Supervised Obesity Reduction Trial for AF ablation patients: results from the SORT-AF trial.

AIMS: Weight management seems to be beneficial for obese atrial fibrillation (AF) patients; however, randomized data are sparse. Thus, this study aimed to investigate the influence of weight reduction on AF ablation outcomes. METHODS AND RESULTS: SORT-AF is an investigator-sponsored, prospective, randomized, multicentre, and clinical trial. Patients with symptomatic AF (paroxysmal or persistent) and body mass index (BMI) 30-40 kg/m2 underwent AF ablation and were randomized to either weight-reduction (group 1) or usual care (group 2), after sleep-apnoea-screening and loop recorder (ILR) implantation. The primary endpoint was defined as AF burden between 3 and 12 months after AF ablation. Overall, 133 patients (60 ± 10 years, 57% persistent AF) were randomized to group 1 (n = 67) and group 2 (n = 66), respectively. Complications after AF-ablation were rare (one stroke and no tamponade). The intervention led to a significant reduction of BMI (34.9 ± 2.6-33.4 ± 3.6) in group 1 compared to a stable BMI in group 2 (P < 0.001). Atrial fibrillation burden after ablation decreased significantly (P < 0.001), with no significant difference regarding the primary endpoint between the groups (P = 0.815, odds ratio: 1.143, confidence interval: 0.369-3.613). Further analyses showed a significant correlation between BMI and AF recurrence for patients with persistent AF compared with paroxysmal AF patients (P = 0.032). CONCLUSION: The SORT-AF study shows that AF ablation is safe and successful in obese patients using continuous monitoring via ILR. Although the primary endpoint of AF burden after ablation did not differ between the two groups, the effects of weight loss and improvement of exercise activity were beneficial for obese patients with persistent AF demonstrating the relevance of life-style management as an important adjunct to AF ablation in this setting. TRIAL REGISTRATION NUMBER: NCT02064114.

Performance and outcome of the subcutaneous implantable cardioverter-defibrillator after transvenous lead extraction.

AIMS: The subcutaneous cardioverter-defibrillator (S-ICD) may be a valuable option in patients after successful transvenous lead extraction (TLE) without indication for pacemaker therapy and persistent risk of sudden cardiac death. The aim of this study was to evaluate device performance, postoperative outcome, and safety in patients who received a S-ICD after TLE compared to patients who underwent de-novo S-ICD implantation. METHODS: A retrospective analysis of all patients included into our institution's S-ICD database between September 2010 and May 2019 was conducted.The patients were divided in two groups, depending on whether they had received their S-ICD after TLE (n = 31) or de-novo (n = 113). RESULTS: The TLE group was significantly older with a mean age of 54.3 ± 15.7 versus 46.7 ± 14.4 years; p = .007. Leading S-ICD indication in the TLE group was previous infection (50%), whereas in the de-novo group the S-ICD was primarily chosen due to young patient age (74.6%). Median duration of follow-up was 527.0 versus 472.5 days, respectively; p = .576. Most common complication during follow-up was inappropriate ICD therapy (12.9% vs. 13.3%); p = 1.000. Pocket erosion/infection occurred in 3.2% versus 3.5% with no reported cases of systemic (re-)infection in either group; p = 1.000. All-cause mortality was low (6.2% vs. 2.7%) and entirely unrelated to S-ICD implantation or the device itself; p = .293. CONCLUSION: The S-ICD is a safe and effective alternative for patients after TLE with very similar results regarding device performance and postoperative outcome, when compared to patients who underwent de-novo S-ICD implantation.

Long-term efficacy and safety of radiofrequency catheter ablation of atrial fibrillation in patients with cardiac implantable electronic devices and transvenous leads.

