Effects of statin therapy on arrhythmic events and survival in patients with nonischemic dilated cardiomyopathy.

OBJECTIVES: We sought to evaluate whether statins were associated with a survival benefit and significant attenuation in life-threatening arrhythmias in patients with nonischemic dilated cardiomyopathy. BACKGROUND: Statins are associated with a reduction in appropriate implantable cardioverter-defibrillator (ICD) therapy in patients with coronary artery disease and improved clinical status in nonischemic dilated cardiomyopathy. METHODS: The effect of statin use on time to death or resuscitated cardiac arrest and time to arrhythmic sudden death was evaluated in 458 patients enrolled in the DEFINITE (DEFIbrillators in Non-Ischemic cardiomyopathy Treatment Evaluation) study. The effect of statin use on time to first appropriate shock was analyzed only in the 229 patients who were randomized to ICD therapy. RESULTS: The unadjusted hazard ratio (HR) for death among patients on versus those not on statin therapy was 0.22 (95% confidence interval [CI] 0.09 to 0.55; p = 0.001). When controlled for statin effects, ICD therapy was associated with improved survival (HR 0.61; 95% CI 0.38 to 0.99; p = 0.04). There was one arrhythmic sudden death in the 110 patients receiving statin therapy (0.9%) versus 18 of 348 patients not receiving statins (5.2%; p = 0.04). The unadjusted HR for arrhythmic sudden death among patients on versus those not on statin therapy was 0.16 (95% CI 0.022 to 1.21; p = 0.08). The HR for appropriate shocks among patients on versus those not on statin therapy was 0.78 (95% CI 0.34 to 1.82) after adjustment for baseline differences in the two groups. CONCLUSIONS: Statin use in the DEFINITE study was associated with a 78% reduction in mortality. This reduction was caused, in part, by a reduction in arrhythmic sudden death. These findings should be confirmed in a prospective, randomized clinical trial.     

Gender difference in arrhythmic occurrences in patients with nonischemic dilated cardiomyopathy and implantable cardioverter-defibrillator

Previous studies indicated that women were less likely to experience ventricular arrhythmia recurrence than men among patients with coronary artery disease and implantable cardioverter defibrillator (ICD). However, it is not clear whether the risk for ventricular tachyarrhythmia is gender-dependent in patients with nonischemic dilated cardiomyopathy. This study included 173 consecutive nonischemic dilated cardiomyopathy patients with a left ventricular ejection fraction of <45% (122 men and 51 women), who received ICD therapy between 1990 and 2008. The average follow-up period was 33 ± 28 months. There was no significant difference in event-free rates of appropriate ICD therapy between genders for all patients (P = 0.15) and by indication of ICD (primary prevention: P = 0.43, secondary prevention: P = 0.24). There was also no significant difference in event-free rates of electrical storm between genders (P = 0.17). In high-risk patients with nonischemic dilated cardiomyopathy who received ICD, there was no gender difference in the incidence of appropriate ICD therapy or electrical storm.     

Non-invasive evaluation of arrhythmic risk in dilated cardiomyopathy:From imaging to electrocardiographic measures

Malignant ventricular arrhythmias are a major adverse event and worsen the prognosis of patients affected by ischemic and non-ischemic dilated cardiomyopathy.The main parameter currently used to stratify arrhythmic risk and guide decision making towards the implantation of a cardioverter defibrillator is the evaluation of the left ventricular ejection fraction.However,this strategy is characterized by several limitations and consequently additional parameters have been suggested in order to improve arrhythmic risk stratification.The aim of this review is to critically revise the prognostic significance of non-invasive diagnostic tools in order to better stratify the arrhythmic risk prognosis of dilated cardiomyopathy patients.     

Ventricular repolarization dynamicity provides independent prognostic information toward major arrhythmic events in patients with idiopathic dilated cardiomyopathy.

