John E. Morch

Clinically unrecognized ventricular dysfunction in young diabetic patients.

Left ventricular function at rest and during supine bicycle exercise was assessed by gated radionuclide angiography in 20 diabetic patients and 18 normal control subjects without clinical evidence of heart disease. The diabetic patients were aged 21 to 44 years and all except one used insulin. No subject developed chest pain or electrocardiographic changes during exercise. Both groups had a similar rest and exercise heart rate and blood pressure, and both achieved similar work loads. The control group had an ejection fraction at rest of 65.4 +/- 6.2% (mean +/- SD) and only 1 of 18 showed a decrease with exercise; peak exercise ejection fraction averaged 77.1 +/- 7.8%. The diabetic group had a mean ejection fraction at rest of 63.7 +/- 6.5%, similar to that of the control group, but 7 of 20 showed a decrease during exercise; the exercise ejection fraction averaged 67.7 +/- 9.7%, significantly lower than that of the control group (p less than 0.01). The diabetic patients varied widely in ejection fraction response to exercise, ranging from an increase of 25% to a decrease of 21%. This response did not correlate with age, sex, duration of diabetes, smoking, retinopathy, exercise heart rate, blood pressure or rate-pressure product, work load attained or ejection fraction at rest. These data suggest that approximately one-third of patients with diabetes have subclinical left ventricular dysfunction without correlation to risk factors for atherosclerosis or other diabetic complications. Whether this is due to unrecognized coronary artery disease or primary myocardial disease remains unknown.

Clinical assessment of external pressure circulatory assistance in acute myocardial infarction. Report of a cooperative clinical trial.

Abstract The clinical effects of early application of external pressure circulatory assistance (EPCA) in acute myocardial infarction were evaluated in a prospective, randomized trial involving 258 patients in 25 institutions. All patients had mild left ventricular failure and received circulatory assistance within the first 24 hours after the onset of symptoms. There were no significant differences between the treatment and control groups, consisting of 142 patients and 116 patients, respectively, with regard to age, sex, race, previous cardiac history, electrocardiographic location of myocardial infarction, Norris prognostic index, admission heart rate, blood pressure and chest roentgenogram, and time from onset of symptoms to hospital admission. There were also no differences between the treatment and control groups with regard to antiarrhythmic, positive inotropic, diuretic and vasodilator therapy. Hospital mortality was significantly decreased, compared with that of control patients, in the group receiving 4 or more hours of external pressure circulatory assistance within the first 24 hours after admission (mortality rate 6.5 percent [7 of 108] in treatment group versus 14.7 percent [17 of 116] in control group, p

Detection of acute myocardial infarction by technetium-99m polyphosphate

Experimental work has shown that technetium-99m (99mTc) pyrophosphate accumulates in recently infarcted myocardium and can be detected by external imaging techniques. Twenty-two 99mTc polyphosphate myocardial studies were performed in 17 patients (in 3 after cardiac surgery) 3 to 20 days after myocardial infarction. Seventeen myocardial studies were performed in 17 control patients (in 6 after cardiac surgery). Twenty millicuries of 99mTc polyphosphate was injected intravenously 60 to 120 minutes prior to gamma camera imaging in several views. Myocardial images were processed by the Gamma-11 computer system using standardized background subtraction and contrast enhancement. Results of 16 myocardial studies performed 4 to 20 days after transmural myocardial infarction in 12 patients were positive in 13 instances and questionable in 1. The location of the myocardial infarction by imaging corresponded to location by standard electrocardiograhic criteria in 8 of the 10 patients with positive findings. In five patients with nontransmural myocardial infarction, results of myocardial imaging were positive in two, questionable in one and normal in one. In one patient with questionable findings results were normal when imaging was repeated 16 days after nontransmural myocardial infarction. Results of 17 control myocardial imaging studies were normal in 16 and questionable in 1. Therefore, 99mTc polyphosphate myocardial imaging appears promising in the detection and location of transmural myocardial infarction. Its accuracy in detecting nontransmural myocardial infarction may be increased with greater experience and development of sophisticated digital analysis techniques. The method may prove useful in clinical situations such as cardiac surgery in which standard diagnostic aids are difficult to interpret.

Prinzmetal's angina with coronary artery spasm. Angiographic, pharmacologic, metabolic and radionuclide perfusion studies.

