Delayed depolarization and histologic abnormalities underlie the Brugada syndrome.

Brugada syndrome (BrS) is a controversial disease whose pathophysiology is still far from being fully understood. Unlike other cardiological disorders, a definite etiology has not yet been established so that it could be summarized under two main chapters: "functional" or "organic", "repolarization" or "depolarization" disorder. Despite initial descriptions leaned towards the organic substrate and delayed depolarization features, functional and repolarization theories have attracted most of the Cardiological attention for many years. Data from electrocardiography, endocavitary tracings, electroanatomic mapping and histopathology, however, demonstrated that BrS is mainly characterized by structural myocardial changes mostly at the right ventricular outflow tract (RVOT), but also at the right ventricle (RV) and by delayed conduction at the same sites. Conduction disorders at different levels may also be present and identify patients at high risk for major arrhythmic events. The aim of the present review is to provide the current state of art of the pathophysiology of BrS, focusing on electro-vectorcardiography and electrophysiological features, histopathology, echocardiography, and cardiac magnetic resonance imaging (CMRI).

Daily Exposure to Air Pollution Particulate Matter Is Associated with Atrial Fibrillation in High-Risk Patients.

Several epidemiological studies found an association between acute exposure to fine particulate matter of less than 2.5 µm and 10 µm in aerodynamic diameter (PM2.5 and PM10) and cardiovascular diseases, ventricular fibrillation incidence and mortality. The effects of pollution on atrial fibrillation (AF) beyond the first several hours of exposure remain controversial. A total of 145 patients with implantable cardioverter-defibrillators (ICDs), cardiac resynchronization therapy defibrillators (ICD-CRT), or pacemakers were enrolled in this multicentric prospective study. Daily levels of PM2.5 and PM10 were collected from monitoring stations within 20 km of the patient's residence. A Firth Logistic Regression model was used to evaluate the association between AF and daily exposure to PM2.5 and PM10. Exposure levels to PM2.5 and PM10 were moderate, being above the World Health Organization (WHO) PM2.5 and PM10 thresholds of 25 µg/m3 and 50 µg/m3, respectively, on 26% and 18% of the follow-up days. An association was found between daily levels of PM2.5 and PM10 and AF (95% confidence intervals (CIs) of 1.34-2.40 and 1.44-4.28, respectively) for an increase of 50 µg/m3 above the WHO threshold. Daily exposure to moderate PM2.5 and PM10 levels is associated with AF in patients who are not prone to AF.

Economic impact of remote monitoring after implantable defibrillators implantation in heart failure patients: an analysis from the EFFECT study.

AIMS: Heart failure (HF) patients with implantable cardioverter-defibrillators (ICD) require admissions for disease management and out-patient visits for disease management and assessment of device performance. These admissions place a significant burden on the National Health Service. Remote monitoring (RM) is an effective alternative to frequent hospital visits. The EFFECT study was a multicentre observational investigation aiming to evaluate the clinical effectiveness of RM compared with in-office visits standard management (SM). The present analysis is an economic evaluation of the results of the EFFECT trial. METHODS AND RESULTS: The present analysis considered the direct consumption of healthcare resources over 12-month follow-up. Standard tariffs were applied to hospitalizations, in-office visits and remote device interrogations. Economic comparisons were also carried out by means of propensity score (PS) analysis to take into account the lack of randomization in the study design. The analysis involved 858 patients with ICD or CRT-D. Of these, 401 (47%) were followed up via an SM approach, while 457 (53%) were assigned to RM. The rate of hospitalizations was 0.27/year in the SM group and 0.16/year in the RM group (risk reduction =0.59; P = 0.0004). In the non-adjusted analysis, the annual cost for each patient was €817 in the SM group and €604 in the RM group (P = 0.014). Propensity score analysis, in which 292 RM patients were matched with 292 SM patients, confirmed the results of the non-adjusted analysis (€872 in the SM group vs. €757 in the RM group; P < 0.0001). CONCLUSION: There is a reduction in direct healthcare costs of RM for HF patients with ICDs, particularly CRT-D, compared with standard monitoring. CLINICAL TRIAL REGISTRATION: http://clinicaltrials.gov/Identifier, NCT01723865.

