Comparative effects of oral verapamil and propranolol on exercise-induced myocardial ischemia and energetics in patients with coronary artery disease: Single-blind placebo crossover evaluation using radionuclide ventriculography

Using multiple-gated equilibrium cardiac blood pool imaging and single-blind placebo crossover protocol, the effects of oral verapamil (VRP) (480 mg/day) were compared to those of oral propranolol (PRP) (320 mg/day) on the left ventricular ejection fraction (LVEF) and regional wall motion (RWM) abnormalities at rest and during supine bicycle exercise in 15 patients with coronary artery disease (CAD). During exercise on placebo before VRP the mean LVEF fell from the resting value of 0.54 ± 0.09 to 0.47 ± 0.12 (p < 0.05); on VRP (plasma level 283 ± 150 ng/dl and noverapamil 220 ± 97 ng/dl) the corresponding values were 0.54 ± 0.11 and 0.53 ± 0.13 (NS). On placebo before PRP, exercise reduced LVEF from 0.54 ± 0.13 to 0.48 ± 0.14 (p < 0.05); on PRP (plasma level 144 ± 59 ng/dl) the resting LVEF was 0.54 ± 0.11 and exercise LVEF 0.52 ± 0.13 (NS). Both drugs reduced the exercise-induced RWM (interoapical) abnormality and ST segment depression but the changes were only significant (p < 0.05) in the case of VRP. PRP attenuated the exercise-induced increase in heart rate by 24.5% (p < 0.005), in systolic blood pressure by 13.4% (p < 0.001), in diastolic pressure by 8.7% (p < 0.005), and in rate-pressure product by 34.5% (p < 0.001). VRP reduced the exercise heart rate response by 10.3% (p < 0.001), systolic pressure by 4.6% (NS), diastolic pressure by 7.9% (p < 0.005), and rate-pressure product by 14.6% (p < 0.001). These data suggest that VRP and PRP exhibit comparable potency in reducing the ischemic consequences of exercise stress in CAD patients. In the case of PRP, the beneficial effect was accountable in terms of reduction in oxygen demand; in the case of VRP, additional mechanisms such as those involving myocardial metabolism or primary changes in perfusion may be involved.     

Radionuclide ejection fraction and regional wall motion during atrial pacing in stable angina pectoris: Comparison with metabolic and hemodynamic parameters

To evaluate the effects of atrial pacing on radionuclide (RNA) ejection fraction (EF) and regional wall motion (RWM), transmyocardial lactate gradients and hemodynamics in stable coronary artery disease (CAD), 12 CAD patients underwent incremental atrial pacing during cardiac catheterization. EF declined from 0.60 ± 0.07 during control state to 0.51 ± 0.11 (p < 0.001) during submaximal pacing (Sub Max P) with 10 of 12 having decreased EF, six developing new RWM abnormalities, and five experiencing mild chest pain. During maximal pacing (Max P), EF declined further to 0.47 ± 0.10 (p < 0.001), with all patients having decreased EF and experiencing moderate to severe chest pain, and nine developing new RWM abnormalities. Percentage lactate extraction (Ex) decreased from +28.3 ± 9.4% to +17.4 ± 11.9% during Sub Max P (p < 0.01), with only one patient producing lactate. During Max P, percentage lactate Ex decreased to ?0.1 ± 15.3% (p < 0.001) with eight patients producing lactate. Significant increases in pulmonary capillary wedge pressure and systemic vascular resistance occurred during Max P, and in mean pulmonary artery pressure and mean systemic arterial pressure during both Sub Max and Max P. Significant decreases in stroke volume index and stroke work index occurred during both pacing levels and cardiac index did not change with pacing. This study demonstrates that RNA may be used to establish decreases in EF and RWM which occur in response to incremental atrial pacing in patients with stable CAD, and that these changes are more consistent and appear earlier than the metabolic consequences of myocardial ischemia induced by pacing stress.     