INTRODUCTION: Long-term efficacy and safety are uncertain in patients with cardiac implantable electronic devices (CIED) and transvenous leads (TVL) undergoing radiofrequency catheter ablation of atrial fibrillation (AF). Thus, we assessed the outcome of AF ablation in those patients during long-term follow-up using continuous atrial rhythm monitoring (CARM). METHODS AND RESULTS: A total of 190 patients (71.3 ± 10.7 years; 108 (56.8% men) were included in this study. At index procedure 81 (42.6%) patients presented with paroxysmal AF and 109 (57.4%) with persistent AF. The ablation strategy included pulmonary vein isolation in all patients and biatrial ablation of complex fractionated electrograms with additional ablation lines, if appropriate. AF recurrences were assessed by CARM- and CIED-related complications by device follow-up. After a mean follow-up of 55.4 ± 38.1 months, freedom of AF was found in 86 (61.4%) and clinical success defined as an AF burden less than or equal to 1% in 101 (72.1%) patients. Freedom of AF was reported in 74.6% and 51.9% (P = 0.006) and clinical success in 89.8% and 59.3% (P < 0.001) of patients with paroxysmal and persistent AF, respectively. In 3 of 408 (0.7%) ablation procedures, a TVL malfunction occurred within 90 days after catheter ablation. During long-term follow-up 9 (4.7%) patients showed lead dislodgement, 2 (1.1%) lead fracture, and 2 (1.1%) lead insulation defect not related to the ablation procedure. CONCLUSION: Our findings using CARM demonstrate long-term efficacy and safety of radiofrequency catheter ablation of AF in patients with CIED and TVL.

Bleeding risk of submuscular ICD implantation with continued oral anticoagulation versus heparin bridging therapy.

Recent studies have shown that subcutaneous or subfascial pacemaker- and ICD implantation with continued oral anticoagulation therapy is associated with lower risk for bleeding complications, when compared to heparin bridging strategies. However, ICD generators are often implanted submuscularly. We therefore compared the bleeding risk with continued phenprocoumon therapy vs. heparin bridging in patients receiving submuscular ICD implantation. Between 01/2013 and 12/2013, 104 patients with need for oral anticoagulation received submuscular ICD or CRT-D implantation in our institution. 46 patients were implanted under continued phenprocoumon therapy while 58 patients received heparin bridging for implantation procedure. All ICD generators were placed submuscularly. The primary outcome of the study was clinically significant bleeding or device pocket hematoma with need for surgical revision. Mean patients age was 63.7 years, 72.1% were male. In patients with heparin bridging therapy, preoperative INR prior to ICD implantation was 1.2 ± 0.31 while in the group of patients on continued phenprocoumon therapy, mean pre-OP INR was 2.4 ± 0.47. In heparin bridging group, 8 (13.8%) patients experienced a clinically relevant pocket hematoma, while only 1 (2.2%) patient on continued phenprocoumon therapy needed surgical revision for pocket hematoma (P = 0.04). No further bleeding complications or clinically relevant pericardial effusion was observed in any of the groups and no perioperative thromboembolic event occurred. Submuscular ICD implantation under continued phenprocoumon therapy was safe and feasible. Compared to patients with heparin bridging therapy, those with continued phenprocoumon therapy had a lower incidence of clinically relevant bleeding complications.

Differences in laser lead extraction of infected vs. non-infected leads.

