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Spontaneous regression of a left anterior descending coronary artery lesion was diagnosed by noninvasive testing (stress electrocardiography and thallium-201 myocardial imaging) and confirmed on selective coronary angiography in a 46-year-old man. The patient's clinical improvement, normalization of stress ECG and thallium-201 imaging, together with the loss of collateral filling, confirm that the regression is genuine. This case provides evidence that regression of coronary atherosclerosis can occur in man.

To investigate the role of intrinsic sympathomimetic activity on left ventricular (LV) function during antianginal therapy with beta-adrenoreceptor antagonists, 23 patients with chronic, exercise-induced angina pectoris and normal or near normal LV function underwent radionuclide ventriculography at rest and during exercise, during 3 randomly allocated periods: (a) treatment with oral propranolol, a drug without intrinsic sympathomimetic activity, 40 to 80 mg 4 times a day; (2) treatment with pindolol, a drug with marked intrinsic sympathomimetic activity, 5 to 10 mg 2 times a day; and (3) a control period. During the control period, the LV ejection fraction decreased from rest (58.9 +/- 8.2%) to exercise (54.3 +/- 10.7%), and the wall motion score decreased from 0.57 +/- 1.08 at rest to 2.39 +/- 2.10 during exercise, p less than 0.001. After propranolol, the ejection fraction did not change significantly at rest (57.2 +/- 8.1%) but improved during exercise (56.8 +/- 11.8%), compared with control values. After pindolol, the ejection fraction did not change at rest (57.9 +/- 8.6%) but improved during exercise (56.9 +/- 8.1%), compared with control values. Similarly, the wall motion score after administration of both agents did not change significantly at rest, but improved during exercise (p less than 0.001). The number of anginal episodes, nitroglycerin tablets consumed, and magnitude of S-T segment depression decreased significantly with both pindolol and propranolol. With both drugs, a similar improvement in exercise tolerance and a similar decrease in exercise heart rate and blood pressure were obtained. It is concluded that pindolol and propranolol, beta-adrenoreceptor antagonists with and without intrinsic sympathomimetic activity, respectively, have similar effects on global and regional LV function in patients with angina pectoris, at doses producing equal suppression of exercise heart rate and similar antianginal effect.

The effects of mitral valve replacement or commissurotomy on cardiac function were studied using radionuclide ventriculography in 13 patients with chronic mitral stenosis and in 8 with chronic mitral regurgitation, before and after mitral valve surgery. The stenosis resulted from rheumatic heart disease in all instances while regurgitation was due to mitral valve prolapse in three patients and rheumatic heart disease in five. Fourteen patients had a Carpentier-Edwards valve inserted and 4 a Lillehei-Kaster disc valve. Three patients with mitral stenosis had an open commissurotomy. All patients underwent supine-rest and symptom-limited exercise radionuclide ventriculography shortly before and 6 to 12 months after operation. The data obtained showed that left ventricular function remained unchanged postoperatively in patients with mitral stenosis but deteriorated in those with mitral regurgitation. Right ventricular function improved postoperatively in those with mitral stenosis but remained unchanged in patients who had regurgitation.

In a 14-month period mitral leaflet prolapse was diagnosed in 85 patients by echocardiography or cineangiography. Chest pain alone was the presenting complaint in 30 patients and linked with palpitation, dyspnoea, or syncope in 9. Eleven presented with major neurological disturbances (9 had transient ischaemic attacks), 10 with palpitation, 4 with undue and persistent fatigue, 2 with dyspnoea, and 2 with dizziness. Seventeen were referred not because of symptoms but because of clicks and murmurs. Overall, chest pain affected 61 patients and unless associated with coronary artery disease was not anginal. Palpitation was admitted by 42 patients; dizziness, lightheadedness, or paraesthesiae by 15, and syncope by 12. Systolic auscultatory abnormalities were noted in 69: 25 had single clicks, 3 had multiple clicks, 19 had both click(s) and murmur, and 22 had a murmur alone. Electrocardiography revealed ST segments flat for greater than 0-10 s in 21, prolonged QTc in 18, and T wave flattening or inversion in inferior limb and lateral chest leads in 14. The exercise stress test was abnormal in 13 of 27 patients. Mitral valve echograms showed definite mitral leaflet prolapse in 61, 'possible' prolapse in 14, and were normal in 8 patients with angiographic proof of mitral leaflet prolapse. Cardiac catheterization with left ventriculography showed prolapse of posterior mitral leaflet in 36, of both leaflets in 2, and left ventricular wall motion abnormalities in 16 cases. Selective coronary arteriography in 31 cases showed major vessel narrowing of larger than or equal to 80 per cent lumen diameter in 4, all with angina. This consecutive series indicates that the physical event of mitral leaflet prolapse is more common than hitherto appreciated, is priminently associated with non-anginal chest pain, palpitation, and neurological disturbances, and in 90 per cent of cases could be shown echocardiographically.

