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Biomedical subjects

H S Hecht

Publications and source records attributed to H S Hecht.

At least 37 records · Page 2Linked to original sources
PubMed1989

Silent ischemia: evaluation by exercise and redistribution tomographic thallium-201 myocardial imaging.

UNLABELLED: To compare the amount of myocardium jeopardized during silent ischemia and painful ischemia, 112 consecutive patients undergoing coronary arteriography with ischemia demonstrated by exercise and redistribution tomographic thallium-201 myocardial imaging (SPECT) were divided into two groups: 84 patients without anginal pain (silent ischemia) and 28 with pain (painful ischemia). The SPECT apical, mid and basal ventricular levels of the short-axis view and the apical portion of the long-axis view were divided into 20 segments. The results were 1) 7.4 +/- 4.7 ischemic segments in silent ischemia and 7.6 +/- 3.7 in painful ischemia (p = NS) with 4.7 +/- 3.6 segments in silent ischemia undergoing total redistribution compared with 5.4 +/- 3.4 in painful ischemia (p = NS); 2) no difference in the incidence of single, double or triple vessel disease between silent and painful ischemic groups; 3) similar anatomic distribution of ischemic segments between the two groups; 4) more positive exercise electrocardiographic (ECG) changes in painful ischemia (70%) than in silent ischemia (32%) (p less than 0.001) with equal amounts of ischemia associated with positive and negative exercise ECG findings. CONCLUSIONS: 1) Patients with silent and painful ischemia during exercise have similar amounts of ischemic myocardium demonstrated by tomographic thallium-201 imaging and similar extent of angiographically documented coronary artery disease despite the absence of pain and the lower incidence of positive exercise ECG findings in silent ischemia. 2) Positive and negative exercise ECG findings were associated with similar amounts of ischemic myocardium.

Angina Pectoris↗
PubMed1984

Superiority of supine bicycle over isometric handgrip exercise in the assessment of ischemic heart disease: an evaluation of left ventricular ejection fraction response using radionuclide angiography.

Left ventricular ejection fraction (LVEF) response to supine bicycle and isometric handgrip exercise was evaluated in 15 patients with documented coronary artery disease (CAD) and stress-induced ischemia using radionuclide angiography. For purposes of analysis, the patients were divided into two groups: group I (n = 7) with single-vessel disease and group II (n = 8) with multiple-vessel disease including 3 with left main artery disease. The studies were repeated 18 days later at similar external workloads to assess reproducibility of both tests. LVEF response to bicycle exercise was different for the two groups. The change in LVEF from rest to peak exercise was +0.04 +/- 0.02 for group I and -0.07 +/- 0.04 for group II (p less than .001). LVEP response to isometric handgrip exercise was not different between the two groups. The change from rest to end of handgrip exercise was -0.02 + 0.02 for group I and -0.05 +/- 0.02 for group II. The reproducibility of LVEF response to bicycle exercise at similar workloads on day 1 and day 19 was good (r = 0.85) while it was poor for isometric handgrip testing (r = 0.67). Our data demonstrate that radionuclide angiographic measurement of LVEF response to supine bicycle exercise testing is superior to LVEF response to isometric handgrip testing in the evaluation of patients with CAD.

Adult↗
PubMed1984

Comparative effects of oral acebutolol and propranolol at rest and during exercise in ischemic heart disease: double-blind placebo crossover study utilizing radionuclide ventriculography.

Acebutolol is a new investigational beta-antagonist which has intrinsic sympathomimetic and cardioselective properties. In this study its effects on the ischemic consequences following supine bicycle exercise were compared to those of propranolol in 16 patients with chronic stable coronary artery disease (CAD) using a double-blind placebo crossover protocol and equilibrium radionuclide ventriculography. In eight patients (group I), the left ventricular ejection fraction (LVEF) at peak exercise fell under control conditions. During chronic acebutolol therapy (400 mg thrice daily), the exercise-induced LVEF (means +/- 1 SD) was significantly higher (37.1 +/- 15.5% versus 42.2 +/- 14.3%; p less than 0.05). The corresponding values during placebo and during propranolol (80 mg thrice daily) were 39.2 +/- 12.3% versus 43.4 +/- 14.8% (p = 0.07). In eight patients (group II) in whom supine bicycle exercise produced increases in LVEF, both acebutolol (58.8 +/- 5.4% versus 53.8 +/- 4.4%) and propranolol (57.8 +/- 5.7% versus 54.1 +/- 4.9%) attenuated the increases. In neither group was the resting LVEF reduced by acebutolol or propranolol. The data show that acebutolol and propranolol are approximately equipotent in minimizing the radionuclide left ventriculographic manifestations of myocardial ischemia induced by supine bicycle exercise.

Acebutolol↗
PubMed1982

Patterns of exercise response in patients with severe left ventricular dysfunction: radionuclide ejection fraction and hemodynamic cardiac performance evaluations.