Comparative effects of diltiazem,propranolol, and placebo on exercise performance using radionuclide ventriculography in patients with symptomatic coronary artery disease: Results of a double-blind,randomized, crossover study

The effects of oral diltiazem (120 mg), propranolol (100 mg), and placebo on exercise performance and left ventricular function were compared before and during symptom-limited supine bicycle exercise by means of multigated radionuclide ventriculography in 12 patients with documented, symptomatic coronary artery disease; a double-blind, randomized crossover protocol was used. Diltiazem increased ejection fraction (EF) at submaximal exercise (+7.0 absolute percentage points, p < 0.02) and maximal exercise (+8.1 percentage points, p < 0.01). Exercise EF was increased by 13.6 percentage points (p < 0.02) in patients with decreased ventricular function (resting EF <50%). Propranolol had no effect on exercise EF at any stage, even when patients with EF <50% were excluded. The increase in total exercise time was significant after diltiazem (+27%, p < 0.01) but not after propranolol (+16%, p = NS). As expected, propranolol decreased both resting (?9 bpm, p < 0.01) and exercise heart rates (?27 bpm, p < 0.001), whereas diltiazem had no significant effect. Propranolol decreased resting diastolic blood pressure (?8 mm Hg, p < 0.02), exercise systolic (?27 mm Hg, p < 0.001) and diastolic (?9 mm Hg, p < 0.01) blood pressures, and rest (p < 0.01) and exercise (p < 0.001) double product. Diltiazem decreased resting systolic blood pressure (?9 mm Hg, p < 0.01) and both resting (?8 mm Hg, p < 0.001) and exercise (?9 mm Hg, p < 0.01) diastolic blood pressures. Diltiazem decreased double product at submaximal (p < 0.005) but not maximal exercise. Angina limited exercise in four patients after diltiazem compared to eight and seven patients after placebo and propranolol respectively (p < 0.05). Thus, diltiazem improved exercise performance with the use of radionuclide ventriculography during symptom-limited supine bicycle ergometry to a greater extent than did propranolol or placebo, and this effect was most apparent in those with decreased left ventricular function.     

Effects of transluminal coronary angioplasty on left ventricular systolic and diastolic function at rest and during exercise

The left ventricular global and regional systolic function, ventricular volumes, and peak diastolic filling rate (PDFR) were studied in 30 patients with coronary artery disease, before and 2 to 5 days after transluminal coronary angioplasty (PTCA), utilizing equilibrium radionuclide angiography at rest and during exercise. At rest, the global ejection fraction (EF) was unchanged before (60 ± 9%) and after PTCA (62 ± 10%). During exercise, global EF increased from 59 ± 11% pre PTCA to 67 ± 10 post PTCA (p < 0.001). Twenty-two patients had abnormal EF response to exercise pre PTCA, versus seven post PTCA (p < 0.001). Improvements in exercise regional EF paralleled the changes in global EF. End-systolic volume was unchanged at rest but decreased significantly with exercise post PTCA (60 ± 36 ml pre vs 49 ± 32 ml post PTCA, p < 0.01). At rest, the PDFR was unchanged post PTCA (2.4 ± 0.9 end-diastolic volume (EDV)/sec pre vs 2.5 ± 0.8 EDV/sec post). During exercise, PDFR increased from 2.1 ± 0.7 EDV/sec pre PTCA to 2.5 ± 0.7 EDV/sec post PTCA (p < 0.02). In conclusion, in patients with coronary artery disease, successful PTCA improves global and regional systolic function during exercise. Diastolic function is improved during exercise, a fact not previously demonstrated.     

