Background-The Food and Drug Administration recently issued a class I recall of the St. Jude Medical Riata implantable cardioverter-defibrillator lead presumably because of increased risk of electric failure and mechanical separation via inside-out abrasion. We sought to examine the incidence and time dependence of inside-out abrasion in asymptomatic patients implanted with the Riata lead. Methods and Results-Asymptomatic patients implanted with the Riata lead at our institution were offered voluntary fluoroscopic screening in 3 views. Electric testing of the Riata lead with provocative isometric muscle contraction was performed at the time of fluoroscopic screening. Of the 245 patients undergoing fluoroscopic screening, 53 (21.6%) patients showed clear evidence of lead separation. Of these externalized leads, 0%, 13%, and 26% had a dwell time of <3 years, 3 to 5 years, and >5 years, respectively (P=0.037). Externalized leads had a significantly pronounced decrease in R-wave amplitude (−1.7±2.9 mV versus +0.35±2.5 mV; P<0.001), and more patients with externalized leads had ≥25% decrease in R-wave amplitude from baseline (28.0% versus 8.1%; P=0.018). One patient with externalization exhibited new noise on near-field electrogram.
Conclusions-The
Despite having an ICD, HD patients have approximately a three-fold increase in total mortality and may therefore not extract the same survival benefits from the ICD as their non-HD counterparts. If duplicated in larger randomized trials, these results may demonstrate the futility of implanting defibrillators in HD patients.
Catheter ablation of the slow atrioventricular (AV) nodal pathway is the treatment of choice for dual AV nodal nonreentrant tachycardia. Rapid ventricular rates during incessant tachycardia may compromise catheter stability and increase the risk of AV block. Conduction via the slow AV nodal pathway may mimic junctional beats with retrograde block, which is an indicator to cease ablation. We report a case of incessant dual AV nodal nonreentrant tachycardia where intravenous isoproterenol was instrumental in facilitating catheter ablation by eliminating these two factors.
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