We investigated the effect of systemic infection or lead endocarditis on the complexity and the success of laser lead extraction (LLE) procedures. Medical records of all patients undergoing LLE between January 2012 and March 2017 were screened with regard to information on systemic infection or lead endocarditis. We treated 184 patients using high-frequency 80 Hz laser sheaths in patients with lead implant duration of ≥ 12 months. Indications for lead extraction were systemic infection and lead endocarditis in 52 cases (28.3%), local infection in 74 cases (40.2%), lead dysfunction in 37 cases (20.1%) and other indications in 21 cases (11.4%). 386 leads were scheduled for LLE: 235 (60.9%) pacing, 105 (27.2%) ICD and 46 (11.9%) CS leads. The mean time from initial lead implantation (systemic infection 96.8 ± 74.7 months vs. 102.1 ± 82.6 non-infected: months; p = 0.4155) and ratio of ICD leads (26.8 vs. 27.4%; p = 0.3411) did not differ significantly between the two groups. Complete procedural success was significantly higher in the systemic infection group (100 vs. 94.7%; p = 0.0077). The mean laser treatment (60.2 ± 48.7 vs. 72.4 ± 61.5 s; p = 0.2038) was numerically lower in the infection group, while fluoroscopy time (9.3 ± 7.6 vs. 12.8 ± 10.3 min; p = 0.0275) was significantly lower in this group. Minor and major complications were low in both groups and did not reveal any statistically significant difference (infected group: one minor complication; pocket hematoma, non-infected: three major complications; emergent sternotomy due to pericardial tamponade). No extraction related mortality was observed. The presence of systemic infection or lead endocarditis in LLE procedures allows for higher complete procedural success. When compared with LLE of non-infected leads, the infected leads require less laser and fluoroscopy times. Due to the scarcity of minor and major complications in general, no statistical significance was found in that regard.

Benefits of routine prophylactic femoral access during transvenous lead extraction.

BACKGROUND: The number of patients requiring lead extraction has been increasing in recent years. Despite significant advances in operator experience and technique, unexpected complications may occur. Prophylactic placement of femoral sheaths allows for immediate endovascular access for emergency procedures and may shorten response time in the event of complications. OBJECTIVE: The purpose of this study was to assess the benefits of routine prophylactic femoral access in patients undergoing transvenous lead extraction (TLE) and to evaluate the methods, frequency, and efficacy of the emergency measures used in those patients. METHODS: We conducted a retrospective analysis of patients who underwent TLE from January 2012 to February 2019. The data were analyzed with regard to procedural complications and deployment of emergency measures via femoral access. RESULTS: Two hundred eighty-five patients (mean age 65.3 ± 15.5 years) were included in the study. Median lead dwell time was 84 months (interquartile range 58-144). Overall complication rate was 4.2% (n = 12), with 1.8% major complications (n = 5). Clinical success rate was 97.2%. Procedure-related mortality was 1.1% (n = 3). Femoral sheaths were actively engaged in 9.1% (n = 26) of cases. Deployment of snares was the most common intervention (n = 10), followed by prophylactic (n = 6) or emergency placement (n = 1) of occlusion balloons, temporary pacing (n = 3), venous angioplasty (n = 3), diagnostic venography (n = 3), and extracorporeal membrane oxygenation (n = 1). We did not observe any femoral vascular complications due to prophylactic sheath placement. CONCLUSION: Routine prophylactic placement of femoral sheaths shortens response time and quickly establishes control in the event of various complications that may occur during TLE procedures.

The Bridge Occlusion Balloon for Venous Angioplasty in Superior Vena Cava Occlusion.

The Bridge Occlusion Balloon is a compliant balloon, specifically designed for temporary Superior vena cava occlusion in case of Superior Vena Cava laceration during lead extraction procedures. We here report the first case, using Bridge Occlusion Ballon for a venous angioplasty in a patient with dysfunctional pacemaker leads and symptomatic Superior Vena Cava occlusion. After successful lead extraction, venography was showing a narrow venous canal. Therefore, venous angioplasty using the Bridge balloon was performed. Especially for high-risk lead extraction cases in patients with Superior Vena Cava stenosis, the Bridge Occlusion Ballon might be used as a combination of a safety-net in case of Superior Vena Cava perforation and for Superior Vena Cava angioplasty.

[Guideline-Based Indications on Pacing and ICD-Therapy]. / Leitliniengerechte Indikationsstellung der Herzschrittmacher- und ICD-Therapie.

In 2016, there were 77 293 pacemakers and 28 953 ICDs implanted in Germany. This makes pacemaker- and ICD-implantations part of the most frequently performed operations in Germany. This article addresses questions of correct indication and patient selection.

