Giuseppe Inama

Evidence of a reentry circuit in the common type of atrial flutter in man.

To investigate the mechanism of atrial flutter (AF) in humans, we studied 13 patients during episodes of spontaneous common AF, with simultaneous multiple atrial endocavitary recordings and atrial programmed stimulation. In all patients, low paraseptal atrial activation preceded high right atrial activation, and the latter preceded mid- or low lateral right atrial activation (recorded in five patients). Programmed atrial stimulation resulted in early reset of the AF cycle, with an unchanged poststimulation AF activation pattern. The poststimulation cycle recorded from an even potential to the site of stimulation was always shorter than the basic flutter cycle length. The poststimulation cycle recorded at the site of stimulation was always equal to or longer than the flutter cycle length.These results strongly favor the existence of a reentry circuit to which the extrastimulus has access.

The Atrial Fibrillation Ablation Pilot Study: an European Survey on Methodology and results of catheter ablation for atrial fibrillation conducted by the European Heart Rhythm Association

AIMSnThe Atrial Fibrillation Ablation Pilot Study is a prospective registry designed to describe the clinical epidemiology of patients undergoing an atrial fibrillation (AFib) ablation, and the diagnostic/therapeutic processes applied across Europe. The aims of the 1-year follow-up were to analyse how centres assess in routine clinical practice the success of the procedure and to evaluate the success rate and long-term safety/complications.nnnMETHODS AND RESULTSnSeventy-two centres in 10 European countries were asked to enrol 20 consecutive patients undergoing a first AFib ablation procedure. A web-based case report form captured information on pre-procedural, procedural, and 1-year follow-up data. Between October 2010 and May 2011, 1410 patients were included and 1391 underwent an AFib ablation (98.7%). A total of 1300 patients (93.5%) completed a follow-up control 367 ± 42 days after the procedure. Arrhythmia documentation was done by an electrocardiogram in 76%, Holter-monitoring in 52%, transtelephonic monitoring in 8%, and/or implanted systems in 4.5%. Over 50% became asymptomatic. Twenty-one per cent were re-admitted due to post-ablation arrhythmias. Success without antiarrhythmic drugs was achieved in 40.7% of patients (43.7% in paroxysmal AF; 30.2% in persistent AF; 36.7% in long-lasting persistent AF). A second ablation was required in 18% of the cases and 43.4% were under antiarrhythmic treatment. Thirty-three patients (2.5%) suffered an adverse event, 272 (21%) experienced a left atrial tachycardia, and 4 patients died (1 haemorrhagic stroke, 1 ventricular fibrillation in a patient with ischaemic heart disease, 1 cancer, and 1 of unknown cause).nnnCONCLUSIONnThe AFib Ablation Pilot Study provided crucial information on the epidemiology, management, and outcomes of catheter ablation of AFib in a real-world setting. The methods used to assess the success of the procedure appeared at least suboptimal. Even in this context, the 12-month success rate appears to be somewhat lower to the one reported clinical trials.

Atrial antitachycardia pacing and managed ventricular pacing in bradycardia patients with paroxysmal or persistent atrial tachyarrhythmias: the MINERVA randomized multicentre international trial

