Indications For Pacing Research Articles

Temporary Epicardial Pacing After Valve Replacement: Incidence And Predictors.

Temporary pacemaker wires are usually inserted in patients after valve replacement and may be beneficial for optimizing myocardial function in patients that develop postoperative hemodynamically significant arrhythmias [Elmi 2002]. Indications for temporary cardiac pacing (TCP) are atrial, ventricular or atrioventricular pacing for bradyarrhythmias and for management of both atrial and ventricular tachyarrhythmias [De Belder 1990; Liebold 1998].Pacemaker wires have two ends - one end has a small needle, which is passed into the myocardial surface, then is cut off. The needles may be coiled or clipped for better fixation. On the other end, the larger needle is used to penetrate the body wall, to pass the wire through to the body surface. There is debate about the ideal site for wire insertion, with agreement that the most common site of insertion is in the right ventricle [Hurle 2002].The complications of PMWs include: bleeding, tamponade, arrhythmias, and even retention with its serious hazards [Kapoor 2011; Smith 2013]. During removal of PMWs, there may be atrial or ventricular lacerations which lead to bleeding and to developing tamponade. This may prolong the hospital stay of patients, especially patients on anticoagulant medications. This study was done on patients who received pacing wires during cardiac surgery. The purpose of the study was to predict risk factors that could lead to cardiac pacing after valve surgery.

Pediatric heart transplantation-What are the risk factors for pacemaker implantation and how much pacing is required?

In an attempt to improve pacemaker therapy after pediatric transplantation, we investigated risk factors, indication for pacing, and pacing burden after pediatric heart transplantation. In this retrospective study, 139 pediatric heart transplant recipients, of whom 122 did not and 17 did require pacemakers, were investigated. Eleven of the 17 patients requiring a permanent pacemaker (PPM) received their heart from a female donor (68.8%); this compares to 48 of 122 patients (43.2%, P = 0.082) in the group not requiring a pacemaker (No PPM). The donor age and height were significantly greater in the PPM group at a median of 25.26 years (16.29-48.00) and 160cm (153-170) compared with 11.96 years (1.73-19.95) and 141cm (89-165) in the No PPM group (P = 0.003 and 0.015, respectively). Of the 17 patients requiring pacemakers, 13 presented with sinus node dysfunction (SND) and four with atrioventricular block. The atrial pacing burden in patients with SND remained above 60% within the 5 years of follow-up investigated. There was no significant difference in mortality between those patients requiring a PPM and those not (Log-Rank test: P = 0.672). We found that in our cohort donor characteristics were key risk factors for pacemaker implantation in transplanted children. The data suggest that when patients require a pacemaker in posttransplant SND, they will require a relevant amount of pacing for at least 5 years. The pacing burden after this point remains to be investigated. Mortality does not differ between pediatric heart transplant patients with and without pacemakers.

Subclinical device-detected atrial fibrillation and stroke risk: a systematic review and meta-analysis.

To determine stroke risk in subclinical atrial fibrillation (AF) and temporal association between subclinical AF and stroke. Pubmed/Embase was searched for studies reporting stroke in subclinical AF in patients with cardiac implantable electronic devices (CIEDs). After exclusions, 11 studies were analysed. Of these seven studies reported prevalence of subclinical AF, two studies reported association between subclinical and clinical AF, seven studies reported stroke risk in subclinical AF, and five studies reported temporal relationship between subclinical AF and stroke. Subclinical AF was noted after CIEDs implant in 35% [interquartile range (IQR) 34-42] of unselected patients with pacing indication over 1-2.5 years. The definition and cut-off duration (for stroke risk) of subclinical AF varied across studies. Subclinical AF was strongly associated with clinical AF (OR 5.7, 95% CI 4.0-8.0, P < 0.001, I2 = 0%). The annual stroke rate in patients with subclinical AF > defined cut-off duration was 1.89/100 person-year (95% CI 1.02-3.52) with 2.4-fold (95% CI 1.8-3.3, P < 0.001, I2 = 0%) increased risk of stroke as compared to patients with subclinical AF < cut-off duration (absolute risk was 0.93/100 person-year). Three studies provided mean CHADS2 score. In these studies, with mean CHADS2 score of 2.1 ± 0.1, subclinical AF was associated with annual stroke rate of 2.76/100 person-years (95% CI 1.46-5.23). After excluding patients without AF, only 17% strokes occurred in presence of ongoing AF. Subclinical AF was noted in 29% [IQR 8-57] within 30 days preceding stroke. Subclinical AF strongly predicts clinical AF and is associated with elevated absolute stroke risk albeit lower than risk described for clinical AF.

