Immediate and mid-term safety and efficacy of single lead VDD pacemakers for patients with atrioventricular block and normal sinus node function--a single centre experience.

INTRODUCTION: Single lead atrial synchronous ventricular pacing (VDD) is increasingly being used in place of conventional dual chamber pacing (DDD) for patients with atrioventricular block and preserved sinus node function. Compared to the latter, VDD pacemakers provide similar haemodynamic benefits derived from atrial synchronous pacing, with the added benefit of an easier implant procedure. OBJECTIVE: To review the use, safety and efficacy of VDD pacing in a single tertiary referral centre. MATERIALS AND METHODS: A review of all patients with atrioventricular block and normal sinus node function implanted with a VDD pacemaker over a 2-year period at a local tertiary cardiac referral centre. Data on complications, atrial sensing performance and maintenance of atrioventricular synchrony during implant and at subsequent follow-up visits were obtained from a prospectively maintained registry and analysed. RESULTS: Forty-one patients (17 males, 24 females) with a mean age of 72 +/- 9 years received VDD pacing for various forms of high-grade atrioventricular block. The average implantation time was 46.8 +/- 17.1 minutes, and a pneumothorax in 1 patient was the only complication. Electrical measurements at implantation and subsequent follow-up visits revealed an initial rapid decrease in atrial signal amplitude (mean atrial P wave at implant 3.1 +/- 1.1 mV, predischarge 1.9 +/- 1.3 mV) which began to stabilise after 3 months, reaching a mean atrial P wave value of 1.3 +/- 0.3 mV at 24 months. The atrial sensing performance (percentage of atrial synchronous ventricular complexes) was 97% over a mean follow-up period of 9.9 months. Four patients (10%) developed paroxysmal atrial tachyarrhythmias. Sinus node dysfunction was not observed in any of our patients during the follow-up period. CONCLUSION: In patients with atrioventricular block and preserved sinus node function, single lead VDD pacing is safe and effective in maintaining a physiological atrial synchronous pacing mode.

Constrictive pericarditis--a rare but important cause of recurrent cardiac failure: a case report.

Constrictive pericarditis (CP) is an uncommon cardiac disease which is often difficult to diagnose because of its vague and myriad clinical presentations. We report a case of a middle-aged lady who had non-specific symptoms and signs for six years before she was eventually diagnosed to have idiopathic constrictive pericarditis. An awareness and understanding of this condition is important, as it is a progressive condition and the likelihood of cure depends very much on its early identification and treatment.

Two case reports on incessant left ventricular tachycardia: curative therapy with radiofrequency ablation.

INTRODUCTION: Incessant ventricular tachycardia is a rare arrhythmia which can be life threatening. Treatment with anti-arrhythmic agents may occasionally fail. CLINICAL PICTURE: We report 2 cases of incessant ventricular tachycardia. The first case was a young man with idiopathic left ventricular tachycardia who was in incessant ventricular tachycardia despite treatment with multiple anti-arrhythmic drugs and developed dilated cardiomyopathy. The second case was an asymptomatic girl with the incidental finding of an incessant ventricular tachycardia which originated from the left ventricular outflow tract. TREATMENT AND OUTCOME: Both patients underwent electrophysiologic study and radiofrequency ablation with complete termination of the tachycardia. CONCLUSION: Radiofrequency catheter ablation in experienced centres should be the first-line therapy for incessant ventricular tachycardia.