Daily remote monitoring of implantable cardioverter-defibrillators: insights from the pooled patient-level data from three randomized controlled trials (IN-TIME, ECOST, TRUST)

Aims

Remote monitoring of implantable cardioverter-defibrillators may improve clinical outcome. A recent meta-analysis of three randomized controlled trials (TRUST, ECOST, IN-TIME) using a specific remote monitoring system with daily transmissions [Biotronik Home Monitoring (HM)] demonstrated improved survival. We performed a patient-level analysis to verify this result with appropriate time-to-event statistics and to investigate further clinical endpoints.

Methods and results

Individual data of the TRUST, ECOST, and IN-TIME patients were pooled to calculate absolute risks of endpoints at 1-year follow-up for HM vs. conventional follow-up. All-cause mortality analysis involved all three trials (2405 patients). Other endpoints involved two trials, ECOST and IN-TIME (1078 patients), in which an independent blinded endpoint committee adjudicated the underlying causes of hospitalizations and deaths. The absolute risk of death at 1 year was reduced by 1.9% in the HM group (95% CI: 0.1–3.8%; P = 0.037), equivalent to a risk ratio of 0.62. Also the combined endpoint of all-cause mortality or hospitalization for worsening heart failure (WHF) was significantly reduced (by 5.6%; P = 0.007; risk ratio 0.64). The composite endpoint of all-cause mortality or cardiovascular (CV) hospitalization tended to be reduced by a similar degree (4.1%; P = 0.13; risk ratio 0.85) but without statistical significance.

Conclusion

In a pooled analysis of the three trials, HM reduced all-cause mortality and the composite endpoint of all-cause mortality or WHF hospitalization. The similar magnitudes of absolute risk reductions for WHF and CV endpoints suggest that the benefit of HM is driven by the prevention of heart failure exacerbation.

High prevalence of arrhythmic and myocardial complications in patients with cardiac glycogenosis due to PRKAG2 mutations

AIMS

Mutations in PRKAG2, the gene encoding for the γ2 subunit of 5'-AMP-activated protein kinase (AMPK), are responsible for an autosomal dominant glycogenosis with a cardiac presentation, associating hypertrophic cardiomyopathy (HCM), ventricular pre-excitation (VPE), and progressive heart block. The aim of this study was to perform a retrospective time-to-event study of the clinical manifestations associated with PRKAG2 mutations.

METHODS AND RESULTS

A cohort of 34 patients from 9 families was recruited between 2001 and 2010. DNA were sequenced on all exons and flanking sequences of the PRKAG2 gene using Sanger sequencing. Overall, four families carried the recurrent p.Arg302Gln mutation, and the five others carried private mutations among which three had never been reported. In the total cohort, at 40 years of age, the risk of developing HCM was 61%, VPE 70%, conduction block 22%, and sudden cardiac death (SCD) 20%. The global survival at 60 years of age was 66%. Thirty-two per cent of patients (N = 10) required a device implantation (5 pacemakers and 5 defibrillators) at a median age of 66 years, and two patients required heart transplant. Only one patient presented with significant skeletal muscle symptoms. No significant differences regarding the occurrence of VPE, ablation complications, or death incidence were observed between different mutations.

CONCLUSION

This study of patients with PRKAG2 mutations provides a more comprehensive view of the natural history of this disease and demonstrates a high risk of cardiac complications. Early recognition of this disease appears important to allow an appropriate management.

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.

Remote monitoring of patients with implantable cardioverter-defibrillators: can results from large clinical trials be transposed to clinical practice?

BACKGROUND

Remote monitoring (RM) is increasingly used to follow up patients with implantable cardioverter-defibrillators (ICDs). Randomized control trials provide evidence for the benefit of this intervention, but data for RM in daily clinical practice with multiple-brands and unselected patients is lacking.

AIMS

To assess the effect of RM on patient management and clinical outcome for recipients of ICDs in daily practice.