A Single-Centre Experience of Subcutaneous Implantable Cardioverter-Defibrillator

Background: Subcutaneous implantable-cardioverter-defibrillator (S-ICD) is an established therapy for patients at risk of sudden cardiac death who do not have an indication for pacing or cardiac resynchronisation. This study aims to describe the initial implant and follow-up experience of S-ICD in our centre.

Leadless pacemaker implantation in young adults with vasovagal syncope and major cardioinhibitory component: About 2 cases

Vasovagal syncope is generally benign but may associated to pacing indication. We report two cases of vasovagal requiring pacemaker implantation. A leadless pacemaker was preferred to conventional pacing. Clinical cases: two women aged 24 and 16, were showing repetitive faintness. They presented prodromal symptoms, without triggering factor, that lead to collapse accompanied by convulsions or serious traumas. After a full neurological check-up and elimination of underlying cardiopathy, the diagnosis of vagal syncope with major cardioinhibitory component was made: for one through an implantable loop recorder with sinusal pauses of more than one minute, for the other with a positive tilt test and demonstration of a 18 seconds sinusal pause on a 72 h Holter ECG. The postural and the beta-blocker treatment being inefficient, pacing was decided. A Medtronic MICRA was implanted, via the right femoral vein, on the interventricular septum. Mean procedure time was 50 minutes. Micra was positioned at the first attempt in both patients with thresholds < 0.5 V. No complications were observed and both patients were treated in our outpatient clinic. No syncope occurred since then in both patients over a follow-up of 2 and 12 months without significant change in electrical parameters. Even if the DDDR pacing is to be favoured as first intention in this indication, the new leadless pacemakers show many advantages: no surgical approach, infections and haemorrhages decrease, displacement risk decrease, aesthetic keeping up with a same longevity to current simple room pacemakers. Thus, leadless pacemaker can be discussed for young patients with indication for pacing associated to vagal syncope. However, data is lacking in these patients, particularly concerning long-term follow-up.

Acute and Long-term Results After Contemporary Subcutaneous Implantable Cardioverter-defibrillator Implantation: A Single-center Experience

Introduction and objectivesThe subcutaneous implantable cardioverter-defibrillator (S-ICD) has emerged as an alternative to the transvenous defibrillator. The incidence of complications is similar, with inappropriate shocks (IS) being more frequent than those occurring with contemporary programming of transvenous defibrillators. Several improvements have been implemented after the S-ICD was approved for use in Europe in 2009. This study reports the results of S-ICD use in a single center, whose experience began late, at the end of 2013. MethodsProspective observational study including consecutive patients with defibrillator indication and no indication for either permanent pacing or cardiac resynchronization who underwent S-ICD implantation. Implant data and long-term follow-up were analyzed. ResultsAn S-ICD was implanted in 50 patients who were deemed suitable after electrocardiographic screening. The mean age was 46.9±15 (range, 15-78) years and 72% were male. Thirty eight percent had left ventricular ejection fraction ≤ 35%. The most frequent heart disease was ischemic heart disease (34%), followed by hypertrophic cardiomyopathy (18%). The intermuscular technique was used, with 3 incisions in 10% and 2 incisions in the remaining 90%. Ventricular fibrillation was induced in 49 patients, with 100% effectiveness in their conversion. After a mean follow-up of 18.1 (range, 2.3-44.8) months, there were no late complications requiring surgical revision, the rate of IS was 0%, and 1 patient (2%) experienced appropriate shocks. ConclusionsImprovements in technology, implant technique and device programming, along with appropriate patient selection, have led to outstanding acute and long-term results, especially regarding the absence of both IS and complications requiring surgical revision.

