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Background Radiofrequency (RF) catheter ablation is one of the most common strategies for the current management of cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL). The interindividual anatomic variability can influence the duration and outcome of ablation procedure. Objective The purpose of this study was to establish complication rates in patients undergoing RF catheter ablation for CTI-dependent AFL, assess the role of CTI morphology in procedural success, and determine the anatomic variability of CTI ex vivo. Methods RF catheter ablation for CTI-dependent AFL was performed in 337 consecutive patients. Angiographically determined CTI morphology was classified as either simple or complex due to pouchlike recesses. Macroscopic and histologic examination of the CTI was performed in 104 heart specimens from consecutive autopsies. Results Complex CTI anatomy was present in 10.9% of AFL patients. RF application time to achieve bidirectional isthmus block was longer in patients showing pouchlike recesses than in those without (10.7 vs 8.3 min; P= .025). Acute procedure failure or major complications occurred in 3 cases, all with complex CTI anatomy. A pouchlike recess of the CTI was present in 9.6% of autopsy hearts. Histomorphometric analysis of the CTI atrial wall demonstrated that the central level was the thinnest in the 3 sectors and the paraseptal level was the thickest. Conclusion Although RF catheter ablation is a safe and effective procedure for AFL treatment, CTI anatomic complexity can affect ablation parameters and outcome. Standard definition of CTI morphologic variants is recommended. Preprocedural assessment of CTI anatomy might lead to personalized ablation preventing potential difficulties and complications.

Aims Implantable cardioverter defibrillators improve survival of patients at risk for ventricular arrhythmias, but inappropriate shocks occur in up to 30% of patients and have been associated with worse quality of life and prognosis. In heart failure patients with cardiac resynchronization therapy defibrillators (CRT-Ds), we evaluated whether a new generation of detection and discrimination algorithms reduces inappropriate shocks. Methods and results We analysed 1983 Medtronic CRT-D patients (80% male, 67 ± 10 years), 1368 with standard devices (Control CRT-D) and 615 with new generation devices (New CRT-D). Expert electrophysiologists reviewed and classified the electrograms of all device-detected ventricular tachycardia/fibrillation episodes. Total follow-up was 3751 patients-years. Incidence of inappropriate shocks at 1 year was 2.8% [95% confidence interval (CI) = 2.0–3.5] in Control CRT-D and 0.9% (CI = 0.4–2.2) in New CRT-D (hazard ratio = 0.37, CI = 0.21–0.66, P < 0.001). In New CRT-D, inappropriate shocks were reduced by 77% [incidence rate ratio (IRR) = 0.23, CI = 0.16–0.35, P < 0.001] and inappropriate anti-tachycardia pacing by 81% (IRR = 0.19, CI = 0.11–0.335, P < 0.001). Annual rate per 100 patient-years for appropriate VF detections was 3.0 (CI = 2.1–4.2) in New CRT-D and 3.2 (CI = 2.1–5.0) in Control CRT-D ( P = 0.68), for syncope was 0.4 (CI = 0.2–0.9) in New CRT-D and 0.7 (CI = 0.5–1.0) in Control CRT-D ( P = 0.266), and for death was 1.0 (CI = 0.6–1.6) in New CRT-D and 3.5 (CI = 3.0–4.1) in Control CRT-D ( P < 0.001). Conclusion Detection and discrimination algorithms used in new generation CRT-D significantly reduced inappropriate shocks when compared with standard CRT-D. This result, with no compromise on VF sensitivity or risk of syncope, has important implications for patients' quality of life and prognosis.