METHODS

We reviewed ICD recipients followed up at our institution in 2009 with RM or with traditional hospital only (HO) follow-up. We looked at the effect of RM on the number of scheduled ambulatory follow-ups and urgent unscheduled consultations, the time between onset of asymptomatic events to clinical intervention and the clinical effectiveness of all consultations. We also evaluated the proportion of RM notifications representing clinically relevant situations.

RESULTS

We included 355 patients retrospectively (RM: n=144, HO: n=211, 76.9% male, 60.3±15.2 years old, 50.1% with ICDs for primary prevention and mean left ventricular ejection fraction 35.5±14.5%). Average follow-up was 13.5 months. The RM group required less scheduled ambulatory follow-up consultations (1.8 vs. 2.1/patient/year; P<0.0001) and a far lower median time between the onset of asymptomatic events and clinical intervention (7 vs. 76 days; P=0.016). Of the 784 scheduled ambulatory follow-up consultations carried out, only 152 (19.4%) resulted in therapeutic intervention or ICD reprogramming. We also found that the vast majority of RM notifications (61.9%) were of no clinical relevance.

CONCLUSION

RM allows early management of asymptomatic events and a reduction in scheduled ambulatory follow-up consultations in daily clinical practice, without compromising safety, endorsing RM as the new standard of care for ICD recipients.

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.

Improvement in acute contractility and hemodynamics with multipoint pacing via a left ventricular quadripolar pacing lead

INTRODUCTION

A quadripolar left ventricular (LV) pacing can deliver multipoint pacing (MPP). It is unknown if this confers improved cardiac function compared to conventional cardiac resynchronization therapy (CRT).

METHODS AND RESULTS

We aimed to characterize changes in acute cardiac contractility and hemodynamics with multisite left ventricular "multipoint" pacing (MPP) in a prospective multicenter study in patients implanted with a CRT-defibrillator incorporating a quadripolar LV lead. The device was programmed to deliver MPP acutely pacing with eight configurations of varying timing delays. Global peak LV radial strain and LV outflow velocity time integral (LVOT VTI) were measured for conventional CRT and each MPP configuration. Out of the eight tested MPP configurations, the one that yielded the best echocardiographic measurement for each patient was defined as "optimal MPP". Forty CRT recipients had complete radial strain datasets suitable for analysis. Compared to conventional CRT, the mean peak radial strain was significantly higher for the optimal MPP configuration (18.3 ± 7.4 vs. 9.3 ± 5.3%, p < 0.001), and at least one MPP configuration was significantly superior (>20%) in 63% of patients. LVOT VTI data were collected in a subset of 13 patients. In these patients, mean VTI was significantly higher for optimal MPP compared to conventional CRT (13.5 ± 2.7 vs. 10.9 ± 3.3 cm, p < 0.01).

CONCLUSION

MPP delivered via a quadripolar LV lead resulted in a significant improvement in acute cardiac contractility and hemodynamics compared to conventional CRT in the majority of patients studied.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov identifier NCT01044784.

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 β-blocker therapy should be continued for all women carrying ICDs in pregnancy as the benefits outweigh the risks of taking this medication.

Acute effects of multisite left ventricular pacing on mechanical dyssynchrony in patients receiving cardiac resynchronization therapy

BACKGROUND

A novel quadripolar left ventricular (LV) pacing lead has the ability to deliver multisite LV pacing (MSLV). We set out to characterize the safety and changes in acute mechanical dyssynchrony with MSLV in cardiac resynchronization therapy (CRT) patients.

METHODS AND RESULTS

Prospective multicenter study in 52 patients receiving CRT. An acute pacing protocol comprising 8 MSLV configurations covering a range of delays was compared with conventional CRT (baseline). Transthoracic tissue Doppler imaging (TDI) was used to measure the standard deviation of time to peak contraction of 12 LV segments (Ts-SD) and delayed longitudinal contraction. No ventricular arrhythmia occurred in any of the 52 patients. Complete TDI datasets were collected in 41 patients. Compared with baseline: 1) The mean Ts-SD was significantly lower for the optimal MSLV configuration (35.3 ± 36.4 vs 50.2 ± 29.1 ms; P < .001); 2) at least 1 MSLV configuration exhibited a significant dyssynchrony improvement in 63% of patients; and 3) the mean number of LV segments with delayed longitudinal contractions was significantly reduced with the optimal MSLV configuration (0.37 ± 7.99 vs 2.20 ± 0.19; P < .001).

