Catecholaminergic Polymorphic Ventricular Tachycardia with QT Prolongation

The QT interval in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT) is typically normal. However, CPVT patients are sometimes misdiagnosed as concealed long QT syndrome (LQTS), because patients with LQTS also manifest with syncope or sudden death following periods of exertion or extreme emotion. We report a CPVT patient with a pathogenic RyR2 mutation associated with a marked QT prolongation, which normalized after flecainide therapy.     

儿茶酚胺敏感性室性心动过速患者的护理

目的探讨儿茶酚胺敏感性室性心动过速(catecholaminergic polymorphic ventricular tachycardia,CPVT)患者的护理特点。方法回顾性分析2005年6月至2011年6月宁波市医疗中心李惠利医院心内科收治的5例CPVT患者的临床资料,并总结其护理经验。结果β受体阻滞剂对大多数CPVT患者效果良好,但对长期足量应用β受体阻滞剂仍不能满意控制心律失常发生的患者,需要采用植入式心律转复除颤器(implantable cardioverter defibrillator,ICD)治疗。结论 CPVT患者护理各有特点,药物治疗为主的CPVT患者应重视解释疏导和心理护理,而安装植入式心律转复除颤器(implantable card-ioverter defibrillator,ICD)患者的应重视术后护理工作。     

频发性室性期前收缩患者室速心动过速发生的影响因素分析

[目的]探讨频发性室性期前收缩(VPB)患者室性心动过速(室速)发生的影响因素.[方法]选择2012年6月至2014年6月本院心内科收治的247例诊断为频发VPB的患者,根据其是否发生室速将其分为室速组(n=73)和非室速组(n=174).记录所有患者临床资料、化验结果、心脏彩超结果等.对可能影响频发VPB中室速发生的危险因素行单因素及多因素Logistic回归分析.[结果]频发VPB的患者室速发生率为29.6％(73/247);两组患者年龄、男性发病率、LVEF、LVEDD比较,差异均具有统计学意义(均P＜0.05).Logistic多因素回归分析显示,LVEF、LVEDD均为影响频发VPB患者室速发生的危险因素(均P＜0.05).[结论]LVEF、LVEDD为频发VPB患者室速发生的危险因素.     

A Case with Catecholaminergic Polymorphic Ventricular Tachycardia Unmasked after Successful Ablation of Atrial Tachycardias from Pulmonary Veins

Catecholaminergic polymorphic ventricular tachycardia (VT) is characterized by polymorphic VT during exercise, and the association of atrial fibrillation (AF) has been reported. However, the mechanism of AF in this disease and the relationship between VT and AF has been obscured. We described a 13-year-old girl who referred for catheter ablation of exercise-induced paroxysmal AF. Multifocal atrial tachycardia mimicking AF on the surface electrocardiogram originated from multiple pulmonary veins (PVs). While AT became non-inducible after the isolation of four PVs, polymorphic VT was initiated by isoproterenol infusion. Polymorphic VT was suppressed during rapid atrial pacing.     

慢性心衰患者不同时间心率变异性与短阵室速的相关性研究

[目的]通过延长(72 h)动态心电图监测慢性心衰患者心率变异性(HRV)与非持续性室速(NSVT)并分析其相关性.[方法]选择2016年3月至2016年9月湖南省人民医院老年病科收治的80例慢性心衰患者,对其行连续72 h动态心电图监测,根据是否检出NSVT将其分为NSVT组(n=30)和无NSVT组(n=50),分析组间HRV指标的差异及NSVT与24 h、48 h、72 h的HRV指标间的相关性.[结果]NSVT组中各项时域指标均低于无NSVT组,但两组间仅24 h内全部窦性R-R间期的标准差(SDNN)比较,差异具有统计学差异(P＜0.01);两组频域指标极低频功率(VLF)、低频功率(LF)、高频功率(HF)比较,差异均无统计学意义(均P＞0.05),NSVT组LF/HF显著高于无NSVT组,差异具有统计学意义(P＜0.05).HRV中的各项时域及频域指标在24 h、72 h仅SDNN、LF/HF与NVST显著相关,48 h时SDNN、全程相邻RR间期之差的平方根(rMSSD)、相邻RR间期相差＞50 ms的个数占总心跳数的百分比(PNN50)、LF/HF与NVST显著相关性,仅48 h中SDNN与NSVT成中等程度相关,其余指标与NSVT成低度相关.随着心衰程度的加重,NSVT的检出率呈升高的趋势,而SDNN均值则随之降低,NYHA心功能Ⅱ级、Ⅲ级、Ⅳ级组间比较差异均有统计学意义(P＜0.01).[结论]通过72 h动态心电图监测发现慢性心衰患者的HRV与NSVT有一定的相关性,SDNN降低及LF/HF升高可作为NSVT的预测因子,从而进一步判断心衰患者的预后.     

