patients with left ventricular dysfunction.

Previous studies show no correlation between resting systolic left ventricular performance assessed as the ejection fraction and exercise tolerance. This study examined the relation between left ventricular diastolic performance and exercise tolerance in 63 patients with left ventricular dysfunction (ejection fraction less than 50%) due to known or suspected coronary artery disease. The 51 men and 12 women, aged 54 +/- 8 years (mean +/- standard deviation), underwent symptom-limited upright exercise testing on a bicycle ergometer. The exercise end-points were angina (n:5), dyspnea (n:16), and fatigue (n:42). The patients were divided into three groups: group 1 (n:28) with normal exercise tolerance (9.5 +/- 2.4 minutes), group 2 (n:18) with mild exercise intolerance (5.8 +/- 0.5 minutes), and group 3 (n:17) had severe exercise intolerance (3.7 +/- 0.9 minutes). The three groups did not differ in age, ejection fraction, end-diastolic volume, exercise end-point, exercise heart rate, and left ventricular peak filling rate at rest. The exercise peak filling rate was, however, significantly higher in group 1 (p = 0.03). Stepwise multivariate discriminant analysis of important variables identified the exercise peak filling rate as the only predictor of exercise tolerance (F = 6.0). Thus, variation in exercise peak filling rate may in part explain the variability of exercise tolerance in patients with left ventricular dysfunction; patients with preserved exercise capacity have higher exercise peak filling rate than those with exercise intolerance.

Adult↗
PubMed1986

Effect of gender on left ventricular function during exercise in patients with coronary artery disease.

This study evaluated the effect of gender on left ventricular (LV) function in 84 men and 20 women with coronary artery disease (CAD) (greater than or equal to 50% luminal narrowing of one or more of the major coronary arteries). All patients underwent rest and upright exercise radionuclide ventriculography on a bicycle ergometer. There were no differences between men and women in age, hypertension, medications, and extent of CAD disease (number of diseased vessels or CAD score). Although men exercised for a longer duration than women, both achieved similar exercise heart rates and blood pressures. Angina pectoris or ST depression during exercise occurred in similar proportion in both groups. The LV ejection fraction and the systolic pressure-to-end-systolic volume ratio at rest and during exercise were similar in both men and women. Thus, men and women with comparable extent of CAD demonstrate similar manifestations of myocardial ischemia and LV dysfunction during exercise. Gender does not appear to influence LV function independent of the extent of CAD.

Adult↗
PubMed1986

Resting thallium-201 myocardial perfusion patterns in patients with severe left ventricular dysfunction: differences between patients with primary cardiomyopathy, chronic coronary artery disease, or acute myocardial infarction.

This study examined the value of resting thallium-201 imaging in differentiating patients with primary cardiomyopathy from those with ischemic cardiomyopathy. There were 15 patients with primary cardiomyopathy (group I); 20 with chronic CAD (group II); and 25 with acute Q wave myocardial infarction (group III). All patients had LVEF less than or equal to 35%. The thallium score was less than 50 (maximum 60) in one patient (7%) in group I, in 17 patients (85%) in group II, and in 25 patients (100%) in group III (p less than 0.0001, I vs II and III). The number of normal segments was 11.4 +/- 4.9 in group I, 6.9 +/- 2.9 in group II, and 7.0 +/- 2.2 in group III (p less than 0.0001, I vs II, III). Reversible defects were present in three patients in group II, three in group III, and none in group I. Abnormal right ventricular thallium uptake was observed in 27% of patients in group I, 25% in group II, and 40% in group III (p = NS). Abnormal lung thallium uptake was observed in 33% in group I, 20% in group II, and 20% in group III (p = NS). Thus, rest thallium imaging is useful in separating patients with primary cardiomyopathy from those with ischemic cardiomyopathy.

Adolescent↗
PubMed1986

Ventricular systolic and diastolic impairment during pacing-induced myocardial ischemia in coronary artery disease: simultaneous hemodynamic, electrocardiographic, and radionuclide angiographic evaluation.