Triple lead cephalic versus subclavian vein approach in cardiac resynchronization therapy device implantation.

Cardiac resynchronization therapy (CRT) device implantation is associated with severe complications including pneumo- and hemothorax. Data on a sole cephalic vein approach (sCV), potentially preventing these complications, are limited. The aim of our study was to compare a sole cSV with a subclavian vein approach (SV) in CRT implantations with respect to feasibility and safety. We performed a prospective cohort study enrolling twenty-four consecutive de-novo CRT implantations (group A) using a sCV at two centers. Fifty-four age-matched CRT patients implanted via the SV served (group B) as reference. Procedural success rate and complications were recorded during a follow-up of 4 weeks. All CRTs could be implanted in group A, with 91.7% using cephalic access alone. In group B, CRT implantation was successfully performed in 96.3%. Procedure and fluoroscopy duration were similar for both groups (sCV vs. SV: 119 ± 45 vs. 106 ± 31 minutes, 17 ± 9 vs 14 ± 9 minutes). Radiation dosage was higher in sCV group vs. SV (2984 ± 2370 vs. 1580 ± 1316 cGy*cm2; p = 0.001). There was no case of a pneumothorax in group of sCV, while two cases were observed using SV. Overall complication rate was similar (sCV: 13.0% vs. SV: 12.5%). de-novo CRT implantation using a triple cephalic vein approach is feasible. Procedure duration and complication rates were similar, while radiation dosage was higher in the sCV compared to the SV approach. Despite its feasibility in the clinical routine, controlled prospective studies with longer follow-up are required to elucidate a potential benefit with respect to lead longevity.

Navigation of lead extraction-is it possible? Impact of preprocedural electrocardiogram-triggered computed tomography on navigation of lead extraction.

OBJECTIVES: As the number of transvenous lead extractions continues to increase, preprocedural protocols for this procedure must be assessed. The objective of this study was to determine whether an electrocardiogram (ECG)-triggered computed tomography (Et-CT) with three-dimensional (3D) reconstructions could aid lead extractors in choosing the optimal tools to improve procedural success and avoid complications. METHODS: In this study, 31 patients scheduled for transvenous lead extraction underwent a preprocedural Et-CT between January 2016 and May 2017. Both 3D-reconstructions and the two-dimensional files were reviewed for possible lead adhesions, calcifications, migrations or perforations. RESULTS: Mean age was 46.7 ± 14.0 years. Seventy-one percent of patients were men, and 29.0% had undergone prior cardiac surgery. Indications for extraction included infection (n = 18, 58.1%), lead dysfunction (n = 8, 25.8%), upgrade (n = 3, 9.7%), severe tricuspid regurgitation (n = 1, 3.2%) and superior vena cava occlusion (n = 1, 3.2%). Eighteen patients had an implantable cardioverter defibrillator (58.1%). Sixty-eight of 70 targeted leads were extracted with a mean of 2.2 leads per patient and an average lead age of 109.3 ± 58.7 months. Et-CT files supported transvenous lead extraction by revealing possible adhesions in 16 patients, 5 perforations and 2 venous occlusions. Lead extraction was performed using the excimer laser, mechanical tools and femoral snares. Complete procedural success was achieved in 93.5% (n = 29) of cases. Clinical success was 100%, and intraoperative mortality was 0%. CONCLUSIONS: A preprocedural Et-CT with 3D reconstructions can help to visualize lead alignment and identify abnormalities that may foreshadow procedural difficulties. A preprocedural Et-CT may therefore aid lead extractors in choosing the optimal extraction tool and strategy.

Evaluation of tricuspid valve regurgitation following laser lead extraction†.

