Prognostic significance of a low T/R ratio in Brugada syndrome.

OBJECTIVES: To determine the prognostic value of a low T/R ratio, defined as the amplitude ratio between the T waves and the R waves, in patients (pts) with a spontaneous type-1 Brugada pattern (SBT1). BACKGROUND: Abnormalities of myocardial repolarization may play a key role in the initiation of ventricular fibrillation (VF) in Brugada syndrome (BrS). Recent studies have shown that the height of the T waves and the T/R ratio are inversely proportional to sudden cardiac arrest (SCA) risk in early repolarization syndrome and hypertrophic cardiomyopathy. METHODS: In an international retrospective study, we reviewed 115 pts. (105 males, 91.3%). 45 had VF and/or SCA (38.7 ±â€¯11.5 years old, all males), while 70 (49.3 ±â€¯12.0 years, 10 women) remained free of ventricular arrhythmia. 6 ECG markers plus the T/R ratio in leads V5 & II were studied. RESULTS: The T/R ratio among leads II & V5 was significantly lower in the VF/SCA group (0.24 [0.14; 0.38]vs. 0.34 [0.24; 0.45]; p = 0.006). 44.4% of pts. in the VF/SCA group had a lowest T/R ratio among leads II & V5 ≤ 0.17 compared to 11.4% in the non-VF/SCA group (p < 0.001). In multivariate analysis, a lowest T/R ratio among leads II & V5 ≤ 0.17 was independently associated with VF/SCA (OR 6.10, 95% CI 1.92-19.40; p = 0.002). Type 1 Brugada pattern in the peripheral leads (OR 10.78) and early repolarization (OR 3.60) were other independent markers of VF/SCA. CONCLUSION: A low T/R ratio among leads II & V5 is an independent marker for VF/SCA risk in patients with type-1 Brugada pattern.

Prediction of ventricular arrhythmias in patients with a spontaneous Brugada type 1 pattern: the key is in the electrocardiogram.

AIMS: There is currently no reliable tool to quantify the risks of ventricular fibrillation or sudden cardiac arrest (VF/SCA) in patients with spontaneous Brugada type 1 pattern (BrT1). Previous studies showed that electrocardiographic (ECG) markers of depolarization or repolarization disorders might indicate elevated risk. We aimed to design a VF/SCA risk prediction model based on ECG analyses for adult patients with spontaneous BrT1. METHODS AND RESULTS: This retrospective multicentre international study analysed ECG data from 115 patients (mean age 45.1 ± 12.8 years, 105 males) with spontaneous BrT1. Of these, 45 patients had experienced VF/SCA and 70 patients did not experience VF/SCA. Among 10 ECG markers, a univariate analysis showed significant associations between VF/SCA and maximum corrected Tpeak-Tend intervals ≥100 ms in precordial leads (LMaxTpec) (P < 0.001), BrT1 in a peripheral lead (pT1) (P = 0.004), early repolarization in inferolateral leads (ER) (P < 0.001), and QRS duration ≥120 ms in lead V2 (P = 0.002). The Cox multivariate analysis revealed four predictors of VF/SCA: the LMaxTpec [hazard ratio (HR) 8.3, 95% confidence interval (CI) 2.4-28.5; P < 0.001], LMaxTpec + ER (HR 14.9, 95% CI 4.2-53.1; P < 0.001), LMaxTpec + pT1 (HR 17.2, 95% CI 4.1-72; P < 0.001), and LMaxTpec + pT1 + ER (HR 23.5, 95% CI 6-93; P < 0.001). Our multidimensional penalized spline model predicted the 1-year risk of VF/SCA, based on age and these markers. CONCLUSION: LMaxTpec and its association with pT1 and/or ER indicated elevated VF/SCA risk in adult patients with spontaneous BrT1. We successfully developed a simple risk prediction model based on age and these ECG markers.

A report on the impact of remote monitoring in patients with S-ICD: Insights from a prospective registry.

