RESUMO
Left ventricular (LV) ejection fraction (LVEF) is the most widely used prognostic marker in cardiovascular diseases. LV global function index (LVGFI) is a novel marker which incorporates the total LV structure in the assessment of LV cardiac performance. We evaluated the prognostic significance of LVGFI, measured by cardiovascular magnetic resonance (CMR), in predicting mortality and ICD therapies in a real-world (ICD) population with secondary ICD prevention indication, to detect a high-risk group among these patients. In total, 105 patients with cardiac MRI prior to the ICD implantation were included (mean age 56 ± 16 years old; 76% male). Using the MRI data for each patient LVGFI was determined and a cut-off for the LVGFI value was calculated. Patients were followed up every four to six months in our or clinics in proximity. Data on the occurrence of heart failure symptoms and or mortality, as well as device therapies and other vital parameters, were collected. Follow up duration was 37 months in median. The mean LVGFI was 24.5%, the cut off value for LVGFI 13.5%. According to the LVGFI Index patient were divided into 2 groups, 86 patients in the group with the higher LVGFI und 19 patients in the lower group. The LVGFI correlates significantly with the LVEF (r = 0.642, p < 0.001). In Kaplan-Meier analysis, a lower LVGFI (<13.5%) was associated with a higher rate of mortality and rehospitalization (p = 0.002). In contrast, echocardiographic LVEF ≤ 33% was not associated with a higher rate of mortality or rehospitalization. Multivariate Cox-regression analysis revealed a lower LVGFI (p = 0.025, HR = 0.941; 95%-CI 0.89-0.99) and diabetes mellitus (p = 0.027, HR = 0.33; 95%-CI 0.13-0.88) as an independent predictor for mortality and rehospitalization. There was no association between the combined endpoint and the LVEFMRT, LVEFecho, NYHA > I, the initial device or a medication (each p = n.s.). Further, in Kaplan-Meier analysis no association was evident between the LVGFI and adequate ICD therapy (p = n.s.). In secondary prevention ICD patients reduced LVGFI was shown as an independent predictor for mortality and rehospitalization, but not for ICD therapies. We were able to identify a high-risk collective among these patients, but further investigation is needed to evaluate LVGFI compared to ejection fraction, especially in patients with an elevated risk for adverse cardiac events.
RESUMO
BACKGROUND: Implantable cardioverter defibrillator (ICD) therapies, even when appropriate, are associated with increased risk. Therapy-reducing strategies have been shown to reduce the mortality rate.MethodsâandâResults:In total, 895 patients with ICD and cardiac resynchronization therapy with defibrillation function (CRT-D) were included in the study; of these, 506 (57%) patients undergoing secondary prevention were included. Devices implanted before May 2014 were programmed according to conventional programming (CP), the others according to our novel programming (NP) with high rate cut-off, longer detection intervals and 4-6 anti-tachycardia pacing (ATP) trains in the ventricular tachycardia (VT) zone. Time-to-first-event for mortality, appropriate and inappropriate therapies were analyzed. Follow-up time was 24.0 months (IQR 13.0-24.0 months). There was a significant reduction in mortality rate (11.4% vs. 25.4%, P<0.001) and in the rate of appropriate (18.8% vs. 42.2%, P<0.001) and inappropriate therapies (5.2% vs. 18.0%, P<0.001) with NP according to Kaplan-Meier analyses. In multivariate analysis, NP (hazard ratio [HR]=0.35; P<0.001), chronic kidney disease (HR=1.55), reduced ejection fraction (EF) (HR=1.35), secondary ICD indication (HR=2.35) and age at implantation (HR=1.02) were associated with mortality reduction. NP was also associated with significant reduction in the rate of appropriate and inappropriate therapies. These results were consistent after stratification for primary and secondary prevention. CONCLUSIONS: Novel ICD programming reduced mortality and morbidity due to appropriate or inappropriate ICD therapies in secondary as well as in primary ICD indication.
