[Treatment with cardiac electronic implantable devices]. / Therapie mit kardialen elektronischen implantierbaren Devices.

Cardiac device therapy provides not only treatment options for bradyarrhythmia but also advanced treatment for heart failure and preventive measures against sudden cardiac death. In heart failure treatment it enables synergistic reverse remodelling and reduces pharmacological side effects. Cardiac resynchronization therapy (CRT) has revolutionized the treatment of reduced left ventricular ejection fraction (LVEF) and left bundle branch block by decreasing the mortality and morbidity with improvement of the quality of life and resilience. Conduction system pacing (CSP) as an alternative method of physiological stimulation can improve heart function and reduce the risk of pacemaker-induced cardiomyopathy. Leadless pacers and subcutaneous/extravascular defibrillators offer less invasive options with lower complication rates. The prevention of infections through preoperative and postoperative strategies enhances the safety of these therapies.

The need for a subsequent transvenous system in patients implanted with subcutaneous implantable cardioverter-defibrillator.

BACKGROUND: The absence of pacing capabilities may reduce the appeal of subcutaneous implantable cardioverter-defibrillator (S-ICD) devices for patients at risk for conduction disorders or with antitachycardia pacing (ATP)/cardiac resynchronization (CRT) requirements. Reports of rates of S-ICD to transvenous implantable cardioverter-defibrillator (TV-ICD) system switch in real-world scenarios are limited. OBJECTIVE: The purpose of this study was to investigate the need for a subsequent transvenous (TV) device in patients implanted with an S-ICD and its predictors. METHODS: All patients implanted with an S-ICD were enrolled from the multicenter, real-world iSUSI (International SUbcutaneouS Implantable cardioverter defibrillator) Registry. The need for a TV device and its clinical reason, and appropriate and inappropriate device therapies were assessed. Logistic regression with Firth penalization was used to assess the association between baseline and procedural characteristics and the overall need for a subsequent TV device. RESULTS: A total of 1509 patients were enrolled (age 50.8 ± 15.8 years; 76.9% male; 32.0% ischemic; left ventricular ejection fraction 38% [30%-60%]). Over 26.5 [13.4-42.9] months, 155 (10.3%) and 144 (9.3%) patients experienced appropriate and inappropriate device therapies, respectively. Forty-one patients (2.7%) required a TV device (13 bradycardia; 10 need for CRT; 10 inappropriate shocks). Body mass index (BMI) >30 kg/m2 and chronic kidney disease (CKD) were associated with need for a TV device (odds ratio [OR] 2.57 [1.37-4.81], P = .003; and OR 2.67 [1.29-5.54], P = .008, respectively). CONCLUSION: A low rate (2.7%) of conversion from S-ICD to a TV device was observed at follow-up, with need for antibradycardia pacing, ATP, or CRT being the main reasons. BMI >30 kg/m2 and CKD predicted all-cause need for a TV device.

Age-related differences and associated mid-term outcomes of subcutaneous implantable cardioverter-defibrillators: A propensity-matched analysis from a multicenter European registry.

BACKGROUND: A few limited case series have shown that the subcutaneous implantable cardioverter-defibrillator (S-ICD) system is safe for teenagers and young adults, but a large-scale analysis currently is lacking. OBJECTIVES: The purpose of this study was to compare mid-term device-associated outcomes in a large real-world cohort of S-ICD patients, stratified by age at implantation. METHODS: Two propensity-matched cohorts of teenagers + young adults (≤30 years old) and adults (>30 years old) were retrieved from the ELISIR Registry. The primary outcome was the comparison of inappropriate shock rate. Complications, freedom from sustained ventricular arrhythmias, and overall and cardiovascular mortality were deemed secondary outcomes. RESULTS: Teenagers + young adults represented 11.0% of the entire cohort. Two propensity-matched groups of 161 patients each were used for the analysis. Median follow-up was 23.1 (13.2-40.5) months. In total, 15.2% patients experienced inappropriate shocks, and 9.3% device-related complications were observed, with no age-related differences in inappropriate shocks (16.1% vs 14.3%; P = .642) and complication rates (9.9% vs 8.7%; P = .701). At univariate analysis, young age was not associated with increased rates of inappropriate shocks (hazard ratio [HR] 1.204 [0.675-2.148]: P = .529). At multivariate analysis, use of the SMART Pass algorithm was associated with a strong reduction in inappropriate shocks (adjusted HR 0.292 [0.161-0.525]; P <.001), whereas arrhythmogenic right ventricular cardiomyopathy (ARVC) was associated with higher rates of inappropriate shocks (adjusted HR 2.380 [1.205-4.697]; P = .012). CONCLUSION: In a large multicenter registry of propensity-matched patients, use of the S-ICD in teenagers/young adults was safe and effective. The rates of inappropriate shocks and complications between cohorts were not significantly different. The only predictor of increased inappropriate shocks was a diagnosis of ARVC.