Serial electrocardiography, technetium-99m pyrophosphate scintigraphy and measurement of myocardial creatine kinase (CK2) and lactic dehydrogenase isoenzyme activity (specifically the LD1 to LD2 ratio) were evaluated prospectively in 26 patients who underwent aortocoronary bypass grafting and 11 patients who underwent valvular or other thoracic surgery, as methods of diagnosing perioperative myocardial infarction. Of the 26 patients who had aorto coronary bypass grafting, 7 (group 1) had myocardial infarction perioperatively; of these, only 2 had positive results from all four diagnostic tests. The other 19 patients (group 2) had no perioperative myocardial infarction and the only diagnostic method yielding positive results was the LD1 to LD2 ratio, in 7 of the 19. In the 11 patients who did not undergo aortocoronary bypass grafting (group 3), only 1 patient had myocardial infarction perioperatively; results from the measurement of CK2 isoenzyme activity and LD1 to LD2 ratio were positive while electrocardiography and 99mTc pyrophosphate scintigraphy yielded negative results. The respective sensitivity (%) and specificity (%) of the four diagnostic methods were as follows: electrocardiography: 38, 100; 99mTc pyrophosphate scintigraphy: 88, 100; LD1 to LD2 ratio: 100, 68; CK2: 38, 100. When the CK2 criterion was redefined, using patients in group 2 as controls, the sensitivity and specificity of this method became 100 and 90 respectively. The authors conclude that 99MTc pyrophosphate scintigraphy and measurement of myocardial creatine kinase isoenzyme are of comparable value and are the most reliable indicators of perioperative myocardial infarction.

The efficacy of gated synchronous acquisition (GSA) after cardiac blood pool labelling in assessing left ventricular function (ejection fraction and regional wall motion) was evaluated in 31 patients within 24 hours of contrast left ventricular angiography. With the R-wave of the electrocardiogram as a physiologic marker, radionuclide data recorded into an on-line computer allowed construction of cardiac blood pool images during sequential periods of the cardiac cycle. The images, of high count density, have good spatial resolution and can be viewed repetitively in real time in a cine mode. The ejection fractions calculated from the left ventricular time-activity curves corrected for background activity correlated well with the ejection fractions determined from dimension analysis of the contrast left ventricular angiograms (r = 0.87). The results were highly reproducible (r = 0.97). Results of analysis of left ventricular wall motion were similar with the two types of angiograms in 26 of the 31 subjects. GSA is a simple, safe means of evaluating left ventricular ejection fraction and regional wall motion noninvasively.

Regular tachycardia with wide QRS complexes may be difficult to classify as supraventricular (SVT) or ventricular (VT) without electrophysiologic studies. We felt that hemodynamic differences between VT and SVT should allow their distinction by echocardiography. In this study, we utilized high speed M-mode echocardiography in the usual projections in eight patients during tachycardia. Two patients had spontaneous VT and three had spontaneous SVT with aberrant conduction. The remaining three were patients in sinus rhythm undergoing electrophysiologic studies in whom right ventricular (RV) pacing (induced VT), right atrial (RA) pacing (induced SVT) and sequential RV-RA pacing (induced VT with 1:1 retrograde conduction) were carried out. The echocardiographic parameters studied included: left ventricular internal dimensions, time during which the mitral valve remained open (MVOT), left ventricular ejection time (LVET) and pre-ejection period. We measured 20 consecutive beats and for each parameter defined its variability. During A-V dissociation (VT, RV pacing) there was always a striking beat-to-beat variability in the values of MVOT (68 percent to 129 percent) and in LVET (41 percent to 175 percent). In contrast, during A-V association (SVT, sequential RV-RA pacing, sinus rhythm) the maximal variability of MVOT and LVET was 22 percent and 12 percent, respectively. Variability during A-V dissociation could be explained by asynchronous timing of atrial systole. We conclude that echocardiography can readily identify atrioventricular dissociation, a feature heavily in favor of a diagnosis of VT.

