Drug therapy considerations in arrhythmias in children

The understanding of the mechanisms of action and side effects of different antiarrhythmic drugs (AAD) are essential for their appropriate use. With the advent of effective and safe ablation therapy, AAD therapy has undergone dramatic changes. This review attempts to understand the rationale behind the clinical use of medical management of different arrhythmias.     

Loss of consciousness and convulsion induced by a ventricular tachycardia mimicking epilepsy in a patient with noncompaction cardiomyopathy: a case report

Convulsions and loss of consciousness can be caused by, among other things, arrhythmias, conduction disorders or epilepsy. In clinical practice it can be difficult to distinguish between these causes of syncope, even for well-trained specialists. Patients with cardiac syncope have a substantial risk of subsequent sudden death. We present a patient with previously unknown noncompaction cardiomyopathy in whom syncope induced by ventricular tachycardia was misinterpreted as epilepsy. We present this case report in order to underline the necessity for cardiological assessment in patients with assumed mild epilepsy or syncope of unknown origin.     

CRT_D介导室性心动过速的研究进展

心室再同步心脏转复除颤器(CRT_D)可有效改善心力衰竭(CHF)患者的运动耐量和生活质量,预防猝死,提高生存率,但CRT_D植入后由于心室激动顺序的改变,使QT间期延长、跨室壁复极离散度(TDR)增加,潜在致室性心律失常风险;且CHF患者通常存在心肌解剖改变,传导的不均一性,也为折返性心动过速的发生提供了维持的机制;而多次电击也可导致肌钙蛋白升高,引起心肌损伤,局部心肌复极离散度增加(DRVR)和QT间期延长,以及电除颤后心肌纤维化和急性细胞损伤,反复室速、室颤也会引起进行性左心功能不全、心肌细胞凋亡、恶化心律失常基质和增加心律失常易感性。CRT_D潜在致室性心律失常作用逐渐引起人们的重视,本文就近年来CRT_D致室性心律失常的电生理机制与临床防治对策等做一综述。     

Unusual Tachycardia Association In A patient Without Structural Heart Disease

We report an unusual association of persistent atrial flutter and bundle branch re-entrant ventricular tachycardia in a young patient without structural heart disease. Atrial flutter masked the infra-Hisian conduction disease, was fundamentally dependent on a long PR interval, and could be a possible trigger of ventricular tachycardia.     

Cardiomyopathy induced by incessant ventricular tachycardia originating in the vicinity of the His bundle

A 04-year-old boy was referred to our institution with severe, progressive heart failure of 4-months duration associated with a persistent wide QRS tachycardia with left bundle branch block and severe left ventricular dysfunction. Because of incessant wide QRS tachycardia refractory to antiarrhythmic drugs, he was referred for electrophysiological study. The ECG was suggestive of VT arising from the right ventricle near the His area. Electrophysiological study revealed that origin of tachycardia was septum of the right ventricle, near His bundle, however the procedure was not successful and an inadvertent complete atrioventricular conduction block occurred. The same ventricular tachycardia recurred. A second procedure was performed with a retrograd aortic approach to map the left side of the interventricular septum. The earliest endocardial site for ablation was localized in the anterobasal region of left ventricle near His bundle. In this location, one radiofrequency pulse interrupted VT and rendered it not inducible. The echocardiographic evaluation showed partial reversal of left ventricular function in the first 3 months. The diagnosis was idiopathic parahisian left ventricular tachycardia leading to a tachycardia mediated cardiomyopathy, an extremely rare clinical picture in children.     

Influence of ethnic background on left atrial markers of inflammation,endothelial function and tissue remodelling

Background

It has been suggested that ethnicity can make a significant difference to the likelihood of thromboembolic stroke related to atrial fibrillation. Ethnic differences have been shown to alter inflammatory and haemostatic factors; however, this may all be confounded by differences in cardiovascular risk factors between different ethnicity. The impact of different ethnicities on the thrombogenic profile is not known. The aim of this study was to investigate differences in markers of inflammation, endothelial function and tissue remodelling between Caucasian and Indian populations with supraventricular tachycardia (SVT).

Circadian Variation in the Occurrence of Paroxysmal Supraventricular Tachycardia in Clinically Healthy Subjects

The purpose of this study was to assess prospectively the circadian distribution of spontaneous paroxysmal Supraventricular tachycardia (PSVT) in drug-free subjects with no previous history or symptoms and signs of concomitant heart or lung disease. Of 112,424 presumably diurnally active patients admitted to the Emergency Department of a city hospital during a 2-year period (1990-1991), a total of 185 patients were screened with these characteristics. Time of symptom onset was exactly recordable in 177 (75 men and 102 women). Analysis of variance documented a higher incidence in the morning-afternoon hours. Cosinor analysis, although not a perfect method for the time series analysis, verified circadian rhythmicity with afternoon peak times. Our findings suggest that a circadian pattern in intrinsic electrical instability of the heart conduction system exists irrespective of the circadian fluctuations in the pathophysiologic mechanisms of the cardiovascular or lung diseases most frequently associated with PSVT itself.     

Remote magnetic navigation vs. manual navigation for ablation of ventricular tachycardia: a meta-analysis

Background

The purpose of this study was to prospectively evaluate the efficacy and safety of remote magnetic navigation (RMN) in comparison with manual catheter navigation (MCN) in performing ventricular tachycardia ablation.

Methods

An electronic search was performed using PubMed (1948–2013) and EMBASE (1974–2013) studies comparing RMN with MCN which were published prior to 31 December 2013. Outcomes of interest were as follows: acute success, recurrence rate, complications, total procedure and fluoroscopic times. Standard mean difference (SMD) and its 95 % confidence interval (CI) were used for continuous outcomes; odds ratios (OR) were reported for dichotomous variables.

Results

Four non-randomised studies, including a total of 328 patients, were identified. RMN was deployed in 191 patients. Acute success and long-term freedom from arrhythmias were not significantly different between the RMN and control groups (OR 1.845, 95 % CI 0.731–4.659, p = 0.195 and OR 0.676, 95 % CI 0.383–1.194, p = 0.177, respectively). RMN was associated with less peri-procedural complications (OR 0.279, 95 % CI 0.092–0.843, p = 0.024). Shorter procedural and fluoroscopy times were achieved (95 % CI -0.487 to -0.035, p = 0.024 and 95 % CI -1.467 to -0.984, p<0.001, respectively).

Conclusion

The acute and long-term success rates for VT ablation are equal between RMN and MCN, whereas the RMN-guided procedure can be performed with a lower complication rate and less procedural and fluoroscopic times. More prospective randomised trials will be needed to better evaluate the superior role of RMN for catheter ablation of ventricular tachycardia.