OBJECTIVES: The objective of this study was to examine the effect of laser lead extraction (LLE) on the development of post-procedural tricuspid regurgitation (TR). Some reports have suggested an increase in TR associated with LLE. We present a series of patients who underwent both, LLE and complete echocardiographic evaluation for TR. METHODS: A single centre analysis of consecutive patients referred for LLE between January 2012 and August 2015. One hundred and three patients had tricuspid valve function evaluated before the procedure with a transthoracic echocardiography (TTE), during the procedure using transoesophageal echocardiography and postoperatively using a TTE. TR was graded from 0 (none) to 4 (severe). RESULTS: We treated 235 leads in 103 patients, including 118 ventricular leads. Seventy-seven were male (74.8%) and 26 female (25.2%), with a mean age of 65.6 ± 15.4 years. Mean time from initial lead implantation was 98.0 ± 67.3 months. Twenty-one patients (20.4%) had ejection fraction below 30%. No intra-procedural worsening of tricuspid valve function was seen with TEE in any of the patients. Ten patients (9.7%) were found to have TR before LLE that returned to normal valve function after the procedure. Two patients (1.9%) experienced mild TR after the procedure (both with tricuspid valve endocarditis). Ninety-one patients (88.3%) did not experience any significant change of the tricuspid valve function after LLE. CONCLUSION: Transthoracic and transoesophageal echocardiography findings showed that laser lead extraction was not associated with a significant increase in the incidence of tricuspid valve regurgitation.

Lead extraction with high frequency laser sheaths: a single-centre experience.

OBJECTIVES: Extraction of chronically implanted cardiac implantable electrophysiological devices leads can be difficult. Excimer laser-assisted extraction with 40 Hz sheaths has shown good results in challenging cases. In 2012, a new 80 Hz high-frequency laser sheath became available that delivers twice as many pulses per second. Here, we report our clinical experience with the new GlideLight 80 Hz laser sheath. METHODS: Between January 2012 and August 2016, 292 leads were treated in 151 patients using 80 Hz GlideLight laser sheath. Lead extraction indications included systemic infection or lead endocarditis n = 35 (23.2%), local infection n = 73 (48.3%), lead dysfunction n = 32 (21.2%), system upgrade n = 5 (3.3%), tricuspid regurgitation n = 3 (2.0%) and other indications n = 3 (2.0). All patient-related and procedural data were collected into a database and analysed. RESULTS: Mean patient's age was 66.2 ± 14.4 years, 73.5% were male. Ninety-one (31.2%) atrial, 159 (54.4%) ventricular and 42 (14.4%) coronary sinus leads had to be extracted. The mean time from initial lead implantation was 98.0 ± 65.2 months. Mean laser treatment time was 67.5 ± 71.3 s, mean laser pulses delivered were 5130 ± 6592. Clinical success was achieved in 99.3% of the cases, while complete procedural success was observed in 96.7%. A failure of extraction was seen in 2 (1.3%) patients. An overall complication rate of 2.0%, including two major (1.3%) and one minor (0.7%) complications, was observed. No periprocedural mortality was seen. CONCLUSIONS: The new GlideLight high-frequency laser sheath allows for a high safety and efficacy in extraction of chronically implanted pacemaker- and implantable cardioverter-defibrillator leads.

Laser lead extraction allows for safe and effective removal of single- and dual-coil implantable cardioverter defibrillator leads: A single-centre experience over 12 years.