Monocentric experience of leadless pacing with focus on challenging cases for conventional pacemaker

Aim: Leadless cardiac pacemaker has been developed to reduce complications related to cardiac pacing and is considered as an alternative to conventional pacemaker although safety and efficacy data in clinical practice are limited. The purpose of this study was to investigate the safety and efficacy profile of Micra Transcatheter Pacing System (TPS) used in daily clinical activity with a focus on challenging cases for conventional pacing. Methods: A total of 66 patients (46 men, 79.1 ± 9.7 years) having a Class I or II indication for ventricular pacing underwent a Micra TPS implant procedure. All patients were enrolled in a prospective registry. Follow-up visits were scheduled at discharge and after 1, 3, 6 and 12 months. Results: Primary indication for pacing was third degree atrioventricular block (30.3%), sinus node dysfunction (21.2%) or permanent atrial fibrillation with bradycardia (45.5%). The device was successfully implanted in 65 patients (98.5%). During follow-up of 10.4 ± 6.1 months (range 1–23 months), electrical measurements remained stable. Mean pacing capture threshold, pacing impedance and R-wave sensing were respectively 0.57 ± 0.32 V, 580 ± 103 Ohms, 10.62 ± 4.36 mV at the last follow-up. One major (loss of function) and three minor adverse events occurred. Pericardial effusion, dislodgement, device related infection or pacemaker syndrome were not observed. Micra TPS implantation was straightforward for patients with congenital or acquired cardiac and/or vascular abnormalities, previous tricuspid surgery and after heart transplantation. Conclusion: Our experience confirms that implantation of Micra is safe and efficient in a real world population including patients who present a challenging condition for conventional pacing.

Subcutaneous implantable cardioverter-defibrillator in prevention of sudden cardiac death in Poland - opinion paper endorsed by the Polish Cardiac Society Working Group on Heart Rhythm

In the past years, cardiovascular mortality has decreased but despite these cardiovascular diseases are responsible for millions of deaths every year in the world and approximately 25% of which are sudden cardiac death (SCD). Implantable defibrillators (ICD) is proven therapy used in primary and secondary SCD prevention. Currently majority of devices use transvenous leads inserted predominantly into the right heart for both pacing and defibrillation. On the other hand, ICD may cause complica-tions, including inappropriate shocks, device-related infection and lead failure. Problems with transvenous leads prompted the development of a subcutaneous defibrillator (S-ICD) with an electrode system that is placed entirely subcutaneously, outside the thoracic cavity. The device may be useful when venous access is difficult, in young patients and in patients at particular risk of infection. S-ICD is not suitable for patients with indications for bradycardia pacing, cardiac resynchronisation therapy and in cases with tachyarrhythmia easily terminated by antitachycardia pacing.

Bilan de cinq ans de stimulation cardiaque dans deux structures hospitalières publiques du Burkina Faso : expérience d’une collaboration avec deux centres hospitaliers d’Auvergne

