Incidence and Predictors of Infections and All-Cause Death in Patients with Cardiac Implantable Electronic Devices: The Italian Nationwide RI-AIAC Registry.

BACKGROUND: The incidence of infections associated with cardiac implantable electronic devices (CIEDs) and patient outcomes are not fully known. AIM: To provide a contemporary assessment of the risk of CIEDs infection and associated clinical outcomes. METHODS: In Italy, 18 centres enrolled all consecutive patients undergoing a CIED procedure and entered a 12-months follow-up. CIED infections, as well as a composite clinical event of infection or all-cause death were recorded. RESULTS: A total of 2675 patients (64.3% male, age 78 (70-84)) were enrolled. During follow up 28 (1.1%) CIED infections and 132 (5%) deaths, with 152 (5.7%) composite clinical events were observed. At a multivariate analysis, the type of procedure (revision/upgrading/reimplantation) (OR: 4.08, 95% CI: 1.38-12.08) and diabetes (OR: 2.22, 95% CI: 1.02-4.84) were found as main clinical factors associated to CIED infection. Both the PADIT score and the RI-AIAC Infection score were significantly associated with CIED infections, with the RI-AIAC infection score showing the strongest association (OR: 2.38, 95% CI: 1.60-3.55 for each point), with a c-index = 0.64 (0.52-0.75), p = 0.015. Regarding the occurrence of composite clinical events, the Kolek score, the Shariff score and the RI-AIAC Event score all predicted the outcome, with an AUC for the RI-AIAC Event score equal to 0.67 (0.63-0.71) p < 0.001. CONCLUSIONS: In this Italian nationwide cohort of patients, while the incidence of CIED infections was substantially low, the rate of the composite clinical outcome of infection or all-cause death was quite high and associated with several clinical factors depicting a more impaired clinical status.

Estimate and reporting of longevity for cardiac implantable electronic devices: a proposal for standardized criteria.

BACKGROUND: Cardiac implantable electronic devices (CIEDs) are widely used according to consensus guidelines in various patient categories. The longevity of CIED is a major determinant of the frequency with which patients require device replacement. Given the mismatch between the useful life of the devices and patient survival, device replacement is often needed. There is a great variability in the criteria used by manufacturers to determine the longevity of pacemakers (PM), implantable defibrillators (ICDs), and devices for cardiac resynchronization therapy (CRT). Thus, a fair comparison and an effective device evaluation is often difficult. METHODS: The objective of this paper is to provide standardized criteria based on typical clinical settings for estimating the longevity of single and dual chamber ICDs, cardiac resynchronization defibrillators (CRT-D), single and dual chamber PMs, and cardiac resynchronization PMs (CRT- P) to be used in health technology assessment for an appropriate comparison among different devices. RESULTS: The proposed parameters, if applied to the current marketed devices, provide longevity values in the range 5-17.2 years. CONCLUSION: The values of longevity with the non-standardized criteria used by the manufacturers result in higher maximum values respect to the proposed standardized criteria for CRT-D, CRTD-MPP, CRT-P, and Dual-chamber PM.

Organization and procedures in contemporary catheter ablation centres: data from the 2018 Italian Catheter Ablation Registry.

AIMS: This report describes the findings of the 2018 Italian Catheter Ablation Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC). METHODS: The Italian Catheter Ablation Registry systematically collects data on the ablation procedures performed in Italy. Data collection was retrospective. A standardized questionnaire was completed by participating centres. RESULTS: We collected data on 15 714 catheter ablation procedures performed in Italy during 2018 in 94 electrophysiology centres. In most centres (75/94, 80%), a single electrophysiology laboratory was available, and a hybrid electrophysiology laboratory was available in 15% (14/94) of centres. In most (93%) centres, at least two electrophysiologists were involved in the catheter ablation procedures. In only 13 out of 94 (14%) electrophysiology laboratories, an anaesthesiologist assists every electrophysiology procedure; in most cases (74/94, 79%), an on-demand anaesthesiology service was available. On-site cardiothoracic surgery was reported in 43 out of 94 (46%) centres.Nonfluoroscopic navigation systems were available in most centres (88/94, 93%). Intracardiac echocardiography was used in 59 out of 94 (63%) electrophysiology laboratories. Atrial fibrillation (31%) was the most frequently treated ablation target, followed by atrioventricular nodal re-entrant tachycardia (20%) and cavo-tricuspid isthmus (15%). In 61.7% of all procedures, a 3D mapping system was used. In about one-third of procedures, a near-zero approach was performed. CONCLUSION: In most Italian electrophysiology centres, a single electrophysiology laboratory was available and at least two electrophysiologists were involved in the ablation procedures. An increasing number of procedures were performed by means of a nonfluoroscopic mapping system with a near-zero approach.

