Projected longevities of cardiac implantable defibrillators: a retrospective analysis over the period 2007-17 and the impact of technological factors in determining longevity.

AIMS: Implanters of cardiac implantable electronic devices cannot easily choose devices by longevity as usually current models only have projected longevity data since those with known performance are obsolete. This study examines how projected device longevities are derived, the influencing factors, and their roles in guiding model choice. METHODS AND RESULTS: Ninety-eight implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy-defibrillator (CRT-D) models released in Europe in 2007-17 were analysed for reported battery capacities, projected longevities for standardized settings stipulated by the French Haute Autorité de Santé (HAS) and manufacturer-chosen settings. Battery capacities and HAS projected longevities increased during the study period. Based on current drain estimation, therapy functions consumed only a small portion (2-7%) of the battery energy for single- and dual-chamber ICDs, but up to 50% (from biventricular pacing) for CRT-Ds. Large differences exist between manufacturers and models both in terms of battery capacity and energy consumption. CONCLUSION: Battery capacity is not the sole driver of longevity for electronic implantable cardiac devices and, particularly for ICDs, the core function consume a large part of the battery energy even in the absence of therapy. Providing standardized current drain consumption in addition to battery capacity may provide more meaningful longevity information among implantable electronic cardiac devices.

"Real-world" performance of the Confirm Rx™ SharpSense AF detection algorithm: UK Confirm Rx study.

Introduction: The novel Confirm Rx™ implantable cardiac monitor (ICM) with SharpSense™ technology incorporates a new P-wave discriminator designed to improve AF detection. This study aimed to evaluate the diagnostic performance of the Confirm Rx™ ICM in detecting AF episodes of varying durations. Methods: We conducted a multicenter retrospective analysis of consecutive patients implanted with a Confirm Rx™ ICM (v1.2) across nine UK hospitals, all with documented AF lasting at least 6 min. Electrocardiograms (ECGs) were manually adjudicated by cardiologists. To account for intra- and inter-reviewer variability, a random sample of 10% of ECGs underwent additional review. Disagreements were resolved by a third reviewer. Diagnostic performance was determined by calculating the gross and patient-averaged positive predictive value (PPV) for AF episodes of different duration. The source of false positive (FP) detection was also categorized. Results: Overall, 16,230 individual ECGs from 232 patients were included. The median AF episode duration was 14 min. R-wave amplitude remained stable during follow-up (0.52 ± 0.27 mV [initial] vs. 0.54 ± 0.29 mV [end of follow-up], p = .10). The gross and patient-averaged PPV were 75.0% and 67.0%, respectively. Diagnostic performance (gross) increased with progressively longer AF episodes: 88.0% for ≥1 h, 97.3% for 6 h, and 100% for 24 h. The main source of FP during tachycardia was T-wave oversensing (54.2%), while in non-tachycardic episodes it was predominantly ectopy (71.2%). The AF burden precision was excellent (93.3%). Conclusion: The Confirm Rx™ ICM diagnostic performance was modest for all AF episodes (75%), with accuracy increasing for longer AF episodes.

Predictive value of the PRAETORIAN score for defibrillation test success in patients with subcutaneous ICD: A subanalysis of the PRAETORIAN-DFT trial.

BACKGROUND: The PRAETORIAN score estimates the risk of failure of subcutaneous implantable cardioverter-defibrillator (S-ICD) therapy by using generator and lead positioning on bidirectional chest radiographs. The PRospective randomized compArative trial of subcutanEous implanTable cardiOverter-defibrillatoR ImplANtation with and without DeFibrillation Testing (PRAETORIAN-DFT) investigates whether PRAETORIAN score calculation is noninferior to defibrillation testing (DFT) with regard to first shock efficacy in spontaneous events. OBJECTIVE: This prespecified subanalysis assessed the predictive value of the PRAETORIAN score for defibrillation success in induced ventricular arrhythmias. METHODS: This multicenter investigator-initiated trial randomized 965 patients between DFT and PRAETORIAN score calculation after de novo S-ICD implantation. Successful DFT was defined as conversion of induced ventricular arrhythmia in <5 seconds from shock delivery within 2 attempts. Bidirectional chest radiographs were obtained after implantation. The predictive value of the PRAETORIAN score for DFT success was calculated for patients in the DFT arm. RESULTS: In total, 482 patients were randomized to undergo DFT. Of these patients, 457 (95%) underwent DFT according to protocol, of whom 445 (97%) had successful DFT and 12 (3%) had failed DFT. A PRAETORIAN score of ