Epicardial and Endocardial Ablation Based on Channel Mapping in Patients With Ventricular Tachycardia and Chronic Chagasic Cardiomyopathy: Importance of Late Potential Mapping During Sinus Rhythm to Recognize the Critical Substrate.

Background Ventricular tachycardia (VT) in patients with chronic chagasic cardiomyopathy (CCC) is associated with considerable morbidity and mortality. Catheter ablation of VT in patients with CCC is very complex and challenging. The main goal of this work was to assess the efficacy of VT catheter ablation guided by late potentials (LPs) in patients with CCC. Methods and Results Seventeen consecutive patients with refractory VT and CCC were prospectively included in the study. Combined endo-epicardial voltage and late activation mapping were obtained during baseline rhythm to define scarred and LP areas, respectively. The end point of the ablation procedure was the elimination of all identified LPs. Epicardial and endocardial dense scars (<0.5 mV) were detected in 17/17 and 15/17 patients, respectively. LPs were detected in the epicardial scars of 16/17 patients and in the endocardial scars of 14/15 patients. A total of 63 VTs were induced in 17 patients; 22/63 (33%) were stable and entrained, presenting LPs recorded in the isthmus sites. The end point of ablation was achieved in 15 of 17 patients. Ablation was not completed in 2 patients because of cardiac tamponade or vicinity of the phrenic nerve and circumflex artery. Three patients (2 with unsuccessful ablation) had VT recurrence during follow-up (39 months). Conclusions Endo-epicardial LP mapping allows us to identify the putative isthmuses of different VTs and effectively perform catheter ablation in patients with CCC and drug-refractory VTs.

Epicardial mapping complicated by multi-vessel coronary spasm and electrical storm.

The case report describes a severe multi-vessel coronary spasm complicating the epicardial mapping in a patient with chronic Chagas cardiomyopathy.

Underuse of Catheter Ablation as First-Line Therapy for Supraventricular Tachycardia.

Background Catheter ablation (CA) is a safe, effective, cost-effective technique and may be considered a first-line strategy for the treatment of symptomatic supraventricular tachycardias (SVT). Despite the high prospect of cure and the recommendations of international guidelines in considering CA as a first-line treatment strategy, the average time between diagnosis and the procedure may be long. The present study aims to evaluate predictors related to non-referral for CA as first-line treatment in patients with SVT. Methods and Results The model was derived from a retrospective cohort of patients with SVT or ventricular pre-excitation referred for CA in a tertiary center. Clinical and demographical features were used as independent variables and non-referral for CA as first-line treatment the dependent variable in a stepwise logistic regression analysis. Among 20 clinical-demographic variables from 350 patients, 10 were included in initial logistic regression analysis: age, women, presence of pre-excitation on ECG, palpitation, dyspnea and chest discomfort, number of antiarrhythmic drugs before ablation, number of concomitant symptoms, symptoms' duration and evaluations in the emergency room due to SVT. After multivariable adjusted analysis, age (odds ratio [OR], 1.2; 95% CI 1.01-1.32; P=0.04), chest discomfort during supraventricular tachycardia (OR, 2.7; CI 1.6-4.7; P<0.001) and number of antiarrhythmic drugs before ablation (OR, 1.8; CI 1.4-2.3; P<0.001) showed a positive independent association for non-referral for CA as SVT first-line treatment. Conclusions The independent predictors of non-referral for CA as first-line treatment in our logistic regression analysis indicate the existence of biases in the decision-making process in the referral process of patients who would benefit the most from catheter ablation. They very likely suggest a skewed medical decision-making process leading to catheter ablation underuse.

Indications, implications and applications of renal denervation. Have we discovered something new?

Hyperactivity of sympathetic nervous system is one of the main mechanisms to play a role in the pathophysiology of hypertension. Its high prevalence and the low rates of adequate blood pressure control with pharmacological treatment brought interest to novel therapeutical strategies. Percutaneous renal sympathetic denervation emerged as an effective and safe alternative to reduce blood pressure in patients with resistant hypertension. Other potential indications to this procedure are heart failure, cases of insulin resistance, obesity, obstructive sleep apnea and cardiac arrhythmias.