Role of catheter ablation of ventricular tachycardia associated with structural heart disease

In patients with structural heart disease, ventricular tachycardia (VT) worsens the clinical condition and may severely affect the shortand long-term prognosis. Several therapeutic options can be considered for the management of this arrhythmia. Among others, catheter ablation, a closed-chest therapy, can prevent arrhythmia recurrences by abolishing the arrhythmogenic substrate. Over the last two decades, different techniques have been developed for an effective approach to both tolerated and untolerated VTs. The clinical outcome of patients undergoing ablation has been evaluated in multiple studies. This editorial gives an overview of the role, methodology, clinical outcome and innovative approaches in catheter ablation of VT.     

Efficacy and safety of combined endocardial/epicardial catheter ablation for ventricular tachycardia in Chagas disease: A randomized controlled study

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Percutaneous epicardial ablation reverses ventricular tachycardia mediated cardiomyopathy

We report on the case of an 18-year-old girl with asymptomatic incessant ventricular tachycardia. Initial attempts at endocardial ablation failed and she was monitored until her cardiac function deteriorated. A percutaneous epicardial approach with electroanatomical mapping was then used which successfully terminated the tachycardia. Left ventricular size and function subsequently returned to normal. This case demonstrates that percutaneous epicardial ablation of ventricular tachycardia is safe and feasible in young patients and highlights the importance of recognising this at an early stage.     

Non-contact mapping in the treatment of ventricular tachycardia after myocardial infarction

The treatment of ventricular tachycardia (VT) in patients with underlying ischaemic heart disease (IHD) remains a challenge. Ablation of these arrhythmias may have a significant impact on quality of life for patients. For those patients with haemodynamically unstable VT, ablation success rates have been improved by the use of non-contact mapping. Care has to be taken in the analysis and interpretation of non-contact mapping studies, as chamber size and filter settings have a large effect on the appearance of the activation maps produced. Despite this limitation the majority of VT exit sites and part of the diastolic pathway can be identified with non-contact mapping techniques.     

Idiopathic epicardial ventricular tachycardia with origin remote from vascular structures

We report a case of a patient with idiopathic left ventricular tachycardia (VT) successfully ablated from the epicardial aspect of the left ventricle, after a previous failed endocardial ablation. The VT appeared to be catecholamine sensitive. An excellent epicardial pacemap was found in the midlateral region of the left ventricle, remote from vascular structures. Following ablation, the patient discontinued antiarrhythmic drug use and has not experienced any recurrence of VT for more than 2 1/2 years.     

Mini-electrodes help identifying hidden slow conduction during ventricular tachycardia substrate ablation

A 69-year-old male with dilated non-ischemic cardiomyopathy and history of sustained monomorphic VT (SMVT) underwent an unsuccessful VT substrate ablation due to the proximity of the earliest activation site to the conduction system. A second attempt was performed using an ablation catheter with mini-electrodes (ME) and multiple extrastimuli to unveil hidden slow conduction (HSC) sites, allowing the performance of a successful ablation. No SMVT was induced thereafter.ME-obtained electrograms permit to accurately localize areas of HSC sites within ventricular tachycardia (VT) substrates. In our case, this allowed safe ablation during sinus rhythm to eliminate the VT substrate.     

Clinical and electrophysiological differences between patients with arrhythmogenic right ventricular dysplasia and right ventricular outflow tract tachycardia.

AIMS: Radiofrequency catheter ablation is considered first line treatment for symptomatic patients with right ventricular outflow tract tachycardia (RVOT). The role of ablation in arrhythmogenic right ventricular dysplasia (ARVD) is more limited. As such, differentiating between the two conditions is essential. METHODS AND RESULTS: This study compared non-invasive findings, magnetic resonance images (MRI), invasive electrophysiological characteristics, results of ablation and long-term outcome in 50 consecutive patients with RVOT (33) or ARVD (17). Structural abnormalities were uniform in the ARVD group; in addition 18 (54%) of the RVOT tachycardia group had MRI abnormalities. At electrophysiological study the tachycardia in the ARVD group displayed features of re-entry in over 80%, but behaved with a triggered automatic basis in 97% with RVOT. Ablation was complete or partial success in 12 (71%) patients with ARVD and ventricular tachycardia (VT) recurred in eight (48%). In the RVOT patients, ablation was a complete success in 97% with recurrent VT in 6%. Long-term success in the RVOT patients was 95% in both patients with and without MRI abnormalities. CONCLUSIONS: Electrophysiological characterization can differentiate ARVD from RVOT. The finding of abnormalities on MRI does not have any bearing on arrhythmia mechanism, acute or long-term success of RFA.     