Mortality after cardioverter-defibrillator replacement: Results of the DECODE survival score index.

BACKGROUND: Device replacement is the ideal time to reassess health care goals regarding continuing implantable cardioverter-defibrillator (ICD) therapy. Only few data are available on the decision making at this time. OBJECTIVES: The goals of this study were to identify factors associated with poor prognosis at the time of ICD replacement and to develop a prognostic index able to stratify those patients at risk of dying early. METHODS: DEtect long-term COmplications after implantable cardioverter-DEfibrillator replacement (DECODE) was a prospective, single-arm, multicenter cohort study aimed at estimating long-term complications in a large population of patients who underwent ICD/cardiac resynchronization therapy - defibrillator replacement. Potential predictors of death were investigated, and all these factors were gathered into a survival score index (SUSCI). RESULTS: We included 983 consecutive patients (median age 71 years (63-78)); 750 (76%) were men, 537 (55%) had ischemic cardiomyopathy; 460 (47%) were implanted with cardiac resynchronization therapy - defibrillator. During a median follow-up period of 761 days (interquartile range 628-904 days), 114 patients (12%) died. In multivariate Cox regression analysis, New York Heart Association class III/IV, ischemic cardiomyopathy, body mass index < 26 kg/m2, insulin administration, age ≥ 75 years, history of atrial fibrillation, and hospitalization within 30 days before ICD replacement remained associated with death. The survival score index showed a good discriminatory power with a hazard ratio of 2.6 (95% confidence interval 2.2-3.1; P < .0001). The risk of death increased according to the severity of the risk profile ranging from 0% (low risk) to 47% (high risk). CONCLUSION: A simple score that includes a limited set of variables appears to be predictive of total mortality in an unselected real-world population undergoing ICD replacement. Evaluation of the patient's profile may assist in predicting vulnerability and should prompt individualized options, especially for high-risk patients.

Lead choice in cardiac implantable electronic devices: an Italian survey promoted by AIAC (Italian Association of Arrhythmias and Cardiac Pacing).

Background: Few data are available regarding lead preferences of electrophysiologists during cardiac implantable electronic devices (CIEDs) implantation. Aim of this survey is to evaluate the leads used, and the reasons behind these choices, in a large population of implanters. Methods: A questionnaire was sent to all 314 Italian centers with experience in CIED implantation. Results: 103 operators from 100 centers (32% of centers) responded. For atrium, passive leads represented first choice for pacemakers and defibrillators (71% and 64% of physicians, respectively), mainly for safety. For right ventricle, active fixation was preferred (61% and 93% operators in pacemaker and defibrillator patients), for higher versatility in positioning and lower dislodgement risk. For left ventricular stimulation, quadripolar leads were preferred by more than 80% of respondents, for better phrenic nerve and myocardial threshold management; active-fixation leads represent a second choice, in order to prevent or manage dislodgement (78% and 17% of respondents, respectively), but 44% of operators considered them dangerous. Conclusions: The choice of leads is heterogeneous. Trends are toward active-fixation right ventricular leads and passive-fixation atrial leads (particularly in pacemaker patients, considered frailer). For left ventricular stimulation, operators' majority want to disposition all kind of leads, although quadripolar leads are the favorites.

Clinical and organizational management of cardiac implantable electronic device replacements: an Italian Survey promoted by AIAC (Italian Association of Arrhythmology and Cardiac Pacing).

AIMS: The aim of this survey was to assess the management and organization of cardiac implantable electronic device (CIED) replacement in Italy. METHODS: A questionnaire consisting of 24 questions on organizational aspects and on the peri-procedural management of anticoagulant therapies and antibiotic prophylaxis was sent via the Internet to 154 Italian arrhythmia centers. RESULTS: A total of 103 out of 154 centers completed the questionnaire (67% response rate). In 43% of the centers, the procedures were performed under day-case admission, in 40% under ordinary admission, and in 17% under either day-case or ordinary admission. The most frequent reason (66%) for choosing ordinary admission rather than day-case admission was to obtain full reimbursement. Although warfarin therapy was continued in 73% of the centers, nonvitamin K oral anticoagulants were discontinued, without bridging, 24 h or less prior to replacement procedures in 88%. Prophylactic antibiotic therapy was systematically administered in all centers; in 97%, the first antibiotic dose was administered 1-2 h prior to procedures. Local antibacterial envelopes were also used in 43% of the centers in patients with a higher risk of device infection. CONCLUSION: This survey provides a representative picture of how CIED replacements are organized and managed in current Italian clinical practice. The choice of the type of hospitalization (short versus ordinary) was more often motivated by economic reasons (reimbursement of the procedure) than by clinical and organizational factors. Peri-procedural management of anticoagulation and prophylactic antibiotic therapy was consistent with current scientific evidence.

