Mp-453092-9 prognostic significance of sustained ventricular arrhythmias occurring under wearable cardioverter defibrillator protection in post-infarct patients with a left ventricular dysfunction

Although the first few months after acute myocardial infarction (MI) are associated with an increased risk of SCD, in particular when LVEF is ≤0.35, prophylactic ICDs are not recommended until LVEF has been reassessed after a period of 40 to 90 days following an acute MI. During this ‘waiting period’, wearable cardioverter defibrillators (WCD) may be used in patients considered at high-risk of SCD, but the prognostic significance of sustained VT/VF occurring under WCD protection is unknown. We sought to evaluate whether the occurrence of VT/VF, successfully treated by a WCD in the early post-MI phase, is associated with a poorer outcome with regard to death or VT/VF recurrences at one year. We recruited a series of patients with an acute MI and a resulting LVEF≤0.35 (evaluated 2-5 days after admission) who were prescribed a WCD upon hospital discharge (for a maximal expected duration of 3 months) and who were subsequently implanted with an ICD either because sustained VT/VF occurred while on WCD (Group A) or because LVEF remained ≤0.35 after the post-MI ‘waiting period’ (Group B). Informed consent was mandatory to participate in the study. Adjudication of arrhythmic events was based on the analysis of ICD/WCD recordings. Based on previous publications, eleven relevant clinical parameters (associated with a higher risk of SCD after MI) were assessed for statistical analysis in addition to the occurrence of VT/VF while on WCD. The study population consisted of 1032 consecutive patients (Group A: n=72, Group B: n=960) from 41 French centers. The median follow-up after ICD implantation was 2.6 years [interquartile range=1.5-3.9]. The clinical characteristics of the patients are shown in Table 1. At one year: 1) VT/VF requiring ICD treatment occurred in 22.2% vs 3.5% (p<0.0001) respectively in Group A and Group B patients and 2) death from any cause occurred in 11.1% vs 3.4% (p=0.001) respectively in Group A and Group B patients (Figure 1). Occurrence of VT/VF while on WCD was independently associated with the occurrence of VT/VF and all-cause death after ICD implantation. Our study suggests that the occurrence of VT/VF, while on WCD in the early post-MI period after an acute MI, is an independent marker of a poorer one-year prognosis in patients with a LVEF≤0.35. Further studies are needed to assess which therapeutic strategies might improve the short-term prognosis in these patients.Tabled 1Table 1: Patient characteristicsVariablesGroup A (n = 72)Group B (n = 960)p-valueGender (male, %)88.9%82.9 %0.25Age at ICD implantation (years, mean ± SD)61.5 ± 9.060.7 ± 10.50.52Current smoker (%)50.7 %47.9 %0.90Diabetes mellitus (%)30.6 %23.2 %0.20History of hypertension (%)47.9 %41.7 %0.32History of atrial fibrillation (%)8.3 %4.8 %0.17History of previous myocardial infarction (%)16.7 %18.8 %0.75Early (<24 hours) coronary revascularization for the index myocardial infarction (%)51.4 %66.3 %0.014Average heart rate during WCD (bpm, mean ± SD)73.2 ± 12.568.3 ± 9.6<0.0001NYHA III/IV class at ICD implantation (%)39.6%19.1%0.001Serum creatinine at ICD implantation [mg/L, median (Q1 - Q3)]10.8 (9.2 - 13.1)10.7 (8.9 - 13.2)0.42LVEF at ICD implantation (%, mean ± SD)29.1 ± 6.629.3 ± 6.20.78 Open table in a new tab