Ventricular Tachycardia and Ventricular Fibrillation in Patients with Short P-R Intervals and Narrow QRS Complexes

Eleven patients with short P-R Intervals and narrow QRS complexes had ventricular tachycardia due to organic heart disease: mitral valve prolapse with mitral insufficiency (2 patients); alcoholic (?) cardiomyopathy (2 patients); and coronary artery disease (7 patients). Intracardiac studies showed short A-H intervals during sinus rhythm in all cases. The onset of ventricular fibrillation (which, to our knowledge, has not been observed in patients having short P-R and A-H intervals coexisting with narrow QRS complexes) was documented in 4 cases. Only 1 patient (with quinidine syncope) had been premedicated. In the 3 other patients the episodes of ventricular fibrillation appeared during bouts of atrial fibrillation with rapid ventricular rates which could have been an expression of the “enhanced A-V conduction” that had been manifested in sinus beats by short P-R and A-H intervals. In clinical settings and physiological conditions proven to be hemodynamicaliy unstable (such as transient ischemia or acute myocardial infarction) these rapid ventricular rates could have led to ventricular fibrillation; directly because of the R-on-T phenomenon, and/or indirectly due to decreased coronary perfusion. Ventricular tachycardia and ventricular fibrillation due to organic heart disease probably occur more often than suggested by the few reported cases in the literature. Its significance, however, has to be clarified by further prospective studies     

Long Runs of Non-Sustained Ventricular Tachycardia on 24-Hour Ambulatory Electrocardiogram Predict Major Arrhythmic Events in Patients with Idiopathic Dilated Cardiomyopathy

This study examined the prognostic significance of the rate and length of non-sustained (NS) ventricular tachycardia (VT) on 24-hour ambulatory electrocardiograms (ECG) recorded in 343 patients with idiopathic dilated cardiomyopathy (IDC) in the prospective Marburg Cardiomyopathy study. NSVT was defined as ≥3 consecutive ventricular premature beats at >120 bpm. During 52 ± 21 months of follow-up, major arrhythmic events defined as sustained VT, VF, or sudden cardiac death occurred in 46 of 343 patients (13%). Patients with 3–4 beat runs of NSVT had a similar arrhythmia-free survival as patients without NSVT on baseline 24-hour ambulatory ECG. The incidence of major arrhythmic events during follow-up increased significantly from 2% per year in patients without NSVT, to 5% per year in patients with 5–9 beat runs of NSVT, to 10% per year in patients with ≥10 beat runs of NSVT (P < 0.05). Unlike the length, the rate of NSVT was similar in patients with versus without subsequent major arrhythmic events (163 ± 23 vs 160 ± 24 bpm). Thus, the length but not the rate of NSVT on 24-hour ambulatory ECG was a predictor of major arrhythmic events in patients with IDC. The presence of NSVT with ≥10 beat runs on ambulatory ECG was associated with a particularly high risk of major arrhythmic events.     

The Potential Role of the Implantable Defibrillator in Malignant Ventricular Arrhythmias

Une arrythmie maligne est celle qui menace la vie du patient sans pouvoir étre efficacement prévue, prévenue, ou traitée. Toute arrythmie répondant à cette définition est une indication à l'implantation d'un défibrillateur. La simplicité de ces propositions n'est qu'apparente, et recouvre le problème le plus difficile posé par les troubles du rythme cardiaque. La défibriJJation par voie transthoracique utilisée depuis vingt ans a été le moyen thérapeutique qui, directement ou surtout indirectement par le biais de l'éléctrophysiologie clinique, a apporté le plus de connaissances dans le domaine des arrythmies cardiaques. Directement ou indirectement, il en sera de mème à long terme pour la technique de défibriliation implantée. Mais les problèmes d'ordre technique, médical, et économique sont ici beaucoup plus complèxes et ne seront pas resolus dans un avenir proche.     

