Thromboembolic phenomena in patients with prosthetic aortic valves who did not receive anticoagulants

Seventy-two patients with Starr-Edwards aortic prostheses of the 2300 series were followed for 1 to 73 months (average, 22 months) without receiving anticoagulants. Nine patients had clinical evidence of an embolic episode (12.5%). One of these patients died, and 5 were left with a significant residual neurological deficit. Two other patients had hemiparesis but recovered fully. Only 1 episode could be considered minor. The reported lower incidence of thromboembolism in patients receiving this prosthesis with adequate anticoagulation has now led us to reverse our previous position and recommend anticoagulation for patients receiving Starr-Edwards aortic prostheses.

Results of treatment of primary carcinoma of the lung. Analysis of 3,000 cases

Three thousand patients with primary carcinoma of the lung entered in the Armed Forces Central Medical Registry are reported. Forty-one per cent had squamous cell, 28.5 per cent adenocarcinoma, 25.2 per cent small cell/undifferentiated, and 4.9 per cent miscellaneous cell types. When first seen, 71.1 per cent had no organ metastases and 50.6 per cent no lymph node metastases. Over-all survival rate was 18.2 per cent at 5 years and 14.5 per cent at 10 years. Survival following definitive resection, palliative resection, definitive radiation, palliative radiation, and chemotherapy was determined both in the presence of mediastinal nodal involvement and in the absence of mediatinal nodal involvement. Where resection for cure could be carried out, 5 year survival rates of 48.8 per cent were possible. The factors affecting this improved outlook in our military population are discussed and, in general, appear to be related to a ready accessibility of medical care and the necessity, because of global commitments, of establishing an early diagnosis. Cell type ecerted some influence on survival, but the major determinant appeared to be the absence of involved nodes at the time of the operation.

Doppler ultrasonic flow detection as an adjunct in the diagnosis of patent ductus arteriosus in premature infants

Since ligation of a patent ductus arteriosus in the neonate with idiopathic respiratory distress syndrome seems to improve the clinical condition of the infant, we have attempted to identify those neonates earlier with the noninvasive Doppler ultrasonic technique, recording brachial arterial flow signals. Sixteen patients were studied. In the 5 with reversed brachial flow who were operated upon, ligation of a PDA resulted in improvement and postoperative correction of brachial flow reversal as evidenced by the Doppler ultrasonic technique.

Dissociation and delayed conduction in the canine right bundle branch

Bipolar electrograms were recorded from five to six sites on the septal right bundle branch (RBB) using a multielectrode patch in ten mongrel dogs. Antegrade activation was recorded along the right bundle during sinus rhythm and during right atrial pacing at varying heart rates. Retrograde activation was produced by pacing from right ventricular epicardium. Right bundle conduction velocities varied from 1.4 to 3.3 m/sec (mean 2.0 m/sec) for antegrade conduction and from 1.8 to 2.7 m/sec (mean 2.1 m/sec) for retrograde activation. Varying degrees of conduction delay were elicited by premature stimulation and mechanical pressure to the right bundle. The conduction delays occurred over small segments of the right bundle branch with regeneration of normal propagation velocity distal to the region of block. The conduction delays were associated with fragmentation of the RBB electograms with initiation of delayed activation waves which traveled variable distances antegrade and retrograde. These data show that stress-induced longitudinal dissociation may produce delayed activation waves within the right bundle branch which may simulate re-entrant arrhythmias.

Paecilomyces varioti endocarditis on a prosthetic aortic valve

Fungal endocarditis following prosthetic valve surgery has assumed increased importance as a cause of postoperative death. We present, to our knowledge, the first case of the fungus Paecilomyces varioti producing endocarditis on a prosthetic aortic valve. This seems to be an extremely indolent organism which exhibits an apparent response to antibiotic therapyl. In vitro evidence suggests that this fungus is sensitive to attainable serum levels of both 5-fluorocytosine and amphotericin B. However, after viewing the extracted valve and the devastating embolic phenomenon in our patient, we believe that medical therapy alone would not suffice. Thus we suggest that prompt valve replacement be performed in future cases.