CONCLUSIONS

Acute MSLV was acutely safe, and a proportion of MSLV vectors resulted in a significant reduction in echocardiographic dyssynchrony compared with conventional CRT.

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.

Two-dimensional speckle-tracking echocardiography for atrioventricular accessory pathways persistent ventricular pre-excitation despite successful radiofrequency ablation

AIMS

The present study was undertaken to investigate the concordance between longitudinal two-dimensional (2D)-speckle-tracking data and endocardial mapping for localizing atrioventricular accessory pathways (AP), and whether longitudinal 2D-speckle-tracking imaging accurately identifies the contractile abnormalities associated with AP and the effect of radiofrequency ablation.

METHODS AND RESULTS

Echocardiograms were repeated twice in 40 patients with Wolff-Parkinson-White (WPW) syndrome (before and early after ablation) and in 40 healthy controls to obtain longitudinal 2D strain and strain rate data. The site of ablation was considered as the gold standard for the AP localization. While control patients had a homogeneous strain pattern, all but two patients with WPW had an abnormal deformation pattern with three peaks in one or two basal contiguous segments: an early peak concomitantly with the delta wave followed by a systolic and a post-sytolic one. The rapid increase in LV longitudinal deformation within the basal pre-excited zone resulted in a pre-systolic peak strain rate at the beginning of the delta wave by SR imaging that was not found in controls. The early basal contraction spread towards the mid-ventricle before merging with the normal activated segments in 15 patients (39%). Contractile abnormalities were no more than one adjacent segment different compared with the AP ablation site in all these 38 patients. Regional strain was impaired in the pre-excited areas especially in AP localized in the interventricular septum. The abnormal deformation pattern persisted in 16 (42%) patients despite successful radiofrequency ablation. However, the difference in the regional strain between WPW patients and controls did not remain after ablation.

CONCLUSION

Longitudinal 2D-speckle-tracking data accurately match with endocardial mapping findings for localizing AP. Longitudinal 2D-speckle-tracking imaging accurately identifies AP-associated contractile abnormalities. Longitudinal 2D-speckle-tracking identifies persistence of local ventricular pre-excitation immediately after successful ablation.

[Current management of atrial fibrillation: rhythm or rate control and thoughts about a new treatment paradigm]

Over the past 30 years, treatment paradigms for atrial fibrillation (AF) patients have changed dramatically. Before 1989, and the publication of the CAST trial results, the primary objective was to maintain or restore sinus rhythm. In the following 20 years, the management of AF patients has focused on the prevention of thrombo-embolic events (with the confrontation of aspirin and oral anticoagulants), and on the debate between rhythm control and rate control. In 2010, the objectives are to reduce symptoms and improve quality of life, to prevent thrombo-embolic complications, and, if possible, to reduce mortality. New anticoagulants will soon be available. Ablative techniques are becoming current practice in selected patients, and the new antiarrhythmic agent dronedarone has shown remarkable clinical results in the ATHENA trial. Overall, ablative techniques can be used in younger patients with paroxysmal or persistent AF refractory to medical treatment a rate control strategy is appropriate in permanent AF, or as second line treatment in patients with other forms of AF.

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.

Impact of the control of symptomatic paroxysmal atrial fibrillation on health-related quality of life

Aims

Patients with atrial fibrillation (AF) consider the related symptoms disruptive to their quality of life (QoL). This study aimed to evaluate the impact of the control of symptomatic paroxysmal AF (PAF) on QoL.