Between May 1980 and April 1981 four patients were referred to one hospital with syncope or recurrent ventricular fibrillation while taking antiarrhythmic or phenothiazine drugs. In all the patients ventricular tachyarrhythmias with the characteristics of torsades de pointes were documented in association with prolonged QT intervals. With removal of the offending agent (in all the patients) supplemented by temporary overdrive pacing (in two patients) the tachyarrhythmias subsided. This study suggests that drug-induced torsades de pointes is an important clinical entity that occurs more frequently than has been suspected.

In a previous report from our laboratory, visual assessment of wall motion in patients with coronary artery disease demonstrated no advantage for pindolol, a beta blocking agent with intrinsic sympathomimetic activity (ISA), over propranolol on impaired regional left ventricular (LV) function. In this study, we reanalyzed the radionuclide ventriculograms using a computer-assisted method of deriving regional ejection fraction. Use of normalized values allowed hypokinetic and normokinetic segments to be identified and examined separately. Pindolol (5-10 mg twice a day) was compared to propranolol (40-80 mg 4 times a day) in 23 patients using a randomized, crossover study design. Supine resting heart rate was reduced less (70 +/- 12 beats/min vs 63 +/- 10 beats/min, p less than 0.01) by pindolol; exercise heart rate was reduced equally by both agents. Derivation of normalized regional LV ejection fractions showed that 17 segments were hypokinetic at rest. Function of these segments increased (p less than 0.02) with pindolol. This improvement was not detected by visual assessment of regional wall motion. Thirty-seven segments were found to be hypokinetic during exercise and a significant (p less than 0.05) improvement in function occurred with pindolol and propranolol. In summary, derivation of normalized regional LV ejection fraction values allows the demonstration of significant improvement in resting LV function with pindolol, but not with propranolol in patients with regional dysfunction due to coronary artery disease. This advantage may provide a rationale for further evaluation of this agent in patients with more widespread ventricular dysfunction.

Short-term amrinone therapy has been shown to exert beneficial hemodynamic effects in patients with heart failure. To determine whether this improvement persists longer, the effects of maximally tolerated doses of amrinone on exercise duration, oxygen consumption, and left ventricular function and volumes were examined during maintenance therapy. After four weeks of amrinone therapy, 75 to 150 mg three times a day (mean 292 +/- 70 mg daily), treadmill exercise duration, maximal oxygen consumption, and functional class were unchanged from control values. Radionuclide-derived ejection fraction and end-diastolic and end-systolic volumes were not altered at rest or during maximal supine exercise. Similarly, significant changes in echocardiographic end-systolic and end-diastolic dimensions did not occur. This lack of clinical benefit on functional capacity and left ventricular function, together with frequent adverse reactions, will limit the application of amrinone in the treatment of heart failure. These findings are relevant to the investigation of amrinone-like derivations presently being studied for the treatment of heart failure. Before their release, these agents will require careful evaluation and demonstration of a therapeutic action during maintenance therapy, together with a low incidence of adverse reactions.

A simple, accurate, noninvasive method is required for the objective evaluation of aortocoronary bypass surgery. Stress myocardial imaging with intravenous injection of potassium-43 or thallium-201 was used an average of 4.4 months after direct myocardial revascularization in 77 patients to assess the accuracy of stress myocardial imaging in predicting completeness of revascularization. The results were correlated with maximal treadmill exercise tests, extent of revascularization and status of bypass grafts (occlusion, stenosis and distal disease). We found stress myocardial imaging to be a more sensitive method than the stress electrocardiogram for the detection of incomplete revascularization. The method appears to be a sensitive noninvasive means of evaluating the results of aortocoronary bypass surgery.