ObjectivesCardiac stimulation becomes a reality in Burkina Faso. The aim of our study was to evaluate this activity over five years and to appreciate the impact of collaboration with French hospitals of Auvergne area in its development. Materials and methodsProspective study including consecutively patients who underwent pacemaker implantation since June 2011. Data collected included indications, time to care, type of stimulation, complications, cost of treatment, and education and quality of life of the patient. ResultsSixty-nine patients received definitive pacemaker from June 2011 to June 2016, of whom 45.5% were women. The mean age was 69 years (extremes 35 to 89s). Almost all patients (94%) were symptomatic (54% syncope and 30% dizziness and lipothymias). The main indication for definitive cardiac pacing was complete atrioventricular block of degenerative origin (83%). The mean time between indication and surgery was 8.2 days, and only 4% of patients received temporary stimulation. The lack of financial support was the main reason for the delay in taking charge. During the study period, the two health centers received support in the form of stimulation equipment, a technical platform, and regular training and practical training. This collaboration made it possible to overcome the lack of material, human and financial resources. We recorded as complications a case of case exteriorization, two cases of benign local hematoma and two cases of probe displacement. The quality of life of the patients improved markedly, none of patients undergoing surgery remained symptomatic. ConclusionThe organization of cardiac stimulation in Burkina Faso is a reality. Efforts must be made to sustain the activity and strengthen collaboration with hospitals in the north.

Resultados agudos y a largo plazo tras implante contemporáneo de desfibrilador subcutáneo: experiencia en un centro

Introduction and objectivesThe subcutaneous implantable cardioverter-defibrillator (S-ICD) has emerged as an alternative to the transvenous defibrillator. The incidence of complications is similar, with inappropriate shocks (IS) being more frequent than those occurring with contemporary programming of transvenous defibrillators. Several improvements have been implemented after the S-ICD was approved for use in Europe in 2009. This study reports the results of S-ICD use in a single center, whose experience began late, at the end of 2013. MethodsProspective observational study including consecutive patients with defibrillator indication and no indication for either permanent pacing or cardiac resynchronization who underwent S-ICD implantation. Implant data and long-term follow-up were analyzed. ResultsAn S-ICD was implanted in 50 patients who were deemed suitable after electrocardiographic screening. The mean age was 46.9±15 (range, 15-78) years and 72% were male. Thirty eight percent had left ventricular ejection fraction ≤ 35%. The most frequent heart disease was ischemic heart disease (34%), followed by hypertrophic cardiomyopathy (18%). The intermuscular technique was used, with 3 incisions in 10% and 2 incisions in the remaining 90%. Ventricular fibrillation was induced in 49 patients, with 100% effectiveness in their conversion. After a mean follow-up of 18.1 (range, 2.3-44.8) months, there were no late complications requiring surgical revision, the rate of IS was 0%, and 1 patient (2%) experienced appropriate shocks. ConclusionsImprovements in technology, implant technique and device programming, along with appropriate patient selection, have led to outstanding acute and long-term results, especially regarding the absence of both IS and complications requiring surgical revision.Full English text available from:www.revespcardiol.org/en

Transcatheter Aortic Valve Implantation In Patients With a Large Aortic Annulus

As the indications for transcatheter aortic valve implantation (TAVI) have expanded, so to have the demands on interventionists to allow as many patients to access this technology as possible. We retrospectively reviewed our TAVI database for patients who had received a 29mm SAPIEN 3 valve despite having an annular area greater than the manufacturer-recommended upper limit of 683mm2, as determined by multi-detector computed tomography (MDCT). Procedural and inpatient outcome data were collected. The study population was 5 of 121 patients receiving a SAPIEN 3 valve since it became available in March 2015. Their annular area ranged from 691 to 800mm2. Valve deployment was successful in all patients. The deployment balloon volume was nominal, except for an additional 1ml in one patient. No patient had a new indication for permanent pacing, and no significant valvular or paravalvular regurgitation (PVR) was identified on post-procedure transthoracic echocardiography. All patients survived to hospital discharge. In this select group of patients we have demonstrated that it is safe and feasible to use the 29mm SAPIEN 3 in patients with annular dimensions greater than those recommended, with minimal balloon overfilling.

Successful Reinnervation of the Diaphragm After Intercostal to Phrenic Nerve Neurotization in Patients With High Spinal Cord Injury.

