title: Efficacy of biphasic shock for transthoracic cardioversion of persistent atrial fibrillation: can we predict energy requirements?
abstract: Although electrical cardioversion of atrial fibrillation (AF) is frequently performed, initial energy requirements for cardioversion of persistent AF is still a matter of debate. The aim of the study was to determine the efficacy of biphasic shocks for transthoracic cardioversion of persistent AF and to predict adequate initial energy. A prospective study enrolled 94 consecutive patients with persistent AF, who were referred for elective cardioversion with a biphasic waveform. The paddles were placed in the anterolateral position. A step-up protocol was used to estimate the cardioversion threshold. The initial shock energy was 50 J, with subsequent increments to 100, 200, and 300 J in the event of cardioversion failure. The mean age of the study group was of about 65 years (6 +/- 11 years) and a median duration of AF was 65 days (3-324). Sixty-two out of 94 patients were men, 55% of the study population was classified as having well-controlled hypertension. The overall success rate of cardioversion was 89%, with a mean 2.2 +/- 1.4 shocks, and effective J 217.8 +/- 113 delivered during repeated cardioversions. The success rate of low energy shocks: 50 and 50 +100 J was 51%. By logistic regression analysis the only independent predictor of success at low energy shock was shorter duration of AF (r =-0.51; P = 0.02). Patients with shorter duration of AF have a higher probability for successful cardioversion with low energy. In patients with longer AF duration, a 200 J shock should be considered for cardioversion as the initial energy.
authors.affiliation: Department of Cardiology Regional District Hospital, Kielce, Poland. energo_kap@poczta.onet.pl
authors.forename: Beata
authors.initials: B
authors.lastname: Wozakowska-Kaplon
authors.forename: Marianna
authors.initials: M
authors.lastname: Janion
authors.forename: Janusz
authors.initials: J
authors.lastname: Sielski
authors.forename: Edyta
authors.initials: E
authors.lastname: Radomska
authors.forename: Dawid
authors.initials: D
authors.lastname: Bakowski
authors.forename: Radoslaw
authors.initials: R
authors.lastname: Bartkowiak
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000628:therapy*; D002908:Chronic Disease; D004554:Electric Countershock / Q000379:methods*; D004562:Electrocardiography / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008432:Mathematical Computing; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D019233:Retreatment; D012815:Signal Processing, Computer-Assisted; D017211:Treatment Failure; D016896:Treatment Outcome