INTRODUCTION: Several clinical studies have demonstrated that remote monitoring (RM) offers potential benefits in transvenous implantable cardioverter defibrillator (ICD). The potential interest of RM in subcutaneous-ICD (S-ICD) recipients has never been evaluated. The aim of this study was to evaluate the alert burden and its clinical relevance in a prospective cohort of S-ICD recipients. METHODS: We prospectively and consecutively enrolled all patients undergoing S-ICD implantation at Lille University Hospital from September 2015 to January 2017 and gave them a LATITUDE™ NXT RM system. The relevance of transmissions was assessed by the following ratio: number of transmissions leading to reaction or intervention per patient/number of transmissions per patient. RESULTS: From September 2015 to January 2017, 69 patients were enrolled with a mean follow-up of 415 ± 96.3 days. The mean age was 44.6 ± 15.6 years old, and 25% (n = 17) had ischemic cardiomyopathy. At the end of follow-up, 12% of the patients had events recorded by RM. These events were related to nine ICD shocks and eight untreated events. A total of 1,423 transmissions were collected. Most of these transmissions were patient-initiated without any event (77%, n = 1,096) or scheduled without any event (19%, n = 272). Only 3.2% ± 1.1 of the transmissions per patient led to reactions or interventions. CONCLUSION: On the basis of the current method of transmitting, S-ICD RM allowed detection of relevant events in 12% of patients but generated a high unactionable transmission burden. As a result of these findings, efforts should be made to optimize transmissions considering automatic transmissions and to focus on patient education.

Impact of remote monitoring on reducing the burden of inappropriate shocks related to implantable cardioverter-defibrillator lead fractures: insights from a French single-centre registry.

AIMS: Lead fractures in implantable cardioverter-defibrillator (ICD) patients may cause inappropriate shocks (ISs). An early diagnosis is essential to prevent adverse clinical events. Implantable cardioverter-defibrillator remote monitoring (RM) permits prompt detection of lead fracture. Limited data define the impact of RM on ISs specifically related to lead fracture. We sought to compare the number of ISs related to lead fracture in patients with vs. without RM follow-up. METHODS AND RESULTS: We checked the registry of our institution and collected, between July 2007 and June 2014, 115 cases of right ventricular lead fractures. All relevant data were documented from patients' files, device-interrogation printouts and electronic records, and remote transmissions databases when applicable. We assessed the ISs that were related to lead fracture. The first study endpoint was the number of ISs per shocked patient. Among the 82 patients with conventional follow-up (CFU) and the 33 patients with RM, a first IS occurred to 32.9% (n = 27) and 30.3% (n = 10, P = 0.83) of the patients, respectively. Shocked patients in the RM group underwent significantly fewer ISs with a mean of 6 ± 2 shocks per patient [median of 3.5 shocks (2-8)] than those in the CFU group with a mean of 18 ± 5 shocks per patient [median of 10 shocks (5-22), P = 0.03]. CONCLUSION: Remote monitoring helps to reduce the burden of ISs related to ICD lead fractures.

Potential role of antitachycardia pacing alerts for the reduction of emergency presentations following shocks in patients with implantable cardioverter-defibrillators: implications for the implementation of remote monitoring.

AIMS: Despite increased use of remote monitoring (RM) to follow up implantable cardioverter-defibrillator (ICD) recipients, many patients still receive ICD shocks in the community and present to the emergency department. Our aim was to identify the best predictors of impending shock delivery that can be measured with an ICD and to identify the most appropriate activities to alert physicians to during RM follow-up. METHODS AND RESULTS: All patients presenting to our institution for ICD shock, from November 2011 to November 2014, were enrolled in this prospective study. Patient characteristics, investigation results, and details of electrical activities from ICD interrogation were recorded at presentation. Presentations were classified as potentially avoidable if activities from a list of set criteria were apparent more than 48 h before index shock. Univariate and multivariate analyses were then used to identify predictors of potentially avoidable shocks. In total, 109 emergency presentations were recorded in 90 patients (male: 85%; 57 ± 16 years; ischaemic cardiomyopathy: 49%; LVEF: 34 ± 13%; electrical storm: 40%), of which 26 (24%) were potentially avoidable. Antitachycardia pacing (ATP) episodes were the most important predictor of impending shock. Potentially avoidable shocks were preceded by more episodes of ATP than unavoidable shocks (13 [3-67] vs. 3 [0-10]; P < 0.001). Patients followed up with RM systems configured to generate alerts following ATP delivery experienced significantly less ICD shocks (24 vs. 16%, P < 0.01). CONCLUSION: Remote monitoring systems that generate alerts following ATP delivery could reduce emergency presentations for ICD shock by 24%, as ATP is a key predictor of impending shock delivery.

