Can amiodarone prevent sudden cardiac death in patients with hemodynamically tolerated sustained ventricular tachycardia and coronary artery disease?

One of the most important challenges in today's cardiology is prevention of sudden cardiac death in high risk patients with coronary artery disease (CAD). Sustained hemodynamically tolerated ventricular tachycardia (HTVT) comprises up to 30 of all cases of monomorphic ventricular tachycardia in patients with CAD. While there is a consensus on treatment of hemodynamically unstable sustained ventricular tachycardia in patients with CAD, some controversies regarding the proper treatment of HTVT exist. We re-examined existing clinical evidence, controversies and current guidelines on the treatment of HTVT in patients with CAD and demonstrated that compared to implantable cardioverter-defibrillator, amiodarone is not an acceptable therapeutic option in patients with ischemic heart disease who suffer from HTVT. © 2005 Springer Science + Business Media, Inc

Coronary slow flow: Benign or ominous?

Objective: Coronary slow flow phenomenon has been arbitrarily defined as delayed coronary blood flow in the absence of obstructive coronary artery disease. The present study sought to investigate the clinical features, natural history, and outcomes of affected patients. Methods: In this prospective cross-sectional study, 217 consecutive patients who had undergone coronary angiography and showed features of coronary slow flow phenomenon were evaluated for demographic and coronary risk factor profile, as well as clinical outcomes, at baseline and following treatment. Results: The study population consisted of 165 (76) males and 52 (24) females. The mean age of patients was 52.6±10 years. Mean ejection fraction was 48.2±5.4, 39.3 had diabetes, 43.3 had hypertension, 49.8 was a cigarette smoker, 41.9 had dyslipidemia, and 15 had a familial history of cardiac disease. Forty-nine percent was detected to have abnormal hsCRP levels. The most prevalent presenting complaint was atypical chest pain. Fifty-four percent of patients had slow blood flow in all three vessels. Thirty-six people had undergone repeat coronary angiography in a follow-up period of 5-7 years due to persisting or worsening clinical symptoms, of whom 6 (16.6) showed significant coronary artery stenosis. Eight (22.2) had mild CAD, and the rest still showed coronary slow flow without significant stenosis. The most common complaint during follow-up and after initiation of medical therapy was nonanginal chest pain. Conclusion: Patients with coronary slow flow phenomenon are predisposed to atherosclerosis and obstructive coronary artery disease. Therefore, this pathology should not be considered as a totally benign condition. Primary and secondary cardiovasculature preventive measures should be constituted and seem worthwhile in this patient population. © Copyright 2015 by Turkish Society of Cardiology

Multiple arrhythmogenic substrate for tachycardia in a patient with frequent palpitations

We report a 26-year-old woman with frequent episodes of palpitation and dizziness. Resting electrocardiography showed no evidence of ventricular preexcitation. During electrophysiologic study, a concealed right posteroseptal accessory pathway was detected and orthodromic atrioventricular reentrant tachycardia incorporating this pathway as a retrograde limb was reproducibly induced. After successful ablation of right posteroseptal accessory pathway, another tachycardia was induced using a concealed right posterolateral accessory pathway in tachycardia circuit. After loss of retrograde conduction of second accessory pathway with radiofrequency ablation, dual atrioventricular nodal physiology was detected and typical atrioventricular nodal reentrant tachycardia was repeatedly induced. Slow pathway ablation was done successfully. Finally sustained self-terminating atrial tachycardia was induced under isoproterenol infusion but no attempt was made for ablation. During 8-month follow-up, no recurrence of symptoms attributable to tachycardia was observed

Efficacy and safety of different antitachycardia pacing sites in the termination of ventricular tachycardia in patients with biventricular implantable cardioverter-defibrillator

Aims: We sought to evaluate the efficacy and safety of different antitachycardia pacing (ATP) sites in heart failure (HF) patients with a biventricular implantable cardioverter-defibrillator (ICD). Methods and results: Between January 2003 and December 2008, 89 consecutive patients with biventricular (BiV) ICDs (Medtronic Inc., St Paul, Minnesota, USA) were enrolled. In these patients, stored electrograms of the true spontaneous ventricular tachycardia (VT) episodes with at least one ATP therapy were analysed. Out of the 89 patients, 46 experienced 259 VT episodes. When we considered all VT forms, both left ventricular (LV)-ATP (91) and BiV-ATP (89) were significantly better than right ventricular (RV)-ATP (72) in terminating VTs (P = 0.03 and 0.04, respectively). In the fastVT zone, there was a trend for higher efficacy of BiV-ATP compared with RV-ATP and LV-ATP (75 vs. 60 vs. 60, P = 0.10). Fast VT acceleration occurred to a similar extent in all ATP groups (20 in RV-ATP vs. 20 in LV-ATP vs. 20 in BiV-ATP, P = NS). In the slow VT zone, RV-ATP was significantly less effective than LV-ATP (74 vs. 100, P = 0.001) and BiV-ATP (74 vs. 100, P = 0.014). Incidence of acceleration was lower with LV-ATP and BiV-ATP than RV-ATP (0 vs. 0 vs. 9, P = 0.03) in the slow VT zone. Conclusions: In HF patients treated with BiV ICD, overall ATP efficacy is higher when delivered from LV or BiV than from RV. Biventricular-ATP and LV-ATP are also safer than RV-ATP in the slow VT zone. Published on behalf of the European Society of Cardiology. All rights reserved

Is the activation potential of Mahaim pathway always a fast potential? Implication for radiofrequency catheter ablation