Shunt dynamics in experimental atrial septal defects

Inorder to study the hemodynamic variables involving the magnitude, direction, and timing of phasic shunt flow, both the interatrial pressure gradient and blood flow along with other pertinent hemodynamic variables were measured instantaneously across a surgically created atrial septal defect (ASD) in seven awake dogs. Atrial and ventricular pacing and infusion of phenylephrine and isoproterenol were used to alter hemodynamic conditions. The wave form of phasic ASD flow was similar both in configuration and timing to the interatrial pressure gradient. During the cardiac cycle, both left-to-right (L-R) and right-to-left (R-L) shunting occurred: atrial contraction augmented L-R flow; the onset of ventricular contraction was associated with R-L flow; during the latter part of ventricular contraction, flow returned to L-R with the maximum L-R shunting occurring in early diastole. Tachycardia, infusion of phenylephrine and isoproterenol did not alter the phasic flow pattern. Both spontaneous and positive pressure respiration decreased net L-R shunting.

Studies of blood flow in aorta-to-coronary venous bypass grafts in man

Pressure-flow measurements were obtained from the vein graft of 57 patients undergoing a single aorta-to-coronary bypass procedure. The flow contour was similar to phasic left coronary artery flow in dogs except for a transient increase during systole possibly related to elongation of the graft. Flow was highest during bypass and decreased to a stable value 30 min after bypass. In 42 patients, flow at this time was 35+/-2 cm(3)/min (mean+/-sem).NO CORRELATIONS WERE DEMONSTRATED BETWEEN FLOW AND THE FOLLOWING: left vs. right grafts, presence or absence of collaterals, total vs. partial block, or the presence or absence of ventricular dyskinesis. In 32 patients, no correlation between these anatomic findings and the presence of reactive hyperemia was demonstrated. In 17 patients, occlusion of the graft for 10 sec resulted in a mean 51.5% flow debt repayment. In nine patients, injection of 0.3 mug of isoproterenol into the graft increased flow from 45+/-6 to 69+/-9 cm(3)/min within 4-7 sec without changes in rate, pressure, time derivative of left ventricular pressure (LV dp/dt), or left ventricular end diastolic pressure (LVEDP). Maximum increases to 87+/-10 cm(3)/min occurred 12-20 sec after injection with concomitant changes in these parameters. Intravenous infusion of norepinephrine did not change vascular resistance, whereas phenylephrine did. In six patients, injection of 0.2 mug of norepinephrine into the graft decreased flow from 49+/-6 to 25+/-5 cm(3)/min within 5-8 sec. Intravenous infusion of 0.15 mg of nitroglycerin decreased coronary vascular resistance from 2.7+/-0.4 to 2.3+/-0.3 mm Hg/cm(3) per min. In five patients, 0.12 mg of nitroglycerin injected into the graft increased flow from 46+/-7 to 71+/-13 cm(3)/min and lasted 20-40 sec.

The electrophysiologic effects of beta-adrenergic blockade and cardiac denervation

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Influence of diphenylhydantoin on electrophysiological properties of the canine heart

These studies were designed to examine the electrophysiological effects of diphenylhydantoin (Dilantin) on the heart of awake dogs. Recording electrodes were implanted over the sinoatrial node, bundle of His, and right bundle branch, and studies were performed 2 to 6 weeks following recovery. Diphenylhydantoin (10 mg/kg) increased heart rate, shortened A-V conduction time and had little or no effect on conduction velocity in Purkinje tissue or total ventricular activation time. Similar effects were noted when heart rate was controlled by pacing. Following cardiac denervation, diphenylhydantoin decreased heart and prolonged A-V conduction time. It raised the threshold of atrial and ventricular muscle with no change of refractory periods. In dogs with heart block, it decreased the maximal rate at which the atria would respond to stimulation. When ventricular tachycardia was induced in dogs with heart block, by toxic doses of deslanoside, diphenylhydantoin abolished the ectopic tachycardia and restored the control rhythm.

Failure of beta-adrenergic blockade to alter ventricular fibrillation threshold in the dog. Evidence for extra-adrenergic effects of pronethalol

The effects of two beta-adrenergic blocking agents, pronethalol and propranolol, on ventricular fibrillation thresholds were tested in dogs. Pronethalol (4.0 mg/kg, 5 dogs) produced a mean increase of 45% in the fibrillation threshold. Propranolol (0.4 mg/kg, 7 dogs) failed to produce a significant change of the fibrillation threshold. To examine the possibility that the difference between the responses to pronethalol and propranolol might be related to the difference in dose of the beta-blocking agents, 4.0 mg/kg of propranolol was given to 3 dogs; this dose also failed to produce a consistent change of ventricular fibrillation threshold. These data indicate that under the conditions of our experiments it was possible to block the beta-adrenergic receptors with propranolol without producing a change of the ventricular fibrillation threshold. The increase of the fibrillation threshold produced by pronethalol was probably a consequence of its quinidine-like properties rather than of its beta-receptor blockade.