The influence of age and gender on left ventricular response to supine exercise in asymptomatic normal subjects

The performance of normal subjects during radionuclide ventriculography has been related to age, but the combined effects of age and sex on exercise ventricular function are not well described. We studied 55 normal volunteers, 27 men (age = 30 ± 10 years) and 28 women (age = 33 ± 14 years), free of chest pain syndromes, during supine rest/exercise radionuclide ventriculography performed to fatigue. Resting left ventricular ejection fraction did not differ between male and female subjects (64 ± 5.4 vs 64 ± 6.1; p = NS). Both the peak left ventricular ejection fraction (78 ± 4.4 vs 72 ± 9.2; p < 0.001) and the change in ejection fraction with exercise (14 ± 4.0 vs 7.9 ± 7.0; p < 0.001) were significantly greater in men compared to respective values in women. Regression analysis showed that sex (r = 0.51; p < 0.001) but not age (r = −0.18; p = 0.19) was a significant predictor of change in ejection fraction with exercise. Data on left ventricular volume response to exercise, available in 43 subjects, revealed that men had a greater percentage of decline in end-systolic volume with exercise than women (−47 ± 15 vs −24 ± 26; p < 0.001). It is concluded that sex exerts a significant influence on normal left ventricular response to fatigue-limited supine exercise and that the gender difference is mediated, in part, by left ventricular end-systolic volume response to exercise.     

Detection of coronary artery disease with exercise two-dimensional echocardiography. Description of a clinically applicable method and comparison with radionuclide ventriculography

Two-dimensional echocardiography (2-D echo) was performed in 73 patients evaluated for coronary artery disease (CAD) and in four normal volunteers before and immediately after a maximal treadmill exercise test. Diagnostic images were obtained from the apical and parasternal windows. In 17 patients with normal coronary arteriograms, ejection fraction (EF) increased from 66 +/- 9% (+/- SD) at rest to 73 +/- 8% after exercise (p less than 0.001), while in 56 patients with proved CAD, EF fell from 56 +/- 13% at rest to 53 +/- 16% after exercise (p less than 0.01). The sensitivity of postexercise 2-D echo for detecting CAD (based on abnormal EF response and/or regional dyssynergy) was 91% (51 of 56 patients) and the specificity was 88% (15 of 17). Sensitivity for one-, two- and three-vessel disease was 64% (seven of 11), 95% (20 of 21) and 100%, respectively. Patients with multivessel disease showed a significant fall in a wall motion score index, from 0.79 +/- 0.25 to 0.63 +/- 0.26. Exercise radionuclide ventriculography (RNV) was also performed in 41 of the subjects (17 normals and 24 CAD patients) on a bicycle ergometer. The overall sensitivity of 2-D echo in this subgroup was 92%, compared with 71% for RNV. The sensitivity of 2-D echo for one-vessel disease (n = 4) was 50%, that for two-vessel disease (n = 12) was 100% and that for three-vessel disease (n = 12) was 100%. Respective values for RNV were 0%, 80% and 90%. The specificity of 2-D echo was 88% and that of RNV was 82%. A significantly higher peak heart rate response was observed on the treadmill than on the bicycle ergometer in both CAD patients and normal subjects. We conclude that postexercise 2-D echo is a clinically applicable technique for the diagnosis and evaluation of CAD patients and compares favorably with exercise RNV.     

Biventricular function in sickle-cell anemia: Radionuclide angiographic and thallium-201 scintigraphic evaluation

Left ventricular (LV) and right ventricular (RV) function were evaluated at rest and during exercise using radionuclide ventriculography in 10 patients, aged 19–53 years, with sickle-cell anemia (SCA). Seven patients were in New York Heart Association functional class I and 3 were in class II. The resting LV ejection fraction (EF) was normal in 9 patients and the resting RVEF was normal in 4. LV dilation and high cardiac output were observed in 6 patients at rest. The LVEF during exercise was normal in all 10 patients, whereas only 2 patients had normal RVEF at rest and during exercise. The LVEF was lower in patients with SCA at rest (54 ± 4 % versus 61 ± 6%, p < 0.001) and exercise (66 ± 4% versus 74 ± 6%, p < 0.001) than in 42 age-matched normal subjects. Rest thallium-201 images from 9 patients showed abnormal RV uptake in 8 and normal LV uptake in 8.Thus, in adult patients with SCA, LV function was normal during exercise in all patients and at rest in all but 1 patient. The LVEF, however, was lower than that in age-matched normal subjects. RV function was abnormal in most patients at rest and during exercise. RV thallium-201 uptake suggested pressure or volume overload (or both), most likely due to pulmonary vaso-occlusive complications of the disease.     

