Implantable Cardioverter‐Defibrillator in Patients With Hypertrophic Cardiomyopathy: Efficacy and Complications of the Therapy in Long‐Term Follow‐up

ICD in Hypertrophic Cardiomyopathy Patients. Introduction: Although implantable cardioverter‐defibrillators (ICDs) are used in sudden cardiac death (SCD) prevention in high‐risk patients with hypertrophic cardiomyopathy (HCM), long‐term results as well as precise risk stratification are discussed in a limited number of reports. The aim of the study was to assess the incidence of ICD intervention in HCM patients with relation to clinical risk profile. Methods and Results: We studied 104 consecutive patients with HCM implanted in a single center. The mean age of study population was 35.6 (SD, 16.2) years with the average follow‐up of 4.6 (SD, 2.6) years. ICD was implanted for secondary (n = 26) and primary (n = 78) prevention of SCD. In the secondary prevention group, 14 patients (53.8%) experienced at least 1 appropriate device intervention (7.9%/year). In the primary prevention (PP) group appropriate ICD discharges occurred in 13 patients (16.7%) and intervention rate was 4.0%/year. Nonsustained VT was the only predictive risk factor (RF) for an appropriate ICD intervention in the PP (positive predictive value 22%, negative predictive value 96%). No significant difference was observed in the incidence of appropriate ICD discharges between PP patients with 1, 2, or more RF. Complications of the treatment included: inappropriate shocks (33.7%), lead dysfunction (12.5%), and infections: 4.8% of patients. Four patients died during follow‐up. Conclusion: ICD therapy is effective in SCD prevention in patients with HCM, although the complication rate is significant. Nonsustained ventricular tachycardia seems to be the most predictive RF for appropriate device discharges. Number of RF did not impact the incidence of appropriate ICD interventions. (J Cardiovasc Electrophysiol, Vol. 21, pp. 883‐889, August 2010)     

Evolutionary Change Mimicking Apical Hypertrophic Cardiomyopathy in a Patient with Takotsubo Cardiomyopathy

In this report, we introduce a case of thickening of the involved left ventricular apical segment on echocardiography and deep T‐wave inversions in precordial leads on electrocardiography transiently seen in the course of recovery from biventricular takotsubo cardiomyopathy, mimicking apical hypertrophic cardiomyopathy. This result suggests that the echocardiographic finding of transient myocardial edema can be identified by cardiac magnetic resonance imaging in takotsubo cardiomyopathy. Additionally, it persisted a few weeks after full functional recovery. We believe that this case will contribute in part toward clarifying the pathophysiology of takotsubo cardiomyopathy.     

Cardiac Sarcoid: A Chameleon Masquerading as Hypertrophic Cardiomyopathy and Dilated Cardiomyopathy in the Same Patient

Sarcoidosis is a multisystem, granulomatous disease of unknown etiology often seen in young adults, with cardiac involvement in more than one‐quarter of sarcoid patients. The clinical presentation of cardiac sarcoid depends upon the location and extent of myocardium involved. Although cardiac sarcoid may produce asymmetrical septal hypertrophy, it is most commonly considered in the differential diagnosis of dilated cardiomyopathy. The hypertrophic stage of cardiac sarcoid is rarely seen. We describe a case of cardiac sarcoid in a young patient wherein a distinctive appearance of the cardiac sarcoid spectrum from “hypertrophic” stage to thinned/scarred stage, masquerading as hypertrophic cardiomyopathy followed by dilated cardiomyopathy, is demonstrated.     

Value of Electro‐Vectorcardiogram in Hypertrophic Cardiomyopathy

The electrocardiogram is an important tool for the initial diagnostic suspicion of hypertrophic cardiomyopathy in any of its forms, both in symptomatic and in asymptomatic patients because it is altered in more than 90 percent of the cases. Electrocardiographic anomalies are more common in patients carriers of manifest hypertrophic cardiomyopathy and the electrocardiogram alterations are earlier and more sensitive than the increase in left ventricular wall thickness detected by the echocardiogram. Nevertheless, despite being the leading cause of sudden death among young competitive athletes there is no consensus over the need to include the method in the pre‐participation screening. In apical hypertrophic cardiomyopathy the electrocardiographic hallmarks are the giant negative T waves in anterior precordial leads. In the vectorcardiogram, the QRS loop is located predominantly in the left anterior quadrant and T loop in the opposite right posterior quadrant, which justifies the deeply negative T waves recorded. The method allows estimating the left ventricular mass because it relates to the maximal spatial vector voltage of the left ventricle in the QRS loop. The recording on electrocardiogram or Holter monitoring of nonsustained monomorphic ventricular tachycardia in patients with syncope, recurrent syncope in young patient, hypotension induced by strain, bradyarrhythmia, or concealed conduction are markers of poor prognosis. The presence of rare sustained ventricular tachycardia is observed in mid‐septal obstructive HCM with apical aneurysm. The presence of complete right bundle branch block pattern is frequent after the percutaneous treatment and complete left bundle branch block is the rule after myectomy.     