Association between air pollution and ventricular arrhythmias in high-risk patients (ARIA study): a multicentre longitudinal study.

BACKGROUND: Although the effects of air pollution on mortality have been clearly shown in many epidemiological and observational studies, the pro-arrhythmic effects remain unknown. We aimed to assess the short-term effects of air pollution on ventricular arrhythmias in a population of high-risk patients with implantable cardioverter-defibrillators (ICDs) or cardiac resynchronisation therapy defibrillators (ICD-CRT). METHODS: In this prospective multicentre study, we assessed 281 patients (median age 71 years) across nine centres in the Veneto region of Italy. Episodes of ventricular tachycardia and ventricular fibrillation that were recorded by the diagnostic device were considered in this analysis. Concentrations of particulate matter of less than 10 µm (PM10) and less than 2·5 µm (PM2·5) in aerodynamic diameter, carbon monoxide, nitrogen dioxide, sulphur dioxide, and ozone were obtained daily from monitoring stations, and the 24 h median value was considered. Each patient was associated with exposure data from the monitoring station that was closest to their residence. Patients were followed up for 1 year and then scheduled to have a closing visit, within 1 more year. This study is registered with ClinicalTrials.gov, number NCT01723761. FINDINGS: Participants were enrolled from April 1, 2011, to Sept 30, 2012, and follow-ups (completed on April 5, 2014) ranged from 637 to 1177 days (median 652 days). The incidence of episodes of ventricular tachycardia and ventricular fibrillation correlated significantly with PM2·5 (p<0·0001) but not PM10. An analysis of ventricular fibrillation episodes alone showed a significant increase in risk of higher PM2·5 (p=0·002) and PM10 values (p=0·0057). None of the gaseous pollutants were significantly linked to the occurrence of ventricular tachycardia or ventricular fibrillation. In a subgroup analysis of patients with or without a previous myocardial infarction, only the first showed a significant association between particulate matter and episodes of ventricular tachycardia or ventricular fibrillation. INTERPRETATION: Particulate matter has acute pro-arrhythmic effects in a population of high-risk patients, which increase on exposure to fine particles and in patients who have experienced a previous myocardial infarction. The time sequence of the arrhythmic events suggests there is an underlying neurally mediated mechanism. From a clinical point of view, the results of our study should encourage physicians to also consider environmental risk when addressing the prevention of arrhythmic events, particularly in patients with coronary heart disease, advising them to avoid exposure to high levels of fine particulate matter. FUNDING: There was no funding source for this study.

Association between remote implantable cardioverter defibrillator monitoring and beta-blocker utilization: An analysis from the EFFECT study.

INTRODUCTION: A substantial number of heart failure patients undergoing implantation of implantable cardioverter defibrillators (ICDs) fail to receive beta-blockers, or receive them at a suboptimal dose. Remote monitoring (RM) is becoming the standard means of following up recipients of ICDs. However, the impact of this shift toward remote ICD follow-up on the quality of drug therapy management in current clinical practice is unknown. The present analysis was aimed at investigating the impact of RM on the dose of beta-blockers achieved, and its association with clinical outcome at 12 months. METHODS: Altogether 987 consecutive patients were enrolled and followed up for at least 12 months in 25 Italian centres. RM was adopted by 499 patients. RESULTS: The number of patients receiving beta-blockers at any dose decreased after 12 months (from 403 (81%) to 370 (74%) for the remote arm and from 389 (80%) to 342 (70%) for the standard arm, both p < 0.02). Nonetheless, the number of patients on beta-blockers at the effective dose increased in both arms (from 60 (12%) to 82 (16%) for remote and from 63 (13%) to 98 (20%) for standard arms respectively, both p < 0.05). At multivariate analysis, RM was not associated with an effective dose of beta-blockers at the follow-up evaluation. However, the adoption of RM (p = 0.003) and the achievement of the effective dose of beta-blockers (p = 0.006) were independently and positively associated with an improved outcome. DISCUSSION: In a 'real-world' setting, we did not find an association between RM and the achieved dose of beta-blockers. However, we reported outcome benefits in achieving the effective dose of beta-blockers during follow-up and in adopting RM.

