Electrical performance and automatic capture characteristics of a 3.5-mm(2) passive fixation lead during 1-year follow-up.

BACKGROUND: Bipolar low polarization electrodes are recommended for a regular AutoCapture (St. Jude Medical, Inc., Sylmar, CA, USA) function in order to effectively detect the evoked response (ER) signal. The objective of this national multicenter registry was to evaluate the electrical performance and the AutoCapture characteristics of the bipolar ventricular pacing lead IsoFlex S, model 1636T or 1646T (St. Jude Medical), in combination with single- and dual-chamber pacemakers. METHODS: Ventricular pacing and sensing thresholds, lead impedance, ER amplitude, and polarization signals were measured at discharge and routine follow-up visits after 1, 3, 6, 9, and 12 months. AutoCapture activation was recommended based on the results of the ER sensitivity test. RESULTS: Of the 252 patients initially included, 109 (43%) have completed the follow-up. The mean ventricular pacing threshold was 0.43 +/- 0.19 V at discharge and 0.68 +/- 0.32 V at 12 months postimplant. The values for the ventricular sensing threshold were between 9.51 +/- 4.12 and 9.99 +/- 4.09 mV at discharge and at the 12-month follow-up. The unipolar lead impedance decreased from 533 +/- 94 to 476 +/- 73 ohms during the follow-up. The mean ER amplitude was 16.47 +/- 6.70 mV at discharge and 17.42 +/- 7.43 mV after 12 months, and the corresponding mean polarization signals were 0.59 +/- 1.00 and 0.74 +/- 1.24 mV, respectively. AutoCapture activation was recommended in at least 95% of the patients investigated over the 12-month follow-up. CONCLUSION: The bipolar ventricular pacing lead IsoFlex S 1636/1646T shows a good electrical performance and is mostly compatible with the AutoCapture algorithm.

Medical treatment of patients with atrial fibrillation aged over 80 years in daily clinical practice: influence of age and CHADS(2) score.

The purpose of the present study was to evaluate clinical data and medical treatment of very elderly patients with atrial fibrillation (AF) who are under-represented in the majority of AF studies. In this retrospective study, patients over 80 years with AF admitted to the cardiology ward during a 1-year period were investigated with respect to the type of AF, clinical characteristics, and rate or rhythm control strategy. In addition, the influence of age and CHADS(2) score on antithrombotic therapy was examined. A total of 169 consecutive patients (mean+/-S.D. age: 84.7+/-4.0 years) were included in this study. Rate control medication was administered in 79% of the patients at discharge. Oral anticoagulation (OAC) was prescribed in only 27.5% of the patients with a CHADS(2) score of > or =2 for reasons of poor compliance or unfavorable clinical conditions. Moreover, patients older than 85 years received OAC less frequently than those aged between 80 and 84 years (7% vs. 36%, p<0.001). Our results indicate a real need for educational programs aimed at instructing all staff involved with this group of patients, so that the necessary pre-conditions for a maximum OAC therapy can be achieved in these very elderly AF patients.