Methods and results

Patients with symptomatic PAF were treated for 48 weeks with open-label flecainide acetate controlled release (Flec CR). Quality of life was assessed by SF-36 and Atrial Fibrillation Severity Scale scores at baseline, Week 12 (W12), W24, and W48. Of the 229 treated patients, 217 were analysed for QoL (123 with controlled and 94 with uncontrolled symptomatic PAF at inclusion). The controlled group had a similar or better QoL (SF-36) at baseline compared with a reference population (significantly better for: physical functioning, bodily pain, and physical component). The uncontrolled group had an inferior QoL (significantly worse for: role physical, general health, vitality, role emotional, social functioning, mental health, and mental component). When treated with Flec CR, the controlled group baseline QoL scores were maintained and the uncontrolled group scores were improved to a level comparable to the controlled group scores. Safety findings reflect the known clinical safety profile of flecainide acetate.

Conclusion

In this study, patients with uncontrolled symptomatic PAF at baseline had an inferior QoL to those with controlled symptomatic PAF. Following treatment with controlled-release flecainide acetate, their QoL improved to a level comparable to controlled patients.

[Atrial fibrillation: challenge of antithrombotic treatment]

Antithrombotic treatment is a crucial challenge in the management of patients with atrial fibrillation (AF). It is the only treatment which can decrease mortality in relation with AF. It can also prevent the first cause of dependency in elderly: stroke. Vitamin K antagonists are the more potent drugs to reduce the risk of ischemic stroke in patient with AF. Aspirin, unfractioned heparine or low molecular weight heparin and thienopyridine can also play a role in the antithrombotic therapy in special situations.

[Management of atrial fibrillation in France: the observational FACTUEL study]

OBJECTIVES

To describe the management of patients with atrial fibrillation (AF) and to study consistency with guidelines on management of AF.

PATIENTS AND METHODS

Observational study on a random sample of cardiologists from a French national database. Each cardiologist had to recruit the first five patients meeting inclusion criteria (patients diagnosed with AF between January 2004 and one month before inclusion and accepting the collection of their medical data).

RESULTS

Between December 2006 and January 2207, 1789 patients aged 71 on average have been recruited by 481 cardiologists. Fifty-one percent were diagnosed with paroxysmal, 15% with persistent and 33% with permanent AF. Restoration of sinus rhythm was preferred in forms considered as paroxysmal or persistent forms whereas control of the ventricular rate was more frequent in AF considered as permanent. Overall, therapeutic guidelines are applied in practice, despite a frequent use of amiodarone in patients with no associated heart disease. Prevention of thromboembolism was observed in 88% of the patients.

CONCLUSIONS

FACTUEL is the biggest observational study on AF ever conducted in France. The therapeutic strategies used by the cardiologists are consistent with the objectives of preventing thromboembolism and controlling heart rhythm and/or rate. In most cases, the treatment used is consistent with the therapeutic guidelines.

Recurrent unexplained syncope may have a cerebral origin: report of 10 cases of arrhythmogenic epilepsy

BACKGROUND

Despite thorough investigation, approximately 15-20% of syncope cases remain unexplained. An underrecognized cause of syncope may occur when partial epileptic discharges profoundly disrupt normal cardiac rhythm, including cardiac asystole, the so-called arrhythmogenic epilepsy (AE).

AIM

To report initial results of observations of AE in patients with recurrent, unexplained, traumatic and/or convulsive syncope.

METHODS

Ten patients aged 49+/-20 years (median 49.5 years; nine women) underwent complete cardiological (including ambulatory Holter electrocardiogram (ECG), echocardiography and head-up tilt test [plus electrophysiology in four patients]) and neurological (including standard electroencephalogram [EEG], computed tomography [CT] and magnetic resonance imaging scan [MRI]) assessments.