Clinically oriented device programming in bradycardia patients: part 1 (sinus node disease). Proposals from AIAC (Italian Association of Arrhythmology and Cardiac Pacing).

: Modern pacemakers have an increasing number of programable parameters and specific algorithms designed to optimize pacing therapy in relation to the individual characteristics of patients. When choosing the most appropriate pacemaker type and programing, the following variables must be taken into account: the type of bradyarrhythmia at the time of pacemaker implantation; the cardiac chamber requiring pacing, and the percentage of pacing actually needed to correct the rhythm disorder; the possible association of multiple rhythm disturbances and conduction diseases; the evolution of conduction disorders during follow-up. The goals of device programing are to preserve or restore the heart rate response to metabolic and hemodynamic demands; to maintain physiological conduction; to maximize device longevity; to detect, prevent, and treat atrial arrhythmia. In patients with sinus node disease, the optimal pacing mode is DDDR. Based on all the available evidence, in this setting, we consider appropriate the activation of the following algorithms: rate responsive function in patients with chronotropic incompetence; algorithms to maximize intrinsic atrioventricular conduction in the absence of atrioventricular blocks; mode-switch algorithms; algorithms for autoadaptive management of the atrial pacing output; algorithms for the prevention and treatment of atrial tachyarrhythmias in the subgroup of patients with atrial tachyarrhythmias/atrial fibrillation. The purpose of this two-part consensus document is to provide specific suggestions (based on an extensive literature review) on appropriate pacemaker setting in relation to patients' clinical features.

Clinically oriented device programming in bradycardia patients: part 2 (atrioventricular blocks and neurally mediated syncope). Proposals from AIAC (Italian Association of Arrhythmology and Cardiac Pacing).

: The purpose of this two-part consensus document is to provide specific suggestions (based on an extensive literature review) on appropriate pacemaker setting in relation to patients' clinical features. In part 2, criteria for pacemaker choice and programming in atrioventricular blocks and neurally mediate syncope are proposed. The atrioventricular blocks can be paroxysmal or persistent, isolated or associated with sinus node disease. Neurally mediated syncope can be related to carotid sinus syndrome or cardioinhibitory vasovagal syncope. In sinus rhythm, with persistent atrioventricular block, we considered appropriate the activation of mode-switch algorithms, and algorithms for auto-adaptive management of the ventricular pacing output. If the atrioventricular block is paroxysmal, in addition to algorithms mentioned above, algorithms to maximize intrinsic atrioventricular conduction should be activated. When sinus node disease is associated with atrioventricular block, the activation of rate-responsive function in patients with chronotropic incompetence is appropriate. In permanent atrial fibrillation with atrioventricular block, algorithms for auto-adaptive management of the ventricular pacing output should be activated. If the atrioventricular block is persistent, the activation of rate-responsive function is appropriate. In carotid sinus syndrome, adequate rate hysteresis should be programmed. In vasovagal syncope, specialized sensing and pacing algorithms designed for reflex syncope prevention should be activated.

Appropriate implantable cardioverter-defibrillator interventions in cardiac resynchronization therapy-defibrillator (CRT-D) patients undergoing device replacement: time to downgrade from CRT-D to CRT-pacemaker? Insights from real-world clinical practice in the DECODE CRT-D analysis.