OBJECTIVES: The purpose of this work was to evaluate whether ventricular repolarization dynamicity predicts major arrhythmic events in patients with idiopathic dilated cardiomyopathy (DCM). BACKGROUND: Arrhythmic risk stratification in patients with DCM is still an open issue. Ventricular repolarization analysis should provide relevant information, but QT interval and QT dispersion failed in predicting arrhythmic risk. METHODS: The following parameters were evaluated in 179 consecutive DCM patients without history of sustained ventricular tachycardia (VT) and/or ventricular fibrillation (VF) at enrollment: QRS duration, QT interval corrected for heart rate, and QT dispersion at electrocardiogram (ECG); left ventricular ejection fraction (LVEF) and left ventricular end-diastolic diameter at echocardiogram; and nonsustained ventricular tachycardia (NSVT), heart rate variability (standard deviation of RR intervals), and ventricular repolarization dynamicity as measured by means of 24-h ECG monitoring, by calculating the slope of linear regression analysis of QT end and RR intervals (QTe-slope) and the value of mean QT end corrected for heart rate. RESULTS: During a mean follow-up of 39 months, 9 patients died suddenly and 15 experienced VT and/or VF. At multivariate analysis, LVEF (p = 0.047), NSVT (p = 0.022), and QTe-slope (p = 0.034) were significantly associated with arrhythmic events. Among the patients with a low LVEF, NSVT and/or steeper QTe-slope identified a subgroup at highest arrhythmic risk. CONCLUSIONS: In patients with DCM, QT dynamicity is independently associated with the occurrence of major arrhythmic events and improves the predictive accuracy of stratifying arrhythmic risk of these patients.     

Familial dilated cardiomyopathy in patients transplanted for idiopathic dilated cardiomyopathy

OBJECTIVE: To evaluate the prevalence, clinical features, and pattern of inheritance of familial dilated cardiomyopathy (DCM) in heart transplant patients. PATIENTS AND METHOD: Patients with idiopathic DCM who had undergone heart transplantation were invited to participate. Patients with alcohol abuse were excluded. A clinical evaluation, 12-lead ECG, echocardiogram, blood tests, and DNA extraction were performed in patients and relatives. Familial DCM was defined as the presence of at least one relative with idiopathic DCM. Possible familial DCM was considered when at least one relative had left ventricular enlargement (LVE) (> 112% predicted LVEDD). RESULTS: One hundred and ninety-nine relatives of 43 families were studied. DCM was familial in 11 probands (25.6%) and possibly familial in 11 (25.6%). Fifteen relatives had DCM (7.5%), 26 (13.1%) LVE, and 5 (2.5%) hypertrophic cardiomyopathy. The pattern of inheritance was autosomal dominant in most families. Five probands (3 with familial DCM) had antecedents of consanguinity and possible recessive inheritance. Six probands (14%, 1 with familial DCM) had relatives with conduction system defects. Creatine kinase was moderately increased in 9 relatives (4.5%), 3 of them with LVE. Fifteen patients had at least moderate alcohol intake. Three of them had familial DCM (relatives without alcohol abuse) and 6 had possible familial DCM. CONCLUSIONS: The prevalence of familial DCM is high in patients who undergo heart transplant. Left ventricular enlargement, conduction system abnormalities, and elevated creatine kinase may be early markers of familial disease. Hypertrophic cardiomyopathy is present in some relatives of patients with idiopathic DCM. Familial DCM is present in patients with a previous diagnosis of alcoholic DCM.     

Patients with recently diagnosed nonischemic cardiomyopathy benefit from implantable cardioverter-defibrillators.

OBJECTIVES: This study sought to determine whether the time from diagnosis to randomization was related to outcome in a clinical trial of implantable cardioverter-defibrillator (ICD) insertion in nonischemic cardiomyopathy. BACKGROUND: Whether the duration of nonischemic cardiomyopathy is related to arrhythmic risk and the possible benefit of ICD insertion is unknown. METHODS: The Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation (DEFINITE) trial randomized 458 patients with nonischemic dilated cardiomyopathy and a left ventricular ejection fraction <36% to receive standard medical therapy with or without an ICD. Patients were randomized regardless of the duration of known cardiomyopathy as long as a reversible cause of left ventricular dysfunction was not present. Patients were divided into recently and remotely diagnosed nonischemic cardiomyopathy groups based on the time from diagnosis of cardiomyopathy to randomization. To categorize patients, cut points of three and nine months were used. RESULTS: Patients with recently diagnosed cardiomyopathy who received an ICD had better survival than those treated with standard therapy at both cut points. This difference in survival was significant at three months (p < 0.05) and was borderline significant at nine months (p = 0.058). Patients with remotely diagnosed cardiomyopathy did not have a significant survival benefit with ICD insertion, but there were no significant differences between ICD benefit in the recent and remote diagnosis groups (p = 0.17 and 0.25). CONCLUSIONS: Patients who have a recent cardiomyopathy diagnosis do not have any less ICD benefit than those with a remote diagnosis. Thus, ICD therapy should be considered in such patients as soon as they are identified as long as a reversible cause of left ventricular dysfunction is excluded.     