RESULTS

After initial evaluation, neurocardiogenic syncope was suspected in six patients with tilt-induced hypotension+/-bradycardia. Further evaluation (prolonged inpatient video-EEG/ECG monitoring) was undertaken because of non-diagnostic syncope or uncertainty about the diagnosis of neurocardiogenic syncope. While monitored in the neurophysiology lab, a syncopal episode similar to the spontaneous episodes recurred in all 10 patients. Cardiac asystole preceded by partial seizure of temporal onset was documented in nine patients; a second-degree atrioventricular (AV) block with a cardiac rhythm of 30 beats per minute preceded by partial seizure of temporal onset was noted in one patient. Eight patients were treated successfully with antiepileptic drugs; two were refractory to antiepileptic therapy and required pacemaker implantation. No patient had recurrent syncope during a median follow-up of 102.5 months (mean 82.2+/-42; range 16-128 months).

CONCLUSIONS

In patients with recurrent, unexplained, traumatic and/or convulsive syncope, AE should be considered as a possible aetiology.

Competing risk analysis of cause-specific mortality in patients with an implantable cardioverter-defibrillator: The EVADEF cohort study

BACKGROUND

Although implantable cardioverter-defibrillator (ICD) therapy has been evaluated in randomized controlled trials, enrolling highly selected patients, mortality events in ICD patients have received little attention in routine medical care. We sought to assess the 24-month total and cause-specific mortality rates and their predictors in "real life" patients with an ICD.

METHODS

The Evaluation Médico-Economique du Défibrillateur Automatique Implantable study was a French multicenter, prospective, observational cohort study of ICD patients with a 2-year follow-up. Cause-specific mortality rates and predictors at implantation of sudden cardiac death (SCD) or progressive heart failure (HF) death were assessed using competing risk methodology.

RESULTS

From June 2001 to June 2003, 2,296 unselected patients were implanted and followed until June 2005. During a mean follow-up of 20.5 +/- 6.7 months, 274 deaths occurred: 29 (10.6%) were SCD and 146 (53.3%) were HF deaths, corresponding to 24-month cause-specific mortality rates of 1.4% (95% confidence interval 0.9%-1.9%) and 6.9% (95% confidence interval 5.8%-8.0%), respectively. Among the characteristics at implantation, ejection fraction (EF) <30% and history of atrial fibrillation were independently associated with SCD; age, high New York Heart Association class, systemic hypertension, prior atrial fibrillation, QRS duration, EF <30%, and lack of beta-blocker therapy were independently associated with HF death.

CONCLUSIONS

In this large cohort of "daily" patients, the 2-year incidence of SCD (1.4%) was comparable with the event rate observed in randomized controlled trials; HF remained the predominant mode of death. An EF <30% at implantation appears to be the most important predictor of ICD-unresponsive SCD.

Risk Factors Related to Infections of Implanted Pacemakers and Cardioverter-Defibrillators

Background— The Prospective Evaluation of Pacemaker Lead Endocarditis study is a multicenter, prospective survey of the incidence and risk factors of infectious complications after implantation of pacemakers and cardioverter-defibrillators.

Methods and Results— Between January 1, 2000, and December 31, 2000, 6319 consecutive recipients of implantable systems were enrolled at 44 medical centers and followed up for 12 months. All infectious complications were recorded, and their occurrence was related to the baseline demographic, clinical, and procedural characteristics. Among 5866 pacing systems, 3789 included 2 and 117 had >2 leads; among 453 implantable cardioverter-defibrillators, 178 were dual-lead systems. A total of 4461 de novo implantations occurred and 1858 pulse generator or lead replacements. Reinterventions were performed before hospital discharge in 101 patients. Single- and multiple-variable logistic regression analyses were performed to identify risk factors; adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated. At 12 months, device-related infections were reported in 42 patients (0.68%; 95% CI, 0.47 to 0.89). The occurrence of infection was positively correlated with fever within 24 hours before the implantation procedure (aOR, 5.83; 95% CI, 2.00 to 16.98), use of temporary pacing before the implantation procedure (aOR, 2.46; 95% CI, 1.09 to 5.13), and early reinterventions (aOR, 15.04; 95% CI, 6.7 to 33.73). Implantation of a new system (aOR, 0.46; 95% CI, 0.24 to 0.87) and antibiotic prophylaxis (aOR, 0.4; 95% CI, 0.18 to 0.86) were negatively correlated with risk of infection.