Comparison of transvenous vs subcutaneous defibrillator therapy in patients with cardiac arrhythmia syndromes and genetic cardiomyopathies.

BACKGROUND: Inherited arrhythmia syndromes and genetic cardiomyopathies attribute in a significant proportion to sudden cardiac death. Implantable cardioverter defibrillators (ICDs) are the cornerstone in the prevention of sudden death in high-risk patients. However, ICD therapy is also associated with high rates of inappropriate shocks and/or device-related complications especially in young patients. OBJECTIVE: To determine the outcome of high-risk patients with inherited arrhythmia syndromes and genetic cardiomyopathies comparing two defibrillator technologies. METHOD: Between 2010 and 2018, 183 consecutive patients from two large German tertiary care centers were enrolled in the study. The majority of patients (83%) had either cardiac channelopathies or idiopathic ventricular fibrillation without cardiac structural abnormalities, while the remaining 17% had a genetic cardiomyopathy (HCM/ARVC). Eighty-six patients (47%) received a transvenous ICD (TV-ICD), while a subcutaneous ICD (S-ICD) was implanted in another 97 patients (53%). RESULTS: During a mean follow-up of 4.3 years, 30 patients had an appropriate ICD therapy (annual rate 3.8%). Fifteen patients experienced an inappropriate shock (annual rate 1.9%). Lead failure occurred in 17 (9%) patients and was less frequent in the S-ICD group (OR 0.48, 95%CI 0.38-0.62). Adverse defibrillator events, defined as a composite of inappropriate shocks and lead failure requiring surgical revision were significantly lower in the S-ICD group as compared to the TV-ICD group (OR 0.55, 95%CI 0.41-0.72). There was a non-significant trend towards lower appropriate shocks in the S-ICD group, that in combination with all-cause shocks yielded in a significantly higher freedom of any shock in the S-ICD group (RR 39%, p = 0.003). No deaths occurred during follow-up. CONCLUSION: The present data favor the use of the subcutaneous ICD for patients with inherited arrhythmia syndromes and genetic cardiomyopathies who do not need anti-bradycardia pacing.

Incidence, mechanisms, and clinical impact of inappropriate shocks in patients with a subcutaneous defibrillator.

AIMS: Inappropriate shocks (IAS) remain a challenge for patients and physicians after implantation of the subcutaneous implantable cardioverter-defibrillator (S-ICD). The aims were to assess and characterize different patterns of IAS. METHODS AND RESULTS: Two hundred and thirty-nine patients were implanted with an S-ICD between 2010 and 2018 for primary and secondary prevention. Follow-up data of at least 6 months were analysed. During a mean follow-up of 34.9 ± 16.0 months, a total of 73 shocks occurred in 38 patients (6%). Forty-three (59%) shocks were considered appropriate due to ventricular tachycardia/ventricular fibrillation, while 30 (41%) were inappropriate and occurred in 19 patients (8%). Myopotentials/noise was the most frequent cause of inappropriate shocks (n = 8), followed by T-wave oversensing (n = 6) and undersensing of the QRS, resulting in adaptation of the automatic gain control and inappropriate shock (n = 5). Seventy-four percent of all IAS occurred on the primary vector, while no IAS occurred on the alternate vector. In seven of eight patients (88%), IAS related to myopotentials have occurred on the primary sensing vector. Multivariate analysis identified taller patients, primary sensing vector and first-generation S-ICD device as predictors for IAS. SMART pass effectively reduced the occurrence of IAS in the second-generation S-ICD system. CONCLUSION: Inappropriate therapies are less frequently observed on the alternate vector. The primary vector seems to be unfavourable with regard to oversensing caused by myopotentials. Inappropriate shocks were associated with an increased rate of rehospitalization but not mortality. These observations have implications for the prevention of inappropriate S-ICD shocks.

