Key result
NSVT cycle length fails to predict appropriate ICD interventions, though fast episodes link to VF.
Why the study?
ICD patients with nonsustained ventricular tachycardias (NSVT) face risk of appropriate therapies, but the relationship between NSVT cycle length and subsequent appropriate interventions is unknown.
Does the cycle length or burden of nonsustained ventricular tachycardias predict subsequent appropriate ICD therapies in patients with LVEF < 45%?
Cohort (n=416)
No
Does the cycle length or burden of nonsustained ventricular tachycardias predict subsequent appropriate ICD therapies in patients with LVEF < 45%?
While NSVT burden predicts subsequent appropriate ICD therapies, NSVT cycle length does not, although it strongly correlates with the cycle length of subsequent treated arrhythmias.
Answers are grounded in this paper and cite their sources.
NSVT cycle length should not guide ICD risk stratification in LVEF <45%; leaves open whether fast episodes warrant closer monitoring.
BACKGROUND: ICD patients with episodes of nonsustained ventricular tachycardias (NSVT) are at risk of appropriate therapies. However, the relationship between the cycle length (CL) of such NSVTs and the subsequent incidence of appropriate interventions is unknown. METHODS: 416 ICD patients with LVEF < 45% were studied. ICD programming was standardized. NSVT was defined as any VT of 5 or more beats at ≥ 150 bpm occurred in the first 6 months after implantation that terminated spontaneously and was not preceded by any appropriate therapy. The mean follow-up was 41 ± 27 months. RESULTS: We analyzed 2201 NSVTs (mean CL = 323 ms) that occurred in 250 patients; 111 of such episodes were fast (CL ≤ 300 ms). Secondary prevention (HR = 1.7; p < 0.001), number of NSVT episodes (HR = 1.05; 95% CI 1.04-1.07; p < 0.001) and beta-blocker treatment (HR = 0.7; p = 0.04) were independent predictors of appropriate interventions; however, the mean CL of NSVTs was not (p = 0.6). There was a correlation between the mean CL of NSVTs and the CL of the first monomorphic VT: r = 0.88; p < 0.001. This correlation was especially robust in individuals with > 5 NSVTs (r = 0.97; p < 0.001), with an agreement between both values greater than 95%. Patients with any fast NSVT experienced a higher incidence of VF episodes (26%) compared to those without NVSTs (3%) or with only slow NSVTs (7%); p < 0.001. CONCLUSIONS: Unlike the burden, the CL of NSVTs is not a predictor of subsequent appropriate interventions. However, there is a close relationship between the CL of NSVTs and that of arrhythmias that will later lead to appropriate therapies.
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Jiménez‐Candil et al. (2021) conducted a cohort in Left ventricular dysfunction with an ICD (n=416). Mean cycle length of nonsustained ventricular tachycardias (NSVT) was evaluated on Appropriate interventions (HR 0.4, 95% CI 0.4-1.5, p=0.6). The mean cycle length of nonsustained ventricular tachycardias did not independently predict subsequent appropriate ICD interventions (HR 0.4), although fast episodes were associated with ventricular fibrillation.
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