Teaching and learning during a visit to China.
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Cardiology↗
Biomedical subjects
I L Macdonald
Publications and source records attributed to I L Macdonald.
Cocaine-induced myocardial infarction.
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Adult↗
Complications of coronary arteriography.
In a prospective study of coronary arteriography with Judkins' technique the rate of major complications in 713 patients was 2.1%, a rate similar to or lower than those reported from other studies, even though more major complications were considered in this study. No deaths occurred. Although the rate of "other" complications was noted as part of the quality care survey, it cannot be compared with that in other studies, since the latter did not consider events such as hematoma or incomplete catheterization. The low complication rate may be related to expeditious procedures, familiarity with the Judkin's technique and the operators' experience. Local quality care assessment or clinical review committees should formally evaluate the complication rates for operative and invasive procedures performed in their own institutions.
Angiography↗
Atrial septal defect in adult identical twins: a variation in theme.
The diagnosis of atrial septal defect was established in monozygotic twin females at age 63. Each patient mimicked a different acquired heart disease. One twin had congestive heart failure and atrial fibrillation and was diagnosed as having rheumatic mitral insufficiency. The other twin had atypical chest pain and systemic hypertension and was thought to have arteriosclerotic heart disease. In each case the correct diagnosis was made at cardiac catheterization. Although the same basic congenital heart lesion was present in both patients, the symptoms and findings differed. Symptomatic improvement was achieved by different therapeutic modalities. One patient had open heart surgery, while the other twin improved with medical therapy.
Cardiac Catheterization↗
Myocardial infarct extension: prevalence, clinical significance, and problems in diagnosis.
To examine the prevalence, clinical significance, and problems in the diagnosis of myocardial infarct (MI) extension, 103 patients with acute MI were studied. Each patient underwent enzymatic infarct sizing in the initial 72 hours and then had quantitative CK-MB (myocardial isoenzyme of serum creatine kinase) analysis at 8-hour intervals over the remaining hospitalization. In addition, daily standard 12-lead ECGs and documentation of prolonged (greater than 15 minutes) resting ischemic chest pain were recorded. MI extension, by CK-MB methods, occurred in 32 (31%) of 103 patients at 5.9 +/- 0.3 days after initial infarction. ECG changes suggesting MI extension occurred in 14 (14%), but only six of these patients had extension by CK-MB. Similarly, recurrent chest pain following initial MI occurred in 28 (27%), but enzymatic extension was evident in only 11 of these patients. MI extension resulted in significantly greater early in-hospital mortality (16%) compared to those patients without MI extension (2.8%, p less than 0.05). Thus MI extension occurs commonly and may explain some early in-hospital deaths post MI. The usual clinical and ECG diagnostic parameters utilized are insensitive indicators of enzymatic MI extension.
Adult↗
Coronary disease progression and its effect on left ventricular function.
To determine the effect of coronary disease progression on left ventricular function, 47 patients who had two cardiac catheterizations at a mean interval of 25 months (range three to 92 months) without intervening surgery were studied. Of these, 35 patients had coronary disease and 12 patients had normal or near normal coronary arteries. Coronary disease progression was seen more often in patients with initial coronary disease than in those without significant disease (66 percent vs 25 percent, p less than 0.02). Left ventricular ejection fraction decreased in patients with coronary disease progression (0.63 +/- 0.03 to 0.51 +/- 0.04, p less than 0.01) but was unchanged in patients without progressive disease (0.58 +/- 0.04 to 0.57 +/- 0.93, p = NS). Interval myocardial infarction was the major cause of deteriorating left ventricular function. The rate or degree of coronary disease progression did not predictably change global left ventricular function, and progressive disease in individual vessels did not predictably alter regional left ventricular function. The presence or development of collateral vessels did not significantly alter ventricular performance.
Angiography↗
Coronary artery spasm during myocardial infarction.
A 51 year old man presented with unstable angina. Following initial improvement, the patient had prolonged, continuous chest pain resulting in myocardial infarction. During the evolving myocardial infarction, coronary angiography was performed and demonstrated coronary spasm superimposed on a high-grade atherosclerotic lesion. The role of coronary spasm in the etiology of myocardial infarction is discussed. Subsequent aorto-coronary bypass surgery was performed uneventfully.
Coronary Angiography↗
Rapidly progressive vegetative endocarditis.
Echocardiography has become a valuable tool in visualizing and localizing vegetations in patients with bacterial endocarditis. Since the natural course of vegetative lesions remains poorly understood, we report a case of a rapidly progressive vegetative lesion in a patient with staphylococcal endocarditis. Although the significance of this observation will require a larger experience, it may represent an accelerated form of disease necessitating surgical management.
Adult↗
Serial angiographic studies before and after acute myocardial infarction in man.
In this study, 6 patients underwent angiographic assessment prior to and subsequent to acute myocardial infarction. The mean inter-angiographic interval was 36 months and the mean infarct to angiography interval was 8 months. Left ventricular ejection fraction decreased from 0.69 to 0.45 after infarction. The degree of left ventricular dysfunction after infarction did not necessarily relate to the site or type of infarction. All patients had significant progression of their coronary lesions with occlusion of a major coronary vessel in the interval. Coronary artery occlusion with infarction produces a variable degree of damage and subsequent left ventricular dysfunction.