Defibrillation failure in patients undergoing replacement of subcutaneous defibrillator pulse generator.

BACKGROUND: Defibrillation threshold (DFT) testing is commonly performed in patients undergoing subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation. Growing evidence indicates that successful DFT testing correlates with the technique used for implantation of the defibrillation lead and pulse generator. However, evidence on whether DFT testing should be performed in patients undergoing S-ICD pulse generator replacement is lacking. OBJECTIVE: The purpose of this study was to determine the outcome of DFT testing in patients undergoing replacement of an S-ICD pulse generator. METHODS: A total of 357 S-ICD implantations were performed between November 2010 and July 2019. Twenty-five consecutive patients underwent S-ICD replacement between 2015 and 2019. Clinical data, perioperative medication, technical measurements, and PRAETORIAN score were assessed and grouped according to the outcome of DFT testing. RESULTS: In 5 of 25 patients (20%), induced ventricular fibrillation was not successfully terminated after the first or second 65-J shock after pulse generator replacement with need for external defibrillation. Repositioning of the pulse generator and/or capsulectomy at the pocket site were necessary to achieve effective DFT with 65 J in all cases. Shock impedance increased in all patients at the time of pulse generator replacement compared to first implantation and was significantly higher in patients with ineffective DFT (119 ± 17 Ω vs 93 ± 26 Ω; P = .03). Otherwise, no differences in clinical characteristics, comorbidities, body mass index, intraoperative medication, or PRAETORIAN score were predictive of defibrillation failure. CONCLUSION: The high proportion of patients with DFT failure after S-ICD pulse generator replacement indicates that DFT testing is mandatory to ensure safe function of the S-ICD.

Long-term results of combined cardiac contractility modulation and subcutaneous defibrillator therapy in patients with heart failure and reduced ejection fraction.

BACKGROUND: Cardiac contractility modulation (CCM) is an electrical-device therapy for patients with heart failure with reduced ejection fraction (HFrEF). Patients with left ventricular ejection fraction (LVEF) ≤35% also have indication for an implantable cardioverter-defibrillator (ICD), and in some cases subcutaneous ICD (S-ICD) is selected. HYPOTHESIS: CCM and S-ICD can be combined to work efficaciously and safely. METHODS: We report on 20 patients with HFrEF and LVEF ≤35% who received CCM and S-ICD. To exclude device interference, patients received intraoperative crosstalk testing, S-ICD testing, and bicycle exercise testing while CCM was activated. Clinical and QOL measures before CCM activation and at last follow-up were analyzed. S-ICD performance was evaluated while both CCM and S-ICD were active. RESULTS: Mean follow-up was 34.3 months. NYHA class improved from 2.9 ± 0.4 to 2.1 ± 0.7 (P < 0.0001), Minnesota Living With Heart Failure Questionnaire score improved from 50.2 ± 23.7 to 29.6 ± 22.8 points (P < 0.0001), and LVEF improved from 24.4% ± 8.1% to 30.9% ± 9.6% (P = 0.002). Mean follow-up time with both devices active was 22 months. Three patients experienced a total of 6 episodes of sustained ventricular tachycardia, all successfully treated with first ICD shock. One case received an inappropriate shock unrelated to the concomitant CCM. One patient received an LVAD, so CCM and S-ICD were discontinued. CONCLUSIONS: CCM and S-ICD can be successfully combined in patients with HFrEF. S-ICD and CCM remain efficacious when used together, with no interference affecting their function.