David E. Welton

Effects of exercise training on left ventricular performance and myocardial perfusion in patients with coronary artery disease

To determine the effects of exercise training on left ventricular performance and myocardial perfusion in coronary artery disease, rest and exercise radionuclide angiocardiography and thallium-201 scintigraphy were performed before and after 12 weeks of training in 16 coronary patients. After training, 15 of the 16 patients had improved exercise tolerance; total treadmill exercise duration increased from (mean +/- standard error of the mean) 491 +/- 37 to 602 +/- 31 seconds (p less than 0.01), and the estimated rate of oxygen consumption (VO2 max) increased from 29.4 +/- 1.4 to 33.8 +/- 1.2 ml/kg per min (p less than 0.001). Resting left ventricular ejection fraction increased from 52 +/- 4 to 57 +/- 4 percent (p less than 0.02); no change occurred in left ventricular functional reserve assessed by ejection fraction and regional wall motion response to exercise at the same rate-pressure product before and after training. Myocardial perfusion at equivalent pre- and post-training cardiac work loads during exercise and on redistribution was unchanged by training. It is concluded that in patients with coronary heart disease, physical training increases exercise tolerance, and results in minimal improvement in resting left ventricular systolic performance. Functional reserve of both left ventricular systolic performance and the coronary circulation appears to be unchanged by exercise training. These data suggest that the beneficial effects of training for 12 weeks in patients with coronary artery disease predominantly result from factors other than improvement in left ventricular pump performance or perfusion.

Recurrent infective endocarditis: Analysis of predisposing factors and clinical features

Abstract To characterize the patient population and clinical features of recurrent infective endocarditis, 117 patients with 142 episodes of infective endocarditis were investigated. Sixty-one (52 per cent) of the total population were drug abusers. Of the 96 who survived the initial episode of infective endocarditis, 58, including 34 drug abusers, were followed for a mean duration of 128 weeks. Recurrent infective endocarditis occurred in 18 of 58 (31 per cent); 14 of 34 (41 per cent) of drug abusers versus four of 24 (17 per cent) of nondrug users (P 0.05). Excluding debilitated patients, mortality was greater in those with recurrent versus initial infections (six of 24 versus nine of 96; P

Value and safety of cardiac catheterization during active infective endocarditis

Abstract Cardiac Catheterization during active infective endocarditis is considered to be hazardous and, consequently, is often delayed. A review was made of experience with 35 patients who underwent Catheterization for severe heart failure (30 patients) and persistent sepsis or recurrent embolization (5 patients) in consideration of surgical intervention. The mean interval from hospital admission to Catheterization was 19 days, and 11 of 35 procedures were performed within 10 days of admission. Precatheterization clinical assessment was incomplete or incorrect in 23 patients. Cardiac Catheterization revealed clinically unsuspected multiple valve involvement in seven patients and documented single valve involvement in six patients with murmurs clinically suggestive of multiple valve endocarditis. In one patient thought to have mitral endocarditis, Catheterization localized the problem to the tricuspid valve. In six patients the study disclosed valve ring abscess and in three it provided anatomic definition of a left to right shunt associated with infection of a ruptured sinus of Valsalva. One additional patient was “cured” of infection by removal of a subclavian catheter fragment. The only complication encountered was transient atrial fibrillation. Catheterization-induced embolization and postcatheterization hemodynamic deterioration did not occur in these 35 patients. It is concluded that cardiac Catheterization yields invaluable hemodynamic and anatomic information and can be performed with minimal risk in patients with infective endocarditis who are being considered for surgery.

Haemophilus parainfluenzae endocarditis: Two cases and review of the literature in the past decade

The Haemophilus species are rare causative agents of endocarditis. The incidence of Haemophilus spp. causing endocarditis has been estimated to be approximately 0.81.3% of adult cases (1). We report a rare case of endocarditis due to Haemophilus parainfluenzae, with the complications of myocardial abscesses and rupture of the aortic valve leaflet.Abstract Twenty-five cases of Haemophilus parainfluenzae endocarditis have been reported in the past 10 years, providing a better current perspective of this disease. We have recently diagnosed and treated two patients with H. parainfluenzae endocarditis, and both underwent surgical intervention for complications of their disease. H. parainfluenzae and the other Haemophilus species causing endocarditis often present with a subacute course, often escape early cultural detection and mimic fungal endocarditis in the propensity for large vessel embolization. Multiple emboli and occlusion of major arterial vessels are especially notable features of H. parainfluenzae endocarditis and have occurred in approximately 30 per cent of the cases reported in the past 10 years. In contradistinction to other types of bacterial endocarditis, the most common cause of death in this series has been neurologic complications following embolization. Development of large vegetations appears to be common and may be an intrinsic property of the Haemophilus species, but it is likely that it also reflects the duration of the disease. Delay in recovery of the organism from blood cultures is characteristic of H. parainfluenzae endocarditis and may be due to the strict requirement for V factor exhibited by some strains. Echocardiography has proved useful in suggesting the diagnosis of endocarditis when blood cultures are negative. Optimal antibiotic therapy of H. parainfluenzae endocarditis has not been determined, but the reported clinical experience suggests that combination therapy with ampicillin and an aminoglycoside is the current treatment of choice. Failure to eradicate the organism after a prolonged trial of appropriate antibiotic therapy is not unusual. Indications for surgery in H. parainfluenzae endocarditis may have to be amended to include potential embolization, especially if large vegetations are demonstrated on echocardiography.

A Mimic of the Sick Sinus Syndrome in a Middle-Aged Athlete

Highly trained athletes may have physiological alterations in cardiac pacemaker and conduction function. This article helps clinicians recognize arrhythmias related to exercise conditioning.