Adult↗
Long-term results following coronary bypass operation. Importance of preoperative actors and complete revascularization.
The initial 102 patients who underwent aorta-coronary bypass grafting between 1969 and 1971 were followed for a mean of 96 months (minimum follow-up 7 years). Preoperative variables predictive of survival at 5 years were stability of angina, previous heart failure, and left ventricular function. Stability of angina, previous heart failure, previous myocardial infarction, and smoking were important predictors of symptomatic status at 5 years. At operation, 62 patients had anatomic or technically complete revascularization, whereas 40 had incomplete revascularization. There was a significantly improved survival rate in those patients who were completely revascularized. The 5 year survival rate was 84% for completely revascularized patients compared to 96% for incompletely revascularized patient (p less than 0.02). This improvement in survival was continued to 9 years. There was also a significant improvement in asymptomatic status of the completely revascularized patients compared to the incompletely revascularized patients. At 2 years, 75% of the completely revascularized subjects were asymptomatic compared to 45% of the incompletely revascularized patients. However, this difference disappeared after 5 years. Thus complete myocardial revascularization is superior to incomplete revascularization in terms of survival and asymptomatic state. Preoperative variables may be useful in predicting postoperative results.
Actuarial Analysis↗
Coronary artery spasm during acute myocardial infarction.
A 51 year old man presented with unstable angina. Following initial improvement, the patient had prolonged, continuous chest pain resulting in myocardial infarction. During the evolving myocardial infarction, coronary angiography was performed and demonstrated coronary spasm superimposed on a high-grade atherosclerotic lesion. The role of coronary spasm in the etiology of myocardial infarction is discussed. Subsequent aorto-coronary bypass surgery was performed uneventfully.
Acute Disease↗
Is it important to preserve the chordae tendinae and papillary muscles during mitral valve replacement?
To evaluate the importance of preserving chordae tendinae and papillary muscles to left ventricular function after mitral valve replacement, 12 dogs had Carpentier-Edwards or Björk-Shiley mitral valves inserted. Cardiopulmonary bypass, systemic hypothermia at 25 degrees C and cold cardioplegia were used. The period of anoxic arrest was 30 minutes. In six dogs, mitral valve replacement was performed after complete excision of the mitral valve. In the other six dogs the anterior leaflet was partially excised but all chordae tendinae and papillary muscles were left intact. Hemodynamic measurements, including left ventricular function following volume loading, were made preoperatively and postoperatively. Left ventricular angiograms were obtained postoperatively in all dogs. Preoperatively there was no significant difference in the left ventricular function curves in the two groups, but postoperatively the curves showed significant differences. In the group with preserved chordae tendinae, left ventricular function improved with volume loading to a left ventricular end-diastolic pressure of 20 mm Hg while in the group with divided chordae tendinae, function improved more slowly and ceased to improve after loading to an end-diastolic pressure of 15 mm Hg. The mean left ventricular ejection fraction following mitral valve replacement with preserved papillary muscles was 0.62 +/- 0.01 and with divided papillary muscles was 0.45 +/- 0.05 (P less than 0.05). The authors conclude that it is important to preserve chordae tendinae and papillary muscles when carrying out mitral valve replacement.
Animals↗
The effect of hemodialysis on cardiac rhythm and performance.
The effects of hemodialysis on cardiac rhythm and left ventricular function were evaluated by Holter electrocardiographic monitoring and M-mode echocardiography in 22 stable patients on regular hemodialysis in hospital. Significant ventricular arrhythmias occurred in 9%. Mean left ventricular volume in diastole (LVVd) decreased significantly after dialysis from 156 +/- 12 ml to 135 +/- 9 ml (P less than 0.001). Similarly, mean left ventricular volume in systole (LVVs) decreased from 51 +/- 9 ml to 42 +/- 6 ml (P less than 0.025). Left ventricular function, as measured by mean velocity of circumferential fiber shortening (VCF), increased significantly for the entire group from 1.25 +/- 0.06 circ/sec to 1.38 +/- 0.06 circ/sec (P less than 0.05). Pre-dialysis VCF was normal in 15 patients (Group 1) and abnormal (less than 1.10 circ/sec) in 7 patients (Group 2). The mean VCF after VCF after dialysis did not change in Group 1 (1.40 +/- 0.05 circ/sec to 1.42 +/- 0.06 circ/sec, P = NS) but increased significantly in Group 2 (0.92 +/- 0.06 circ/sec to 1.29 +/- 0.12 circ/sec, P less than 0.005). There was no significant change in cardiac output or peripheral vascular resistance. Hemodialysis, when performed with careful potassium monitoring, has a low incidence of ventricular arrhythmias. In addition, hemodialysis reduces left ventricular volumes and improves overall cardiac performance in patients with abnormal left ventricular function predialysis.
Adult↗