Radionuclide left ventricular volume curves in angiographically proved normal subjects and patients with three-vessel coronary disease

To determine the diagnostic value of measurements obtained from radionuclide left ventricular volume curves, we compared 12 patients with normal coronary arteries (NL) to 12 patients with three-vessel coronary artery disease (3V CAD). Maximum and mean rates of ejection and filling, times of maximum ejection and filling, durations of systole and diastole, and percentages of ejection and filling during each third were measured at rest and during exercise. The only group differences at rest were a 39 msec (p = 0.002) delay in the time of maximal filling and a 6% (p = 0.04) decrease in first third filling fraction in the 3V CAD patients. The overlap in values for these two parameters, however, did not allow good separation of the patients into NL and 3V CAD groups. During exercise, maximal and mean rates of ejection and filling were significantly lower in the 3V CAD group, but these measurements did not improve on the discriminative value of heart rate and ejection fraction alone. Thus, in both the resting and exercise states, measurements of instantaneous changes in left ventricular volume added little diagnostic information.     

Relationship of thallium-201 myocardial perfusion pattern to regional and global left ventricular function with exercise

Thallium-201 redistribution pattern after exercise was related to rest and exercise left ventricular regional and global function, measured by radionuclide ventriculography, in 61 patients, 50 with coronary artery disease (CAD). Sixteen patients had exclusively transient thallium defects, suggesting ischemia: in this group, mean left ventricular ejection fraction (LVEF) was 65% at rest, falling to 58% during exercise (p < 0.01). Eight patients had exclusively persistent thallium defects, suggesting scar: LVEF was unchanged during exercise, 58% to 59%. LVEF increased during exercise in the 17 patients without exercise thallium defects, seven with CAD: 66% to 73% (p < 0.05). Individual LV wall segments which exhibited translent or persistent thallium defects contracted abnormally both at rest and during exercise as compared to LV segments without exercise thallium defects. We conclude that: (1) only transient thallium defects rellably predict worsening left ventricular global function during exercise; (2) both transient and persistent thallium defects can be associlated with resting dyssynergy; and (3) in some CAD patients, apparent hypoperfusion does not necessarlly predict left ventricular dysfunction during exercise.     

Relation of right ventricular ejection fraction to exercise capacity in chronic left ventricular failure

Although the left ventricle is traditionally viewed as the heart's main pumping chamber, no correlation has been shown between left ventricular (LV) ejection fraction (EF) at rest and exercise capacity in patients with chronic LV failure. Because vasodilators with venodilating activity increase exercise capacity more than predominant arterial dilators in patients with LV failure, right ventricular (RV) function may relate to exercise capacity in these patients. In 25 patients with chronic LV failure, caused by coronary artery disease in 12 patients and idiopathic dilated cardiomyopathy in 13 patients, RVEF and LVEF at rest were measured by radionuclide angiography. Maximal upright bicycle exercise testing was also performed to determine maximal oxygen consumption, which averaged only 13 ± 4 ml/min/kg. The LVEF at rest was 26 ± 10% and did not correlate with maximal oxygen consumption (r = 0.08). However, the RVEF was 41 ± 12% and correlated with maximal oxygen consumption (r = 0.70, p < 0.001) in the same patients. The correlation was stronger (r = 0.88) in patients with coronary artery disease than in those with idiopathic dilated cardiomyopathy (r = 0.60). Thus, RVEF at rest is more predictive of exercise capacity than LVEF in the same patients with chronic LV failure. These results are consistent with the clinical observation that only venodilating agents increase exercise capacity of patients with chronic LV failure.     

