Thomas H. Johnson

Sympathetic Reinnervation of the Sinus Node and Exercise Hemodynamics After Cardiac Transplantation

BACKGROUND Sympathetic cardiac reinnervation occurs variably after cardiac transplantation (CT) in humans. We hypothesized that sinus node reinnervation would partially restore normal chronotropic response to exercise. METHODS AND RESULTS Thirteen recent CT recipients, 28 late CT recipients (> or =1 year after CT), and 20 control subjects were studied. Sinus node sympathetic reinnervation was determined by heart rate (HR) change after tyramine injection into the artery that perfused the sinus node. HR changes of <5 and > or =15 bpm were defined, respectively, as denervation and marked reinnervation. During treadmill exercise, HR, blood pressure, and expired O(2) and CO(2) were measured. All early transplant recipients exhibited features typical of denervation (basal HR, 88+/-2 bpm; peak HR, 132+/-4 bpm, peaking 1.8+/-0.3 minutes after exercise cessation and slowly declining after exercise). A similar pattern was found in the 12 late transplant recipients with persistent sinus node denervation. However, in patients with marked reinnervation, exercise HR rose more (peak HR, 142+/-4 and 141+/-2 bpm), peaked earlier after cessation of exercise (0.7+/-0.4 and 0. 3+/-0.1 minute), and fell more rapidly. Exercise duration and maximal oxygen consumption were not related significantly to reinnervation status, but a trend existed for longer exercise time in markedly reinnervated patients. CONCLUSIONS The present studies suggest that sympathetic reinnervation of the sinus node is accompanied by partial restoration of normal HR response to exercise. Both maximal oxygen consumption and exercise duration were markedly shorter in CT patients than in control subjects, and most of the difference was not related to innervation status.

Marked spontaneous improvement in ejection fraction in patients with congestive heart failure

PURPOSE The overall prognosis for patients with congestive heart failure is poor. Defining specific populations that might demonstrate improved survival has been difficult. We therefore examined our patient database for patients with congestive heart failure who demonstrated sustained improvement in left ventricular function and associated resolution of signs and symptoms of congestive heart failure. PATIENTS AND METHODS We identified 11 patients with severe congestive heart failure (average ejection fraction 21.9 +/- 4.23% (+/- SD) who developed spontaneous, marked improvement over a period of follow-up lasting 4.25 +/- 1.49 years. All 11 patients were initially symptomatic with exertional dyspnea and fatigue for a minimum duration of 3 months. They form a subset of a larger group of 97 patients with chronic congestive heart failure that we have followed with sequential ejection fraction measurements. All 11 patients were treated with digitalis diuretics, and either converting-enzyme inhibitors or a combination of isosorbide dinitrate and hydralazine. Ten of the 11 patients had a history consistent with chronic alcoholism, and each reportedly abstained from alcohol during follow-up. RESULTS During the follow-up period, the average ejection fraction improved in 11 patients from 21.9 +/- 4.23% to 56.64 +/- 10.22%. Late follow-up indicates an average ejection fraction of 52.6 +/- 8.55% for the group. Congestive heart failure resolved in each case. CONCLUSIONS We conclude that selected patients with severe congestive heart failure can markedly improve their left ventricular function in association with complete resolution of heart failure. This appears to be particularly evident in those patients with chronic alcoholism who subsequently abstain.

The synthesis and structure of 10,11-bistrifluoromethyl-i,o-bicyclo[7.2.2]trideca-10,12-diene. A highly strained inside-outside bicycloalkane derivative.

Abstract 10,11-Bistrifluoromethyl-i,o-bicyclo[7.2.2]trideca-10,12-diene has been prepared by the Diels-Alder addition of hexafluoro-2-butyne to cis, trans-cycloundeca-1,3-diene. Purification was accomplished via formation of an iron tricarbonyl complex whose structure was established via X-ray crystallography.

Kinetic resolution of dialkylcyclopropanes

Es wird die direkte kinetisch kontrollierte Enantiomerentrennung bei trans-1,2-Dimethylcyclopropan (I) beschrieben.