Prognostic value of heart rate variability for sudden death and major arrhythmic events in patients with idiopathic dilated cardiomyopathy

OBJECTIVE: This study was designed to evaluate the prognostic value of heart rate variability for sudden death, resuscitated ventricular fibrillation or sustained ventricular tachycardia in patients with idiopathic dilated cardiomyopathy. BACKGROUND: Previous studies have shown that heart rate variability could predict arrhythmic events and sudden death in postinfarction patients, but the prognostic value of heart rate variability for arrhythmic events or sudden death in patients with idiopathic dilated cardiomyopathy has not been established. METHODS: Time and frequency domain analysis of heart rate variability on 24-h electrocardiographic (ECG) recording was assessed in 116 patients with idiopathic dilated cardiomyopathy (91 men, aged 51+/-12 years, left ventricular ejection fraction 34+/-12%). RESULTS: Mean follow-up (+/-SD) was 53+/-39 months. Sixteen patients reached one of the defined study end-points (sudden death, resuscitated ventricular fibrillation or sustained ventricular tachycardia) during follow-up. Using multivariate analysis, only reduced standard deviation of all normal-to-normal intervals (SDNN) (p = 0.02) and ventricular tachycardia during 24-h ECG recording (p = 0.02) predicted sudden death and/or arrhythmic events. For SDNN, a cutoff level of 100 ms seemed the best for the risk stratification. CONCLUSIONS: Decrease in heart rate variability is an independent predictor of arrhythmic events and sudden death in idiopathic dilated cardiomyopathy, whether the mechanism of sudden death is ventricular tachyarrhythmia or not.     

Different criteria of cardiac resynchronization therapy and their prognostic value for worsening heart failure or major arrhythmic events in patients with idiopathic dilated cardiomyopathy

There are still controversies about pertinent criteria for cardiac resynchronization therapy (CRT) and prophylactic indications for biventricular cardioverter-defibrillators, particularly in idiopathic dilated cardiomyopathy (IDC). This study compared several criteria for resynchronization therapy in IDC among those of several completed trials. In 201 patients with IDC, the relative risk for (1) death from heart failure (HF) or heart transplantation and (2) sudden death or sustained ventricular tachyarrhythmia were calculated separately according to the inclusion criteria of the Multisite Stimulation in Cardiomyopathy (MUSTIC), InSync, Multicenter InSync Randomized Clinical Evaluation (MIRACLE), Pacing Therapies for Congestive Heart Failure (PATH-CHF), Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure (COMPANION), and CONTAK studies. The percentage of patients meeting the criteria ranged from 6% for those of MUSTIC to 23% for those of CONTAK. In a follow-up of 51 +/- 42 months, 28 patients died (15 from progressive HF, 13 from sudden death), 20 underwent heart transplantation, and 12 had sustained ventricular tachyarrhythmia. Relative risks of worsening HF ranged from 3.14 (95% confidence interval [CI] 1.41 to 6.99, p = 0.005) for the MIRACLE criteria to 4.63 (95% CI 1.76 to 12.2, p = 0.0019) for the MUSTIC criteria. Only the CONTAK criteria were significantly associated with a risk for major arrhythmic events (2.65, 95% CI 1.19 to 5.95, p = 0.018). Arrhythmic events constituted 16% of all cardiac events for the MUSTIC patients, 11% for InSync patients, 31% for PATH-CHF patients, 36% for MIRACLE patients, 38% for COMPANION patients, and 42% for CONTAK patients. In conclusion, in IDC, the less restrictive criteria for CRT were associated with the greatest risk for arrhythmic events. In contrast, patients with the MUSTIC criteria for CRT mainly had a risk for worsening HF and may not benefit from biventricular cardioverter-defibrillators.     