Aims Atrial fibrillation (AF) is a common comorbidity in bradycardia patients. Advanced pacemakers feature atrial preventive pacing and atrial antitachycardia pacing (DDDRP) and managed ventricular pacing (MVP), which minimizes unnecessary right ventricular pacing. We evaluated whether DDDRP and MVP might reduce mortality, morbidity, or progression to permanent AF when compared with standard dual-chamber pacing (Control DDDR). Methods and results In a randomized, parallel, single-blind, multi-centre trial we enrolled 1300 patients with bradycardia and previous atrial tachyarrhythmias, in whom a DDDRP pacemaker had recently been implanted. History of permanent AF and third-degree atrioventricular block were exclusion criteria. After a 1-month run-in period, 1166 eligible patients, aged 74 ± 9 years, 50% females, were randomized to Control DDDR, DDDRP + MVP, or MVP. Analysis was intention-to-treat. The primary outcome, i.e. the 2-year incidence of a combined endpoint composed of death, cardiovascular hospitalizations, or permanent AF, occurred in 102/385 (26.5%) Control DDDR patients, in 76/383 (19.8%) DDDRP + MVP patients [hazard ratio (HR) = 0.74, 95% confidence interval 0.55–0.99, P = 0.04 vs. Control DDDR] and in 85/398 (21.4%) MVP patients (HR = 0.89, 95% confidence interval 0.77–1.03, P = 0.125 vs. Control DDDR). When compared with Control DDDR, DDDRP + MVP reduced the risk for AF longer than 1 day (HR = 0.66, 95% CI 0.52–0.85, P < 0.001), AF longer than 7 days (HR = 0.52, 95% CI 0.36–0.73, P < 0.001), and permanent AF (HR = 0.39, 95% CI 0.21–0.75, P = 0.004). Conclusion In patients with bradycardia and atrial tachyarrhythmias, DDDRP + MVP is superior to standard dual-chamber pacing. The primary endpoint was significantly lowered through the reduction of the progression of atrial tachyarrhythmias to permanent AF. ClinicalTrials.gov Identifier NCT00262119.

VENTRICULAR ARRHYTHMIAS AND SUDDEN DEATH IN ATHLETES

Sudden death (SD) in the athlete typically occurs during or immediately after strenuous physical exertion. It is always a dramatic, unexpected event because the victim is apparently in excellent physical condition. Whereas SD is extremely rare in professional, well-trained, and medically supervised athletes,, it more frequently occurs in a sporting population with a lesser degree of training and medical care. Although SD in athletes is no longer exceptional, relatively few complete reports are available on this topic. Moreover very little is known about the arrhythmic event that leads to cardiac arrest even if the latter is generally considered as a consequence of malignant ventricular arrhythmias. Most SD in athletes occurs in the setting of established acquired and/or congenital structural abnormalities of the heart. They are sometimes so relevant that it almost seems incredible that the subject can exercise at high levels. This study considers the problem of sudden arrhythmic death in the athlete from the standpoint of the pathologist and the arrhythmologist. We will look at the pathologists viewpoint by looking for the anatomic substrate of arrhythmias and by trying to identify the mechanisms of cardiovascular adaptation that followed a maximum level of sport activity until the final event occurred. In this regard literature and personal data are available. The arrhythmologists goal is to identify athletes at risk of sudden arrhythmic death, which we did on the basis of data gathered at our center relative both to athletes referred for arrhythmias and athletes otherwise believed normal.

Transesophageal atrial pacing: A first-choice technique in atrial flutter therapy

Here we report on a study of 181 episodes of spontaneous atrial flutter (AF) (mean atrial cycle length 250 +/- 32 msec) treated by transesophageal atrial pacing (TAP) in 138 patients (92 men and 46 women; mean age 59.5 +/- 12.6 years). TAP was effective in 163 episodes (90%); sinus rhythm resumption was immediate in 36 (19.9%) and followed a short period of atrial fibrillation in 64 (35.3%); in 63 episodes (34.8%) a stable atrial fibrillation was obtained. TAP was unsuccessful in 18 cases (10%). All the patients tolerated the procedure well. A statistical elaboration with the Fisher exact test did not evidence a correlation between efficacy and age, sex, atrial cycle length, or underlying heart disease but showed a significant correlation between efficacy and AF duration of less than 1 day (p less than 0.05) and absence of antiarrhythmic pharmacologic pretreatment (p less than 0.01). These data strongly support the immediate first-choice use of TAP in AF therapy.