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.     

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.     

胸导联心电图R-ST-T变化对心尖肥厚型心肌病的诊断价值

目的探讨胸导联心电图R-ST-T变化与心尖肥厚型心肌病(AHCM)的关系.方法对经超声心动图和/或左心室造影确诊的42例AHCM病人(AHCM组)及35例非AHCM病人(对照组)的心电图进行对比分析,分析胸导联心电图R-ST-T变化(R波增高呈RV4＞RV5＞RV3,T波倒置呈TV4＞TV5＞TV3,ST段下移,且均无动态演变)对判断AHCM的临床价值.结果 AHCM组心电图出现异常42例(100%).胸导联心电图R-ST-T变化在AHCM的出现率为78.6%,显著高于对照组的8.6%(P＜0.01).胸导联心电图R-ST-T变化预测AHCM的敏感度为78.6%、特异度为91.4%.5例AHCM病人胸导联心电图R-ST-T变化早于超声心动图及左心室造影改变.结论胸导联心电图R-ST-T变化是诊断AHCM的敏感、特异的预测指标,心电图对AHCM的诊断具有早期预测意义.     

Electroanatomical Mapping‐Guided Endocardial and Epicardial Ablation of Sustained Ventricular Tachycardia Originating From Alcohol Septal Ablation‐Induced Scar in a Patient With Hypertrophic Obstructive Cardiomyopathy

Ventricular Tachycardia After Alcohol Septal Ablation. A 76‐year‐old female developed 2 different ventricular tachycardias (VTs) 5 years after alcohol septal ablation (ASA) for symptomatic hypertrophic obstructive cardiomyopathy. VT#1 was a small macroreentry at the anterior border of the low‐voltage zone, suggesting the ASA‐scar and eliminated by endocardial ablation at a site recording fractionated potentials covering the mid‐diastolic and presystolic periods. VT#2 was a focal VT and eliminated by epicardial cryoablation at the basal posterior left ventricle, suggesting the posterior border of the ASA‐scar. Using the electroanatomical mapping, we demonstrated that the mechanism of the VTs was reentry at the edge of the ASA‐scar. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1296‐1299, November 2010)     

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.     

Echocardiography and Cardiac MRI in Mutation‐Negative Hypertrophic Cardiomyopathy in an Older Patient: A Case Defining the Need for ICD

We report the case of a 67‐year‐old man with hypertrophic cardiomyopathy who presented for a second opinion about implantable cardio‐defibrillator (ICD) placement after a witnessed syncopal episode. Despite his older age, being mutation‐negative, and having a maximal septal thickness of 2.2 cm on echocardiography, he demonstrated rapid progression of myocardial fibrosis on cardiac MRI, correlating to ventricular tachyarrhythmias and syncope. We review the role of echocardiography and cardiac MRI in optimizing medical care for such patients who may not otherwise meet criteria for an ICD placement or further interventions.     

Effects of Myocardial Perfusion on QT Dispersion in Patients with Hypertrophic Cardiomyopathy

Background: In patients with hypertrophic cardiomyopathy (HCM), myocardial ischemia and myocardial fibrosis as well as ventricular tachyarrhythmia are frequently observed. An increase of heterogeneity of repolarization provided the development of ventricular tachyarrhythmia. The aims of the present study are to evaluate the influence of exercise‐induced myocardial perfusion abnormalities on QT dispersion and to assess whether QT dispersion was involved in ventricular tachycardia (VT) in patients with HCM. Methods: Thirty‐eight patients with HCM and 20 control subjects underwent an exercise stress test, and QT intervals were measured pre‐exercise and at 3 minutes after peak exercise. All subjects underwent thallium (TI)‐201 stress myocardial imaging, and their TI‐201 defect score and exerciseinduced myocardial ischemia were evaluated. Results: Twelve patients (31%) revealed sustained or nonsustained VT. The pre‐exercise QTc dispersion (QTcD) was significantly correlated with the Tl‐201 defect score (r = 0.61, P < 0.0001). The QTcD at 3 minutes after peak exercise was significantly greater in patients with exerciseinduced myocardial ischemia than without exercise‐induced myocardial ischemia (96 ± 36, 72 ± 24 ms^1/2, P < 0.03). The QTcD at 3 minutes after peak exercise was significantly greater in patients with VT than without VT (111 ± 23, 64 ± 17 ms^1/2, P < 0.0001). Conclusion: It is suggested that the degree of myocardial fibrosis influences the pre‐exercise QTcD, and exercise‐induced myocardial ischemia precipitates the increase in the QTcD at 3 minutes after peak exercise in patients with HCM. The increased QTcD at 3 minutes after peak exercise may play a role in identifying patients at a potentially higher risk. A.N.E. 2000;5(1):60–67