An optimal active-can lead configuration during implantable cardioverter defibrillator (ICD) placement is important to obtain an adequate defibrillation safety margin. The purpose of this multicenter study was to evaluate the rate of the first shock success at defibrillation testing according to the type of lead implant (single vs. dual coil) and shock polarity (cathodal and anodal) in a large series of consecutive patients who received transvenous ICDs.This was a multicenter study enrolling 469 consecutive patients. Single- versus dual-coil leads and cathodal versus anodal polarity were evaluated at defibrillation testing. In all cases, the value of the energy for the first shock was set to 20 J less than the maximum energy deliverable from the device.A total of 469 patients underwent defibrillation testing: 158 (34 %) had dual-coil and 311 (66 %) had single-coil lead systems configuration, 254 (54 %) received anodal shock and 215 (46 %) received cathodal shock. In 35 (7.4 %) patients, the shock was unsuccessful. No significant differences in the outcome of defibrillation testing using single- versus dual-coil lead were observed but the multivariate analysis showed an increased risk of shock failure using cathodal shock polarity (OR 2.37, 95 % CI 1.12-5.03).Both single- and dual-coil transvenous ICD lead systems were associated with high rates of successful ICD implantation, and we found no significant differences in ventricular arrhythmias interruption between the two ICD lead systems configuration. Instead, anodal defibrillation was more likely to be successful than cathodal defibrillation.

Laboratorio di Elettrofisiologia Dipartimento di Cardiologia Ospedale Civile di Mirano, Mirano, Italy;†Az. Ospedaliera S. Maria della Misericordia, Udine, Italy; ‡Azienda Ospedaliera Sacro Cuore Don Calabria, Negrar,Italy; §Ospedale Mater Salutis di Legnago, Legnago, Italy; ¶Ospedale Santa Maria del Carmine, Rovereto, Italy

Pacemaker (PM) and implantable cardiac defibrillator (ICD) malfunction is a serious and frequent finding in clinical setting. Depending on baseline rhythm and the type of malfunction, symptoms with different severity can occur, from no symptoms to syncope and sudden death due to asystole or ventricular fibrillation. Unfortunately, symptoms, such as asthenia, dizziness, dyspnea, and palpitations, are often vague, and this can lead to a dangerous delay in cardiac implantable electronic device (CIED) malfunction detection. An ECG recording and careful device and lead evaluation by means of telemetry are necessary for the diagnosis. A great help to early detection of CIED malfunctions is coming from remote control, allowing therapeutic interventions within 24 h since the malfunction occurs in most cases.

Hyperkalaemia is an electrolyte disturbance that can have effects on myocardial conduction causing electrocardiographic changes. Several factors may predispose to and promote potassium serum level increase leading to typical electrocardiographic abnormalities. We describe the case of a patient who presented with hyperkalaemia and an electrocardiographic aspect consistent with a sine-wave pattern.

Background— The role of pacing sites and atrial electrophysiology on the progression of atrial fibrillation (AF) to the permanent form in patients with sinus node dysfunction (SND) has never been investigated. The aim of the study was to investigate the relationship between atrial electrophysiology and the efficacy of atrial pacing at the low interatrial septum (IAS) or at the right atrial appendage (RAA) to prevent persistent/permanent AF in patients with SND. Methods and Results— The Electrophysiology-Guided Pacing Site Selection (EPASS) Study was a prospective, controlled, randomized study. Atrial refractoriness, basal and incremental conduction times from the RAA to the coronary sinus ostium were measured before implantation, and the difference (ΔCTos) was calculated. Patients with ΔCTos ≥50 ms (study group) and those with ΔCTos P =0.047). Conclusions— In patients with SND and intra-atrial conduction delay, low IAS pacing was superior to RAA pacing in preventing progression to persistent or permanent AF. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00239226.

Lead removal is removal of a pacing or defibrillator lead using any technique. It includes two completely different procedures: lead explant and lead extraction. Lead explant is the removal of a lead using simple traction techniques, which is usually possible for leads implanted for less than 1 year. Lead extraction is removal of a lead implanted for more than 1 year or that requires the assistance of specialized equipment in order to be removed. Lead extraction is by far the more complex procedure. As it carries some risks for the patient, clear indications, expertly trained personnel, adequate tools, and appropriate environment and facilities are mandatory for its safe removal [1], [2].