Conclusions— This study identified several factors of risk of device infection and confirmed the efficacy of antibiotic prophylaxis in recipients of new or replacement pacemakers or implantable cardioverter-defibrillators.

Can we implant cardioverter defibrillator under minimal sedation?

Aim In a prospective study, we tested the feasibility of implantable cardioverter-defibrillator (ICD) implantation under local anaesthesia (LA) with minimal sedation (MS) vs. short general anaesthesia (SGA) for defibrillation test (DT).

METHODS AND RESULTS

We implanted ICDs in 118 patients between October 2002 and November 2003. Surgery was performed under LA with MS. Depending on the day of admission, patients had DT without SGA with a shock delivered when patient is unconscious (MS group, n = 73) or with short general anaesthesia (SGA group, n = 45). The patients were asked to rate the intensity of pain on a 10-point visual analogue scale (VAS) at the end of the implantation procedure and for the patient of MS group just after DT (VAS-DT). Visual analogue scale was not influenced by the type of anaesthesia (MS vs. SGA). Univariate analysis showed that NYHA >III, 3 leads implanted and an incomplete understanding of the explanation on the procedure were risk factors of VAS >4. Only understanding of the explanation on the procedure has an influence on pain in multivariate analysis.

CONCLUSION

ICD implantation under MS even for DT is feasible and acceptable for the patient.

Reducing Unnecessary Right Ventricular Pacing with the Managed Ventricular Pacing Mode in Patients with Sinus Node Disease and AV Block

BACKGROUND

Frequent and unnecessary right ventricular apical pacing increases the risk of atrial fibrillation or congestive heart failure. We evaluated a new pacing algorithm, managed ventricular pacing (MVP) which automatically changes modes between AAI/R and DDD/R in patients receiving pacemakers for symptomatic bradycardia.

METHODS

Patients were randomized to the MVP mode or DDD/R mode for 1 month and then crossed over to the alternate pacing modality for an additional month. On completion of the crossover phase, the pacing mode selected was individualized and patients were followed for an additional 4 months.

RESULTS

Of the 129 patients who successfully completed the crossover study, the cumulative percent ventricular pacing was significantly reduced in the MVP mode (median 1.4%) compared to the DDD/R mode (median 89.6%, 94.0% relative reduction; 95% CI 89.3-98.8%, P < 0.001). Patients with sinus node disease (SND, n = 51) when compared to patients with AV block (AVB) (n = 68) experienced a greater reduction in ventricular pacing with the MVP mode compared to the DDD/R mode (median relative reduction 99.1%; 95% CI 97.5-99.9% vs median relative reduction 60.1%; 95% CI 16.7-93.9% P < 0.001). The reduced percent ventricular pacing during MVP was sustained over longer term follow-up.

CONCLUSIONS

The majority of patients with a bradycardia indication for cardiac pacing do not require ventricular pacing most of the time. The MVP mode significantly reduces unnecessary right ventricular pacing. This mode benefits even patients with intermittent AVB and is sustained over longer term follow-up.

[Implantable cardioverter defibrillators in pediatric patients: results in a series of 33 cases]

Implantable defibrillator is the recognized treatment of sudden cardiac death. Miniaturization of the devices allows implantation in children.

METHODS

This multicentric retrospective study analyzed data of 33 children aged 18 years and less who were implanted from 1990 to 2005.

RESULTS

Age of patients are 10 to 18 years, 20 patients were implanted after a resuscitation of sudden death, 10 after a syncope, 2 after a ventricular tachycardia and 1 in a prophylactic way. Tachycardias on primary electrical disease are most frequent (46%). Hypertrophic cardiomyopathy accounts for 22%, DAVD for 14%, congenital cardiopathies for 12%. Seventeen patients received appropriate shocks and 14 patients had inappropriate shocks. There were two unexplained deaths. Five leads fractures and two device infections were noted.

