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.

In this report major risk factors in coronary heart disease (CHD) are reviewed, with particular emphasis on the role of nutrition. International and national epidemiologic data indicate that reducing or eliminating certain risk factors (e.g., a diet high in cholesterol and saturated fats) may reduce the risk of premature CHD. Most trends indicate that many Americans are more concerned about diet for health reasons. Preventive measures for CHD are also discussed.

Hemodynamically significant primary anomalies of the coronary arteries are those which alter myocardial perfusion. There are four major types: coronary artery fistulae, origin of the left coronary artery from the pulmonary artery, congenital coronary stenosis or atresia, and origin of the left coronary artery from the right sinus of Valsalva, with subsequent passage of the vessel between the aorta and right ventricular infundibulum. The angiographic features of these lesions are discussed.

Valve prostheses have played an important part in the past two decades in the management of patients with valvular heart disease. However, many of the devices used in valve replacement have introduced new clinical problems. This paper deals with some of the problems associated with valve replacement, including one not previously emphasized--valve prosthesis-patient mismatch, which may cause obstruction to ventricular outflow and/or inflow.

Intraventricular conduction defects are common following repair of various forms of congenital heart disease. Such defects may affect adversely the long-term prognosis of patients in whom cardiac hemodynamics were adequately restored. Review of previously published studies suggests that the site of the conduction defect may be the reason for the different prognoses reported for patients from different institutions. The so-called "trifascicular block" pattern which sometimes occurs following open heart surgery is probably due to a more extensive lesion to the branching and penetrating parts of the His bundle rather than additional injury to the posterior left bundle branch fibers. Transient complete heart block in the immediate postoperative period seems to be a predictor for late development of complete heart block or sudden death at least as powerful as right bundle branch block and left anterior hemiblock.

Epicardial mapping provides a method for defining antegrade and retrograde sites of pre-excitation. It is best undertaken only after a careful, detailed preoperative electrophysiological study has been performed. The potential pitfalls of the technique are many and technical expertise must be constantly available to maintain a functioning system. For these reasons, it is not likely to lend itself to widespread application. The same techniques can be applied to localization of the site of origin of atrial or ventricular dysrhythmias, localization of myocardial ischemia and infarction, as well as to differentiate between epicardial delays due to conduction delay and those caused by intramural myocardial delay.

A review is given on the use of programmed electrical stimulation of the heart in patients suffering from tachycardia. The application of this technique makes it possible to evaluate mechanisms of tachycardia directly in the human heart. By repeating the same stimulation program following drug administration the effect of drugs on arrhythmia mechanisms can be studied. There are several factors, however, that influence the amount of information on mechanism and pathway of tachycardia and selection of appropriate therapy that can be obtained during the study. These factors as well as how information obtained programmed electrical stimulation of the heart has resulted in a better use of the 12-lead electrocardiogram as a diagnostic tool are discussed.

Despite a decade of experience with aortocoronary bypass grafting embracing 300,000 or more operations, indications for its use remain controversial. The controversy persists because of a lack of adequate controls with which to compare the clinical course of operated patients; only 1248 have been reported who have been studied in a carefully controlled and random manner. Benefit has been claimed frequently by comparing the course of patients treated surgically with medically treated patients followed the decade before. Such comparisons are not valid in view of the well documented changes in the natural history of coronary artery disease that have been occurring during the last decade. Despite a low operative mortality and rate of graft closure, available data in the literature do not indicate that initial symptomatic improvement necessarily persists, or that myocardial infarctions, arrhythmias, or congestive heart failure will be prevented, or that life will be prolonged in the vast majority of operated patients.

The presentation, management, and follow-up of 31 patients with discrete membranous subaortic stenosis (DMSS) is presented. DMSS comprised 16% of 185 patients with congenital left ventricular (LV) obstruction. Only one patient was older than 40 years. The rarity of DMSS in older patients in both our population and in the literature is noted, and possible explanations are discussed. One-quarter of these patients had dyspnea, chest pain, or syncope combined with electrocardiographic left ventricular hypertrophy (LVH) and strain, and these all had peak LV outflow gradients (PSG) greater than 85 mm Hg. One-quarter had neither symptoms nor electrocardiographic abnormalities and all had PSG less than 90 mm Hg. Bacterial endocarditis was found in 13%, and in 13% an immediate family member also had congenital LV obstruction. Following surgical resection (25 patients), 18 were asymptomatic, two had residual fibromuscular obstruction, and four developed new fibromuscular obstruction after from one to six years (leading in one to late sudden death). Thus, even after resection, these patients require continued re-evaluation for residual or new LV obstruction.

Electrocardiograms and cardiac electrograms now frequently are measured for both clinical and experimental purposes by direct digital sampling, with no recording of the signal in analog form. This study examined the question of what sampling rates were required to measure accurately the continuous waveforms from the digital samples. Body surface waveforms and intracellular and extracellular waveforms measured directly from cardiac tissues were evaluated. Cardiac measurements included waveforms from the atrium, ventricle, atrioventricular transmission system and individual Purkinje strands. Sampling rates as high as 15,000 samples/sec were required to record accurately extracellular waveforms of the ventricular conduction system. Decreasing sampling rates were required as the recording site shifted through the ventricle to the body surface, where sampling rates as high as 1500 samples/sec were necessary.

Recently, the availability of a number of specific inhibitors of the renin-angiotensin system has made it possible to address certain critical questions concerning the role of angiotensin II in physiologic homeostasis and in a number of pathologic states. These studies indicate that angiotensin II does not have an obligatory role in blood pressure maintenance in the normal, sodium replete individual, but it is essential following sodium depletion. The role of angiotensin II in feedback control of renin secretion is confirmed as is its importance in aldosterone stimulation both in relation to posture and sodium depletion. Angiotensin II is responsible for the initial pressor response of experimental renovascular hypertension and appears to be important in the initiation of chronic renovascular hypertension. Converting enzyme blockers and competitive inhibitors of angiotensin II are helpful in the diagnosis of clinical renovascular hypertension and in the identification of renin dependent hypertensives. Homeostatic mechanisms leading to maintenance of blood pressure and accumulation of edema in experimental congestive heart failure appear to be dependent on angiotensin II.