Cost comparison of two implantable cardiac monitors in two different settings: Reveal XT in a catheterization laboratory vs. Reveal LINQ in a procedure room.

AIMS: Implantable cardiac monitors (ICMs) are used for long-term heart rhythm monitoring, e.g. to diagnose unexplained syncope or for detection of suspected atrial and ventricular arrhythmias. The newest ICM, Reveal LINQ™ (Medtronic Inc.), is miniaturized and inserted with a specific insertion tool kit. The procedure is therefore minimally invasive and can be moved from catheterization laboratory (cath lab) to a less resource intensive setting. This study aims to assess the change in procedure costs when performed outside the cath lab. METHODS AND RESULTS: A bottom-up costing methodology was used. Data were collected from interviews with physicians, cath lab managers, and financial controllers. Hospitals in the Netherlands, France, and the UK were included in this study. The cost comparison of a Reveal XT implantation in a cath lab setting vs. a Reveal LINQ insertion outside a cath lab resulted in an estimated reduction of €662 for the UK, €682 for the Netherlands, and €781 for France. These cost savings were primarily realized through fewer staff, less equipment, and overhead costs. The net effect on savings depends on the price differential between these two technologies. The patient care pathway can be improved due to the possibility to move the procedure out of the cath lab. CONCLUSION: Inserting the miniaturized version of the ICM is simpler and faster, and the procedure can take place outside the cath lab in a less resource intensive environment. Hospitals save resources when the higher price of the Reveal LINQ does not outweigh these savings.

Decreased delivery of inappropriate shocks achieved by remote monitoring of ICD: a substudy of the ECOST trial.

INTRODUCTION: Inappropriate shocks remain a highly challenging complication of implantable cardioverter defibrillators (ICD). We examined whether automatic wireless remote monitoring (RM) of ICD, by providing early notifications of triggering events, lowers the incidence of inappropriate shocks. METHODS AND RESULTS: We studied 433 patients randomly assigned to RM (n = 221; active group) versus ambulatory follow-up (n = 212; control group). Patients in the active group were seen in the ambulatory department once a year, unless RM reported an event requiring an earlier ambulatory visit. Patients in the control group were seen in the ambulatory department every 6 months. The occurrence of first and further inappropriate shocks, and their causes in each group were compared. The characteristics of the study groups, including pharmaceutical regimens, were similar. Over a follow-up of 27 months, 5.0% of patients in the active group received ≥1 inappropriate shocks versus 10.4% in the control group (P = 0.03). A total of 28 inappropriate shocks were delivered in the active versus 283 in the control group. Shocks were triggered by supraventricular tachyarrhythmias (SVTA) in 48.5%, noise oversensing in 21.2%, T wave oversensing in 15.2%, and lead dysfunction in 15.2% of patients. The numbers of inappropriate shocks delivered per patient, triggered by SVTA and by lead dysfunction, were 74% and 98% lower, respectively, in the active than in the control group. CONCLUSION: RM was highly effective in the long-term prevention of inappropriate ICD shocks.

Costs of remote monitoring vs. ambulatory follow-ups of implanted cardioverter defibrillators in the randomized ECOST study.