The significance of platelet-vessel wall prostaglandin equilibrium during exercise-induced stress

Alterations in platelet-generated thromboxane A₂ (TXA₂) and vessel wall-generated prostacyclin (PGI₂) have been assoclated with myocardial ischemia. To examine TXA₂ - PGI₂ equilibrium at rest and during exercise stress, we studied 13 normal subjects and 15 coronary artery disease patients. Plasma TXB₂ and 6-keto-PGF_1α were measured as stable metabolites of TXA₂ and PGI₂, respectively, by radioimmunoassay. In normal subjects, plasma TXB₂ levels increased 24% during exercise from 135 ± 30 to 168 ± 42 pg/ml (p = NS). Plasma 6-keto-PGF_1α levels increased 224% from 54 ± 17 to 175 ± 57 pg/ml (p < 0.05). In coronary artery disease patients, although resting plasma TXB₂ levels (mean 136 ± 43 pg/ml) were comparable to levels in normal subjects, a greater increase (82%) occurred during exercise (mean 248 ± 70 pg/ml; p < 0.02 compared to resting levels). Resting plasma 6-keto-PGF_1α levels (mean 94 ± 28 pg/ml) were also similar to normal subjects but increased only by 43% during exercise (mean 134 ± 53 pg/ml; p = NS compared to resting levels). These data suggest that: in normal subjects TXA₂ and PGI₂ increase during exercise, PGI₂ increasing more than TXA₂, and although coronary disease patients have resting TXA₂ and PGI₂ levels in the normal range, TXA₂ levels increase more than PGI₂ levels during exercise. These observations may have a bearing on the mechanism of exercise-induced angina pectoris in certain coronary artery disease patients.     

Effects of nitroglycerin on supine and upright exercise in mitral stenosis

Resting, supine, and upright exercise hemodynamics were studied in 11 patients with pure or predominant mitral stenosis before and after 0.4 mg sublingual nitroglycerin. Resting mean pulmonary wedge pressure was reduced from 27 ± 1.6 to 21 ± 1.6 mm Hg (p < 0.001), while mean cardiac index (2.98 ± 0.40 vs 2.68 ± 0.30 cc/min/m²; NS) and mean heart rate (82 ± 4.4 vs 87 ± 6.7 bpm; NS) were unchanged after nitroglycerin. Resting mean left ventricular end-diastolic pressure dropped from 11 ± 1.7 to 8 ± 1.1 mm Hg (p < 0.02) after nitroglycerin, while stroke index (37 ± 5.1 vs 32 ± 3.8 mm Hg; NS) was unchanged. Left ventricular systolic pressure fell from 122 ± 6.0 to 111 ± 3.1 mm Hg (p < 0.001) after nitroglycerin. At peak supine exercise similar qualitative changes were observed. Mean pulmonary wedge pressure was lower after nitroglycerin (43 ± 2.3 vs 36 ± 2.1 mm Hg; p < 0.02), while cardiac index (3.62 ± 0.39 vs 3.4 ± 0.26 cc/min/m²; NS) and heart rate (116 ± 7.1 vs 113 ± 4.6 bpm; NS) were not different. Left ventricular end-diastolic pressure (13 ± 1.4 vs 10 ± 1.3; NS) was slightly but not significantly reduced by nitroglycerin. Left ventricular stroke index (34 ± 3.4 vs 31 ± 2.2 mm Hg; NS) was unchanged by nitroglycerin. Left ventricular systolic pressure (137 ± 7.3 vs 127 ± 6.1 mm Hg; p < 0.02) was reduced 10 mm Hg at peak supine exercise after nitroglycerin. During upright exercise, peak heart rate (160 ± 8.1 vs 160 ± 8.0 bpm; NS) and peak systolic blood pressure (117 ± 5.7 vs 112 ± 2.8 mm Hg; NS) were not changed with nitroglycerin. Exercise duration was improved after introglycerin (5.02 ± 0.62 vs 5.66 ± 0.65 minutes; p < 0.02). Thus sublingual nitroglycerin lowers mean pulmonary wedge pressure to reduce pulmonary congestive symptoms, improves supine exercise hemodynamics, and may enhance treadmill exercise duration in some patients with pure or predominant mitral stenosis.     