Aim: Ventricular tachycardia (VT)/ventricular fibrillation (VF) occurrence after cardiac resynchronization therapy-defibrillator (CRT-D) replacement is unknown; hence, there is no practical guideline to recommend either CRT-D or CRT-pacemaker at the time of device replacement. We observed the 1-year VT/VF occurrence after CRT-D replacement in a subanalysis of the Detect Long-term Complications after ICD Replacement (DECODE) registry. Methods and results: A total of 332 consecutive patients who had undergone CRT-D replacement from 2013 to 2015 were enrolled in 36 Italian centres. The primary endpoint was the number of patients with any appropriate implantable cardioverter-defibrillator (ICD) interventions during 12-month follow-up. The secondary endpoint comprised death from any cause and appropriate ICD interventions. At replacement, 214 (64.5%) patients had a left ventricular ejection fraction ≤ 35% and 138 (41.6%) patients had a secondary prevention indication for ICD. Seventy (21.1%) patients had no longer indication to ICD therapy. During a median follow-up period of 406.5 (362-533) days, VT/VF requiring therapy delivery occurred in 57 (17%) patients, specifically in 7% of those who no longer had an ICD indication. On multivariate analysis, number of criteria for ICD replacement independently predicted appropriate ICD intervention during follow-up [hazard ratio (HR) = 1.62, 95% confidence interval (CI) 1.07-2.46; log-rank P = 0.02]. The combined endpoint of death from any cause or appropriate ICD therapy occurred in 76 (23%) patients. Only NYHA class remained associated with this combined endpoint (HR = 1.97, 95% CI 1.23-3.14; P = 0.005). Conclusions: The DECODE registry showed the 'real-world' experience of CRT-D recipients approaching device replacement, in which 7% of patients who no longer had an indication for ICD therapy experienced appropriate ICD interventions.

Fibrilación auricular: un importante problema de salud pública / Atrial fibrillation: a serious public health issue

En los últimos 20 años la fibrilación auricular (FA) se ha transformado en uno de los problemas de salud pública más importantes. Su prevalencia (2%) duplica la reportada a fines de la década pasada y se incrementa con el envejecimiento. La FA es más frecuente en hombres que en mujeres, con una relación 1,2:1. La incidencia de FA oscila entre 0,21 y 0,9 cada 1.000 personas/año. La forma más frecuente de FA es la permanente, que ocurre en aproximadamente 50% de los pacientes, mientras que la paroxística y la persistente ocurren cada una en aproximadamente 25% de los pacientes. La FA está frecuentemente asociada a enfermedades cardíacas y comorbilidades. Las enfermedades concomitantes más frecuentes son: enfermedad arterial coronaria, valvulopatías y miocardiopatías. Las comorbilidades más frecuentes son: hipertensión, diabetes, insuficiencia cardíaca, enfermedad pulmonar obstructiva crónica, falla renal, ataque cerebrovascular (ACV) y trastornos cognitivos. La FA paroxística ocurre en pacientes más jóvenes, y en contraste con las formas persistente y permanente, está asociada con una menor carga de enfermedades cardíacas y comorbilidades. Generalmente, la FA tiene una historia de larga duración caracterizada por progresión desde la forma paroxística a la permanente, con frecuentes recurrencias y síntomas perturbadores. Los pacientes con FA tienen un riesgo de ACV y muerte, respectivamente, cinco y dos veces mayor que la población normal. En el mundo real, los pacientes con FA continúan siendo subtratados con anticoagulantes orales y en un pequeño porcentaje de los casos son asignados de forma inapropiada a estrategia antiarrítmica o son tratados con fármacos antiarrítmicos inadecuados. El manejo de la FA es costoso, siendo el gasto anual por paciente significativamente diferente en los distintos países. Para mejorar la calidad de la asistencia son necesarios esfuerzos para mejorar la implementación de las recomendaciones de las guías de práctica clínica.

In the last 20 years atrial fibrillation (AF) has become one of the most important public health issues. Its prevalence (2%) is double than that reported at the end of the last decade and it increases with aging. AF occurs more frequently in males than in females with a ratio of 1.2:1. The incidence of AF ranges between 0.21 and 0.9 per 1000 person/years. The most frequent form of AF is permanent AF that occurs in approximately 50% of patients while the paroxysmal and the persistent forms occur approximately in 25% of patients each. AF is frequently associated with cardiac diseases and comorbidities. The commonest concomitant diseases are: coronary artery disease, valvular heart disease and cardiomyopathies. The commonest comorbidities are: hypertension, diabetes, heart failure, chronic obstructive pulmonary disease, renal failure, stroke and cognitive disturbances. Paroxysmal AF occurs in younger patients and in contrast with the persistent and the permanent forms is associated with a reduced burden of both cardiac diseases and comorbidities. Generally, the history of AF is long lasting, characterized by the progression from the paroxysmal to the permanent form, burdened by frequent recurrences and disturbing symptoms. Patients with AF have a risk of stroke and death 5 fold and 2 fold higher than normal people respectively. In the real world, patients with AF are still undertreated with oral anticoagulants and in a discrete percentage of cases assigned to inappropriate antiarrhythmic strategy or treated with inadequate specific antiarrhythmic drugs. AF management is costly; expenditure per patient/per year is significantly different in different countries. Efforts to improve the implementations of guidelines recommendations are needed to improve furtherly the quality of care.