OBJECTIVES: Lead extraction in patients with multiple or old leads of an implantable cardioverter defibrillator (ICD) is challenging. As adhesions are common at the side of the shock coils, we investigated success and procedural complication rates of laser lead extraction procedures in single- and dual-coil leads. METHODS: Between January 2001 and June 2013, 41 single- and 145 dual-coil ICD leads were extracted from 171 patients using laser sheaths. Procedural data, success rates and complications were collected into a database and retrospectively analysed. RESULTS: The mean patient age was 58.2 ± 16.1 years. The mean time from initial lead implantation to extraction was 50.3 ± 18.4 and 45.8 ± 14.5 months in the single- and dual-coil group, respectively (P = 0.1). In the single-coil group, complete procedural success was achieved in 36 of 37 (97.3%) cases, and clinical success in all cases (100.0%). In the dual-coil group, complete procedural success was seen in 131 out of 134 (97.8%) patients, and clinical success in 132 of 134 cases (98.5%). The transvenous extraction failed in 2 cases (1.5%). The overall complication rate was 2.7% in the single-coil group and 3.7% in the dual-coil group, respectively (P = 1.0). No deaths occurred during the 30-day follow-up. The mean laser treatment time was 1.8 ± 1.5 min for the single-coil group and 2.5 ± 1.2 min for dual-coil group (P = 0.002). CONCLUSIONS: Laser lead extraction allows for safe and effective removal of ICD leads. Compared with single-coil leads, the extraction of dual-coil leads is associated with longer laser treatment times but without statistically significant differences in complications and procedural success rates.

[Percutaneous implantable transcatheter pacemaker]. / Perkutan Katheter-basiert implantierbare Herzschrittmacher.

Electrical cardiac pacing today is the standard therapy for symptomatic bradycardia. Importantly, despite technical advantages, complications associated with conventional transvenous pacing leads and pockets are still challenging in a relevant number of patients. Beyond cosmetic benefits, miniaturized leadless pacemaker may partly overcome these limitations and beneficially influence implantation-related physical restrictions. Initial findings with single-chamber pacemakers for right ventricular pacing, which are completely implanted via a femoral venous vascular access, are promizing. In summary, leadless pacing offers novel perspectives regarding cardiac implantable electronic devices although acute safety and the long-term performance of these systems needs to be determined in more detail.

Coronary Sinus Lead Removal: A Comparison between Active and Passive Fixation Leads.

BACKGROUND: Implantation of coronary sinus (CS) leads may be a difficult procedure due to different vein anatomies and a possible lead dislodgement. The mode of CS lead fixation has changed and developed in recent years. OBJECTIVES: We compared the removal procedures of active and passive fixation leads. METHODS: Between January 2009 and January 2014, 22 patients at our centre underwent CS lead removal, 6 active and 16 passive fixation leads were attempted using simple traction or lead locking devices with or without laser extraction sheaths. Data on procedural variables and success rates were collected and retrospectively analyzed. RESULTS: The mean patient age was 67.2 ± 9.8 years, and 90.9% were male. The indication for lead removal was infection in all cases. All active fixation leads were Medtronic® Attain StarFix™ Model 4195 (Medtronic Inc., Minneapolis, MN, USA). The mean time from implantation for the active and passive fixation leads was 9.9 ± 11.7 months (range 1.0-30.1) and 48.7 ± 33.6 months (range 5.7-106.4), respectively (p = 0.012). Only 3 of 6 StarFix leads were successfully removed (50%) compared to 16 of 16 (100%) of the passive fixation CS leads (p = 0.013). No death or complications occurred during the 30-day follow-up. CONCLUSION: According to our experience, removal of the Starfix active fixation CS leads had a higher procedural failure rate compared to passive.

Signalling components involved in the coupling of alpha 1-adrenoceptors to phospholipase D in neonatal rat cardiac myocytes.

