title: The effect of biphasic waveform tilt in transvenous atrial defibrillation.
abstract: Atrial defibrillation can be accomplished using low energy shocks and transvenous catheters. The biphasic waveform tilt required to achieve optimal atrial defibrillation thresholds (ADFTs) is, however, not known. The effect of single capacitor biphasic waveform tilt modification on ADFT was assessed in 20 patients. Following AF induction the defibrillation pulses were delivered between the catheters positioned in the coronary sinus and the right atrium. The single capacitor biphasic waveform shocks, delivered over the same pathways, consisted of 65% tilt (65/65 biphasic waveform) to produce an overall tilt of 88%, or 50% tilt (50/50 biphasic waveform) to produce an overall tilt of 75%. Although 65/65 biphasic waveform delivers more energy, the shorter duration 50/50 biphasic waveform reduced stored energy ADFT 21%, from 1.34 +/- 0.82 J with 65/65 biphasic to 1.06 +/- 0.81 J. These differences were not statistically significant. Nine patients had lower ADFT with 50/50 biphasic waveform while five patients had lower ADFT with 65/65 biphasic waveform. Equivalent reduction in ADFT was seen in the remaining six patients. The ADFT was 0.83 +/- 0.65 J when both tilts were considered. In conclusion, biphasic waveform tilt modification may affect the ADFT in an individual patient. The optimal biphasic waveform for ADFT is not known.
authors.affiliation: Electrophysiology Laboratory, Milwaukee Heart Institute of Sinai Samaritan Medical Center, Wisconsin, USA.
authors.forename: J
authors.initials: J
authors.lastname: Sra
authors.forename: S
authors.initials: S
authors.lastname: Bremner
authors.forename: D
authors.initials: D
authors.lastname: Krum
authors.forename: A
authors.initials: A
authors.lastname: Dhala
authors.forename: Z
authors.initials: Z
authors.lastname: Blanck
authors.forename: S
authors.initials: S
authors.lastname: Deshpande
authors.forename: M
authors.initials: M
authors.lastname: Biehl
authors.forename: H
authors.initials: H
authors.lastname: Li
authors.forename: M R
authors.initials: MR
authors.lastname: Jazayeri
authors.forename: M
authors.initials: M
authors.lastname: Akhtar
mesh_terms: D000328:Adult; D001281:Atrial Fibrillation / Q000209:etiology / Q000628:therapy*; D006328:Cardiac Catheterization; D002304:Cardiac Pacing, Artificial; D017115:Catheter Ablation; D004554:Electric Countershock / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D013617:Tachycardia, Supraventricular / Q000601:surgery