Internal cardioverter defibrillator (ICD) therapy has come a long way since its introduction in the 1980s as the first-line treatment for the few fortunate survivors of recurrent sudden cardiac arrest (SCA). Secondary- and primary-prevention trials enrolling patients with either ischemic or nonischemic cardiomyopathy with depressed left ventricular ejection fraction (LVEF) and NYHA II–IV (AVID, CIDS, CASH, MADIT, MUSTT, MADIT II, DEFINITE) have overwhelmingly demonstrated that ICD therapy reduces total mortality compared with anti-arrhythmic drug therapy and/or optimal medical therapy [1, 2, 3, 4, 5, 6, 7]. The most recent trials (COMPANION and SCD-HeFT) [8, 9] focused on patients with NYHA class II–IV heart-failure (HF) symptoms and depressed LVEF: ICD alone or combined with a left ventricular lead for cardiac resynchronization significantly reduced total mortality as compared with optimal medical therapy (ACE inhibitors/ARB blockers, beta-blockers, canrenoate, diuretics) and amiodarone.

To evaluate the prevalence of severe right atrial conduction delay in patients with sinus node dysfunction (SND) and atrial fibrillation (AF) and the effects of pacing in the right atrial appendage (RAA) and in the inter-atrial septum (IAS).Forty-two patients (15 male, 72 +/- 7 years) underwent electrophysiologic study to measure the difference between the conduction time from RAA to coronary sinus ostium during stimulation at 600 ms and after extrastimulus (DeltaCTos). Patients were classified as group A if DeltaCTos60 ms and group B if60 ms. Each Group was randomized to RAA/IAS pacing and algorithms ON/OFF.Fifteen patients (36%, group A) had DeltaCTos = 76 +/- 11 ms and 27 patients (64%, group B) had DeltaCTos = 36 +/- 20 ms. Twenty-two patients were paced at the RAA and 20 at the IAS. During the study, no AF recurrences were reported in 11 of 42 (26%) patients, independently of RAA or IAS pacing. Patients from group A and RAA pacing had 0.79 +/- 0.81 episodes of AF/day during DDD, which increased to 1.52 +/- 1.41 episodes of AF/day during DDDR + Alg (P = 0.046). Those with IAS pacing had 0.5 +/- 0.24 episodes of AF/day during DDD, which decreased to 0.06 +/- 0.08 episodes of AF/day during DDDR + Alg (P = 0.06). In group B, no differences were reported between pacing sites and pacing modes.Severe right atrial conduction delay is present in one-third of patients with SND and AF: continuous pacing at the IAS is superior to RAA for AF recurrences. In patients without severe conduction delay, no differences between pacing site or mode were observed.

From January 2003 to February 2005, 30 consecutive patients (mean age 54±8.7 years, 27 male, 3 female) waiting for a catheter ablation of atrial fibrillation underwent gadolinium-enhanced magnetic resonance imaging (MRI) before the procedure. Variant pulmonary vein anatomy was observed in 12 (40%) of patients. The most frequent was a common left trunk (5 patients). Right middle pulmonary vein was observed in 4 cases, two right middle pulmonary veins in 2 cases and a common right trunk in 2 cases. One patient showed a common right trunk together with a common left trunk. Our study demonstrates the high frequency of variant pulmonary vein anatomy in the general population and demonstrates the value of MRI in facilitating catheter ablation of atrial fibrillation. Potentials benefits of obtaining preprocedural MRI include the ability to quantitatively evaluate the number, size, and shape of the pulmonary veins and the eventual choice of alternative mapping or ablation tools.

A 71-year-old male patient with end-stage heart failure, atrial fibrillation, congestive and low output symptoms, underwent biventricular pacing and atrioventricular junction ablation while anuric and hypotensive. Following atrioventricular junction ablation blood pressure increased by 20 mmHg during biventricular but not during right ventricular apical pacing. A rapid clinical improvement was observed and the patient was discharged from the hospital in NYHA functional class III.