CONCLUSION

Implantable defibrillator is an effective treatment for children high-risk of sudden death. Occurrence of inappropriate shocks due to sinusal tachycardia, infections and leads fractures are frequent.

Post-operative use of heparin increases morbidity of pacemaker implantation

AIMS

The objective of this study is to characterize the incidence of peri-operative severe adverse events (AEs) related to the post-operative use of heparin in patients undergoing pacemaker surgery.

METHODS AND RESULTS

We retrospectively compared the outcome of 38 patients with mechanical valves (MVs) and 76 patients with atrial fibrillation (AF) with control cases matched for gender, age, and surgical details. Heparin was systematically used post-operatively in MV patients, but left to clinical judgment in AF patients. The relative risk for severe haemorrhagic AEs was 11 (CI 1.5-81.1, P < 0.01) in the MV group when compared with matched controls and 8 (CI 1.0-62.5, P < 0.05) in the AF group. Overall, the relative risk of heparin use in the post-operative period was 14 (CI 1.88-104, P = 0.0006) and the post-operative stay was prolonged from 7 days in this group when compared with control cases (P < 0.0001).The variables associated with haemorrhage were the delay to restart heparin after surgery and the presence of an MV.

CONCLUSION

Post-operative use of heparin increases morbidity of pacemaker implantation. A different approach to management of these patients is possible.

[Clinical evolution of patients following investigation of atrial vulnerability after a first cerebral ischaemic accident]

Atrial vulnerability reflects the ability of the atrium to fibrillate. ISAV (Ischemic stroke and atrial vulnerability) is a French epidemiological registry whose main goal is to assess the evolution modalities of patients in whom an electrophysiological study of the atrium has been performed. A group of 269 patients with a history of non elucidated ischemic stroke and an electrophysiological study of the atrium performed in a mean delay of 3 months after the stroke has been included. Their mean age at the time of the stroke was 55 +/- 15.8 years. The electrophysiological study has measured the effective refractory period of the atrium, the locoregional right intra-atrial conduction time, the index of latent atrial vulnerability and assessed the inductibility. The mean delay between the date of the stroke and the date of the last news was 4.4 +/- 2.8 years. We observed 12 deaths and 11 patients presented during the follow up a spontaneous atrial arrhythmia and 17 a recurrence of stroke. If we consider the occurrence of the 28 combined events (atrial arrhythmia and/or stroke), it is not correlated with the presence of an atrial septal defect nor with the existence of an atrial vulnerability. On the contrary this occurrence is correlated with tobacco consumption and/or arterial hypertension; 82% of patients have these risk factors versus 54% of patients without events (p = 0.004). This association is not significant in patients younger than 55 years.

Clinical predictors and prognostic significance of electrical storm in patients with implantable cardioverter defibrillators

AIMS

Insufficient data exists regarding predictors of electrical storms (ES) and clinical outcome in patients treated with an implantable cardioverter defibrillator (ICD). The purpose of this study was to delineate a subgroup of patients likely to experience ES and to determine the impact of ES on mortality in ICD recipients.

METHODS AND RESULTS

Baseline characteristics of 307 ICD-treated patients were retrospectively analysed. ES was defined as two or more ventricular tachyarrhythmias within 24 h leading to an immediate electrical therapy (antitachycardia pacing and/or shock), separated by a period of sinus rhythm. Clinical characteristics and survival of 123 patients experiencing a total of 294 episodes of ES (median 2 ES/patient, range 1-9), were compared with those of 184 ES-free patients during a median follow-up of 826 days (inter-quartile 1141 days). Median actuarial duration for the first ES occurrence after ICD implant was 1417 days [95% confidence interval (CI) 1061-2363] with a median follow-up of 816 days (7-4642 days) in ES-free patients. Univariate analysis identified older age, depressed left ventricular ejection fraction (LVEF), ventricular tachycardia (VT) as index arrhythmia, chronic renal failure and absence of lipid-lowering drugs as variables significantly associated with an increased risk of ES. Multivariable Cox analysis confirmed an independent predictive value for chronic renal failure [hazard ratio (HR) 1.54, 95% CI 0.95-2.51, P=0.052], VT (HR 2.20, 95% CI 1.44-3.37, P=0.0003), and LVEF (HR 0.98, 95% CI 0.97-0.99, P=0.027). In contrast, diabetics (HR 0.49, 95% CI 0.27-0.90, P=0.022) were less affected by ES. There was no difference in survival between both groups.