To evaluate the exercise response of the severely diseased left ventricle, 13 patients with chronic congestive cardiomyopathy with mean resting ejection fraction (EF) of 18.8 +/- 9.6% underwent maximal supine bicycle exercise with hemodynamic and radionuclide monitoring. Two patterns of exercise response were noted. Group I (n = 7) was characterized by significant (p less than 0.001) increases in stroke work index (SWI) (+52%), stroke volume index (SVI) (+34%), mean arterial pressure (AP) (+23%), and cardiac index (CI) (+119%) and by a decrease in systemic vascular resistance (SVR) (-45% p less than 0.001). In group II (n = 6) there were no significant changes in SWI (-15%), AP (+11%), and SVR (-17%)(; SVI decreased significantly (-14%, p less than 0.05), and the increase in CI, although significant (+27%, p less than 0.01), did not achieve the level of Group I. EF did not change with exercise in either group. There were no significant differences at rest in any of the above variables, and the pulmonary capillary wedge pressures at maximal exercise were similar. We conclude that there are two patterns of exercise response in patients with severe congestive heart failure (CHF) and that these patterns may have important therapeutic and prognostic implications.

Adult↗
PubMed1982

Reproducibility of equilibrium radionuclide ventriculography in patients with coronary artery disease: response of left ventricular ejection fraction and regional wall motion to supine bicycle exercise.

To evaluate the reproducibility of ejection fraction (EF) and regional wall motion (RWM) analyses by rest and exercise equilibrium radionuclide ventriculography (RNV) in the presence of coronary artery disease (CAD), 18 patients underwent two maximum, multistage supine bicycle exercise studies separated by an interval of 2 weeks. There were no significant differences in EF between the two studies, both at rest (56.0 +/- 13.8% vs 58.2 +/- 11.7%, p = NS) and with exercise (51.1 +/- 17.6% vs 54.3 +/- 17.6%, p = NS) and a highly significant correlation was shown between the two groups of values (rest r = 0.90, exercise r = 0.93, p less than 0.001). There was no significant difference in the change from rest to exercise (-4.9 +/- 12.0% vs -3.8 +/- 11.5%, p = NS) between the two studies and the correlation was highly significant (r = 0.69, p less than 0.01). The interstudy variabilities were 2.2 +/- 6.1% and 1.2 +/- 7.3% for rest and exercise, respectively, and 2.0 +/- 9.2% for the change from rest to exercise. Ninety-four percent of both rest and exercise regions had similar RWM. Eighty-one percent of the abnormally contracting regions were common to both exercise studies. Utilizing conventional criteria for the diagnosis of CAD, 11 patients had abnormal EF response and nine had abnormal RWM response to exercise on both studies. Combining EF and RWM criteria resulted in the diagnosis of CAD in 15 patients in both studies. We conclude that: (1) there were no significant differences in rest and exercise radionuclide EF and RWM between two supine bicycle exercise studies performed 2 weeks apart in patients with stable CAD and there were significant correlations between the two studies; (2) despite these correlations, the interstudy variabilities emphasize the need for the inclusion of reproducibility studies in all evaluations of interventions by exercise radionuclide ventriculography; and (3) the variations in EF and RWM response to exercise result in lack of uniformity between the two studies regarding the diagnosis of CAD based on conventional RNV criteria.

Adult↗
PubMed1982

Noninvasive detection and localization of coronary stenoses in patients: comparison of resting dipyridamole and exercise thallium-201 myocardial perfusion imaging.

Two noninvasive tests to detect and localize coronary stenoses were compared in a fully blinded protocol. Thallium201 myocardial perfusion imaging (MPI) following maximal treadmill exercise and pharmacologic coronary vasodilation with intravenous dipyridamole (DP) was performed in 33 patients. Thallium201 imaging defects in six myocardial perfusion regions were correlated with stenoses in their respective vascular distributions. Disease severity was determined with coronary arteriograms using a computer-assisted method. 198 myocardial regions were evaluated; 101 were supplied by at least one major artery with a greater than or equal to 50% stenosis (luminal diameter narrowing). The sensitivity and specificity for detecting a greater than or equal to 50% stenosis were 85% and 64% (p less than 0.005), respectively, for DP and 84% and 68% (p less than 0.005) for exercise-thallium201 imaging. A particular combination of anterior and septal imaging defects was useful in detecting left anterior descending artery stenoses proximal to its first septal branch. DP administration was safe in this group of patients; however, 42% experienced transient chest pain. Although the overall sensitivity and specificity of the two methods were not significantly different, DP-MPI appeared more sensitive than exercise-MPI (70% vs 52%, p less than 0.01) in detecting coronary stenoses in the 40% to 60% range. DP-thallium201 MPI provides a useful alternative test for potential coronary disease patients unable to perform maximal exercise.

Adult↗
PubMed1981

Comparative evaluation of segmental asynergy in remote myocardial infarction by radionuclide angiography, two-dimensional echocardiography, and contrast ventriculography.

