Pacing and clinical electrophysiology : PACE
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Pacing Clin Electrophysiol · Dec 1997
Comparative StudySteroid-eluting epicardial pacing electrodes: six year experience of pacing thresholds in a growing pediatric population.
Indications for pacemaker implantation in the pediatric population often include sinus or atrioventricular node dysfunction following surgery for congenital heart defects. However, patient size, cardiac defects, and vascular and valvular concerns may limit transvenous lead utilization. Since the epicardial surface of these patients often exhibits variable degrees of fibrosis from scar tissue formation or pericardial adhesions, chronic low output (2.5/1.6 V, 0.3 ms) epicardial pacing from implant is not currently recommended in children due to frequent threshold changes and electrode exit block. ⋯ Mean ventricular pulse width thresholds (0.12 ms +/- 0.05 ms) were significantly higher (P < 0.001) than atrial thresholds (0.06 ms +/- 0.03 ms) at implant and throughout the study period. The thresholds in the patients following cardiac surgery were comparable to those without previous cardiac surgery (P = NS). Stable low thresholds may be chronically maintained for up to 6 years for epicardial steroid-eluting electrodes irrespective of pacing site or associated cardiac surgery.
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Pacing Clin Electrophysiol · Dec 1997
Relation between left atrial size and secondary atrial arrhythmias after successful catheter ablation of common atrial flutter.
Catheter ablation provides an effective cure for patients with typical atrial flutter. However, these patients may have the potential to develop atrial tachyarrhythmias other than common atrial flutter. This study examines clinical and echocardiographic predictors for the occurrence of uncommon atrial flutter or atrial fibrillation after abolition of common atrial flutter. ⋯ On Kaplan-Meier analysis, time to occurrence of postablation atrial arrhythmias was significantly shorter in patients with enlarged left atrium (P < 0.02). In conclusion, symptomatic uncommon atrial flutter and atrial fibrillation develops in a substantial proportion of patients after successful ablation of common atrial flutter. Out of a series of clinical and echocardiographic parameters, preablation left atrial size is the best predictor for the occurrence of these postablation atrial arrhythmias.