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Biomedical subjects

H MacVaugh

Publications and source records attributed to H MacVaugh.

11 recordsLinked to original sources
PubMed1979

Cellular electrophysiology of human myocardial infarction. 1. Abnormalities of cellular activation.

Ventricular tissues were obtained at the time of operation from 12 patients who underwent aneurysmectomy or mitral valve replacement. The electrophysiologic characteristics of these tissues were determined in a tissue bath using microelectrodes. Normal-appearing action potentials were recorded from surviving Purkinje fibers and ventricular muscle cells within infarcted ventricular tissues. Normal muscle action potential recordings from infarcted tissues were similar to action potentials from noninfarcted papillary muscles, except that the duration of the action potential was significantly longer in the former. In other areas slow response potentials were recorded. These action potentials conducted slowly and were eliminated by verapamil. We observed verapamil-sensitive slow response automaticity, but this did not correlate with ventricular tachycardias, present in three patients. Variable amplitude responses arising from normal resting potentials and characterized by stimulus intensity-dependent changes in action potential amplitude were recorded in tissues from two patients. These potentials had many characteristics similar to the slow response, but were not eliminated by verapamil. We also saw inexcitable cells with both normal and abnormal resting potentials. The heterogeneous electrophysiologic characteristics of these tissues provide a likely substrate for arrhythmias and may be the source of the ectopic ventricular rhythms observed in these patients.

Action Potentials↗
PubMed1979

Tricuspid valvular incompetence and rupture of the ventricular septum caused by nonpenetrating trauma.

A young adult involved in an automobile accident had tricuspid valvular incompetence and rupture of the ventricular septum owing to blunt trauma. He had a successful repair of the ventricular septal defect and replacement of the tricuspid valve. Tricuspid valvular incompetence owing to nonpenetrating trauma is uncommon. Blunt trauma resulting in rupture of the ventricular septum is rare. Rupture of the membranous portion of the ventricular spetum is extremely rare. This is the first report of a patient having a combination of these lesions.

Adult↗
PubMed1979

Retinal arteriolar changes as an indicator of coronary artery disease.

Funduscopic examination was performed in 70 non diabetic, nonhypertensive patients without valvular heart disease undergoing coronary angiography for evaluation of chest pain syndromes to determine if retinal arteriolar changes could reliably predict presence of coronary artery disease. Retinal arteriolar changes were graded with respect to light reflex, vessel caliber, arteriovenous crossing defects, and vessel tortuosity without knowledge of angiographic findings. Each coronary vessel was graded with respect to its most occlusive lesion by angiography; coronary index was derived for each patient without knowledge of eye findings. Abnormal light reflex changes were the most sensitive indicators of presence and extent of coronary artery disease. Abnormal vessel tortuosity and decreased caliber were less sensitive but more specific; their presence also suggested more extensive coronary lesions. Thus, funduscopic examination demonstrating specific retinal arteriolar lesions may indicate presence of coronary artery disease and may correlate with extent of lesions in selected patients.

Adult↗
PubMed1978

Fascicular conduction distrubances after coronary bypass surgery.

Two hundred patients underogoing coronary bypass graft surgery were studied to determine the frequency and significance fo new fascicular conduction distrubances. The follow-up period ranged from 13 to 39 months. New disturbances developed in 39 patients (20 percent). Isolated right bundle branch block (6 percent) and left anterior hemiblock (6 percent) were the most common disturbances. Righ bundle branch block was usually transient and was not associated with further complications in the follow-up period. However, patients with either transient or persistent left bundle branch block or left anterior hemiblock, or both, had (1) increased later mortality compared with patients without new fascicular conduction disturbances (5 of 26 versus 11 of 161; P less than 0.02), and (2) increased late myocardial infarction (2 of 26 versus 2 of 161; P less than 0.05). New left fascicular conduction disturbances after coronary surgery identified a subset of patients with more extensive ischemic heart disease, suggesting that these patients require close follow-up care.

Adult↗
PubMed1978

Surgery using cardiopulmonary bypass in the elderly.