Radionuclide angiography (RNA), two-dimensional echocardiography (2DE), and contrast ventriculography (CVG) were compared in the evaluation of regional wall motion (RWM) in 58 patients with remote myocardial infarction (MI). All 58 patients were studied by 2DE, 52 by RNA, and 24 by CVG. Severe degrees of segmental asynergy (akinesia/dyskinesia) were noted more often by 2DE (56% of all segments, p less than 0.005) and CVG (52%, p less than 0.05) than by RNA (39%). The apex more the most frequent site of akinesia/dyskinesia by all technique (43% by RNA, 36% by 2DE, and 45% by CVG). 2DE and RNA agreed in 64% of regions (p less than 0.005), 2DE and CVG agreed in 68% (p less than 0.005), and RNA and CVG agreed in 70% (p less than 0.005); the highest agreement was for the apical region. Dyskinesia was noted in 77% of patients by RNA, in 71% by 2DE, and 79% by CVG. RNA and CVG agreed in 89% of patients and in 57% of regions, 2DE and CVG agreed in 67% of patients and in 53% of regions, and RNA and 2DE agreed in 71% of patients and in 38% of regions. Combined RNA and 2DE detected dyskinesia in 94% of the 16 patients with dyskinesia by CVG who underwent all three techniques and in 90% of the 52 patients studied by RNA and 2DE. We conclude that (1) RNA, 2DE an CVG agree significantly in the evaluation of regional wall motion; (2) there is better agreement concerning the presence or absence of dyskinesia in a given patients than the exact region involved; and (3) the combination of RNA and 2DE is more useful than either alone as a screening procedure for the detection of ventricular dyskinesia.

Adult↗
PubMed1981

Exercise-induced regional wall motion abnormalities on radionuclide angiography. Lack of reliability for detection of coronary artery disease in the presence of valvular heart disease.

Exercise-induced regional wall motion abnormalities on radionuclide angiography have been thought to be a reliable indicator of coronary artery disease. To evaluate their reliability, particularly in patients with valvular heart disease, exercise radionuclide angiography was performed in 12 normal subjects, 35 patients with coronary artery disease and 19 patients with valvular heart disease and normal coronary arteries. Exercise-induced regional wall motion abnormalities were found in none of the normal subjects, 63 percent of the patients with coronary artery disease and 42 percent of those with valvular heart disease and were predominantly inferoapical in location in the group with valvular heart disease. We conclude that exercise-induced regional wall motion abnormalities are not reliable for the detection of coronary artery disease in patients with valvular heart disease.

Adult↗
PubMed1981

Intravenous dipyridamole combined with isometric handgrip for near maximal acute increase in coronary flow in patients with coronary artery disease.

Twenty-four patients with coronary artery disease were studied during cardiac catheterization to determine the effects of sustained isometric handgrip exercise and intravenous dipyridamole and their combination on coronary and systemic hemodynamics and measured coronary luminal caliber. During 4 to 5 minutes of 25 percent maximal handgrip, blood pressure and heart rate increased 24 and 19 percent, respectively, coronary sinus flow increased to 1.7 x baseline value, and epicardial coronary arteries constricted to increase predicted flow resistance by 40 percent in 36 diseased arterial segments. After a 4 minute intravenous infusion of dipyridamole (0.56 mg/kg body weight), systemic pressure decreased 8 percent, heart rate increased 23 percent, coronary sinus flow increased to 2.4 x baseline value and coronary luminal caliber was unchanged. During isometric handgrip initiated 6 minutes after the infusion of dipyridamole, systemic pressure and heart rate increased to 14 and 31 percent, respectively, above control values, coronary sinus flow increased to 3.3 x baseline value (3.8 x baseline value in patients with normal anterior perfusion) and stenotic flow resistance increased by 36 percent. The response of coronary flow to the combined stresses was 68 percent greater than the response to dipyridamole alone (p less than 0.02); these flow levels exceed values previously reported for the human coronary circulation. Aminophylline plus nitroglycerin appears to assure patient safety.

Acute Disease↗
PubMed1981

Reverse redistribution: worsening of thallium-201 myocardial images from exercise to redistribution.

Reverse redistribution (RR) i.e., worsening of images from exercise to redistribution, was noted in 21 (7%) of 300 consecutive thallium-201 (201TI) exercise and redistribution myocardial imaging studies. In 13, there were reversible defects consistent with ischemia in addition to redistribution defects. Twenty RR defects were noted in 15 patients who underwent cardiac catheterization; 9 had triple, 4 had double and 2 had single vessel coronary artery disease. Seventeen (85%) of the RR defects were in the distribution of severely diseased vessels; 8 with 100% occlusion and 9 with 90-99% stenosis. The remainder were associated with 50-60% stenoses. Ten RR areas (50%) were supplied by collateral vessels and 3 (15%) by bypass grafts. Fourteen of the 18 (78%) areas studied with left ventriculography were associated with abnormally contracting segments. These results suggest that RR is a marker for significant coronary artery disease.

Cardiac Catheterization↗