Antitachycardia pacing therapies to terminate atrial tachyarrhythmias: the AT500 Italian Registry

Background Antitachycardia pacing (ATP) therapies may have a r ole to play in treating paroxysmal atrial tachyarrythmias. The Medtronic AT500 is a new DDDRP pacemaker providing automatic ATP therapies and prevention algorithms. Method A total of 131 patients (age 71 ± 9 years, 71 male and 60 female) were enrolled in the AT500 Italian Registry after receiving the device. After implant, diagnostic features were enabled. They classify arrhythmias as atrial fibrillation (AF) or atrial tachycardia (AT) according to their rate, atrioventricular association and regularity. ATP therapies and prevention algorithms were enabled at first month follow-up visit. ATP therapies were programmed to treat episodes classified as AT at their onset or during their progression. Therapies were automatically delivered 1 min after episode detection. Results During a follow up of 3·3 ± 2·9 months, 5593 AT/AF episodes were detected and treated in 21 patients, and 2065 (36%) were classified by the device as successfully terminated. In a subgroup of patients for whom electrogram information was available, the device classified 96 (37·4%) of the 256 recorded episodes as successfully terminated. The effect of ATP on AF burden was closely related to the efficacy of ATP. A reduction in AF burden was more evident in those patients in whom ATP therapy efficacy was greater than 50% in terminating episodes. ATP efficacy was greater (52·6%) in episodes classified at onset as AT t han in those classified at onset as AF (28·6%). ATP efficacy was also higher in patients with long pre-therapy P‐P cycle interval and in patients with atrial lead implanted at the inter-atrial septum. Conclusion The present study demonstrates the safety and efficacy of automatic ATP therapies for terminating AT/AF, with a sophisticated dual-chamber pacemaker. Atrial ATP terminated 36·9% of treated AT/AF episodes without any proarrhythmic effects in a population of patients with indications for pacemaker implantation and/or a history of AF. (Eur Heart J Supplements 2001; 3 (Suppl P): P16‐P24)

Italian cardiological guidelines for sports eligibility in athletes with heart disease: part 1.

In Italy the existence of a law on health protection of competitive sports since 1982 has favored the creation and the revision of these cardiological guidelines (called COCIS), which have reached their fourth edition (1989-2009). The present article is the second English version, which has summarized the larger version in Italian. The experience of the experts consulted in the course of these past 20 years has facilitated the application and the compatibility of issues related to clinical cardiology to the sports medicine field. Such prolonged experience has allowed the clinical cardiologist to acquire knowledge of the applied physiology of exercise and, on the other hand, has improved the ability of sports physicians in cardiological diagnostics. All this work has produced these guidelines related to the judgment of eligibility for competitive sports in the individual clinical situations and in the different cardiovascular abnormalities and/or heart disease. Numerous arguments are debated, such as interpretation of the athletes ECG, the utility of a preparticipation screening, arrhythmias, congenital heart disease, cardiomyopathies, arterial hypertension, ischemic heart disease and other particular issues.

Far-field R wave oversensing in dual chamber pacemakers designed for atrial arrhythmia management: Effect of pacing site and lead tip to ring distance

The aim of the study was to determine the incidence and practical implications of far‐field R wave oversensing (FFRWO) and its association with pacing site and lead tip to ring spacing (TTRS) in implantable devices designed to diagnose and treat atrial tachyarrhythmias and programmed with a fixed and short postventricular blanking period. The study included 395 patients who were implanted with a DDDRP pacemaker and prospectively followed. At implant and follow‐up visits FFRWO was assessed by analyzing lead electrical measures and atrial tachyarrhythmic episodes collected in the device diagnostics. During a median follow‐up of 12 months 11 (2.8%) of 395 patients showed a clinically significant FFRWO that induced inappropriate detection or pacemaker malfunctioning. The atrial pacing site of these 11 patients was right atrium appendage (RAA) for 3 patients, representing 1.1% of 254 RAA patients, coronary sinus ostium (CSO) for 7 patients, representing 7.4% of 94 CSO patients (P < 0.005 vs RAA), and lateral wall (LW) for 1 (2.9%) of 34 LW patients. The minimal value of the FFRWO to P wave ratio, measured at implant, associated with a clinically significant FFRWO was 0.6; therefore, a value of 0.5 was used as a cutoff to identify patients at risk of undesirable device behavior induced by FFRWO: there were 11 (9.6%) of 114 of RAA patients with short (≤ 10 mm) TTRS, 22 (18.8%) of 117 of RAA patients with long (≥ 17 mm) TTRS (P < 0.05 vs short TTRS), 21 (30.6%) of 64 of CSO patients short TTRS (P < 0.001 vs RAA patients with short TTRS) and 3 (30%) of 10 of CSO patients with long TTRS. The analysis showed that, despite the short postventricular blanking time, FFRWO inducing undesired functioning in AT500 pacemakers is infrequent (2.8% of patients). Compared to RAA, the CSO lead position was more frequently associated with FFRWO.TTRS < 10 mm was associated with lower risk of clinically significant FFRWO in RAA.