AIMS: The Effectiveness and Cost of ICD follow-up Schedule with Telecardiology (ECOST) trial evaluated prospectively the economic impact of long-term remote monitoring (RM) of implantable cardioverter defibrillators (ICDs). METHODS AND RESULTS: The analysis included 310 patients randomly assigned to RM (active group) vs. ambulatory follow-ups (control group). Patients in the active group were seen once a year unless the system reported an event mandating an ambulatory visit, while patients in the control group were seen in the ambulatory department every 6 months. The costs of each follow-up strategy were compared, using the actual billing documents issued by the French health insurance system, including costs of (i) (a) ICD-related ambulatory visits and transportation, (b) other ambulatory visits, (c) cardiovascular treatments and procedures, and (ii) hospitalizations for the management of cardiovascular events. The ICD and RM system costs were calculated on the basis of the device remaining longevity at the end of the study. The characteristics of the study groups were similar. Over a follow-up of 27 months, the mean non-hospital costs per patient-year were €1695 ± 1131 in the active, vs. €1952 ± 1023 in the control group (P = 0.04), a €257 difference mainly due to device management. The hospitalization costs per patient-year were €2829 ± 6382 and €3549 ± 9714 in the active and control groups, respectively (P = 0.46). Adding the ICD to the non-hospital costs, the savings were €494 (P = 0.005) or, when the monitoring system was included, €315 (P = 0.05) per patient-year. CONCLUSION: From the French health insurance perspective, the remote management of ICD patients is cost saving. CLINICAL TRIALS REGISTRATION: NCT00989417, www.clinicaltrials.gov.

Pregnancy in women with an implantable cardioverter-defibrillator: is it safe?

AIMS: To describe obstetric/neonatal and cardiac outcomes for a cohort of women carrying implantable cardioverter-defibrillators (ICDs) during pregnancy. METHODS AND RESULTS: All women in routine follow-up at our institution for ICD implantation who became pregnant between 2006 and 2013 were included in this study. All ICDs were pre-pectoral devices with bipolar endocardial leads. Obstetric/neonatal and cardiac outcomes were assessed during pregnancy and post-partum. Twenty pregnancies were conceived by 12 women carrying ICD devices, 14 of which resulted in live births and none in maternal death. Seven of these women had structural cardiomyopathies and five had channelopathies. No device-related complications were recorded. Twelve shocks (nine transthoracic and three from ICDs) were experienced during pregnancy by two women, one of whom miscarried shortly afterwards at 4 weeks gestation. One stillbirth, three miscarriages and one termination were recorded for women with long QT syndrome, repaired tetralogy of Fallot and repaired Laubry-Pezzi syndrome, respectively. Intrauterine growth restriction, low birth weight, and neonatal hypoglycaemia were recorded in four, three, and five pregnancies, respectively. CONCLUSIONS: Pregnancy had no effect on ICD operation and no evidence was found to link ICD carriage with adverse pregnancy outcomes, although one miscarriage may have been induced by ICD shock therapy. A worsening of cardiac condition occurs in specific cardiac diseases and ß-blocker therapy should be continued for all women carrying ICDs in pregnancy as the benefits outweigh the risks of taking this medication.

A randomized study of remote follow-up of implantable cardioverter defibrillators: safety and efficacy report of the ECOST trial.

AIMS: The ECOST trial examined prospectively the long-term safety and effectiveness of home monitoring (HM) of implantable cardioverter defibrillators (ICD). METHODS AND RESULTS: The trial's primary objective was to randomly compare the proportions of patients experiencing ≥ 1 major adverse event (MAE), including deaths from all causes, and cardiovascular, procedure-related, and device-related MAE associated with HM (active group) vs. ambulatory follow-ups (control group) in a sample of 433 patients. The 221 patients assigned to the active group were seen once a year, unless HM reported an ICD dysfunction or a clinical event requiring an ambulatory visit, while the 212 patients in the control group underwent ambulatory visits every 6 months. The characteristics of the study groups were similar. Over a follow-up of 24.2 months, 38.5% of patients in the active and 41.5% in the control group experienced ≥ 1 MAE (P < 0.05 for non-inferiority). The overall number of shocks delivered was significantly lower in the active (n = 193) than in the control (n = 657) group (P < 0.05) and the proportion of patients who received inappropriate shocks was 52% lower in the active (n = 11) than in the control (n = 22) group (P < 0.05). At the end of the follow-up, the battery longevity was longer in the active group because of a lower number of capacitor charges (499 vs. 2081). CONCLUSION: Our observations indicate that long-term HM of ICD is at least as safe as standard ambulatory follow-ups with respect to a broad spectrum of MAE. It also lowered significantly the number of appropriate and inappropriate shocks delivered, and spared the device battery. Clinical trials registration NCT00989417.

Basal exit site of clinical ventricular tachycardia is an independent predictor of antitachycardia pacing failure in implantable cardioverter-defibrillators recipients.

