Published in:
01-11-2015
Differences in ventricular tachyarrythmias and antitachycardia pacing effectiveness according to the ICD indication (primary versus secondary prevention): an analysis based on the stored electrograms
Published in: Journal of Interventional Cardiac Electrophysiology | Issue 2/2015
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Purpose
To determine whether monomorphic ventricular tachycardias (VTs) have different characteristics and/or responses to antitachycardia pacing (ATP) with respect to the indication—primary prevention (PP) versus secondary prevention (SP)—among ICD patients with left ventricular dysfunction.
Methods
We prospectively studied 551 VT (cycle length [CL] 329 ± 35 ms; PP 34 %) occurring in 67 ICD patients with left ventricular dysfunction (LVEF 35 ± 8 %). ICD programming was standardized, including ATP for slow (CL 400–321 ms) and fast VT (CL 250–320 ms). We analyzed the following aspects: CL, percentage of variability of the 12 RR intervals prior to ATP (P-RR)—which was calculated by dividing the mean difference between each R-R interval with the next one by the CL × 100—and type of termination: immediate (VT ceased immediately upon ATP completion) or delayed (VT persisted after ATP).
Results
ATP was successful in 86 % of VTs. VTs occurring in SP patients had a lower P-RR, median (IQR) 2.7 % (1.2–3.7) versus 1.9 % (0.9–3.2); p = 0.002; they terminated immediately after ATP less frequently (27 % versus 12 %; p < 0.001), and although they were more frequently slow (51 % versus 67 %; p = 0.01), ATP was less effective in them, 92 versus 80 % (p = 0.02).
Conclusions
VTs occurring in SP patients are slower, more stable, and they terminate less frequently at ATP. Therefore, compared with PP, SP patients seem to have fewer self-terminating VTs.