Do atrial tachyarrhythmias beget ventricular tachyarrhythmias in defibrillator recipients?

Objectives This study was designed to analyze the incidence of “dual tachycardia”—ventricular tachycardia (VT) or ventricular fibrillation (VF) preceded by paroxysmal atrial tachycardia (AT) or atrial fibrillation (AF)—in patients receiving dual-chamber implantable cardioverter defibrillators (ICDs). Background Paroxysmal AT/AF occurs commonly in patients who receive ICDs for the treatment of life-threatening VT/VF. Although AF is associated with an adverse prognosis in the setting of structural heart disease, the relationship between AT/AF and VT/VF is unclear. Methods We followed 537 patients undergoing implantation of the Jewel AF ICD (Model 7250, Medtronic, Minneapolis, Minnesota) for 11.4 ± 8.2 months. These included 398 patients with a history of at least two episodes of AT or AF during the preceding year as well as 139 patients enrolled because of VT/VF alone. Results There were 233 dual tachycardia episodes in 45 patients during follow-up. Overall, 8.9% of episodes detected as VT/VF were dual tachycardias, and 20.3% of patients with VT/VF had at least one dual tachycardia episode. The median duration of AT/AF preceding the first VT/VF detection was 1.09 h (25% to 75% quartile 0.24 to 33.4 h). When AT/AF continued between two consecutive VT/VF detections, the median interdetection interval was 11 min. When AT/AF terminated either because of a ventricular therapy or spontaneously, the median interdetection interval was prolonged to 71 h (p < 0.001) Conclusions Dual tachycardia is common in ICD recipients with a history of AT/AF. The duration of AT/AF preceding the first VT/VF detection is ≤1 h about 50% of the time. Termination of the AT/AF significantly delays the time to the next VT/VF detection.