BACKGROUND: Little is known about predictors of antitachycardia pacing (ATP) failure in implantable cardioverter defibrillator (ICD) recipients. Distance between the stimulation site and the ventricular tachycardia (VT) site of origin may critically affect ATP effectiveness. We hypothesized that ATP may be less effective in ICD patients who had basal VT than in those who had apical VT. METHODS: We reviewed data from 52 patients with sustained monomorphic VT and left ventricular disease referred for ICD implantation. ATP was delivered exclusively at the right ventricular apex. The clinical VTs site of origin (basal, midventricular, or apical) was determined in each patient, using 12-lead electrocardiogram. VTs episodes treated with ATP during the 1-year follow-up were studied. ATP success rate (%), defined as the ratio between the number of successful ATP sequences and the number of delivered ATP sequences, was determined in each patient. RESULTS: VT exit site was apical in 19 patients (36%), basal in 18 patients (35%), and midventricular in 15 patients (29%). In those 52 patients, 1,393 ATP sequences, delivered to treat 761 VT episodes, were analyzed. ATP success rate was found to be associated with the VT site of origin (median [interquartile range]): basal (33%[11-67]), midventricular (50%[37-100]), apical (100%[41-100]) (P = 0.027). Multivariate analysis identified basal VT site of origin as an independent predictor of ATP failure (P = 0.023). CONCLUSION: ATP is less effective in ICD patients who had basal VT than in those who had apical VT before ICD implantation.

Clopidogrel increases bleeding complications in patients undergoing heart rhythm device procedures.

BACKGROUND: Management of antiplatelet therapy at the time of device implantation remains controversial. This study aimed to assess the risk of bleeding complications in patients receiving clopidogrel at the time of cardiac device surgery. METHODS: We performed a retrospective case-control study. Between 2004 and 2010, 101 consecutive patients receiving clopidogrel underwent cardiac device surgery (pacemaker or implantable cardioverter-defibrillator implantation, and generator replacement) in our institution. Controls were 1:1 matched on age, sex, device, type of procedure, number of leads implanted, and venous approach (cephalic or subclavian). A significant bleeding complication was defined as pocket hematoma requiring surgical evacuation or prolonged hospitalization, hemothorax, pericardial effusion, or tamponade. RESULTS: Bleeding complications occurred more frequently in patients receiving clopidogrel at the time of device procedure: 11.9% versus 4.0% (P = 0.037; odds radio [OR] 3.27 [1.02-10.5]). Significant bleeding complications were noted in 12 patients (11.9%) receiving clopidogrel, including two patients with pericardial effusion and one patient with hemothorax. Four controls (4.0%) had bleeding complications (three pocket hematomas and one pericardial effusion). The single factor associated with increased bleeding complications in patients receiving clopidogrel was subclavian puncture (P = 0.008). In the entire cohort (n = 202), multivariate analysis identified two independent predictors of significant bleeding complications: clopidogrel treatment at the time of surgery (P = 0.03; OR 3.7 [1.1-12.6]) and subclavian venous puncture (P = 0.03; OR 3.44 [1.1-10.4]). CONCLUSIONS: Clopidogrel treatment at the time of heart rhythm device procedures is associated with an increased risk of significant bleeding complications. Subclavian puncture seems to strongly increase hemorrhagic complications in this setting.

Stereotactic Radioablation for Ventricular Tachycardia in the Setting of Electrical Storm.