Remote monitoring improves outcome after ICD implantation: the clinical efficacy in the management of heart failure (EFFECT) study.

AIMS: Internet-based remote interrogation systems have been shown to reduce emergency department and in-office visits in patients with implantable cardioverter defibrillators (ICDs), resulting in increased efficiency for healthcare providers. Nonetheless, studies sized to demonstrate the impact of remote monitoring on patients' outcome have been lacking. METHODS AND RESULTS: The EFFECT study was a multicentre clinical trial aimed at measuring and comparing the outcome of ICD patients conventionally followed-up by means of in-clinic visits (Standard arm) or by remote monitoring (Remote arm) in the clinical practice of 25 Italian centres. From 2011 to 2013, 987 consecutive patients were enrolled and followed up for at least 12 months. The primary endpoint was the rate of death and cardiovascular hospitalizations. Remote monitoring was adopted by 499 patients. Patients in the Standard and Remote arms did not differ significantly in terms of baseline clinical characteristics, except for a more frequent use of ICD with cardiac resynchronization therapy (CRT-D) in the Remote arm (48 vs. 36%, P < 0.001). One-year rates of the primary combined endpoint were 0.27 events/year for patients in the Standard arm and were 0.15 events/year for those in the Remote arm (incident rate ratio, 0.55; 95% CI, 0.41-0.73; P < 0.001). The endpoint rates in the Standard and Remote arms were 0.27 and 0.08 events/year, respectively, among CRT-D recipients (P < 0.001), and 0.28 vs. 0.21 among ICD patients (P = 0.094). The rates of in-office visits were 1.9 per year in the Standard arm and 1.7 per year in the Remote arm. CONCLUSION: Compared with the standard follow-up through in-office visits, remote monitoring is associated with reduced death and cardiovascular hospitalizations in patients with ICD in clinical practice. CLINICAL TRIAL REGISTRATION: URL: http://clinicaltrials.gov/ Identifier: NCT01723865.

Ventricular couplets but not isolated extrasystoles induce a "female" sustained, supraventricular tachycardia. What is the mechanism?

This is the case of a 28-year-old woman with sustained supraventricular tachycardia induced only by monomorphic ventricular couplets but not by isolated extrasystoles. The careful examination of electrocardiogram (ECG) was able to identify the mechanism of the tachycardia in the absence of electrophysiologic investigation. The tachycardia resulted sustained and symptomatic only during periods.

Networking and data sharing reduces hospitalization cost of heart failure: the experience of GISC study.

RATIONALE, AIMS AND OBJECTIVES: Heart failure (HF) is a concerning public health burden in Western society because, despite the improvement of medical treatments, it is still associated with adverse outcomes (high morbidity and mortality), resulting in one of the most expensive chronic disease in Western countries. Hospital admission particularly is the most expensive cost driver among the several resources involved in the management of HF. The aim of our study was to investigate the cost of hospitalization before and after the enrolment to a new strategy (GISC) in the management of patients with HF. METHODS: We enrolled a cohort of 90 patients. Patients were eligible to the study if they were hospitalized with a new diagnosis of HF or a diagnosis of decompensated HF. The enrolment to the study corresponded to the enrolment to the GISC intervention. We calculated the cost for every hospital admission at 6 and 12 months before and after the enrolment using the tariff paid for the diagnosis-related group. RESULTS: Comparing per-patient cumulative cost before and after the enrolment, we showed that patient's hospitalization was less expensive after the enrolment to the GISC intervention. The strategy resulted in an average cumulative estimated saving of €439322.00 (95% CI €413890.70; €464753.40) at 6 months and of €832276.80 (95% CI €786863.70; €877690.00) at 12 months after the enrolment. CONCLUSIONS: We found out that the intervention was a cost-saving strategy for follow-up of the patients suffering from HF at 6 and 12 months after the enrolment compared with hospitalizations' cost before the recruitment.