This study included 89 patients, 70-82 years (mean 72.8 years), who had procedures using cardiopulmonary bypass since 1955. Twenty-six patients had elective aortic valve replacement (AVR), with two hospital deaths. One patient who underwent emergency AVR for bacterial endocarditis died of septic shock. Ten patients had AVR and coronary artery bypass surgery (CABG), with one hospital death (10%). Fourteen patients had mitral valve replacement (MVR), with eight hospital deaths (57%). Two died of left ventricular rupture after leaving the operating room, and the remainder died of low cardiac output. Twenty-five patients had CABG with no early deaths. Seven patients had aneurysms of the thoracic aorta, with two early deaths. Six patients had other procedures with one death, making a total of 16 operative deaths in the 89 patients. Eighty-four of the patients (94%) were New York Heart Association (NYHA) Functional Class III or IV for congestive heart failure and/or angina, preoperatively. Of these, 12 were in extremis immediately before surgery, and six survived. There were 10 late deaths. The actuarial survival rates for one, two and five years for all patients were 69% (40 patients), 47% (20 patients) and 21% (seven patients), respectively. At recent follow-up (mean 20 months) 84% of the hospital survivors were symptomatically improved at least one NYHA Functional Class. We conclude that CABG and/or AVR can be performed in elderly patients with a low hospital mortality and with symptomatic improvement. However, MVR in the elderly carries an unusually high mortality (7.3 times greater than patients less than 70, in our experience), and this risk must be weighed when considering MVR in these patients.

Aged↗
PubMed1978

Aspirin- and coumadin-related bleeding after coronary- artery bypass graft surgery.

We studied 100 consecutive patients to evaluate the potential effect of platelet active and antithrombotic agents prescribed preoperatively on bleeding complications after coronary-artery bypass graft surgery. Preoperative hemostatic values were normal in all patients. Mean mediastinal blood loss was significantly greater in 13 patients taking aspirin (892 +/- 91 ml) and six patients taking Coumadin (warfarin sodium) (858 +/- 168 ml) within 7 days of surgery than in 64 control subjects (439 +/- 28, P less than 0.001). Less marked but similar differences (P less than 0.05) were noted with other agents inhibiting platelet function. However, in nine patients given heparin, mean mediastinal blood loss (436 +/- 61 ml) was no different from that of control subjects. The degree of mediastinal blood loss did not correlate with age, sex, mean total operative time, bypass time, or number of vessels diseased or bypassed. In addition, patients taking aspirin or Coumadin required prolonged chest tube drainage compared to those in heparin or control groups (34 +/- 4 versus 20 +/- 1 h) (P less than 0.001).

Aged↗
PubMed1976

Coronary artery surgery. Operative technique and patient education.

Coronary artery surgery, the preferred technique for myocardial revascularization in patients with ischemic heart disease, promptly increases blood flow to areas of the myocardium distal to the coronary obstruction. CAS completely relieves angina in 90% of patients. The risk of 1 to 5% is decreasing as operative technique and patient selection improve. Patients having CAS need comprehensive preoperative and discharge teaching to restore them to normal, active, optimistic lives.

Aftercare↗
PubMed1975

Early and late effects of the coronary bypass operation on cardiac contractility and coordination.

In 100 cases of coronary heart disease, cardiac contractility was studied before and after coronary bypass by a flow method, the force ballistocardiogram, and by a pressure method, the carotid pulse derivative. The two methods gave very similar results in most cases, and the agreement of their averages was impressive. A marked increase in cardiac strength, reaching its maximum a month or two after operation, followed the procedure in most cases. Cardiac coordination was also improved at this time in many subjects, but complete cardiac normality was very rarely attained. This early postoperative improvement was greater in hearts judged to be weak before operation than in those judged to be normal in strength. The early cardiac improvement was seldom held in its entirety, but usually declined at a rate, which, if continued, would abolish the postoperative improvement in about three years. This rate of cardiac decline was many times faster than that found in healthy persons or in unoperated cases of mild angina as age advanced. Nevertheless, in over 1/3 of our cases followed for a year and a half or longer, their hearts were still stronger or better coordinated, or both, than they had been before operation, and there is reason to believe that the decline was leveling. At their last test, the great majority of patients still reported that subjective improvement in their angina continued. This subjective improvement was significantly related to objective improvement of cardiac contractility in our date, but there was one striking exception to this rule. Previous studies of results following internal mammary artery ligation anf the Vineberg procedure afford an important control to the present work.

Adult↗