Aneurysmectomy and endocardial resection for ventricular tachycardia: Favorable hemodynamic and antiarrhythmic results in patients with global left ventricular dysfunction

Sixty-two patients underwent aneurysmectomy and endocardial resection for control of recurrent sustained ventricular tachycardia (VT). Forty patients also had coronary artery bypass grafting (CABG) (1.5 grafts per patient). The mean preoperative left ventricular end-diastolic pressure (LVEDP) was 18 ± 8 mm Hg, cardiac index (Cl) was 2.7 ± 0.7 L/min/m², and ejection fraction (EF) was 28 ± 10%. In a subset of 32 patients with clearly demarcated aneurysmal and contracting ventricular sections, the mean EF of the residual contracting section (CSEF) was 35 ± 13%, and 26 of these patients had a CSEF < 45%. There were five operative deaths (8%). No hemodynamic findings distinguished the patients who died during surgery. Patients with an LVEDP above the group mean or an overall EF below the group mean had an operative mortality of 10% and 7%, respectively. In the subgroup of 26 patients with a CSEF < 45%, the operative mortality was 12%. In the surgical survivors as a whole the LVEDP decreased from 17 ± 8 to 14 ± 5 mm Hg (p < 0.005) and the overall EF increased from 28 ± 9% to 39 ± 10% (p < 0.001) while the normal CI did not change. Linear regression analysis revealed that patients with the highest preoperative LVEDPs and the lowest overall EFs were most likely to have improvement in these parameters postoperatively. Patients with a preoperative CSEF < 45% had similar postoperative changes in their LVEDP (17 ± 6 to 15 ± 4 mm Hg) and overall EF (24 ± 7% to 38 ± 11%). In addition, the incidence of inducible VT postoperatively was similar in patients with a preoperative CSEF < 45% (4 of 23) and in the rest of the group (8 of 34, p = NS). We conclude that: (1) patients with ventricular aneurysms and medically refractory VT often have marked dysfunction of the residual contracting LV section; (2) aneurysmectomy and endocardial resection is an effective mode of therapy for VT and can be performed with a low operative mortality in this patient population; and (3) postoperatively the angiographic EF usually increases and the LVEDP often decreases, especially in patients with the most marked preoperative LV dysfunction.     

Individual variability of radionuclide ventriculography in stable coronary artery disease patients over one year

To determine the individual reproducibility of radionuclide ventriculography over an extended period of time, 33 patients with stable coronary artery disease were studied at rest and during three stages of exercise on two occasions separated by 1 year. The individual interstudy variability of ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume, and cardiac output was determined by calculating the mean and standard deviation of the difference between the individual studies (initial - 1 year). Despite high correlations between an EF measured at study 1 and study 2 of 0.96 at rest and 0.87 during maximal exercise, the individual interstudy difference was 0.01 +/- 0.04 and -0.02 +/- 0.09, respectively. The correlation of percent change in EF from rest to maximal exercise was 0.49 and the individual interstudy differences was -1.2 +/- 19%. Correlations of the EDV were 0.81 at rest and 0.72 during maximal exercise while the individual difference was 0.7 +/- 38 and -0.8 +/- 49 ml, respectively. Considering two standard deviations as the confidence limits for a true change, an EF change of 8 EF units (0.08) at rest and 18 (0.18) during exercise, and EDV changes of approximately 100 ml are needed in an individual to state with confidence that the observed difference between the two studies are true changes and not the result of technologic variability. Because of the large individual interstudy variability in EF and volume measurement, caution must be taken in assuming that any change over a year is due to more than technique variability.     

Evaluation of changes in myocardial function on exercise in patients with coronary artery disease using gated MIBI scintigraphy.