Morphology of right atrial appendage for permanent atrial pacing and risk of iatrogenic perforation of the aorta by active fixation lead.

BACKGROUND: Permanent atrial pacing usually involves lead placement in the right atrial appendage (RAA). Anatomical studies addressing features predisposing to complications are scanty. OBJECTIVE: To assess the morphology of RAA in the perspective of pacing, including the morphology of tenia sagittalis (TS) and the spatial relationship with the aorta. METHODS: The gross anatomy of the RAA has been analyzed in a consecutive series of 100 hearts following a case of iatrogenic perforation of the aorta by active fixation lead located in the RAA. Transmural RAA sections were taken from 40 hearts to assess the wall thickness at the level of pectinate muscles (PMs) and of inter-PMs spaces and the distance between adjacent PMs. RESULTS: The TS was present in 90% of cases (single trunk, 76%; double trunk, 13%; and triple trunk, 1%), demarcating the proximal antral RAA region (facing the adjacent aorta) from the distal saccular RAA region (facing the pulmonary infundibulum). The RAA free wall in the inter-PMs spaces is usually paper-thin and translucent. Histomorphometric analysis reveals that the RAA wall mean thickness was 1.38 ± 0.05 mm (range 0.64-4.25 mm) at the level of PMs and 0.39 ± 0.23 mm (range 0.09-1.05 mm) at the level of inter-PMs spaces. The mean distance between adjacent PMs was 0.88 ± 0.99 mm (range 0.04-4.12 mm). CONCLUSION: In 90% of hearts, a well-defined TS separates the distal saccular from the proximal antral RAA, the latter being closely adjacent to the ascending aorta. The paper-thin wall between PMs is potentially at risk of perforation, and aortic injury could occur when active fixation leads are anchored in the antral RAA, as demonstrated in an iatrogenic fatal case.

Manpower and outpatient clinic workload for remote monitoring of patients with cardiac implantable electronic devices: data from the HomeGuide Registry.

BACKGROUND: This study aimed to assess manpower and resource consumption of the HomeGuide workflow model for remote monitoring (Biotronik Home Monitoring [HM], Biotronik SE & Co. KG, Berlin, Germany) of cardiac implantable electronic devices in daily clinical practice. METHODS: The model established a cooperative interaction between a reference nurse (RN) for ordinary management, and a responsible physician (RP) for medical decisions in each outpatient clinic. RN reviewed remote transmissions and alerts, addressing critical cases to the RP. RESULTS: A total of 1,650 patients were enrolled in 75 sites: 25% pacemakers (PM), 22% dual-, 27% single-chamber implantable defibrillators (ICD), 2% PM with cardiac resynchronization therapy (CRT), and 24% ICD-CRT. During a median follow-up of 18 (10-31) months, 3,364 HM sessions were performed (74% by the RN, 26% by the RP) to complete 18,478 remote follow-ups. Median duration of remote follow-ups was 1.2 (0.6-2.0) minutes, corresponding to a manpower of 43.3 (4.2-94.8) minutes/month every 100 patients for nurses and 10.2 (0.1-31.1) for physicians (P < 0.0001). RN submitted 15% of remote transmissions to RP, who decided unscheduled follow-ups in 12% of the cases. The median manpower for phone calls was 1.9 (0.8-16.5) minutes/month every 100 contacted patients. There were 2.84 in-hospital visits/patient, 0.46 of which triggered by HM findings. A cumulative per-patient HM follow-up time of 15.4 minutes (20% of total follow-up time) allowed remote detection of 73% of actionable events. CONCLUSIONS: HM implemented in the HomeGuide workflow model required <1 hour/month every 100 patients to detect the majority of actionable events with limited administrative workload.

Prognostic value of endocardial voltage mapping in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia.