This study examined the impairment in systolic and diastolic performance of both ventricles during pacing-induced myocardial ischemia in 12 men with coronary artery disease. Simultaneous hemodynamic, ECG, and radionuclide angiographic assessments were made: pre pacing (pre-P); intermediate pacing (P-1); maximum pacing (P-2); and immediately after pacing (post pacing (P-P). The prepacing measurements were made with the patient in the supine position and during leg elevation. Pacing produced a leftward and upward shift in the diastolic pressure-volume relation, a progressive decrease in left ventricular (LV) end-diastolic volume (p less than 0.003) and right ventricular (RV) end-diastolic volume (p less than 0.01), concomitant with an increase in the pulmonary artery wedge pressure (p less than 0.004) and the right atrial pressure (p less than 0.04). The shift in the LV pressure-volume relation was associated with an initial increase (P-1), followed by a decrease (P-2) in the peak filling rate (p less than 0.001). Pacing also resulted in systolic dysfunction: abnormal LV ejection fraction responses in eight patients, LV regional wall motion abnormalities in eight patients, and abnormal RV ejection fraction responses in seven patients. Leg elevation resulted in a 7% increase in cardiac output, a 20% increase in RV end-diastolic volume, a 28% increase in right atrial pressure, a 29% increase in pulmonary artery wedge pressure, and a 10% increase in LV end-diastolic volume (p less than 0.05). Thus, the ischemic response to pacing results in systolic and diastolic LV and RV dysfunction, with the diastolic impairment being more frequent than the systolic impairment.

Aged↗
PubMed1986

Determinants of the changes in left ventricular end-diastolic volume during upright exercise in patients with coronary artery disease.

We examined the changes in left ventricular (LV) end-diastolic volume (EDV) during symptom-limited upright exercise in 160 patients with coronary artery disease. Patients were divided into three groups based on the degree of exercise-induced LV dilation: group I (n = 66) had no increase in EDV (less than 10% change), group II (n = 38) had mild increase (10% to 24%), and group III (n = 56) had moderate or severe increase (greater than or equal to 25%). The patients with exercise-induced LV dilation had smaller resting EDV (p = 0.0001), higher resting LV ejection fraction (EF) (p = 0.008), and a greater decrease in EF with exercise (delta EF) (p = 0.007). A significant correlation was found between resting EDV and the degree of LV dilation with exercise (r = -0.45, p less than 0.001), and a weaker correlation between the degree of LV dilation and delta EF (r = -0.28, p less than 0.01). Multivariate discriminant analysis of important clinical, anatomic, and exercise descriptors identified three variables that best predicted the presence or absence of LV dilation during exercise: resting EDV (F = 38.2), resting EF (F = 24.2), and delta EF (F = 21.5). Thus, the degree of LV dilation during upright exercise is not related to age, gender, and extent of coronary artery disease, but is determined by the resting EDV, the resting EF, and the EF response to exercise.

Adult↗
PubMed1986

Age-related changes in left ventricular diastolic performance.

Previous studies show that the radionuclide-derived indices of left ventricular (LV) diastolic performance are abnormal at rest in many patients with coronary artery disease (CAD), even in those with normal resting ejection fraction (EF) and no prior myocardial infarction. This study examined the age-related changes in LV peak filling rate and time to peak filling rate in 65 subjects between the ages of 20 and 75 years with a low likelihood of CAD. All subjects had normal resting EF (greater than or equal to 50%), and none had prior infarction. There was a significant age-related decline in resting peak filling rate (r = -0.47, p less than 0.001) and exercise peak filling rate (r = -0.52, p less than 0.001), but no age-related effect in the time to peak filling rate. Of the 29 subjects less than 50 years of age, 26 (90%) had resting peak filling rate greater than or equal to 2.5 EDV/sec (3.1 +/- 0.6, mean +/- SD) compared to 17 of 36 subjects (47%) greater than or equal to 50 years of age (2.6 +/- 0.6) (p = 0.002). In a subgroup of 28 subjects with a history of hypertension, the age-related effect was more marked than in the remaining 37 subjects without such a history (r = -0.66 vs -0.33). Thus, the peak filling rate at rest and during exercise decreases with advancing age; the high frequency of observed abnormality in the peak filling rate at rest in patients with CAD may conceivably be related in part to age differences between patients with CAD and the control group.

Adult↗