Basal Exit Site of Clinical Ventricular Tachycardia is an Independent Predictor of Antitachycardia Pacing Failure in Implantable Cardioverter‐Defibrillators Recipients

Background: Little is known about predictors of antitachycardia pacing (ATP) failure in implantable cardioverter defibrillator (ICD) recipients. Distance between the stimulation site and the ventricular tachycardia (VT) site of origin may critically affect ATP effectiveness. We hypothesized that ATP may be less effective in ICD patients who had basal VT than in those who had apical VT. Methods: We reviewed data from 52 patients with sustained monomorphic VT and left ventricular disease referred for ICD implantation. ATP was delivered exclusively at the right ventricular apex. The clinical VTs site of origin (basal, midventricular, or apical) was determined in each patient, using 12‐lead electrocardiogram. VTs episodes treated with ATP during the 1‐year follow‐up were studied. ATP success rate (%), defined as the ratio between the number of successful ATP sequences and the number of delivered ATP sequences, was determined in each patient. Results: VT exit site was apical in 19 patients (36%), basal in 18 patients (35%), and midventricular in 15 patients (29%). In those 52 patients, 1,393 ATP sequences, delivered to treat 761 VT episodes, were analyzed. ATP success rate was found to be associated with the VT site of origin (median [interquartile range]): basal (33%[11–67]), midventricular (50%[37–100]), apical (100%[41–100]) (P = 0.027). Multivariate analysis identified basal VT site of origin as an independent predictor of ATP failure (P = 0.023). Conclusion: ATP is less effective in ICD patients who had basal VT than in those who had apical VT before ICD implantation. (PACE 2012; 35:1209–1216)     

Predictors of Device Activation for Ventricular Arrhythmias and Survival in Patients with Implantable Pacemakers/Defibrillators

Predictors of survival and arrhythmia recurrence for patients with implanted defibrillators have been reported but patients with sustained, well-tolerated ventricular tachycardia were often excluded from these trials. Arrhythmia recurrence and survival in populations including these patients have been less well studied. The purpose of the present study was to examine predictors of spontaneous ventricular arrhythmias and mortality in patients who received a tiered therapy antitachycardia pacemaker/defibrillator for ventricular tachycardia, fibrillation, or both. Three hundred thirty-seven patients who received a Ventritex CADENCE® tiered therapy antitachycardia device at one of 19 participating centers between July 11, 1989 and March 4, 1991 are included in this retrospective analysis. Diagnostic summary data and stored electrograms telemetered from the implanted device were assessed to determine characteristics of recurrent arrhythmias. Mean follow-up was 360 ± 10 (SEM) days. Thirty-three patients died during follow-up. At least one recurrent ventricular arrhythmia was observed in 205 patients (61 %). A total of 7,539 episodes were observed with a mean of 37 ± 5 per patient. Patients with recurrent ventricular arrhythmias were slightly but significantly older (64 ± 0.7 vs 59 ± 1.2 years; P < 0.001) but were not distinguished by gender or underlying structural disease. Patients whose presenting arrhythmia was monomorphic ventricular tachycardia were more likely to experience recurrent ventricular arrhythmias (69% recurrence rate) than patients presenting with ventricular fibrillation or polymorphic ventricular tachycardia (46% recurrence rate; P < 0.001). Cycle length of spontaneous tachycardia was also a predictor of arrhythmia recurrence. Patients having slower ventricular arrhythmias were less likely to remain recurrence free. Mean left ventricular ejection fraction was similar for patients with and without recurrences. Younger age and absence of arrhythmia recurrence but not presenting arrhythmia were predictors of survival. We conclude that age and presentation with monomorphic ventricular tachycardia are important predictors of arrhythmia recurrence for this patient population. Exclusion of patients with monomorphic ventricular tachycardia underestimates the rate of recurrent ventricular arrhythmias and utilization of device therapy.     

Polymorphic Ventricular Tachycardia Induced During Tilt Table Testing in a Patient with Syncope and Probable Dysfunction of the Sinus Node

We present a case of life-threatening arrhythmia occurring during tilt table testing in a 44-year-old man with syncope. Polymorphic ventricular tachycardia occurred while the patient was tilted up under the intravenous infusion of isoproterenol (2 μg/min). No ischemia, QTc prolongation, or electrolyte abnormality preceded this event. The arrhythmia was not induced by programmed ventricular stimulation or exercise testing. Based on electrophysiological and clinical data, the diagnosis of sick sinus syndrome was entertained.     

Elimination of Ventricular Arrhythmia in Catecholaminergic Polymorphic Ventricular Tachycardia by Targeting “Catecholamine‐Sensitive Area”: A Dominant‐Subordinate Relationship between Origin Sites of Bidirectional Ventricular Premature Contractions

We report on a patient diagnosed with catechoaminergic polymorphic ventricular tachycardia (CPVT) who underwent catheter ablation of ventricular premature contractions (VPCs) induced by epinephrine. VPCs were classified roughly into three types. Type 1 and Type 2 VPCs (right bundle branch block [RBBB] configuration and inferior axis) were eliminated by radiofrequency applications at the left aortic sinus of Valsalva and the anterolateral papillary muscle (APM), respectively. Although no spontaneous VPCs were seen after the elimination of Type 1 and 2 VPCs, pacing resulting in capture at the APM induced Type 3 VPC (RBBB configuration and superior axis) reproducibly. The electrophysiological findings observed in our representative case have important implications both for understanding the pathophysiology of CPVT and for considering therapeutic strategies.     