We studied the effects of coronary artery spasm on perfusion of the microvasculature in a patient with Prinzmetals angina. Intracoronary injections of 99mTc and 131I-labelled macroaggregated human serum albumin were performed (1) at rest, (2) during spontaneous angina, (3) after the administration of nitroglycerin and (4) during pacing-induced spasm and the resultant scans compared. The resting scan was normal. Pain and spasm were associated with a perfusion defect that was localized to the anterior and inferior walls of the left ventricle. The localization of the perfusion defect corresponded with angiographically demonstrated spasm involving left anterior descending and distal circumflex coronary arteries. A subsequent myocardial infarction was localized by 43K scanning to the same perfusion area. Metabolic and parasympathetic stimulation studies were performed but were inconclusive. The patients recurrent pains were ultimately controlled with large oral doses of isosorbide dinitrate.

Rest and Exercise Ventricular Function in Adults With Congenital Ventricular Septal Defects

Rest and exercise right and left ventricular function were compared using equilibrium gated radionuclide angiography in 19 normal sedentary control subjects (mean age 28 years, range 22 to 34) and 34 patients with hemodynamically documented congenital ventricular septal defect (VSD) (mean age 27 years, range 20 to 40). The 34 patients with VSD were divided into 3 groups: those in Group 1 (17 patients) had pulmonary to systemic blood flow ratios of less than 2 to 1; those in Group 2 (12 patients) had prior surgical closure of VSD (mean interval from surgery 17 years, range 9 to 22), and those in Group 3 (5 patients) had Eisenmengers complex. Gated radionuclide angiography was performed at rest and during each level of graded supine bicycle exercise to fatigue. Heart rate, blood pressure, maximal work load achieved, and right and left ventricular ejection fractions were assessed. The control subjects demonstrated an increase in both the left and right ventricular ejection fractions with exercise (0.70 +/- 0.07 to 0.79 +/- 0.05 and 0.46 +/- 0.06 to 0.57 +/- 0.04; p less than 0.001 for left and right ventricles, respectively). All study groups failed to demonstrate an increase in ejection fraction in either ventricle with exercise. Furthermore, resting left ventricular ejection fraction in Groups 2 and 3 was lower than that in the control subjects (0.59 +/- 0.09 and 0.54 +/- 0.06 versus 0.70 +/- 0.07; p less than 0.001) and resting right ventricular ejection fraction was lower in Group 3 versus control subjects (0.30 +/- 0.07 versus 0.46 +/- 0.06; p less than 0.001). Thus (1) left and right ventricular function on exercise were abnormal in patients with residual VSD as compared with control subjects; (2) rest and exercise left ventricular ejection fractions remained abnormal despite surgical closure of VSD in the remote past; (3) resting left and right ventricular function was abnormal in patients with Eisenmengers complex; (4) lifelong volume overload may be detrimental to myocardial function.

Long-term angiographic assessment of the influence of coronary risk factors on native coronary circulation and saphenous vein aortocoronary grafts

The influence of smoking, hyperlipidemia, and glucose intolerance on graft patency and rate of progression of obstructive disease in the native circulation was assessed in 99 patients 1 1/2 years after aortocoronary bypass grafting. There were 24 patients in whom none of these risk factors was identified. There were 42 patients with one, 29 with two, and four with three risk factors. Overall graft patency rate was 74%. Graft patency was not significantly influenced by any of these factors either singly or in combination. Progression of obstructive disease in both proximal and distal segments of grafted vessels and in nongrafted vessels was not significantly increased by the presence of one, two, or three risk factors. Over all, there was progression in 56% of segments proximal to grafts, in 8% distal to grafts, and in 14% of nongrafted vessels. Longer term studies will be required to establish any adverse influence of these risk factors on saphenous vein bypass grafts and native circulation.

