Arrhythmogenic Right Ventricular Cardiomyopathy 2012: Diagnostic Challenges and Treatment

ARVC 2012 . The most common presentation of arrhythmogenic right ventricular cardiomyopathy (ARVC) is palpitations or ventricular tachycardia (VT) of left bundle branch morphology in a young or middle‐aged individual. The 12‐lead electrocardiogram may be normal or have T‐wave inversion beyond V₁ in an otherwise healthy person who is suspected of having ARVC. The most frequent imaging abnormalities are an enlarged right ventricle, decrease in right ventricular (RV) function, and localized wall motion abnormalities. Risk factors for implantable cardioverter defibrillator include a history of aborted sudden death, syncope, young age, decreased left ventricular function, and marked decrease in RV function. Recent results of treatment with epicardial ablation are encouraging. (J Cardiovasc Electrophysiol, Vol. 23 pp. 1149‐1153, October 2012)     

Radiofrequency Catheter Ablation of Sustained Monomorphic Ventricular Tachycardia in Hypertrophic Cardiomyopathy

Monomorphic VT in HCM. Introduction : Incessant monomorphic ventricular tachycardia (VT) with a right bundle branch block morphology and a northwest axis is a rare arrhythmic complication in a patient with hypertrophic cardiomyopathy and apical left ventricular aneurysm.
Methods and Results : The origin of this VT was localized using the following criteria: the presence of entrainment without fusion, equal internals from the stimulus to the beginning of the QRS complex and from the electrogram to the QRS complex during VT, and the first postpacing interval identical to the tachycardia cycle length. Radiofrequency energy applied to the septoapical part of the apical left ventricular aneurysm terminated the tachycardia within 2 seconds.
Conclusion : Using criteria to guide radiofrequency (RF) ablation of VT in patients with coronary artery disease, an incessant monomorphic VT in a patient with hypertrophic cardiomyopathy was successfully ablated.     

Arrhythmias in Hypertrophic Cardiomyopathy

Arrhythmias in Hypertrophic Cardiomyopathy. Arrhythmias, particularly atrial fibrillation and nonsustained ventricular tachycardia, are common in adult patients with hypertrophic cardiomyopathy. Atrial fibrillation has long been thought to herald an ominous prognosis, but this is probably not the case, and in the majority of patients atrial fibrillation can be controlled without accelerated symptomatic deterioration. Uncontrolled observations indicate that low dose amiodarone may be the most useful drug in paroxysmal and chronic atrial fibrillation. The detection of nonsustained ventricular tachycardia on ambulatory electrocardiogram monitoring remains the single most useful indicator of the risk of sudden death in the adult patient, and the treatment of choice is again low dose amiodarone. The mechanism of sudden death, and the mode of action of amiodarone in preventing it, are not known for certain in the majority of patients. The risk of sudden death is higher in children and adolescents, but arrhythmias are less common, and no useful predictive marker of increased risk has been found. The role of invasive electrophysiological studies and the place of the implantable cardioverter-defibrillator in hypertrophic cardiomyopathy have not yet been established.     

Long‐Term Outcomes of Inducible Very Fast Ventricular Tachycardia (Cycle Length 200–250 ms) in Patients With Ischemic Cardiomyopathy

Very Fast Ventricular Tachycardia. Background: The long‐term outcomes of patients with inducible very fast ventricular tachycardia (VFVT) of cycle length (CL) 200 to 250 ms have not been well studied. Methods: Consecutive patients with ischemic cardiomyopathy with a left ventricular ejection fraction (LVEF) of ≤40% (n = 300) underwent programmed ventricular stimulation (PVS) and were divided into 4 groups based on results of the study. Group A were noninducible, had induced ventricular fibrillation (VF), or polymorphic VT (CL < 200 ms); group B had inducible VFVT (200–250 ms); group C had inducible fast ventricular tachycardia (FVT; CL 251–320 ms); and group D had inducible slow VT (CL >320 ms). The primary endpoint was spontaneous ventricular arrhythmia or sudden death. Results: The mean age was 63 ± 12 years and mean LVEF was 29 ± 7%. At mean follow‐up of 38 ± 25 months (median 30 months), the primary endpoint rate was 6.6%, 34%, 44%, and 71% in groups A, B C, and D, respectively (P < 0.001). Neither mode of induction of VT nor LVEF altered the observed pattern in the primary endpoint. There was no significant difference in the primary endpoint among implanted cardioverter defibrillator recipients in groups B and C (38% vs 45%, P = 0.43). Adjusted hazard ratios for the primary endpoint compared to group A were 3.2, 3.5, and 7.0 in groups B, C, and D, respectively (P < 0.05). Conclusions: Inducible VFVT (200–250 ms) is a clinically significant arrhythmia with adverse long‐term outcomes and should not be considered a nonspecific finding of PVS. (J Cardiovasc Electrophysiol, Vol. 21, pp. 262–269, March 2010)     

Successful Catheter Ablation of Hemodynamically Unstable Monomorphic Ventricular Tachycardia in a Patient with Hypertrophic Cardiomyopathy and Apical Aneurysm

Patients with hypertrophic cardiomyopathy (HCM) and left ventricular (LV) apical aneurysm represent a previously under-recognized but important subgroup within this heterogeneous disease spectrum. Apical aneurysms and the contiguous areas of myocardial fibrosis have been associated with monomorphic ventricular tachycardia (VT) and increased risk for adverse clinical events including sudden cardiac death, prioritizing the application of primary prevention implantable defibrillators. However, VT may be repetitive, thereby raising considerations for additional treatment strategies such as radiofrequency ablation. In this report, we describe such a patient with HCM and apical aneurysm in whom the mapping and ablation procedure was effective in identifying and abolishing the VT focus.     

