| Part IFragmented QRS is associated with all-cause mortality and ventricular arrhythmias in patient with idiopathic dilated cardiomyopathty[Background] Idiopathic dilated cardiomyopathy is a serious heart disease damaging human being's health, and most patients die of heart failure or malignant ventricular arrhythmias. So it has important clinical significance to estimate prognosis of these patients using simple and convenient noninvasive techniques. Several studies have showed that fragmented QRS complexes on a routine 12-lead electrocardiogram were associated with increased mortality and arrhythmic events in patients with coronary artery disease, but relatively little data were available regarding idiopathic dilated cardiomyopathy.[Objective] The purpose of this study was to evaluate the relationship between fragmentation of QRS and the combined endpoint of all-cause mortality and ventricular arrhythmias in patients with idiopathic dilated cardiomyopathy.[Methods] Patients who were diagnosed as idiopathic dilated cardiomyopathy with left ventricular dysfunction (ejection fraction, EF< or=40%) at our hospital from January 1,2009 to December 31,2009 were analyzed respectively. According to QRS duration and the existence of f-QRS on 12-lead ECG, the study populations were divided into three groups:1) the f-QRS group (QRS< 120ms and with fragmented QRS, n=51),2) the wQRS group (QRS> or= 120ms, n=48), and 3) the non-fQRS group (QRS< 120ms and without fragmented QRS, n=29).[Results] A total of 128 patients (mean age 54±14 years, male 68 %) were control into this study. f-QRS was present in 28 patients (21.9 %),17 patients (13.3%), and 20 patients (15.6%) of inferior, lateral, and anterior leads, respectively, and was present in more than one lead set in 14 cases (10.9%). LVEF was significantly lower in the f-QRS group than the non-fQRS group (29%±6%vs 33%±7%, P=0.013). Left ventricular end-diastolic dimension in the f-QRS and the wQRS groups were 68.8±7.9mm and 69.4±9.0mm, respectively, which was significantly larger than in the non-fQRS group (65.2±6.5mm, P<0.05 for both). During a mean follow-up of 14±5 months,25 (19.5%) patients had deaths or ventricular arrhythmic events. The combined endpoint of all-cause mortality and ventricular tachyarrhythmias was significantly higher in the f-QRS and wQRS groups than the non-fQRS group (23.5%,25%, and 3.4%, respectively; P<0.05 for both). Event-free was significantly decreased in the f-QRS group versus the non-fQRS group (P=0.02). Univaritae Cox regression analysis revealed that f-QRS (odds ratio [OR] 7.90, P=0.015) was a stronger predictor of mortality and arrhythmic events in idiopathic dilated cardiomyopathy patients.[Conclusion] f-QRS on 12-lead ECG has a high predictive value for the combined endpoint of all-cause mortality and ventricular tachyarrhythmias in idiopathic dilated cardiomyopathy patients with left ventricular dysfunction. Part II Clinical application and follow up of implantable cardioverter-defibrillator[Background] Malignant ventricular arrhythmias, ventricular tachycardia (VT) or ventricular fibrillation (VF), are the main reason of sudden cardiac death. The implantable cardioverter-defibrillator (ICD) provides a significant reduction in mortality in survivors of sudden cardiac arrest and high-risk patients with cardiovascular disease. Inappropriate detection and therapy of ICD are the most common side effects and impact the quality-of-life in ICD patients. Inappropriate shocks will reduce cardiac function and increase mortality risk. Several studies identify some predictors for inappropriate shocks, but they show less consistency.[Objective] The purpose of this study was to assess the incidence of tachycardia, the capability of ATP therapy for termination of ventricular tachycardia, and the incidence and predictors of inappropriate shocks in ICD patients.[Methods] From March 2007 to August 2010, patients who receive ICD implantation for preventing the sudden cardiac death in Fu Wai Cardiovascular Hospital were enrolled in this study. Patients were followed up by regular intervals after implantation. During follow-up, the occurrence of arrhythmia, all-cause mortality, the rate of successful termination ventricular tachycardia by ATP and inappropriate shocks were noted.[Results] A total of 115 ICD patients (mean age 51±17 years, male 67.8%) were include in the analysis.93.9% reveived an ICD for sudden cardiac death second prevention, and 72.7% received single-chamber ICDs. During the follow-up period of 14±11 months,8 patients died and the major cause of death was heart failure (5 cases,62.5%).58 patients (50.4%) experienced appropriate therapy (ATP and/or shock) due to sustained ventricular arrhythmia. ATP was attempted for 783 sustained VT episodes in 46 patients (40%), and 652 (83.3%) of the VT episodes were successfully terminated by ATP. Six VT events were accelerated by ATP and required termination by ICD shock.22 patients (19.1%) experienced inappropriate detections and therapies and 17 patients (14.8%) had inappropriate shocks. The median time from ICD implantation to first inappropriate shock was 114 (1～1006) days. Univaritae Cox regression analysis revealed that a history of atrial fibrillation (odds ratio [OR] 5.3,95% CI 1.88～14.92, P=0.002) was a stronger predictor of the occurrence of inappropriate shocks.[Conclusion] Sustained VT terminated by ATP therapy was efficiency and safe; ICD inappropriate shocks were a common complication after implantation and a history of atrial fibrillation can increase inappropriate shocks risk.
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