BACKGROUND: Stereotactic body radiotherapy (SBRT) has been reported as a safe and efficient therapy for treating refractory ventricular tachycardia (VT) despite optimal medical treatment and catheter ablation. However, data on the use of SBRT in patients with electrical storm (ES) is lacking. The aim of this study was to assess the clinical outcomes associated with SBRT in the context of ES. METHODS: This retrospective study included patients who underwent SBRT in the context of ES from March 2020 to March 2021 in one tertiary center (CHU Lille). The target volume was delineated according to a predefined workflow. The efficacy was assessed with the following end points: sustained VT recurrence, VT reduced with antitachycardia pacing, and implantable cardioverter defibrillator shock. RESULTS: Seventeen patients underwent SBRT to treat refractory VT in the context of ES (mean 67±12.8 age, 59% presenting ischemic heart disease, mean left ventricular ejection fraction: 33.7± 9.7%). Five patients presented with ES related to incessant VT. Among these 5 patients, the time to effectiveness ranged from 1 to 7 weeks after SBRT. In the 12 remaining patients, VT recurrences occurred in 7 patients during the first 6 weeks following SBRT. After a median 12.5 (10.5-17.8) months follow-up, a significant reduction of the VT burden was observed beyond 6 weeks (-91% [95% CI, 78-103]), P<0.0001). The incidence of implantable cardioverter defibrillator shock and antitachycardia pacing was 36% at 1 year. CONCLUSIONS: SBRT is associated with a significant reduction of the VT burden in the event of an ES; however, prospective randomized control trials are needed. In patients without incessant VT, recurrences are observed in half of patients during the first 6 weeks. VT tolerance and implantable cardioverter defibrillator programming adjustments should be integrated as part of an action plan defined before SBRT for each patient.

Contributions of remote monitoring to the follow-up of implantable cardioverter-defibrillator leads under advisory.

AIMS: Automatic daily transmission of data from implantable cardioverter-defibrillators (ICDs) enables the remote monitoring of device status and leads function. We report on a 2-year experience with remote monitoring in 40 recipients of high-voltage ICD leads, prone to fracture and under advisory since October 2007. METHODS AND RESULTS: The ICDs were remotely monitored as well as systematically interrogated in the ambulatory department every 3 months. The patients were also seen in case of abnormal lead impedance, or other manifestations consistent with lead dysfunction. Over a mean follow-up of 22 ± 4 months after ICD implantation, four lead dysfunctions were suspected because of remotely transmitted oversensing of noise artifacts, abrupt rise in pacing impedance, or both. A lead fracture needing lead replacement was confirmed in three patients (7.5%), two of them before any inappropriate therapy and one after the delivery of three inappropriate shocks. No lead failure was observed in the remaining 36 patients, either at the time of ambulatory visits or during remote monitoring. CONCLUSION: Remote monitoring allowed the early and reliable detection of ICD leads failure without requiring any patient intervention.

Usefulness of remote monitoring for the early detection of back-up mode in implantable cardioverter defibrillators.

BACKGROUND: Reversion of an implantable cardioverter defibrillator (ICD) to back-up mode degrades the operating capabilities of the device, puts patients at risk and requires rapid intervention by a manufacturer's technician. AIM: To illustrate the usefulness of remote monitoring of ICDs for the early detection of reversion to back-up mode. METHODS: In our centre, all patients implanted with an ICD, with or without resynchronisation, were offered remote monitoring as soon as the technology became available. Alerts triggered by the remote monitoring system were included prospectively in a register. During a mean follow-up of 5.7±1.3 years, a total of 1594 patients with an ICD (441 with resynchronisation function) followed with remote monitoring were included in the register. RESULTS: Among 15,874 alerts, only 10 were related to a reversion to back-up mode. Among those, seven reversions were caused by radiotherapy, two were fake events and one was caused by magnetic resonance imaging. Except for the two fake events, the eight other patients had an emergency admission for the resetting and reprogramming of their ICD. None of the reversion to back-up mode alerts was followed by a clinical alert (i.e. a shock alert) before the ICD problem was resolved. CONCLUSIONS: Reversion to back-up mode is a very rare event, accounting for 0.06% of total alerts; remote monitoring facilitates the early detection of this critical event to resolve the problem faster than the next scheduled follow-up. Remote monitoring can prevent serious damage to the patient and avoids systematic ambulatory control of the ICD after each radiotherapy session.

Usefulness of head-up tilt test combined with video electroencephalogram to investigate recurrent unexplained atypical transient loss of consciousness.

