In order to analyze the impact of different polarity and electrode designs on the acute pacing and sensing characteristics of pacemaker leads, 80 patients with complete heart block or sinus node dysfunction undergoing pacemaker implantation received eight different leads from five manufacturers. Once the leads were positioned, volt and current thresholds, P wave, peak-to-peak, and slew rate were assessed prospectively. There was no statistically significant difference between acute pacing thresholds, sensing characteristics, or unipolar and bipolar pacing thresholds. Active fixation leads allow atrial mapping and lead placement in areas generally inaccessible to tined tip leads. This is an advantage, especially for patients with a history of open heart surgery.

Electrodes, Implanted↗

PubMedDate not supplied

Transcatheter electrical AV junction ablation: predictors of success.

The initial and long-term results of transcatheter electrical ablation in 29 patients with drug-refractory supraventricular tachyarrhythmias were analyzed. Ablation was immediately successful (defined as induction of chronic complete heart block) in 25 patients (86.2%). Among the group in whom ablation was unsuccessful, there were more patients with ectopic atrial tachycardia and a higher incidence of narrow QRS escape rhythm following the initial ablation. A His amplitude equal to or greater than 0.3 mV was correlated with success. Complications of ablation included deep venous thrombosis and ventricular arrhythmias. Post-ablation stress testing was superior to ambulatory monitoring in identifying early return of atrioventricular conduction.

Adult↗

PubMedDate not supplied

The Maze procedure: surgical therapy for refractory atrial fibrillation.

Although atrial fibrillation is well tolerated by most patients, in some patients the consequences may be severe. The Maze procedure is a new open-heart operation that creates a carefully designed maze of incisions in the atrial myocardium; this maze then acts as an electrical conduit to channel atrial impulses from the sinoatrial node to the atrioventricular node. The Maze procedure has been shown to restore sinus rhythm and atrial systole (thus reducing the risk of thromboembolism), improve hemodynamics, alleviate palpitations, and eliminate the need for antiarrhythmic and anticoagulant drugs. We describe our first patient to undergo this operation.

Aged↗

PubMedDate not supplied

Durability of bipolar coaxial endocardial pacemaker leads compared with unipolar leads.

BACKGROUND: The coaxial design allows for thinner bipolar endocardial pacemaker leads, but recent reports have suggested a higher incidence of failure for this sophisticated configuration. OBJECTIVE: To compare the long-term survival of bipolar coaxial and unipolar leads. METHODS: Retrospective follow-up. RESULTS: Between January 1, 1980 and June 30, 1991, 1142 bipolar coaxial leads and 1181 unipolar leads were implanted at the Cleveland Clinic. The mean follow-up was 33 +/- 32 months (range 1 to 138 months). Ten bipolar coaxial leads failed (0.88%), as did 9 unipolar leads (0.76%). At 5 years the cumulative survival was 98.6% for both types of leads; however, at 10 years the survival of bipolar coaxial leads was only 92.4% compared with 98.6% of unipolar leads (P = .03; relative risk 2.7, 95% confidence interval = 1.1 to 6.9). CONCLUSIONS: The sophisticated design of bipolar coaxial leads could be the cause of their increased vulnerability. The benefit-to-risk ratio of this design should be prospectively reevaluated.

Electrodes, Implanted↗