Dilate Kardiyomiyopati Hastalarında Fragmente Qrs ve Fragmente Geniş Qrs'in Mortalite ve Aritmik Olayları Öngördürücülüğü

Abstract

Dilated cardiomyopathy patients are at increased risk for ventricular tachyarrythmias an sudden cardiac death (SCD). Ventricular tachycardia and ventricular fibrilation take responsibility of approximately 2/3 of deaths in this patient group. Implantable cardioverter defibrillator (ICD) implantation is proven to be the most effective therapy in preventing SCD. İt is widely accepted that left ventricular ejection fraction (LVEF) is the most valuable predictor of SCD in this population. But even when a LVEF of 35 % is taken as a cut-off, the incidence of appropriate ICD therapy is relatively low, prompting better risk stratification. This incidence is even lower in patients with nonischemic cardiomyopathy. Fragmented QRS (fQRS) a depolarisation abnormality described as various RSR` patterns with or without Q waves on a 12-lead resting ECG. Based on their duration, they are subclassified into fQRS complexes (QRS duration <120 ms) and fragmented wide-QRS complexes (f-wQRS; QRS duration >120 ms). Various RSR` patterns include an additional R wave (R`) or notching in the nadir of the S wave, or the presence of >1 R` (fragmentation) in 2 contiguous leads, corresponding to a major coronary artery territory. Several studies mostly conducted with ischemic cardimoyopathy patients showed inconsistent results about the value of QRS fragmentation in predicting appropriate ICD therapy and mortality incidence in patients with DCMP. The aim of this study was to evaluate the prognostic value of QRS fragmentation in nonischemic cardimyopathy patients who receive ICD?s for primary prophylaxis. 172 (121 male, mean age 57,30±13,57) consecutive nonischemic dilated cadiomyopathy (NIDCMP) patients who received ICD?s for primary prevention of SCD were retrospectively evaluated. 96 patients (55,6%) did not have fragmentation on their resting ECG. 55 (31,9%), 22 (12,7%) and 3 (1,7%) patients had QRS fragmentation on 1, 2, and 3 terriotires respectively. 114 (66,3%) patients had QRS fragmentation on <3 leads, and 58 patients (%33,7) had ? 3 leads with QRS fragmentation on their resting ECG?s. During a median follow up of 23 (range 1-116) months,42 patients (%24.4) had ICD therapy(ATP/shock) due to ventricular tachyarrhythmias and 14 (%8.1) patients died from any cause. Patients with fQRS or f-wQRS in at least one ECG territory had more appropiate ICD therapies than patients without QRS fragmentation (33% vs. 17%, p<0.05). Patients with QRS fragmentation on at least one ECG territory had significantly more deaths than patients without QRS fragmentation (11.5 % vs. 5.1 %, p<0.05). Significantly more patients in the group with QRS fragmentation on at least one ECG territory reached combined end point wich consisted of appropriate ICD therapy and all cause mortality (37.1% vs. %17, p<0.05). The frequency of patients who reached endpoints increased as the number of ECG territories with QRS fragmentation increased (p<0.05). This finding was consistent for all three endpoints evaluated. Patients with ? 3 leads with QRS fragmentation had more appropriate ICD therapies than patients with < 3 leads with fQRS or f-wQRS (27.1 % vs. 5.9%, p<0.05). Patients with ? 3 leads with QRS fragmentation died (15.5 % vs. 4.4 %, p<0.05) and reached combiend end point (4.1.3 % vs. 25.3 %, p<0.05) more frequetly than patients with < 3 leads with QRS fragmentation. In ROC (Receiver Operating Curve) analysis the number of leads with QRS fragmentation achieved an area under curve 0.643 ( p=0.004 ) for the ability to predict appropriate ICD therapy. A cut-off value for number of leads with QRS fragmentation of >2 predicted appropriate ICD therapy with sensitivity of 50 % and specifity of 76 %. Multivariate Cox regression analysis revealed that presence of QRS fragmentation in 2 ECG territories and 3 ECG territories were independent predictors of appropriate ICD therapy with hazard ratios of 5.641 (p=0.001) and 10.290 (p=0.002) respectively. Presence of QRS fragmentation in ?3 leads was independent predictor of appropriate ICD therapy, all cause mortality and combined end point with hazard ratios of 2.767 (p=0.001), 3.725 (p=0.02) and 2.757 (p=0.001) respectively. Kaplan-Meier survival analysis revealed that survival reduced as the number of territories with QRS fragmentation increased and that patients with ?3 leads with QRS fragmentation had reduced survival (p<0.05). As a conclusion, presence and extencity of QRS fragmentation on surface ECG predicted appropriate ICD therapy and all cause mortality in primary prevention DCMP patients.