BACKGROUND: Convulsive syncope and epileptic seizure share many similar clinical features. Early diagnosis is critical for choosing the appropriate management strategy. AIM: Our aim was to evaluate the diagnostic yield of an innovative diagnostic strategy - combined head-up tilt test (HUT)/video electroencephalogram (EEG) monitoring - in patients with unexplained seizure-like transient loss of consciousness (T-LOC). METHODS: Combined HUT/video EEG was performed in patients with unexplained atypical T-LOC with both syncope and seizure characteristics remaining undiagnosed after a first-line investigation. T-LOC diagnosis was achieved in case of reproduction of usual symptoms. Events were classified as vasovagal, psychogenic or epilepsy. The link between EEG abnormalities and T-LOC was determined by an epilepsy specialist. Clinical follow-up was performed to assess T-LOC recurrence. RESULTS: Hundred and one consecutive patients were prospectively enrolled (median age 26 [19; 46] years; 72% female) and underwent combined HUT/video EEG between 2007 and 2015. Antiepileptic drugs were being prescribed in 42% of patients. Combined HUT/video EEG was diagnostic in 67% of patients, leading to diagnosis of vasovagal syncope in 59 patients and psychogenic pseudosyncope in nine cases. Antiepileptic drugs were discontinued in 18 patients without epilepsy. Independent predictors of a definitive diagnosis were the presence of prodromal symptoms (odds ratio 5.97, 95% confidence interval 1.37-26; P=0.017) and a history of myoclonic jerks during T-LOC (odds ratio 4.36, 95% confidence interval 1.71-11.15; P=0.002). CONCLUSIONS: Combined HUT/video EEG is useful for investigating recurrent unexplained atypical seizure-like T-LOC, especially in patients with a history of myoclonic jerks or with documented interictal non-specific EEG abnormalities.

Incidence and clinical relevance of slow ventricular tachycardia in implantable cardioverter-defibrillator recipients: an international multicenter prospective study.

BACKGROUND: This study aims to assess the incidence and clinical relevance of slow ventricular tachycardia (VT) and the effectiveness and/or deleterious effects of antitachycardia pacing in slow VT in implantable cardioverter-defibrillator recipients. METHODS AND RESULTS: This multicenter prospective randomized study included 374 patients (326 men) without prior history of slow VT (<148 bpm) implanted with a dual-chamber implantable cardioverter-defibrillator. Patients had a 3-zone detection configuration: a slow VT zone (101 to 148 bpm), a conventional VT zone (>148 bpm), and a ventricular fibrillation zone. Patients were randomized to a treatment group (n=183) with therapy activated in the slow VT zone or a monitoring group (n=191) with no therapy in the slow VT zone. During follow-up (11 months), 449 slow VTs occurred in 114 patients (30.5% slow VT incidence); 181 VTs (54 patients) occurred in the monitoring group; 3 were readmitted to the hospital; and lightheadedness and palpitations occurred in 4 and 250 (60 patients) in the treatment group treated by antitachycardia pacing (89.8% success rate) and shock delivery (n=2). There were 10 crossovers from the monitoring to treatment group and 3 crossovers from the treatment to monitoring group (P=0.09). Quality of life scores were not different between groups. CONCLUSIONS: Slow VT incidence (<150 bpm) is high (30%) in implantable cardioverter-defibrillator recipients without prior history of slow VT, has limited clinical relevance, and is efficiently and safely terminated by antitachycardia pacing.

Long-term outcome of implantable cardioverter-defibrillator implantation in secondary prevention of sudden cardiac death.

BACKGROUND: Little is known about the long-term outcomes of patients who receive an implantable cardioverter-defibrillator (ICD) for purely secondary prevention indications. AIMS: To assess the rates and predictors of appropriate therapies over a very long-term follow-up period in this population. METHODS: Between June 2003 and August 2006, 239 consecutive patients with structural left ventricular disease and a secondary prophylaxis indication for ICD therapy (survivors of life-threatening ventricular tachyarrhythmias) were prospectively enrolled. An extended follow-up of these patients was carried out. The primary endpoint was the occurrence of appropriate device therapy. Secondary endpoints were all-cause death, electrical storm and inappropriate therapy. RESULTS: The study population consisted of 239 patients (90% men; mean age 64±12 years; 72% ischaemic cardiomyopathy; left ventricular ejection fraction 37±12%). During a median follow-up of 7.8 (3.5-9.3) years, appropriate device therapy occurred in 139 (58.2%) patients. Death occurred in 141 patients (59%), electrical storm in 73 (30.5%) and inappropriate therapy in 42 (17.6%). Multivariable analysis identified patients whose presenting arrhythmia was ventricular fibrillation as being less likely to require appropriate device therapy than those whose presenting arrhythmia was ventricular tachycardia (sub-hazard ratio 0.62, 95% confidence interval 0.40-0.97; P=0.04). Independent predictors of all-cause death were age at implantation (P<0.0001), wide QRS complexes (P=0.024), creatinine concentration (P=0.0002) and B-type natriuretic peptide at implantation (P=0.0001). CONCLUSION: Secondary prevention ICD recipients exhibit a high risk of appropriate device therapy and death over prolonged follow-up. Patients who presented initially with ventricular fibrillation were less likely to require the delivery of appropriate device therapy.