Technetium-99m-methoxy-isobutyl-isonitrile (MIBI) is a myocardial perfusion agent which allows simultaneous assessment of left ventricular function. We evaluated left ventricular (LV) function with exercise using a new method of myocardial profiling in 43 patients with chest pain. Twenty-eight had significant coronary artery disease and 15 were normal on coronary angiography. Results were compared to equilibrium radionuclide ventriculography. MIBI fractional shortening (FS) correlated well with ejection fraction (EF) on exercise (r = 0.79, P = less than 0.001). There was also a good correlation between changes in global function from rest to exercise (r = 0.82, P = less than 0.001) with a sensitivity of diagnosing CAD of 71% and specificity of 80%. New regional wall abnormalities were detected in 25/28 with CAD with a sensitivity of 89% and specificity of 60%. There was also a close correlation between mean diameters measured with gated MIBI scans and volumes measured with RNV, end-diastolic diameter (EDD) versus end-diastolic volume (EDV) r = 0.78 (P = less than 0.001) at rest and r = 0.74 (P = less than 0.001) on exercise and end-systolic diameter (ESD) versus end-systolic volume (ESV) r = 0.72 (P = less than 0.001) at rest and r = 0.72 (P = less than 0.001) on exercise. This produced a sensitivity for detecting CAD of 79% and a specificity of 73%. These results show that gated MIBI scanning on exercise provides information comparable to RNV so enhancing the diagnostic usefulness of MIBI.     

Sequential postoperative assessment of left ventricular performance with gated cardiac blood pool imaging following aortocoronary bypass surgery

The comparative effects of normothermic intermittent ischemic arrest (IIA) and cardioplegia (C) on left ventricular (LV) performance were assessed by gated cardiac blood pool imaging in 57 patients undergoing aortocoronary bypass surgery. In 34 patients, IIA was employed; 23 patients received C. Patients were studied preoperatively, sequentially in the immediate postoperative period at 30-minute intervals, and at 1 week after the operation. C and IIA groups did not differ in mean (± SEM) age, anginal class, number of diseased vessels, previous myocardial infarction, or preoperative ejection fraction (EF) (50 ± 3% vs 50 ± 2% [p = ns]). Aortic cross clamp time was greater with C than IIA (50 ± 5 minutes vs 28 ± 3 minutes [p = 0.001]). During the six sequential postoperative studies, transient LV dysfunction (≥ 7% decrease in absolute EF) was observed in 10 patients receiving C and in 16 patients receiving IIA. By time of discharge, 24 of 26 patients had returned to preoperative EF. Mean EF at discharge in the cardioplegia group did not differ compared to preoperative EF; in the IIA group, EF increased compared to preoperative EF (50 ± 2% vs 55 ± 2% [p < 0.01]). These data suggest that in patients with normal preoperative LV performance both C and IIA afford satisfactory myocardial preservation during aortocoronary bypass surgery.     

Assessment of regional left ventricular function using gated radionuclide angiography

A simple method for the assessment of regional left ventricular (LV) function using gated radionuclide angiography is described. The method divides the LV region of interest in the left anterior oblique view into quadrants using a count-weighted center point and a transparent overlay. The regional ejection fraction (EF) was determined at rest and during upright bicycle exercise for each of 3 quadrants identified as posterior, septal and apical. The study group consisted of 50 patients with chest pain. Nine of these patients had normal coronary arteries and 41 had significant coronary artery disease (CAD). Regional EF measurements were highly reproducible at rest and exercise in all regions. Regional EF values at rest were compared with the subjective assessment of wall motion on the contrast ventriculogram and were significantly lower in regions with abnormal wall motion. Regional EF increased with exercise in all patients with normal coronary arteries. In patients with CAD and normal regional wall motion at rest, the regional exercise response was significantly more sensitive (p = 0.004) than global exercise response and marginally more sensitive (p = 0.06) than the subjective assessment of exercise wall motion on visual radionuclide images in the diagnosis of CAD. These results suggest that the measurement of regional LV function may be useful in the noninvasive diagnosis of CAD.     