BACKGROUND: Endocardial voltage mapping (EVM) identifies low-voltage right ventricular (RV) areas, which may represent the electroanatomic scar substrate of life-threatening tachyarrhythmias. We prospectively assessed the prognostic value of EVM in a consecutive series of patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). METHODS AND RESULTS: We studied 69 consecutive ARVC/D patients (47 males; median age 35 years [28-45]) who underwent electrophysiological study and both bipolar and unipolar EVM. The extent of confluent bipolar (<1.5 mV) and unipolar (<6.0 mV) low-voltage electrograms was estimated using the CARTO-incorporated area calculation software. Fifty-three patients (77%) showed ≥1 RV electroanatomic scars with an estimated burden of bipolar versus unipolar low-voltage areas of 24.8% (7.2-31.5) and 64.8% (39.8-95.3), respectively (P=0.009). In the remaining patients with normal bipolar EVM (n=16; 23%), the use of unipolar EVM unmasked ≥1 region of low-voltage electrogram affecting 26.2% (11.6-38.2) of RV wall. During a median follow-up of 41 (28-56) months, 19 (27.5%) patients experienced arrhythmic events, such as sudden death (n=1), appropriate implantable cardioverter defibrillator interventions (n=7), or sustained ventricular tachycardia (n=11). Univariate predictors of arrhythmic outcome included previous cardiac arrest or syncope (hazard ratio=3.4; 95% confidence interval, 1.4-8.8; P=0.03) and extent of bipolar low-voltage areas (hazard ratio=1.7 per 5%; 95% confidence interval, 1.5-2; P<0.001), whereas the only independent predictor was the bipolar low-voltage electrogram burden (hazard ratio=1.6 per 5%; 95% confidence interval, 1.2-1.9; P<0.001). Patients with normal bipolar EVM had an uneventful clinical course. CONCLUSIONS: The extent of bipolar RV endocardial low-voltage area was a powerful predictor of arrhythmic outcome in ARVC/D, independently of history and RV dilatation/dysfunction. A normal bipolar EVM characterized a low-risk subgroup of ARVC/D patients.

Effectiveness of remote monitoring of CIEDs in detection and treatment of clinical and device-related cardiovascular events in daily practice: the HomeGuide Registry.

AIMS: The HomeGuide Registry was a prospective study (NCT01459874), implementing a model for remote monitoring of cardiac implantable electronic devices (CIEDs) in daily clinical practice, to estimate effectiveness in major cardiovascular event detection and management. METHODS AND RESULTS: The workflow for remote monitoring [Biotronik Home Monitoring (HM)] was based on primary nursing: each patient was assigned to an expert nurse for management and to a responsible physician for medical decisions. In-person visits were scheduled once a year. Seventy-five Italian sites enrolled 1650 patients [27% pacemakers, 27% single-chamber implantable cardioverter defibrillators (ICDs), 22% dual-chamber ICDs, 24% ICDs with cardiac resynchronization therapy]. Population resembled the expected characteristics of CIED patients. During a 20 ± 13 month follow-up, 2471 independently adjudicated events were collected in 838 patients (51%): 2033 (82%) were detected during HM sessions; 438 (18%) during in-person visits. Sixty were classified as false-positive, with generalized estimating equation-adjusted sensitivity and positive predictive value of 84.3% [confidence interval (CI), 82.5-86.0%] and 97.4% (CI, 96.5-98.2%), respectively. Overall, 95% of asymptomatic and 73% of actionable events were detected during HM sessions. Median reaction time was 3 days [interquartile range (IQR), 1-14 days]. Generalized estimating equation-adjusted incremental utility, calculated according to four properties of major clinical interest, was in favour of the HM sessions: +0.56 (CI, 0.53-0.58%), P < 0.0001. Resource consumption: 3364 HM sessions performed (76% by nurses), median committed monthly manpower of 55.5 (IQR, 22.0-107.0) min × health personnel/100 patients. CONCLUSION: Home Monitoring was highly effective in detecting and managing clinical events in CIED patients in daily practice with remarkably low manpower and resource consumption.

Remote follow-up of pacemakers in a selected population of debilitated elderly patients.