Epidemiology of atrial fibrillation: European perspective.

In the last 20 years, atrial fibrillation (AF) has become one of the most important public health problems and a significant cause of increasing health care costs in western countries. The prevalence of AF is increasing due to our greater ability to treat chronic cardiac and noncardiac diseases, and the improved ability to suspect and diagnose AF. At the present time, the prevalence of AF (2%) is double that reported in the last decade. The prevalence of AF varies with age and sex. AF is present in 0.12%-0.16% of those younger than 49 years, in 3.7%-4.2% of those aged 60-70 years, and in 10%-17% of those aged 80 years or older. In addition, it occurs more frequently in males, with a male to female ratio of 1.2:1. The incidence of AF ranges between 0.21 and 0.41 per 1,000 person/years. Permanent AF occurs in approximately 50% of patients, and paroxysmal and persistent AF in 25% each. AF is frequently associated with cardiac disease and comorbidities. The most common concomitant diseases are coronary artery disease, valvular heart disease, and cardiomyopathy. The most common comorbidities are hypertension, diabetes, heart failure, chronic obstructive pulmonary disease, renal failure, stroke, and cognitive disturbance. Paroxysmal AF occurs in younger patients and with a reduced burden of both cardiac disease and comorbidities. Generally, the history of AF is long, burdened by frequent recurrences, and associated with symptoms (in two thirds of patients). Patients with AF have a five-fold and two-fold higher risk of stroke and death, respectively. We estimate that the number of patients with AF in 2030 in Europe will be 14-17 million and the number of new cases of AF per year at 120,000-215,000. Given that AF is associated with significant morbidity and mortality, this increasing number of individuals with AF will have major public health implications.

Stroke prophylaxis in high-risk patients with atrial fibrillation: rhythm vs. rate control strategy.

PURPOSE: "Rhythm" and "Rate" control strategies require partially different organization, and a different involvement of Specialists and General Practitioners; we verified whether the strategy assignment modified the approach to stroke prophylaxis. METHODS: Survey in general practice: 233 GPs identified all patients with codified atrial fibrillation (AF) diagnosis, checked the diagnosis (ECG/hospital discharge document), and filled a structured questionnaire on stroke risk-factors, prophylactic therapy, and reasons for warfarin non prescription in CHADS ≥2 patients. Data were collected as an "aggregate." RESULTS: Population observed: 295,906 patients aged >14; 6,036 with confirmed AF; 5,888 with complete data about anti-thrombotic prophylaxis are analyzed here. In the "rhythm strategy" group 45.6% of the CHADS score ≥2 patients (594) were on warfarin, vs. 73.2% (1,741) in the "rate strategy" group (p<0.0001). Overall reasons for warfarin non-use were significantly different in the two groups: clinical contraindications (12.3% vs. 19.7%), side effects (5.5% vs. 8.5%), patients' refusal (12.2% vs. 15.2%), unreliable patient/care-giver (14.4% vs. 25.9%); reasons were unknown to the GP in 55.6% in rhythm control vs. 30.9% in rate control group. CONCLUSIONS: Anti-thrombotic prophylaxis in CHADS ≥2 patients is different in subjects assigned to the Rhythm vs. the Rate control strategy, as well as reported reasons for warfarin non use. GPs do not know why warfarin is not used in a large percentage of cases, mainly in the rhythm control strategy group. Improving efforts should probably be differently tailored for patients assigned to the "rhythm" or the "rate" control strategy.

Frequency, patient characteristics, treatment strategies, and resource usage of atrial fibrillation (from the Italian Survey of Atrial Fibrillation Management [ISAF] study).