Activation of phospholipase D (PLD) is assumed to be one major pathway by which alpha(1)-adrenoceptors (alpha(1)ARs) induce hypertrophic responses in cardiac myocytes. Heterotrimeric G proteins, protein kinase C (PKC) isoforms, protein tyrosine kinases, monomeric GTPases of the ADP-ribosylation factor (ARF) and Rho families, and as important cofactor phosphatidylinositol 4,5-bisphosphate (PIP(2)) seem to participate in the G protein-coupled receptor dependent regulation of PLD. We therefore studied the role of these components in the coupling of alpha(1)ARs to PLD in neonatal rat cardiac myocytes (NRCM). Stimulation of alpha(1)ARs, most likely of the alpha(1A) subtype, by noradrenaline increased PLD activity three- to fourfold concomitant with the stimulation of phospholipase C (PLC). In contrast, the partial agonist phenylephrine stimulated PLC, but failed to increase PLD activity. The PLC and PLD responses were pertussis toxin insensitive and treatment of the cells with the G(q)-activating toxin of Pasteurella multocida stimulated both phospholipases about fourfold. Over-expression of the G(q)-and G(i)-type-specific regulator of G protein signalling RGS4 blunted alpha(1)AR-induced PLC and PLD stimulation. Ro 31-8220, known to inhibit Ca(2+)-dependent and -independent PKC isoforms, strongly inhibited PLD activity, whereas Gö 6976, known to inhibit preferentially Ca(2+)-dependent PKC isozymes, was without effect. The ARF signalling inhibitor brefeldin A, protein tyrosine kinase inhibitors and the Rho-inactivating toxin B of Clostridium difficile blunted alpha(1)AR-induced PLD stimulation and largely reduced the cellular PIP(2) content. In membranes of toxin B-treated NCRM, PLD activity was similarly reduced, but was fully restored by addition of exogenous PIP(2). We conclude, that alpha(1A)ARs stimulate PLD activity via a G(q/11)-PLCbeta-novel PKC isoform-dependent pathway in NRCM. ARF and Rho GTPases as well as protein tyrosine kinases contribute to PLD stimulation in NRCM, most likely by regulating the supply of PIP(2).

The bridge occlusion balloon for venous angioplasty in superior vena cava occlusion

Abstract The Bridge Occlusion Balloon is a compliant balloon, specifically designed for temporary Superior vena cava occlusion in case of Superior Vena Cava laceration during lead extraction procedures. We here report the first case, using Bridge Occlusion Ballon for a venous angioplasty in a patient with dysfunctional pacemaker leads and symptomatic Superior Vena Cava occlusion. After successful lead extraction, venography was showing a narrow venous canal. Therefore, venous angioplasty using the Bridge balloon was performed. Especially for high-risk lead extraction cases in patients with Superior Vena Cava stenosis, the Bridge Occlusion Ballon might be used as a combination of a safety-net in case of Superior Vena Cava perforation and for Superior Vena Cava angioplasty.

Shock efficacy of subcutaneous implantable cardioverter-defibrillator for prevention of sudden cardiac death: initial multicenter experience.

BACKGROUND: Recently, subcutaneous implantable cardioverter-defibrillator (S-ICD) has become available. The aim of our study was to assess the efficacy of S-ICD in a clinical setting. METHODS AND RESULTS: Between June 2010 and July 2011, 40 consecutive patients (42 ± 15 years; body mass index, 27 ± 6 kg/m(2); left ventricular ejection fraction, 47 ± 15%; 28 men) received an S-ICD for primary (n=17) or secondary prevention (n=23 [58%]) at 3 institutions in Germany. Intraoperative defibrillation efficacy testing failed in 1 patient with severely reduced left ventricular ejection fraction; testing was effective in all other patients. All episodes stored in the S-ICD were analyzed for appropriate and inappropriate detection, as well as effective shock delivery to convert ventricular tachyarrhythmia into sinus rhythm. During a median follow-up of 229 (interquartile range, 116-305) days, 4 patients experienced 21 episodes, with correct detection of ventricular tachyarrhythmia and subsequent shock therapy. A total of 28 shocks were delivered in these 4 patients. Mixed logistic regression modeling revealed a shock efficacy of 96.4% (95% CI, 12.8%-100%). The efficacy of first shocks, however, was only 57.9% (95% CI, 35.6%-77.4%). Four episodes were incorrectly classified as ventricular tachyarrhythmia, which led to inappropriate shock delivery in 2 patients. CONCLUSIONS: Ineffective shock delivery may occur in patients with S-ICD, even after successful intraoperative testing. Multicenter trials are required with close monitoring of safety and efficacy end points to identify patients who may be at risk for shock failure.