Familial dilated cardiomyopathy: a worse prognosis compared with sporadic forms.

OBJECTIVE--To establish the time of onset of dilated cardiomyopathy (DCM) by review of annual chest x rays, which are obligatory in Hungary. DESIGN--A retrospective survey of chest x rays of a cohort of confirmed cases of DCM, to assess time of onset of cardiomegaly. Clinical course was compared by follow up over a mean of six years from the time of diagnosis. SUBJECTS--240 patients with DCM (31 familial, 209 non-familial). Diagnosis was made by echocardiography in all cases and confirmed by coronary angiography and heart biopsy in some cases. MAIN RESULTS--At diagnosis, the mean age of the patients was 31.8 years in the familial group and 39.6 years in the non-familial group (P < 0.05). The time between the onset of cardiomegaly (cardiothoracic ratio > 0.45) and clinical diagnosis was 8.0 and 10.1 years respectively (P < 0.05). The six year survival was 6% in the familial group and 23% in the non-familial group (P < 0.05). CONCLUSIONS--The familial form of DCM is the more malignant form: it occurs at an earlier age and progresses more rapidly than non-familial DCM.     

Prognostic guides in patients with idiopathic or ischemic dilated cardiomyopathy assessed for cardiac transplantation

In an attempt to identify which parameters predict survival in advanced dilated cardiomyopathy, 232 patients presenting for assessment for cardiac transplantation were investigated and followed for 10 +/- 12 months (range 2 weeks to 5 years). Etiology of dilated cardiomyopathy included ischemic heart disease (33%), idiopathic (42%) and miscellaneous (25%). In each patient, 26 parameters were recorded. Whole group survival was 68% at 1 year, 56% at 2 years, 41% at 3 years and 25% at 4 years. On Cox multivariate regression analysis, 3 parameters predicted survival: New York Heart Association symptom class (p less than 0.0001), pulmonary capillary wedge pressure (p less than 0.008) and plasma atrial natriuretic factor level (p less than 0.002). On paired testing of actuarial survival curves, plasma noradrenaline also held predictive value (p less than 0.002), as did left ventricular ejection fraction less than or equal to 20% on radionuclide ventriculography (p = 0.007) and presence of greater than or equal to 4 beats of ventricular tachycardia on Holter monitoring (p = 0.007). Treatment with amiodarone did not appear to influence survival. Conventional determinants of prognosis in cardiomyopathy (symptom class, wedge pressure, nonsustained ventricular tachycardia and ejection fraction) do not alone always adequately differentiate survival in this group of high risk patients. More attention to plasma noradrenaline and to atrial natriuretic factor levels may give important additional information in the context of assessment of patients for transplantation.     

Gene mutations in adult Japanese patients with dilated cardiomyopathy.

BACKGROUND: Some patients with dilated cardiomyopathy (DCM) have mutations of the genes that encode sarcomeric or cytoskeletal proteins of cardiomyocytes, but the prevalence of these mutations in Japan remains unclear. METHODS AND RESULTS: A group of 99 unrelated adult patients with DCM (familial n=27, sporadic n=72) were screened for the following genes: cardiac beta-myosin heavy chain, cardiac myosin-binding protein C (MYBPC3), regulatory and essential myosin light chains, alpha cardiac actin, alpha tropomyosin, cardiac troponin T, cardiac troponin I, cardiac troponin C, dystrophin, and lamin A/C. A mutation (R820Q) in MYBPC3 was found in an aged patient. In addition, dystrophin mutations were identified in 3 male patients (2 with exon 45-48 deletion and 1 with exon 48-52 deletion). The prevalence of dystrophin mutations in male patients with DCM was 4.4% (3 of 68). No mutations involving amino acid changes were identified in the other genes. CONCLUSIONS: Although cases of adult patients with DCM caused by mutations of the genes encoding sarcomeric or cytoskeletal proteins of cardiomyocytes are infrequent in Japan, it may be advisable to screen older DCM patients for MYBPC3 mutations, and male patients with familial DCM for dystrophin mutations.