Our objective in this study was to extend diaphragmatic pacing therapy to include paraplegic patients with high cervical spinal cord injuries between C3 and C5. Diaphragmatic pacing has been used in patients experiencing ventilator-dependent respiratory failure due to spinal cord injury as a means to reduce or eliminate the need for mechanical ventilation. However, this technique relies on intact phrenic nerve function. Recently, phrenic nerve reconstruction with intercostal nerve grafting has expanded the indications for diaphragmatic pacing. Our study aimed to evaluate early outcomes and efficacy of intercostal nerve transfer in diaphragmatic pacing. Four ventilator-dependent patients with high cervical spinal cord injuries were selected for this study. Each patient demonstrated absence of phrenic nerve function via external neck stimulation and laparoscopic diaphragm mapping. Each patient underwent intercostal to phrenic nerve grafting with implantation of a phrenic nerve pacer. The patients were followed, and ventilator dependence was reassessed at 1 year postoperatively. Our primary outcome was measured by the amount of time our patients tolerated off the ventilator per day. We found that all 4 patients have tolerated paced breathing independent of mechanical ventilation, with 1 patient achieving 24 hours of tracheostomy collar. From this study, intercostal to phrenic nerve transfer seems to be a promising approach in reducing or eliminating ventilator support in patients with C3 to C5 high spinal cord injury.

Leadless Pacing: Current State and Future Direction.

Leadless pacing is now an established alternative to conventional pacing with subcutaneous pocket and transvenous lead for patients with class I or II single-chamber pacing indication. Available 12-month follow-up data shows a 48% fewer major complication rate in patients with Micra™ compared to a historical control group in a nonrandomized study [1]. There is one system with Food and Drug Administration (FDA) approval and two with the Communauté Européenne (CE) mark. The OPS code for the implantation is 8–83d.3 and the procedure has recently been rated as a “new Examination and Treatment Method (NUB)” in the German DRG system, meaning adequate reimbursement is negotiable with health insurance providers. The systems offer similar generator longevity and programming possibilities as conventional pacemaker systems, including rate response, remote monitoring, and MRI safety. The biggest downsides to date are limitations to single-chamber stimulation, lack of long-time data, and concerns of handling of the system at the end of its life span. However, implant procedure complication rates and procedure times do not exceed conventional pacemaker operations, and proper training and patient selection is provided.

Right ventricular and tricuspid valve function in patients chronically implanted with leadless pacemakers.

Leadless cardiac pacing has recently been proposed as alternative to conventional right ventricular (RV) pacing. With this approach, devices are directly screwed or fixed with tines in the RV wall, but the possible consequences on RV and tricuspid valve (TV) structure and function remain unknown. We thus conducted a study to evaluate this potential impact in chronically implanted patients. Repeated echocardiographic studies were performed prior to implantation, at discharge, and 2 months thereafter on all consecutive patients implanted with a leadless pacemaker at our centre between October 2014 and end-December 2015. Whenever possible, patients were evaluated in non-paced rhythm. Anatomical and functional parameters of RV, TV, and left cardiac structures were assessed. Overall, 23 patients (12 females, aged 85.2 ± 6.3 years) were included, with 14 implanted using Nanostim™ (Saint Jude Medical) and 9 with Micra™ (Medtronic). Indications for pacing were paroxysmal atrio-ventricular block in 12 patients, intermittent sinus bradycardia in 5, unexplained syncope in 3, and atrial fibrillation with slow ventricular rate in the remaining 3. The pacing percentage was 34 ± 42% at the last visit. Most devices were implanted in the septo-apical or mid-septal region. There were no significant changes in echocardiographic parameters observed. One patient developed significantly increased TV regurgitation, without abnormal leaflet motion or TV annulus size changes, suggesting it to be due to RV pressure changes. In patients chronically implanted with leadless pacemakers, there were no significant changes in heart structure and function observed, especially concerning the RV and TV.

52 Suitability for subcutaneous implantable cardioverter-defibrillator therapy – the impact of different selection policies

BackgroundWith subcutaneous ICDs (S-ICD) not offering the same range of pacing therapies as transvenous systems (T-ICD), it is unclear how many ICD recipients may be suitable for a S-ICD. In...

To pace or not to pace? Or how to pace?