AIMS: The majority of patients with pacemakers are very elderly, many being >85-years old. They often suffer from serious illnesses and have great difficulty in walking. The aim of our study was to compare remote pacemaker monitoring with in-home checks of pacemakers, in terms of applicability, efficacy, and cost in a selected population of debilitated elderly patients. METHODS AND RESULTS: We selected 72 subjects (mean age 87 ± 8 years) among elderly debilitated patients with Medtronic pacemakers, compatible with the Carelink(®) remote monitoring system (13 patients with DDD pacemaker; 59 patients with single-lead VDD pacemaker). Remote follow-up was compared with in-home checks performed by nurses in 326 patients in similar clinical conditions. A total of 190 transmissions were received by remote monitoring (mean transmissions per month: 7.0; mean per patient: 2.6; range 1-6) during 27 months of follow-up. In this period, seven pacemakers were replaced owing to battery exhaustion, after a mean of 6.7 years from implantation. The occurrence of atrial or ventricular high-rate episodes was reported in 98 transmissions (53%). Nineteen patients died (annual mortality: 11.7%). On comparing the costs borne by the hospital for in-home checks, both for medical personnel and transportation, the estimated average saving was €32 per year per patient. CONCLUSION: Our study shows that the remote follow-up of pacemakers is a reliable, effective, and cost-saving procedure in elderly, debilitated patients. Moreover, remote controls provided an accurate and early diagnosis of arrhythmia occurrence.

Clinical evaluation of defibrillation testing in an unselected population of 2,120 consecutive patients undergoing first implantable cardioverter-defibrillator implant.

OBJECTIVES: The purpose of this study is to assess the effectiveness of defibrillation testing (DT) in patients undergoing implantable cardioverter-defibrillator (ICD) insertion. BACKGROUND: Although DT is considered a standard procedure during ICD implantation, its usefulness has not been definitively proven. METHODS: The SAFE-ICD (Safety of Two Strategies of ICD Management at Implantation) study is a prospective observational study designed to evaluate the outcome of 2 strategies: performing defibrillation testing (DT+) versus not performing defibrillation testing (DT-) during de novo ICD implants. No deviation from the centers' current practice was introduced. In all, 2,120 consecutive patients (836 DT+ and 1,284 DT-) age ≥18 years were enrolled at 41 Italian centers from April 2008 to May 2009 and followed up for 24 months until June 2011. The primary endpoint was a composite of severe complications at ICD implant and sudden cardiac death or resuscitation at 2 years. RESULTS: The primary endpoint occurred in 34 patients: 12 intraoperative complications (8 in DT+ group; 4 in DT- group) and 22 during follow-up (10 in DT+ group; 12 in DT- group). Overall, the estimated yearly incidence (95% confidence interval) was DT+ 1.15% (0.73 to 1.83) and DT- 0.68% (0.42 to 1.12). The difference between the 2 groups was negligible: 0.47% per year (-0.15 to 1.10). Mortality from any cause was similar at 2 years (adjusted hazard ratio: 0.97 [0.76 to 1.23], p = 0.80). CONCLUSIONS: In this large cohort of new ICD implants, event rates were similar and extremely low in both groups. These data indicate a limited clinical relevance for DT testing, thus supporting a strategy of omitting DT during an ICD implant. (Safety of Two Strategies of ICD Management at Implantation [SAFE-ICD]; NCT00661037).

Role of an aggressive rhythm control strategy on sinus rhythm maintenance following intra-operative radiofrequency ablation of atrial fibrillation in patients undergoing surgical correction of valvular disease.

