Pacemaker contact sensitivity is a rare condition. Less than 25 reports of pacemaker skin reaction have been described over the past 30 years. This report describes one patient who developed contact dermatitis after implantation of two subsequent pacemakers. The diagnosis was made with skin patch tests that were positive to polyurethane 75D and polysulfone beige, two of the pacemaker and connector components. Review of the literature and general guidelines for the management of this unusual condition is depicted in this report.

The present study validates that smaller surface (i.e., 1.5 mm2) steroid-eluting electrode designs offer excellent pacing and sensing performance with significantly higher pacing impedances. Although questions remain as to the cause of late exit block in two patients in this series, this relatively small surface electrode design offers promise toward achieving greater pacing efficiency and a theoretical 13%-16% (minimum) enhancement in permanent pacemaker longevity.

Numerous complications induced by pacemaker electrodes have been reported. Although mild tricuspid regurgitation is a well-documented complication of transvenous right ventricular pacemaker leads secondary to abnormal valve coaptation, severe tricuspid regurgitation resultingfrom perforation of the tricuspid valve itself is a rare complication. This case report details a patient with severe tricuspid regurgitation secondary to impingement of the tricuspid valve by a permanent pacing lead that was diagnosed by transesophageal echocardiography. Surgical repair was advocated because of symptomatic significant tricuspid regurgitation.

SUMMARY The electrophysiologic effects of intravenously administered propranolol (0.1 mg/kg) on three parameters of sinus node function were examined in ten symptomatic patients with sinus node dysfunction. The patients ranged in age from 26 to 79 years. Symptoms ranged from fatigue to frank syncope. Sinoatrial (SA) block and sinus pauses were observed in one patient; sinus pauses alone were observed in three patients. Five (5/10) patients had intraatrial block; three (3/10) patients had atrioventricular block; four (4/10) patients had an intraventricular conduction disturbance. At the time of electrophysiologic study, two patients had a control spontaneous sinus cycle length that exceeded 1000 msec. Following propranolol, the mean spontaneous cycle length increased by 17.4% THE BRADYARRHYTHMIAS that occur in patients with sinus node dysfunction are thought to reflect disturbances of sinus node automaticity and/or sinoatrial conduction.' The normal interactions between the parasympathetic and sympathetic nervous systems modulate the spontaneous heart rate.' Catecholamines exert a positive chronotropic effect on the sinus node and have also been shown to accelerate conduction in Purkinje fibers with abnormal conduction.4' 6 If catecholamines can also shorten sinoatrial conduction time that is prolonged, then the magnitude of the disturbance(s) of sinus node automaticity and/or sinoatrial conduction could not only be determined by the extent and nature of the cellular disturbance but also by the amount of catecholamines acting at their receptor sites in cardiac cells. Hence the accelerative and restorative effects of catecholamines on sinus node automaticity and sinoatrial conduction may play an important role in determining the magnitude of the electrophysiologic disturbance(s) in patients with sinus node dysfunction. Conversely, a #-adrenergic receptor blocking agent might have marked effects on sinus node automaticity and sinoatrial conduction in patients with sinus node dysfunction. This report examines the electrophysiologic effects of propranolol on three parameters of sinus node function in patients with sinus node dysfunction. MethodsElectrophysiologic study was performed in ten patients with symptomatic sinus node dysfunction. The patients' ages ranged from 26 to 79 years. Informed consent was obtained in all patients.Patients were evaluated prior to electrophysiologic study. History, physical examination and routine laboratory data From the

A 55-yr-old male undergoing varicose vein surgery with an extradural block complained of chest pain. E.c.g. changes and subsequent examination of the heart including coronary angiography suggested the diagnosis of Prinzmetal's variant angina. The therapeutic implications of this condition in patients undergoing anaesthesia and surgery are discussed.