Measurement of left anterior descending coronary arterial blood flow: Technique, methods of blood flow analysis and correlation with angiography*

This study was designed to determine if any correlation exists between the degree of narrowing of the left anterior descending coronary artery and blood flow in this vessel as estimated by the 133 xenon bolus technique. Thirty-four patients were studied at rest; 15 had a normal left anterior descending coronary artery angiographically and the remaining 19 had 50 to 90 percent stenosis of this vessel. After a bolus infusion of 133 xenon into the left coronary artery, blood was withdrawn continuously from the great cardiac vein with counts accumulated over 0.5 to 1 second. The washout curves were analyzed and blood flow of the left anterior descending coronary artery per unit volume was determined by the exponential, cubic polynomial and height/area methods. There was no correlation between the degree of narrowing on angiograms and the flow values determined by any of the methods of analysis. Two alternative explanations are discussed: Either flow is maintained in a severely stenosed vascular tree or the methods of measuring flow and estimating arterial narrowing are inaccurate.

Radionuclide angiography and endomyocardial biopsy in the assessment of doxorubicin cardiotoxicity

Thirty-eight patients with a mean age of 53.2 years (19 to 75 years of age), who were receiving doxorubicin (D) for malignant disease, were studied in order to determine the relationship between functional and morphologic myocardial changes at different dose levels. Serial patient evaluations included physical examination, chest x-ray, electrocardiogram (ECG), endomyocardial biopsy (EMB), and rest-exercise gated nuclear angiography (GNA), at doses of D ranging from 144 to 954 mg/m2 (mean, 426 mg/m2). Physical examination, chest x-ray, and ECG proved to be insensitive predictors of D cardiotoxicity. Correlation of GNA and EMB in 31 patient evaluations, exclusive of known heart disease, did not reveal any false-positive angiograms, and all abnormal GNAs were associated with abnormal biopsies. Use of stress GNA uncovered six abnormal ventricles which could have been missed with a rest GNA alone. It has been suggested that: (1) GNA is a reliable monitor of D therapy; (2) an exercise study should be performed when the rest ejection fraction is normal, but is unnecessary when the rest EF is abnormal; (3) all patients with a resting ejection fraction of less than 45%, exclusive of other cardiac disease, should have D discontinued; and (4) endomyocardial biopsy is useful in assessing D cardiotoxicity in patients with other possible causes of an abnormal GNA.

Effect of intravenous and intracoronary nitroglycerin on left ventricular wall motion and perfusion in patients with coronary artery disease

Abstract Left ventricular anterior wall motion and distribution of coronary perfusion were assessed by contrast cineangiography and the dual isotope-labeled intracoronary microsphere technique before and after intravenous or intracoronary administration of nitroglycerin in 30 patients with significant left anterior descending coronary artery disease and resting anterior wall asynergy. Perfusion was measured in 11 additional control patients before and after administration of saline solution. Reversible asynergy was observed in 6 (43 percent) of 14 patients after systemic (intravenous) nitroglycerin and in 7 (44 percent) of 16 patients after intracoronary nitroglycerin. Significant reductions of blood pressure and improved wall motion were noted in both groups receiving nitroglycerin, suggesting afterload reduction as the common mechanism. There was also a small increase in end-diastolic volume index in patients with reversible asynergy after intracoronary administration of nitroglycerin, but no significant trends in preload change after intravenous administration. Ejection fraction increased significantly in patients with reversible asynergy after both intravenous and intracoronary nitroglycerin. Both intravenous and intracoronary nitroglycerin resulted in significant increases and decreases in distribution of coronary perfusion to the anterior wall. However, these changes were randomly distributed and improved perfusion did not consistently occur with improved wall motion. In conclusion, both intravenous and intracoronary nitroglycerin may reverse wall motion asynergy and produce both favorable and unfavorable changes in perfusion in patients with coronary disease. The common mechanism in improving wall motion with either intravenous or intracoronary nitroglycerin was afterload reduction, suggesting that the systemic effects of nitroglycerin are the most important in reversing asynergy.

Mitral Regurgitation Measured by Continuous Infusion of 133Xenon An Evaluation of the Method in 91 Patients

Abstract Mitral regurgitant flow levels and fractions were measured in 91 patients using a constant infusion of 133 xenon solution as an indicator. Regurgitant flow measurements ranged from 0.01 to 11.8 liters/min. Uniformity of left atrial mixing and negligible recirculation was achieved. The 133 xenon method was compared with other methods of measuring mitral regurgitation. This convenient technique was of great assistance in reaching conclusions about patients with mixed mitral stenosis and regurgitation, multiple valve replacement or mitral regurgitation associated with myocardial disease. We conclude that, because of the few sources of error and its clinical reliability, the 133 xenon method is one of the most accurate available.