CONCLUSION

ES is frequent but does not increase mortality in ICD's recipients. Patients with severe systolic dysfunction, chronic renal failure and VT as initial arrhythmia are likely to experience ES. Diabetics are less affected by ES.

Cardiac resynchronisation therapy reduces functional mitral regurgitation during dynamic exercise in patients with chronic heart failure: an acute echocardiographic study

OBJECTIVES

To assess non-invasively the acute effects of cardiac resynchronisation therapy (CRT) on functional mitral regurgitation (MR) at rest and during dynamic exercise.

METHODS

21 patients with left ventricular (LV) systolic dysfunction and functional MR at rest, treated with CRT, were studied. Each patient performed a symptom-limited maximal exercise with continuous two dimensional Doppler echocardiography twice. The first exercise was performed with CRT; the second exercise was performed without CRT. Mitral regurgitant flow volume (RV), effective regurgitant orifice area (ERO) and LV dP/dt were measured at rest and at peak exercise.

RESULTS

CRT mildly reduced resting mitral ERO (mean 8 (SEM 2) v 11 (2) mm(2) without CRT, p = 0.02) and RV (13 (3) v 18 (3) ml without CRT, p = 0.03). CRT attenuated the spontaneous increase in mitral ERO and RV during exercise (1 (1) v 9 (2) mm(2), p = 0.004 and 1 (1) v 8 (2) ml, p = 0.004, respectively). CRT also significantly increased exercise-induced changes in LV dP/dt (140 (46) v 479 (112) mm Hg/s, p < 0.001).

CONCLUSION

Attenuation of functional MR, induced by an increase in LV contractility during dynamic exercise, may contribute to the beneficial clinical outcome of CRT in patients with chronic heart failure and LV asynchrony.

Myocardial asynchronism is a determinant of changes in functional mitral regurgitation severity during dynamic exercise in patients with chronic heart failure due to severe left ventricular systolic dysfunction

AIMS

Functional mitral regurgitation (MR) and myocardial asynchronism occur commonly in patients with dilated cardiomyopathy and affect adversely their prognosis and symptoms. The aim of this study was to evaluate the mechanisms of changes in MR severity during dynamic exercise in patients with chronic heart failure (CHF).

METHODS AND RESULTS

Seventy patients with CHF due to left ventricular (LV) systolic dysfunction [LV ejection fraction (EF) <40%] and functional MR were studied. All were in sinus rhythm. Medications were left unchanged for the study. Each patient performed a maximal symptom-limited exercise test with continuous 2D-Doppler echocardiography. Mitral regurgitant volume (RV) and effective regurgitant orifice (ERO) were determined at rest and during exercise. LV asynchrony using Doppler tissue imaging and interventricular asynchrony using conventional pulsed-Doppler were evaluated at rest. Resting LV EF averaged 25+/-8%. Mean resting LV and interventricular mechanical delays were 56+/-50 and 43+/-37 ms, respectively. The overall median values for mitral ERO and RV did not significantly change during dynamic exercise (11 [7-16] vs. 11 [6-21] mm2 and 14 [10-22] vs. 12 [9-23] mL, respectively). However, changes in mitral ERO and RV were individually variable and significantly correlated with the degree of LV asynchronism (r=0.66, P<0.0001 and r=0.66, P<0.0001, respectively).

CONCLUSION

Changes in MR are variable during dynamic exercise. LV asynchronism at rest substantially contributes to worsening of functional MR during dynamic exercise in patients with CHF due to LV systolic dysfunction.