OBJECTIVE: The purpose of this study was to evaluate the impact of adhering to a strict follow up regimen on mid-term efficacy of intraoperative radiofrequency ablation in maintaining sinus rhythm for patients with atrial fibrillation undergoing cardiac surgery. METHODS: We enrolled 52 patients with atrial fibrillation and valve disease divided in 2 groups: group 1 (26 patients) underwent intraoperative radiofrequency ablation and was followed by a team of skilled cardiologists who treated recurrences with amiodarone and electrical cardioversion; group 2 (26 patients) was treated with intraoperative radiofrequency ablation but patients were thereafter treated by their local hospital or personal cardiologist. RESULTS: There were no intraoperative deaths or complications related to radiofrequency ablation. Twenty four months after the operation, freedom from atrial fibrillation was 60% in group 1 and 32% in group 2 (p=0.02). Group 1 also showed a reduction in atrial volume (p≤0.05). CONCLUSION: Postoperative follow up with electrical and pharmacologic cardioversion combined with radiofrequency ablation achieves higher rate of sinus rhythm maintenance. After ablation, electrical cardioversion is effective even in patients with enlarged left atrium, long history of atrial fibrillation, or previous failed electrical cardioversion.

Should all individuals with a nondiagnostic Brugada-electrocardiogram undergo sodium-channel blocker test?

BACKGROUND: The diagnostic Brugada-electrocardiogram (Br-ECG) is characterized by "coved-type" ST-segment elevation (type 1) in V(1) to V(2)/V(3). The sodium-channel blocker test is clinically used to unmask diagnostic Br-ECG in patients with nondiagnostic "saddle-back" Br-ECG (type 2 and type 3). OBJECTIVE: To assess the prognostic value of the sodium-channel blockers test in individuals with a nondiagnostic Br-ECG. METHODS: We studied 153 consecutive patients (128 men; age 41.7 ± 14.0 years) with a type 2/3 Br-ECG who underwent a sodium-channel blocker test with either flecainide (48%) or ajmaline (52%). Nondiagnostic Br-ECGs were identified during the evaluation of cardiac arrest in 5 patients (3%), syncope in 36 (24%), cascade family screening in 48 (31%), and incidental ECG in 64 (42%). A spontaneous type 1 Br-ECG was systematically excluded by serial ECGs (6.1 ± 0.4) and recording of right precordial leads both at standard and second and third intercostal spaces. RESULTS: The sodium-channel blocker test result was positive in 76 (50%) patients. During a follow-up of 59 ± 33 months, 9 (5.9%) patients experienced events such as syncope (n = 4), appropriate interventions of defibrillator (n = 4), or sudden death (n = 1). A positive sodium-channel blocker test was associated with a significantly higher event rate in symptomatic patients (P = .01) but not in asymptomatic individuals (P = .18). No events occurred among asymptomatic individuals with an incidental nondiagnostic Br-ECG. CONCLUSIONS: In asymptomatic individuals with a nondiagnostic Br-ECG, the incidence of events is low regardless of the sodium-channel blocker test result while in symptomatic patients a positive sodium-channel blocker test result is associated with an adverse arrhythmic outcome and may contribute to risk stratification.

Syncope while driving: pathophysiological features and long-term follow-up.

BACKGROUND: Approximately 3% to 10% of patients with syncope experience episodes while driving. The aim of our study was to identify their clinical and pathophysiological features, estimate the incidence of recurrence, and correlate these characteristics with recurrence. METHOD: We prospectively studied 40 patients who experienced syncope while driving and 50 subjects who experienced syncope in other situations. All cases underwent upright tilt test (UTT), with simultaneous ECG and beat-to-beat blood pressure recordings, to analyze heart rate variability, total peripheral resistance (TPR), and stroke volume (SV). RESULTS: Patients who experienced syncope while driving suffered more frequently from hypertension (40% vs 20%) and vasodepressive reactions during the UTT (52% vs 26%). Moreover, these patients had increased heart rates (p=0.007) and lower SVs (p=0.006) during a positive UTT. TPR rose immediately before symptoms appeared only in patients who suffered from nondriving syncope (p=0.006). During a mean follow-up of 1793±573 days, 8 syncopic patients while driving had recurrences (20%) but never while driving. They were older, experienced more episodes of syncope, and had a higher incidence of vasodepressive reactions during UTT. CONCLUSIONS: Our study confirms a good prognosis for patients who experience syncope while driving, and indicates that more accurate risk stratification is needed in subjects aged over 50 years, who have had more than 4 episodes of loss of consciousness and vasodepressive reactions during UTT.