New-generation atrial antitachycardia pacing (Reactive ATP) is associated with reduced risk of persistent or permanent atrial fibrillation in patients with bradycardia: Results from the MINERVA randomized multicenter international trial

BACKGROUNDnAtrial fibrillation (AF) is a frequent comorbidity in patients with pacemaker and is a recognized cause of mortality, morbidity, and quality-of-life impairment. The international MINimizE Right Ventricular pacing to prevent Atrial fibrillation and heart failure trial established that atrial preventive pacing and atrial antitachycardia pacing (DDDRP) in combination with managed ventricular pacing (MVP) reduce permanent AF occurrence in comparison with standard dual-chamber pacing (DDDR).nnnOBJECTIVEnWe aimed to determine the role of new-generation atrial antitachycardia pacing (Reactive ATP) in preventing AF disease progression.nnnMETHODSnPatients with dual-chamber pacemaker and with previous atrial tachyarrhythmias were randomly assigned to DDDR (n = 385 (33%)), MVP (n = 398 (34%)), or DDDRP+MVP (n = 383 (33%)) group. The incidence of permanent AF, as defined by the study investigator, or persistent AF, defined as ≥7 consecutive days with AF, was estimated using the Kaplan-Meier method, while its association with patients characteristics was evaluated via multivariable Cox regression.nnnRESULTSnAt 2 years, the incidence of permanent or persistent AF was 26% (95% confidence interval [CI] 22%-31%) in the DDDR group, 25% (95% CI 21%-30%) in the MVP group, and 15% (95% CI 12%-20%) in the DDDRP+MVP group (P < .001 vs. DDDR; P = .002 vs. MVP). Generalized estimating equation-adjusted Reactive ATP efficacy was 44.4% (95% CI 41.3%-47.6%). Multivariate modeling identified high Reactive ATP efficacy (>44.4%) as a significant predictor of reduced permanent or persistent AF risk (hazard ratio 0.32; 95% CI 0.13-0.781; P = .012) and episodes characteristics, such as long atrial arrhythmia cycle length, regularity, and the number of rhythm transitions, as predictors of high ATP efficacy.nnnCONCLUSIONnIn patients with bradycardia, DDDRP+MVP delays AF disease progression, with Reactive ATP efficacy being an independent predictor of permanent or persistent AF reduction.

Catheter ablation of Wolff-Parkinson-White syndrome associated with congenital absence of inferior vena cava.

In the present report we describe a patient (a 36-year-old woman with 15 year history of supraventricular tachyarrhythmias) with congenital absence of inferior vena cava (IVC) revealed during radiofrequency (RF) catheter ablation procedure for right postero-septal Wolff-Parkinson-White syndrome (WPW). For the absence of IVC, the ablation procedure was more difficult, because we had to perform the ablation with the catheters (the ablator catheter and the coronary sinus catheter) introduced both through the superior vena cava. The application of RF energy (35 Watt for 60 seconds) at successful site abolished accessory pathway conduction. The following day was performed the venous angiography, showing the absence of the IVC and a venous return via paravertebral venous plexus to the azygous vein and superior vena cava into the right atrium. Computer tomography confirmed the absence of the IVC with azygous continuation. The drainage via the azygous system modified the radiological image on chest roentgenogram of the right mediastinal silhouette. During cardiogenesis fusion of the IVC and organisation of the heart occur between the 33rd to 40th embryonic days. It is therefore possible that some unknown teratogenic mechanism at this critical period might have caused, in the patient, both the developmental arrest of IVC and failure of regression of atrio-ventricular anatomical and electrical continuity in the right postero-septal region.