Introduction: Accessory pathways (AP) exhibiting Mahaim physiology are amenable to radiofrequency (RF) catheter ablation. The recording of an AP potential is an excellent guide for selection of ablation site. The purpose of this study is to determine whether the pathway potential is always a fast potential. Methods: Ten patients (six females, mean age, 30±12 years) with preexcited tachycardias involving a Mahaim pathway underwent electrophysiological study and subsequent attempts at RF ablation. Mahaim potentials (M-potential) recorded at the site of successful ablation were reviewed and classified by at least two reviewers. Results: In all patients, Mahaim pathways were characterized as atriofascicular types. The M-potential was fast in seven patients (group one), and slow in the remaining patients (group two). All group two patients had a history of prior failed ablation. Atrial electrograms were recorded closer to the QRS onset in group one. Atrium to fast M-potential (42±15 ms) was shorter than atrium to slow M-potential (83±12 ms, P=0.03) but M-potentials were recorded with similar distance before local ventricular electrogram (P=NS). Ablation was successful in all patients with mean of 2.9±1.4 RF applications per patient. Ablation data were similar between the two groups (P=NS). No complications occurred. During 12 months of follow-up, no recurrence was observed. Conclusion: Our results illustrated that the activation potential of Mahaim pathways is not always a fast potential. One-third of Mahaim pathways can be mapped and ablated when the slow type of M-potential was used as a target for ablation. We also confirmed high efficacy of catheter ablation of Mahaim pathways guided by activation potentials. © 2005 The European Society of Cardiology. Published by Elsevier Ltd. All rights reserved

Coexistence of atrioventricular nodal reentrant tachycardia and idiopathic left ventricular outflow-tract tachycardia

Double tachycardia is a relatively rare condition. We describe a 21 year old woman with history of frequent palpitations. In one of these episodes, she had wide complex tachycardia with right bundle branch and inferior axis morphology. A typical atrioventricular nodal tachycardia was induced during electrophysiologic study, aimed at induction of clinically documented tachycardia. Initially no ventricular tachycardia was inducible. After successful ablation of slow pathway, a wide complex tachycardia was induced by programmed stimulation from right ventricular outflow tract. Mapping localized the focus of tachycardia in left ventricular outflow tract and successfully ablated via retrograde aortic approach. During 7 month's follow-up, she has been symptom free with no recurrence. This work describes successful ablation of rare combination of typical atrioventricular nodal tachycardia and left ventricular outflow tract tachycardia in the same patient during one session

Familial atrial standstill in association with dilated cardiomyopathy

Atrial standstill is an extremely uncommon arrhythmia that rarely appears to be familial and genetically determined. Atrial standstill has been associated with several conditions including, but not restricted to, congenital heart disease, valvular heart disease, conduction disturbances, Brugada syndrome, myocardial infarction, and amyloidosis. Only a few cases of familial clustering of atrial standstill have been reported so far. This report represents a family with atrial standstill associated with syncope, dilated cardiomyopathy, and sudden cardiac death

Optimal side of implant for single-lead VDD pacing: Right-sided versus left-sided implantation

Background: Atrial undersensing occurs in a considerable number of patients with single-lead VDD pacing. This study tried to determine the role of implant side in maintenance of the VDD mode in patients with isolated atrioventricular (AV) block. Methods: Eighty-two patients with isolated AV block (46 females; mean age, 58 ± 17 years) received a single-lead VDD pacemaker (Medtronic Kappa, n = 70 and St. Jude Medical Affinity, n = 12). The patients were randomly assigned to one of two implantation groups (group I: right-sided VDD and group II: left-sided VDD). In each group, the P-wave amplitudes were determined at implantation, predischarge, 2-month, and 6-month follow-up. At each follow-up visit, stored event histograms of pacemaker were also retrieved. The atrial sensing measurements were compared between two groups. Results: Implantation was easier from right side (1.7 ± 1.0 vs 2.8 ± 1.7 attempts, P = 0.001). Implant P-wave was higher in group I compared to group II (4.2 ± 1.7 vs 2.7 ± 1.0 mV, P < 0.0001). During follow-up, higher P-wave amplitudes were obtained in group I both at predischarge (2.6 ± 1.3 vs 1.4 ± 1.1 mV, P < 0.0001), 2-month (2.8 ± 1.8 vs 1.3 ± 1.0 mV, P < 0.0001), and 6-month (2.9 ± 1.7 vs 1.3 ± 0.9 mV, P < 0.0001) evaluations but remained stable throughout the 6 months in both groups. After implantation, VDD function was better maintained in group I than group II (100 vs 90, P = 0.026). Incidence of atrial undersensing was lower in group I than group II (P = 0.026) in last follow-up visit. Conclusions: Implant side has a significant influence on atrial sensing performance in single-lead VDD pacing. Thus, right-side implantation should be the preferred approach for the implantation of VDD single-lead systems

Latent atriofascicular pathway participating in a wide complex tachycardia: Differentiation from ventricular tachycardia

Accessory pathways with anterograde decremental conduction properties usually are characterized by presence of antegrade preexcitation during atrial pacing. We report a 38-year-old man with frequent episodes of palpitation. No evidence of ventricular preexcitation was seen during sinus rhythm or atrial pacing. All electrophysiologic maneuvers were compatible with an antidromic tachycardia using atriofascicular pathway as the antegrade limb and the atrioventricular nodal pathway as retrograde limb. Radiofrequency ablation at recording site of accessory pathway potential resulted in cure of tachycardia with no recurrence during 3-month follow-up. This report indicated that atriofascicular pathway-mediated tachycardia should be considered in differential diagnosis of all cases of wide complex tachycardia with left bundle branch morphology and left axis. © 2006, The Authors