Effects of diltiazem-induced calcium blockade upon exercise capacity in effort angina due to chronic coronary artery disease

Few data are available regarding the effects of calcium blockade upon exercise tolerance in patients with stable effort angina due to coronary artery disease (CAD). Therefore we compared the effects of the calcium blocking agent, diltiazem (D), to placebo (P) in 12 patients with chronic effort angina and catheterization documented fixed CAD. The 8-week total protocol consisted of a 1-week baseline period followed by the double-blind randomized crossover alternate 1-week administration of P and D in doses of 120, 180, and 240 mg. Maximal exercise tests (MET) were performed at the end of each 1-week period, while rest radionuclide ventriculography (RVG) was obtained during 240 mg D and corresponding crossover P. Resting heart rate decreased from baseline and initial P at D doses of 60 and 240 mg, but not from P during crossover period. No changes were observed at any dose of D either at rest or during MET in systolic blood pressure or rate · pressure double product. D at 240 mg, but not lower doses, increased MET duration (437 vs 490 seconds, p < 0.01) and time to angina (383 vs 441 seconds, p < 0.01). Ejection fraction by RVG was greater with D than P (0.54 vs 0.50, p < 0.05). Thus these data indicate that calcium blockade with diltiazem provides antianginal efficacy by reducing myocardial oxygen demand, and increases exercise tolerance without depression of myocardial performance in effort angina patients with fixed chronic CAD.     

Sensitivity and specificity of nuclear phase analysis versus ejection fraction in coronary artery disease

Phase standard deviation (SD) and skew characteristics of the first Fourier harmonic of equilibrium radionuclide volume curves were examined and compared during rest and during supine bicycle exercise with ejection fraction (EF) changes and the development of ischemia in 17 control subjects and in 2 groups of patients (n = 57) with coronary artery disease (CAD). Group I comprised 37 patients with CAD; IA was a subgroup of 20 patients with previous myocardial infarction (MI) and IB a subgroup of 17 patients with CAD without MI (all with coronary stenosis greater than 75% diameter narrowing). Group II comprised 20 patients with CAD who had undergone coronary bypass surgery. In the Group I subjects, phase SD was the most sensitive indicator of CAD at rest (Group I, 56%; Group IA, 70%, and Group IB, 29%), and the EF was the most sensitive indicator at submaximal (Group I, 78%; Group IA, 86%, and Group IB, 64%) and maximal exercise (Group I, 70%; Group IA, 93%, and Group IB, 53%). When phase SD and skewness were combined with EF changes, little increase in sensitivity occurred in Group I (rest 61%, submaximal exercise 88% and maximal exercise 76%). The results from Group II subgroups were qualitatively similar to those observed with Group I subgroups. These data reveal a marginally improved sensitivity for detection of CAD during supine bicycle radionuclide ventriculography when phase measurements were added to changes in global EF values.     

Exercise training improves lipoprotein lipid profiles in patients with coronary artery disease

The effects of endurance exercise training on plasma lipoprotein lipids were determined in 10 men, ages 46 to 62 years, with coronary artery disease (CAD). Patients maintained body weight, health-related behaviors, and stable diets throughout the program. Training was at 50% to 85% of maximal oxygen consumption (V?O₂ max) for 40 to 60 minutes, 3 to 5 days/week for 29 ± 7 weeks. Training increased V?O₂ max (31 ± 19%, p < 0.001), reduced plasma cholesterol (C) (?8 ± 4%, p < 0.01), low-density lipoprotein-C (LDL-C) (?9 ± 9%, p < 0.01), and triglyceride (TG) (?13 ± 32%, p < 0.05) concentrations, and increased high-density lipoprotein-C (HDL-C) levels (11 ± 13%, p < 0.05) and $\text{HDL-C}\text{LDL-C}$ ratios (25 ± 20%, p < 0.01). Changes in LDL-C and V?O₂ max were correlated (r = ?0.73, p ± 0.01), while the changes in LDL-C and HDL-C each correlated inversely with pretraining lipoprotein levels (^rLDL-C = ?0.77, p < 0.01; ^rHDL-C = ?0.68, p < 0.05). Thus potentially “antiatherogenic” benefits of exercise seem to be due to a training effect, since they correlate best with changes in V?O₂ max and are maximal in patients with initially low V?O₂ max, high LDL-C, and low HDL-C levels.