Atrial fibrillation (AF) is 1 of the most important healthcare issues and an important cause of healthcare expenditure. AF care requires specific arrhythmologic skills and complex treatment. Therefore, it is crucial to know its real affect on healthcare systems to allocate resources and detect areas for improving the standards of care. The present nationwide, retrospective, observational study involved 233 general practitioners. Each general practitioner completed an electronic questionnaire to provide information on the clinical profile, treatment strategies, and resources consumed to care for their patients with AF. Of the 295,906 patients screened, representative of the Italian population, 6,036 (2.04%) had AF: 20.2% paroxysmal, 24.3% persistent, and 55.5% permanent AF. AF occurred in 0.16% of patients aged 16 to 50 years, 9.0% of those aged 76 to 85 years, and 10.7% of those aged ≥85 years. AF was symptomatic despite therapy in 74.6% of patients and was associated with heart disease in 75%. Among the patients with AF, 24.8% had heart failure, 26.8% renal failure, 18% stroke/transient ischemic attack, and 29.3% had ≥3 co-morbidities. The rate control treatment strategy was pursued in 55%. Of the 6,036 patients with AF, 46% received anticoagulants. The success rate of catheter ablation of the AF substrate was 50%. In conclusion, in our study, the frequency of AF was 2 times greater than previously reported (approximately 0.90%), rate control was the most pursued treatment strategy, anticoagulants were still underused, and the success rate of AF ablation was lower than reported by referral centers.

Indication to cardioverter-defibrillator therapy and outcome in real world primary prevention. Data from the IRIDE [Italian registry of prophylactic implantation of defibrillators] study.

AIMS: Several trials demonstrated the life saving role of implantable cardioverter-defibrillators (ICD) in primary prevention of sudden cardiac death (SCD). The aim was to evaluate the clinical characteristics and 4-year outcome of consecutive patients treated in clinical practice by prophylactic ICD implantation on the basis of class I recommendations and up-to-date ICD programming. METHODS AND RESULTS: IRIDE multi-center, prospective and observational study enrolled 604 consecutive patients (mean age: 66 ± 10 years) treated by ICD between 01/01/2006 and 30/06/2010. Main characteristics were similarly distributed among the inclusion criteria of MADIT II (24%), SCD-HeFT (24%), COMPANION (26%) and MADIT-CRT (18%) trials, while a small number of patients met the MUSTT and MADIT (7%) inclusion criteria. Single-chamber ICDs were implanted in 168 (28%) patients, dual-chamber in 167 (28%) and biventricular in 269 (43%) patients. ATP programming was activated in 546 (90%) patients. Overall survival and rate of appropriate ICD intervention by ATP and/or shock at 12-24-36-48 months of follow-up were 94%, 89%, 80%, 75% and 16%, 28%, 37% and 50%, respectively. No difference in mortality rate between the groups who received or did not receive appropriate ICD interventions was demonstrated (p=ns). CONCLUSIONS: The IRIDE study confirms the effectiveness in real world practice of ICD implantation in patients at risk of SCD. The life saving role of ICD therapy increases as the duration of follow-up is prolonged and the survival benefit is similar in patients who received or did not receive appropriate device treatment, thus suggesting a beneficial effect of up-to-date device programming.

Dual-chamber implantable cardioverter defibrillators reduce clinical adverse events related to atrial fibrillation when compared with single-chamber defibrillators: a subanalysis of the DATAS trial.

AIMS: The aim of the present analysis of the DATAS study was to compare the impact of dual- vs. single-chamber defibrillators on atrial fibrillation (AF) occurrence and AF-related clinical events in patients with Class I indication for implantable cardioverter defibrillators (ICDs) and no indication for dual-chamber pacing. METHODS AND RESULTS: Three hundred and thirty-four patients were randomized, through a centralized assignment, to single-chamber ICDs, dual-chamber ICDs programmed as single-chamber ICDs, and dual ICDs with full diagnostics and AF prevention and therapy capabilities. The latter two groups in the first 8 months of the study, when the study design was that of a randomized parallel trial, were compared in the present analysis. The primary endpoint was composed by the following AF-related clinical events: permanent AF, AF-related hospitalizations, cardiac-embolic events, and inappropriate ICD shocks due to AF misclassification. Two hundred and twenty-three patients were available for this analysis, of whom 111 in the single-chamber-simulated group and 112 in the dual-chamber true group. Atrial fibrillation-related composite endpoint raw incidence was 9 of 111 (8.1%) in the single-chamber group vs. 1 of 112 (0.9%) in the dual-chamber group (P = 0.0098 by Fisher's exact test). Single-chamber ICDs were associated with a significantly higher risk to develop the AF-related composite endpoint by Cox regression analysis (hazard ratio 8.25, 95% CI 1.03-65.96, P = 0.047) and by the Kaplan-Meier survival analysis (log-rank test, P = 0.047). CONCLUSION: Dual-chamber ICDs compared with single-chamber ICDs reduced the incidence of an endpoint composed by permanent AF, AF-related hospitalizations, and ICD shocks deemed inappropriate due to AF misclassification.