Value of Heart Rate Variability Parameters for Prediction of Serious Arrhythmic Events in Patients with Malignant Ventricular Arrhythmias

Heart rate variability (HRV) assesses the electrical stability of the heart and can identify patients at risk of sudden cardiac death (SCD). The value of 10 HRV parameters from 24 hour ECG (in both time and frequency domain) to predict serious arrhythmic events (SAE) in a group of 56 patients with ventricular tachycardia and/or ventricular fibrillation of different etiologies not due to acute myocardial infarction was explored. Eighteen patients had low left ventricular ejection fractions (LVEF). During follow-up (6–46 months, mean = 24) 8 SCD and 12 recurrences of malignant ventricular arrhythmias or ICD discharges were recorded. Proportional hazard analysis (Cox model) for SAE revealed that the mean of all 5 minute standard deviation of RR intervals (SD) and the amplitude of low frequency spectrum (L) were independent risk factors of SAE (P < 0.05). The best models were: SD+EF and L+EF where predictive values were high (sensitivity approximately 60%, specificity over 95%, positive predictive value over 90% and negative predictive value approximately 80%). Event-free survival curves revealed a significantly shorter survival in patients with EF < 40%: 47% vs. 92%, SD < 43 ms; 56% vs. 92% and L < 16 ms; 56% vs. 89% (all P < 0.001) after 2 years. The subgroup with low EF and SD < 43 ms revealed a significantly shortened survival (27% vs 83% at 2 years, P < 0.01). Some HRV parameters, SD from the time and L from the frequency domain, were predictive of a fatal outcome in VT/VF patients. Combined SD +EF and L +EF values are powerful predictors of serious arrhythmic events.     

院内猝死32例临床分析

目的：探讨猝死的病因、诱因及流行病学特征,为临床防治猝死提供依据。方法：回顾性分析32例猝死病例的临床资料。结果：32例中男性多见,无明显职业分布;基础疾病38％为心血管系统,其次为呼吸系统;仅28％有明确诱因,发作以夏冬季常见,24h中以凌晨和夜间多见。全部经心肺复苏,仅1人存活。结论：应针对猝死的特征进行一系列的干预．以积极防治猝死。     

Causes of Death in Patients with Unipolar Single Chamber Ventricular Pacing: Prevalence and Circumstances in Dependence on Arrhythmias Leading to Pacemaker Implantation

Cardiac pacing improves the prognosis of patients with severe impulse formation and conduction disturbance, though sudden death can occur frequently in paced patients. In the present study, we analyzed the causes and the circumstances of 378 deaths in 2,243 paced patients followed over a 5-year period. Sudden cardiac death occurred in 71 of these 378 patients (18.7%), 56 patients died of stroke (15%), heart failure was the cause of death in 91 subjects (24%). We analyzed the causes of death in two groups with respect to the arrhythmia that had led to pacemaker implantation. The prevalence of cardiac sudden death was higher in patients with AV block than in patients with sick sinus syndrome, while stroke was more frequent in patients with sick sinus syndrome, particularly those with both fast and slow components. Atrial fibrillation is common in patients with sick sinus syndrome and is an important well-known risk factor for stroke. Death from heart failure was frequently reported in our population, but in our study group only a few patients had heart failure at the moment of pacemaker implantation. We conclude that sudden death is a common event in paced patients and the disturbance that led the patient to pacemaker implantation was also a factor in the cause of death.     

The Effect of Procainamide on Delayed Activation Potentials in a Patient with Ventricular Tachycardia

In a patient with ventricular tachycardia and previous myocardial infarction, delayed activation potentials were recorded from a region of the posterolateral wall of the left ventricle at electrophysiological study. Procainamide, administered intravenously, initially caused increased delay and later, in higher dosage, second-degree block of the delayed potentials.     

Initiation of Ventricular Tachycardia by Interruption of Pacemaker-Mediated Tachycardia in a Patient with a Dual-Chamber Implantable Cardioverter Defibrillator

A 74-year-old man with a dual-chamber implantable cardioverter defibrillator implanted 3 years before experienced multiple ventricular tachycardias (VTs). All episodes were initiated by pacemaker-mediated tachycardia (PMT) that was either stopped by atrial undersensing or the tachycardia termination algorithm of the device. After the termination of PMT, two rapid ventricular paced beats, the first initiated by artificial triggering and the second due to retrograde conduction of the first one, initiated VT that was successfully terminated by antitachycardia pacing or a direct current shock of the device . All episodes revealed this pattern of initiation with a short-long-short ventricular sequence inducing VT.