Isthmus characteristics of reentrant ventricular tachycardia after myocardial infarction.

BACKGROUND: The reentrant mechanism of postinfarct ventricular tachycardia (VT) has been documented by surgical mapping analysis, but little is known about postinfarct VT circuits and the characteristics of their related protected isthmus with the use of 3D catheter mapping systems. METHODS AND RESULTS: A 3D electroanatomic mapping was performed in 21 patients with well-tolerated, postinfarct, sustained VT. In total, 33 episodes of tachycardia (mean cycle length 432+/-74 ms) were induced and mapped. Complete maps demonstrated macroreentrant circuits with 1 loop (n=8) or 2 loops (n=25) rotating around a protected isthmus bounded by 2 approximately parallel conduction barriers that consisted of a line of double potentials, a scar area, or the mitral annulus. A total of 26 critical isthmi were identified for the 33 VTs mapped, with the same isthmus being shared by 2 to 4 different tachycardic morphologies in 5 patients. On average, isthmi were 31+/-7 mm long (ranging from 18 to 41 mm) and 16+/-8 mm wide (ranging from 6 to 36 mm) and harbored diastolic electrograms. The isthmus axis was oriented parallel to the mitral annulus plane in perimitral circuits and perpendicular to the mitral annulus plane in all other circuits. Linear radiofrequency ablation performed across the most accessible part of the isthmus prevented the recurrence of tachycardia in 19 patients (90%) with a follow-up at 16+/-8 months. CONCLUSIONS: Detailed 3D electroanatomic mapping is helpful in reconstructing postinfarct VT circuits and in defining the characteristics of their related protected isthmi. The wide range of isthmus width values supports the need of linear radiofrequency lesions to eliminate the reentrant substrate of postinfarct VTs.

Validation of an Organizational Management Model of Remote Implantable Cardioverter-Defibrillator Monitoring Alerts.

BACKGROUND: Implantable cardioverter-defibrillators (ICDs) are a standard means of sudden cardiac death prevention. Compared with ambulatory visits, remote monitoring (RM) of ICD recipients has improved the quality of health care and spared its resources. Few studies have addressed the organization of RM. We optimized and validated our institutional model of RM organization for ICD recipients. METHODS AND RESULTS: This observational study of 562 ICD recipients compared 2 RM periods consisting of iterative, qualitative, and quantitative (1) device diagnostic evaluations by nurses and cardiologists; and (2) selected decisional trees. The main study end points were the professional interventions prompted by, and times allocated to, RM alerts. During the first period, 1134 alerts occurred in 427 patients (286 patient-year), of which 376 (33%) were submitted to cardiologists' reviews, compared with, 1522 alerts in 562 patients (458 patient-year), of which 273 (18%) were submitted to cardiologists' reviews during the second period (P<0.001). An intervention was prompted by 73 of 376 (19.4%) alerts in the first versus 77 of 273 (28.2%) in the second period (P=0.009). The mean time to manage an alert was 4 minutes 31 s in the first versus 2 minutes 10 s in the second period (P<0.001). The annual numbers of alert-related hospitalizations were 10.8 versus 8.1 per 100-patient-year (P=0.230), and annual numbers of alert-related visits were 9.8 and 6.1 per 100-patient-year (P=0.081), respectively. CONCLUSIONS: An optimized RM organization based on automated alerts and decisional trees enabled a focus on clinically relevant events and a decrease in the consumption of resources without compromising the quality of ICD recipients' care.