Substrate Characterization and Catheter Ablation for Monomorphic Ventricular Tachycardia in Patients With Apical Hypertrophic Cardiomyopathy

VT Ablation in Apical Hypertrophic Cardiomyopathy . Introduction: Monomorphic ventricular tachycardia (VT) is uncommon in apical hypertrophic cardiomyopathy (HCM). The purpose of this study was to define the substrate and role of catheter ablation for VT in apical HCM. Methods: Four patients with apical HCM and frequent, drug refractory VT (mean age of 46 ± 10 years, left ventricular [LV] ejection fraction; 54 ± 14%) underwent catheter ablation with the use of electroanatomic mapping. Endocardial mapping was performed in 4 patients and 3 patients underwent epicardial mapping. Results: In 3 patients, VT was related to areas of scar in the apical LV where maximal apical wall thickness ranged from 14.5 to 17.8 mm, and 2 patients had apical aneurysms. Endocardial and epicardial substrate mapping revealed low voltage (<1.5 mV) scar in both endocardial and epicardial LV in 2 and only in the epicardium in 1 patient. Inducible VT was abolished with a combination of endocardial and epicardial ablation in 2 patients, but was ineffective in the third patient who had intramural reentry that required transcoronary ethanol ablation of an obtuse marginal vessel for abolition. The fourth patient had focal nonsustained repetitive VT from right ventricular outflow tract (RVOT), consistent with idiopathic RVOT‐VT, that was successfully ablated. During follow‐ups of 3‐9 months, all patients remained free from VT. Conclusion: Monomorphic VT in apical HCM can be due to endocardial, epicardial or intramural reentry in areas of apical scar. Epicardial ablation or transcoronary alcohol ablation is required in some cases. (J Cardiovasc Electrophysiol, Vol. 22, pp. 41‐48, January 2011)     

ACCF/AHA肥厚型心肌病诊断治疗指南2011解读

肥厚型心肌病是一种常见的心血管疾病。该指南是由美国心脏病学院基金会(ACCF)和美国心脏协会(AHA)联合推出的第一部关于肥厚型心肌病的指南。现就指南中涉及到肥厚型心肌病定义、诊断方法、病程特点以及治疗手段进行概括及解读。     

Advantages of a Subcutaneous Implantable Cardioverter‐Defibrillator in LAMP2 Hypertrophic Cardiomyopathy

Danon disease is a rare X‐linked lysosomal disease causing severe hypertrophic cardiomyopathy (LAMP2 cardiomyopathy) and an extremely poor prognosis in males, with several reported cases of sudden cardiac death despite the use of transvenous implantable cardioverter defibrillators (TV‐ICD). We describe a case in which a TV‐ICD was unable to defibrillate induced ventricular fibrillation (VF), but a wholly subcutaneous system (S‐ICD) was successful in terminating induced VF and spontaneous ventricular tachycardia. These findings have relevance to the selection of device therapy in the management of these individuals and a wider group of young patients with severe hypertrophic cardiomyopathy.     

Mode of Induction of Ventricular Tachycardia and Prognosis in Patients with Coronary Disease: The Multicenter UnSustained Tachycardia Trial (MUSTT)

Introduction: Programmed stimulation is an important prognostic tool in the evaluation of patients with an ejection fraction ≤40% after myocardial infarction. Many believe that ventricular tachycardia (VT) requiring 3 ventricular extrastimuli (VES) for induction is less likely to occur spontaneously and has less predictive value. However, it is unknown whether the mode of VT induction is associated with long-term prognosis.
Methods and Results: We analyzed a cohort of 371 patients enrolled in MUSTT who had inducible monomorphic VT and who were not treated with antiarrhythmic drugs or an implantable cardioverter defibrillator during the trial. Patients in whom sustained VT was induced with 1 or 2 VES or burst pacing (single VES n = 15, double VES n = 127, burst n = 7, total n = 149) were compared with those in whom VT was induced with 3 VES (n = 222). Compared with the others, patients requiring 3 VES were closer to their most recent myocardial infarction (17 vs 51 months, P = 0.035) and showed a trend toward a lower ejection fraction (26% vs 30%, P = 0.057). VT requiring 3 VES had a shorter cycle length (240 vs 260 ms, P < 0.001). Despite these findings, there was no difference in the incidence of arrhythmic death or cardiac arrest (HR 1.02; 95% CI 0.69-1.51) or all-cause mortality (HR 1.03; 95% CI 0.76-1.39) according to the mode of induction in adjusted analyses.
Conclusions: The prognostic significance of VT induced by 3 VES is similar to that of VT induced by 1 or 2 VES, or burst pacing, in patients with coronary disease and abnormal LV function.