title: Dissimilar ventricular rhythms: implications for ICD therapy.
abstract: Sensing of left ventricular (LV) activity in some devices used for cardiac resynchronization therapy (CRT) was designed primarily to prevent the delivery of an LV stimulus into the LV vulnerable period. Such a sensing function of the LV channel is not universally available in contemporary CRT devices. Recordings of LV electrograms may provide special diagnostic data unavailable solely from the standard right ventricular electrogram and corresponding marker channel. We used the LV sensing function of Biotronik CRT defibrillators to find 3 cases of dissimilar ventricular rhythms or tachyarrhythmias. Such arrhythmias are potentially important because concomitant slower right ventricular activity may prevent or delay implantable cardioverter-defibrillator therapy for a life-threatening situation involving a faster and more serious LV tachyarrhythmia. Dissimilar ventricular rhythms may not be rare and may account for cases of unexplained sudden death with a normally functioning implantable cardioverter-defibrillator and no recorded terminal arrhythmia.
authors.affiliation: Florida Heart Rhythm Institute, Tampa, Florida 33615, USA. ssbarold@aol.com
authors.forename: S Serge
authors.initials: SS
authors.lastname: Barold
authors.forename: Andreas
authors.initials: A
authors.lastname: Kucher
authors.forename: Herbert
authors.initials: H
authors.lastname: Nägele
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Buenfil Medina
authors.forename: Michael
authors.initials: M
authors.lastname: Brodsky
authors.forename: Frederic E
authors.initials: FE
authors.lastname: Van Heuverswyn
authors.forename: Roland X
authors.initials: RX
authors.lastname: Stroobandt
mesh_terms: D000368:Aged; D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D004562:Electrocardiography / Q000379:methods; D004867:Equipment Design; D004869:Equipment Safety; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D012494:Sampling Studies; D012720:Severity of Illness Index; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D014693:Ventricular Fibrillation / Q000175:diagnosis / Q000401:mortality / Q000628:therapy