Chronic apical right ventricular pacing may impair left ventricular function and cause heart failure in patients with indication for antibradycardia pacing and normal left ventricular ejection fraction at baseline, through multiple electro-mechanical changes. We describe the case of a patient who needed an upgrade to cardiac resynchronization therapy and developed angina early after single chamber right ventricular pacing and discuss pacing induced cardiomyopathy.

Conduction Abnormalities and Permanent Pacemaker Implantation After Transcatheter Aortic Valve Replacement Using the Repositionable LOTUS Device: The United Kingdom Experience

ObjectivesThe authors report the incidence of pacemaker implantation up to hospital discharge and the factors influencing pacing rate following implantation of the LOTUS bioprosthesis (Boston Scientific, Natick, Massachusetts) in the United Kingdom. BackgroundTranscatheter aortic valve replacement (TAVR) is associated with a significant need for permanent pacemaker implantation. Pacing rates vary according to the device used. The REPRISE II (Repositionable Percutaneous Replacement of Stenotic Aortic Valve Through Implantation of Lotus Valve System) trial reported a pacing rate of 29% at 30 days after implantation of the LOTUS device. MethodsData were collected retrospectively on 228 patients who had the LOTUS device implanted between March 2013 and February 2015 across 10 centers in the United Kingdom. Twenty-seven patients (12%) had pacemakers implanted pre-procedure and were excluded from the analysis. ResultsPatients were aged 81.2 ± 7.7 years; 50.7% were male. The mean pre-procedural QRS duration was 101.7 ± 20.4 ms. More than one-half of the cohort (n = 111, 55%) developed new left bundle branch block (LBBB) following the procedure. Permanent pacemakers were implanted in 64 patients (32%) with a median time to insertion of 3.0 ± 3.4 days. Chief indications for pacing were atrioventricular (AV) block (n = 46, 72%), or LBBB with 1st degree AV block (n = 11, 17%). Amongst those who received a pacemaker following TAVR the pre-procedural electrocardiogram findings included: No conduction disturbance (n = 41, 64%); 1st degree AV block (n = 10, 16%); right bundle branch block (n = 6, 9%) and LBBB (n = 5, 8%). LBBB (but not permanent pacemaker) occurred more frequently in patients who had balloon aortic valvuloplasty before TAVR (odds ratio [OR]: 1.25; p = 0.03). Pre-procedural conduction abnormality (composite of 1st degree AV block, hemiblock, right bundle branch block, LBBB) was independently associated with the need for permanent pacemaker (OR: 2.54; p = 0.048). The absence of aortic valve calcification was also associated with a higher pacing rate (OR: 0.55; p = 0.031). Multivariate regression analysis did not show an independent association between depth of implant, valve oversizing, balloon post-dilatation, and the need for pacing post-procedure. ConclusionsFollowing implantation of the repositionable LOTUS valve, 55% of patients developed LBBB and 32% of patients required a pacemaker during their index hospital admission. Patients with pre-procedural conduction disturbance and non-calcified aortic valves were more likely to need pacing. No other anatomic features were identified with increased pacing requirement with the LOTUS device.

Nouvelles techniques de stimulation dans le domaine des cardiopathies congénitales

The number of children and adult with congenital heart disease requiring implantation of cardiac pacemaker or cardioverter defibrillator is constantly increasing. The lead between stimulation/defibrillation site and the generator constitutes the main weakpoint of those devices despite the numerous recent technological advances: use of bipolar probes, corticoid elution electrodes, insulation improvement, magnetic resonance imaging (MRI) compatibility. Risk of device failure remains high in this population. Long term adverse events with endovascular devices remain high. That point leads us to review our implantation strategies. We try to favour an extravascular solution whenever possible. Subcutaneous defibrillators may be proposed to patients at high risk for severe ventricular arrhythmia without cardiac pacing indication. Patients should have a rigorous pre-implantation screening procedure to minimize the increased risk of inappropriate shock. New single chamber, VVIR-type, leadless pacemakers can be implanted directly into the right ventricle. Miniaturized implantable loop recorders help in management of palpitations and syncopes: it increases diagnosis yield and helps arrhythmias burden assessment. Development of remote monitoring (implantable loop recorder, pacemaker and defibrillator) helps to reduce the incidence of adverse clinical events by providing an early detection of clinically relevant events such as arrhythmias and device failure.