Incidence and significance of pleomorphism in patients with postmyocardial infarction ventricular tachycardia. Acute and long-term outcome of radiofrequency catheter ablation.

AIMS: The prognostic significance of multiple ventricular tachycardia (VT) morphologies, whether spontaneous or induced, was investigated in patients who underwent radiofrequency catheter ablation (RFCA) for postinfarction ventricular tachycardia. METHODS AND RESULTS: We studied 137 patients with postinfarction ventricular tachycardia. Catheter ablation of all induced ventricular tachycardias was attempted. A single ventricular tachycardia morphology was documented in 102/137 patients (MONO group); 35 patients had spontaneous pleomorphism (PLEO group). Multiple VT morphologies were induced in 58/102 (57%) MONO patients and in all PLEO patients. A higher rate of arrhythmia suppression was obtained in MONO as compared to PLEO patients (162/212 [76%] vs. 43/110 [39%]). Clinical presentation (VT pleomorphism) (OR: 0.22, CI: 0.08-0.62) and the induced VT cycle (mean PLEO/MONO: 338/385 ms, OR: 1.06) were independent predictors of acute RFCA success. Among MONO patients, the procedure was successful in 75% of the patients with a single induced ventricular tachycardia compared to 64% of those with multiple tachycardias. The acute success rate was lower in PLEO patients (23%). PLEO patients had a significantly higher 3- and 5-year arrhythmia recurrence rate than MONO patients. RFCA acute success was the only independent predictor of long-term outcome in multivariate analysis. CONCLUSIONS: Spontaneous, but not induced, VT pleomorphism in patients with prior myocardial infarction adversely affects the acute and long-term success rate of RFCA.     

Atrioventricular nodal reentrant tachycardia associated with idiopathic ventricular tachycardia: clinical and electrophysiologic characteristics

Background

Case reports have described the coexistence of ventricular tachycardia (VT) and supraventricular tachycardia in the same patient. This study examines the frequency of dual atrioventricular nodal (AVN) physiology, AVN echo beats, and atrioventricular nodal reentrant tachycardia (AVNRT) in patients with VT.

Methods

Programmed atrial and ventricular stimulation was performed in 132 consecutive patients referred for electrophysiologic study of symptomatic VT. Of the 132, 99 patients had structural heart disease, and 33 patients had idiopathic ventricular tachycardia (IVT).

Results

Among the 33 patients with IVT, 23 had dual AVN physiology. Compared with patients with structural heart disease undergoing VT ablation, dual AVN pathways (70% vs 27%, P < .0001), dual AVN pathways with echo beats (24% vs 8%, P = 0.03), and AVNRT (21% vs 1%, P = .0002) were more common in patients with IVT.

Conclusion

Dual AVN physiology and AVNRT appear to be associated with IVT. This finding suggests that patients with IVT should undergo a complete electrophysiologic evaluation, and the diagnosis of coexistent AVNRT should be considered in this population.     

Effect of first ventricular tachycardia cycle length on rate of ventricular arrhythmia recurrence in patients with implantable cardioverter-defibrillator

Background

Some controversies exist regarding the proper treatment of hemodynamically tolerated and slow ventricular tachycardia (VT). We intended to assess the effect of cycle length of first VT episode on total ventricular arrhythmia burden in a cohort of patients with implantable cardioverter-defibrillator (ICD).

Method

Between March 2000 and March 2005, 195 patients underwent ICD implantation at our center. We included 158 patients (mean age, 58.3 ± 12.9 years) with follow-up of 3 months or more in this study. Clinical, electrocardiographic, and ICD-stored data and electrograms were collected and analyzed.

Results

During the follow-up of 16.7 ± 10.6 months, 45 (28.5%) and 20 (12.6%) patients received first appropriate ICD therapy for VT and ventricular fibrillation, respectively. We divided the 45 patients with VT (based on the median value of VT cycle length) into 2 groups. Although patients with VT cycle length of less than 350 had higher total mean number of appropriate ICD therapy (25 vs 6.3, P = .023), during multivariate regression analysis, only left ventricular ejection fraction (EF) of less than 25% (P = .020) was correlated with total number of appropriate ICD therapy. First VT cycle length (P = .341), QRS duration (P = .126), age (P = .405), underlying heart disease (P = .310), indication of ICD implantation (P = .113), and sex (P = .886) have failed to predict the total burden of ventricular arrhythmia during the follow-up period.

Conclusion

After adjustment for left ventricular EF, initial VT cycle length per se did not confer a lower risk for subsequent ventricular arrhythmia recurrence compared with those with faster VT. Left ventricular EF of less than 25% was correlated with higher ventricular arrhythmia burden in patients with ICD.