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Implantable Cardioverter Defibrillator Shock Despite Termination of Ventricular by Antitachycardia Pacing During Charging

Sercan OKUTUCU M.D., Şefik Görkem FATİHOĞLU, M.D., Kudret AYTEMİR M.D., Ali OTO M.D. Hacettepe University Faculty of , Deparment of , Ankara, Turkey

ABSTRACT

In this paper, we aimed to present an unusual example of ICD following successful termination of by antitachycardia pacing.

ANAHTAR KELİMELER Antitachycardia pacing, implantable cardioverter defibrillator, shock

Şarj Sırasında Uygulanan Antitaşikardik Pacing ile Ventriküler Taşikardinin Sonlandırılmasına Karşın İmplante Edilebilir Defibrilatör Şoku

ÖZET

Bu yazıda antitaşikardik pacing ile başarılı bir şekilde sonlandırılan aritminin sonrasında gözlenen nadir şokunu sunmayı amaçladık.

KEYWORDS Antitaşikardik pacing, implante edilebilir kardiyoverter defibrilatör şok

İLETİŞİM ADRESİ Dr. Kudret AYTEMİR Hacettepe Üniversitesi Tıp Fakültesi, Kardiyoloji Anabilim Dalı, Ankara, Türkiye Implantable Cardioverter Defibrillator Shock Despite Termination of Ventricular Tachycardia by Antitachycardia Pacing During Charging 191

Case report is delivered and before the high-energy shock A 31-year-old man with arrhythmogenic is given, the ICD reconfirms the presence of right ventricular and episo- the tachycardia and proceeds to synchronizati- des of ventricular tachycardia had an implant on (2-4). of a dual chamber implantable cardioverter- The process of reconfirmation prior to de- defibrillator (ICD) (Maximo II DR D284DRG, livery of a high-energy therapy is done using Medtronic Inc., Minneapolis, MN, USA) for a sequence of detection intervals lasting 60ms prevention of sudden cardiac death. The ICD more than the lower limit of the slowest detecti- was programmed with a ventricular tachycardia on interval programmed with VT (or VF) thera- (VT) zone at 350ms (171 bpm) and a ventricular pies. If ATP during charging is disabled, the re- fibrillation (VF) zone at 300ms (200 bpm). The confirmation begins as the charging is initiated. fast ventricular tachycardia (FVT) zone was off When ATP during charging is enabled, the re- but antitachycardia pacing (ATP) during char- confirmation process begins at the end of char- ging was programmed on. ging (3-4). In both instances, delivery of high- One week later he admitted to our depart- energy therapy will be inhibited by the occur- ment with a complaint of an ICD shock while rence of 80% ventricular events that fall out of seated watching television. Interrogation of the the VT or VF (if VT therapy is disabled) inter- ICD device was performed. The patient was fo- val plus 60ms (2,3). und to receive a burst as well as a 34.6 joule As could be observed in Figure 2, patient re- shock for an episode of tachyarrhythmias (Figu- ceived a burst of 8 beats for a tachycardia fal- re 1). Electrogram revealed a tachycardia with ling in the VF zone. The tachycardia that was atrioventricular (AV) dissociation at median ra- detected was a ventricular tachycardia with a te of 206 bpm treated with ATP during char- cycle length of 290ms. The arrhythmia was tre- ging. Interestingly, despite termination of the ated as VF because its rate fell within the VF tachycardia with ATP, the device went on to de- zone. The burst successfully terminated the epi- liver an inappropriate shock for sinus tachycar- sode of VT and the patient went back into sinus dia (Figure 2). tachycardia with frequent ventricular extrasy- stoles at an average cycle length of 390ms. That Discussion rate was slightly slower than the set VT zone Intracardiac electrogram shown in Figu- (350ms) but did fall into the reconfirmation in- re 2 revealed that the patient received an ICD terval of 410ms (350 + 60ms) and led to the de- shock for a rhythm and a rate that was lower livery of a 34.6-joule shock (1-3). than the programmed VT or VF zones. ATP du- This case illustrates an unusual example of ring charging is a feature of Medtronic devices ICD shock following successful termination of that is designed to reduce the number of shocks arrhythmia by ATP. A solution for this problem delivered by an ICD for the treatment of tach- would be to program the patient to receive ATP yarrhythmias (1). When programmed, ATP du- before charging. With ATP before charging, full ring charging leads to the delivery of a burst of redetection of the arrhythmia has to occur befo- ventricular pacing while the capacitors are char- re initiation of the next ATP sequence or shock. ging for a high-energy therapy. After the ATP Alternatively, keeping an FVT zone program-

CİLT 8, SAYI 2, Haziran 2010 192 Türk Aritmi, Pacemaker ve Elektrofizyoloji Dergisi

FİGURE 1

Summary of ventricular tachycardia episode. med on (rather than turning it off when ATP du- ring charging is enabled) would have similarly avoided the problem (1-3).

CİLT 8, SAYI 2, Haziran 2010 Implantable Cardioverter Defibrillator Shock Despite Termination of Ventricular Tachycardia by Antitachycardia Pacing During Charging 193 İGURE 2 F Intracardiac electrograms.

CİLT 8, SAYI 2, Haziran 2010 194 Türk Aritmi, Pacemaker ve Elektrofizyoloji Dergisi

REFERENCES

1. Medtronic EnTrust, Virtuoso, Maximo II and Secura ICDs and Concerto CRT-D, Maximo II and Consulta System Reference Guides. 2. Schoels W, Steinhaus D, Johnson WB, et al. Optimizing implantable cardioverter-defibrillator treatment of rapid ventricular tachycardia: antitachycardia pacing therapy during charging. Heart Rhythm 2007; 4: 879-85. 3. Wilkoff BL, Williamson BD, Stern RS, et al. Strategic programming of detection and therapy parameters in implantable cardioverter-defibrillators reduces shocks in primary prevention patients: results from the PREPARE (Primary Prevention Parameters Evaluation) study. J Am Coll Cardiol 2008; 52: 541-50. 4. Bernier M, Essebag V. Inappropriate Shock Despite Successful Termination of Supraventricular Tachycardia by Antitachycardia Pacing during Charging. Pacing Clin Electrophysiol 2010; 33: 81–83

CİLT 8, SAYI 2, Haziran 2010