Cardiac Resynchronization Therapy With Wireless Left Ventricular Endocardial Pacing: The SELECT-LV Study

BackgroundA total of 30% to 40% of patients with congestive heart failure eligible for cardiac resynchronization therapy (CRT) either do not respond to conventional CRT or remain untreated due to an inability or impediment to coronary sinus (CS) lead implantation. The WiSE-CRT system (EBR Systems, Sunnyvale, California) was developed to address this at-risk patient population by performing biventricular pacing via a wireless left ventricular (LV) endocardial pacing electrode. ObjectivesThe SELECT-LV (Safety and Performance of Electrodes implanted in the Left Ventricle) study is a prospective multicenter non-randomized trial assessing the safety and performance of the WiSE-CRT system. MethodsA total of 35 patients indicated for CRT who had “failed” conventional CRT underwent implantation of an LV endocardial pacing electrode and a subcutaneous pulse generator. System performance, clinical efficacy, and safety events were assessed out to 6 months post-implant. ResultsThe procedure was successful in 97.1% (n = 34) of attempted implants. The most common indications for endocardial LV pacing were difficult CS anatomy (n =12), failure to respond to conventional CRT (n = 10), and a high CS pacing threshold or phrenic nerve capture (n = 5). The primary performance endpoint, biventricular pacing on the 12-lead electrocardiogram at 1 month, was achieved in 33 of 34 patients. A total of 28 patients (84.8%) had improvement in the clinical composite score at 6 months, and 21 (66%) demonstrated a positive echocardiographic CRT response (≥5% absolute increase in LV ejection fraction). There were no pericardial effusions, but serious procedure/device-related events occurred in 3 patients (8.6%) within 24 h, and 8 patients (22.9%) between 24 h and 1 month. ConclusionsThe SELECT-LV study demonstrates the clinical feasibility for the WiSE-CRT system, and provided clinical benefits to a majority of patients within an otherwise “failed” CRT population. (Safety and Performance of Electrodes Implanted in the Left Ventricle [SELECT-LV]; NCT01905670)

Is there a prognostic relevance of electrophysiological studies in bundle branch block patients?

The present European guidelines suggest a diagnostic electrophysiological (EP) study to determine indication for cardiac pacing in patients with bundle branch block and unexplained syncope. We evaluated the prognostic relevance of an EP study for mortality and the development of permanent complete atrioventricular (AV) block in patients with symptomatic bifascicular block and first-degree AV block. The HV interval is a poor prognostic marker to predict the development of permanent AV block in patients with symptomatic bifascicular block (BFB) and AV block I°. Thirty consecutive patients (mean age, 74.8 ± 8.6 years; 25 males) with symptomatic BFB and first-degree AV block underwent an EP study before device implantation, according to current guidelines. For 53 ± 31 months, patients underwent yearly follow-up screening for syncope or higher-degree AV block. Thirty patients presented with prolonged HV interval during the EP study (mean, 82.2 ± 20.1 ms; range, 57-142 ms), classified into 3 groups: group 1, <70 ms (mean, 62 ± 4 ms; range, 57-67 ms; n = 7), group 2, >70 to ≤100 ms (mean, 80 ± 8 ms; range, 70-97 ms; n = 18), and group 3, >100 ms (mean, 119 ± 14 ms; range, 107-142 ms; n = 5). According to the guidelines, patients in groups 2 and 3 received a pacemaker. The length of the HV interval was not associated with the later development of third-degree AV block or with increased mortality. Our present study suggests that an indication for pacemaker implantation based solely on a diagnostic EP study with prolongation of the HV interval is not justified.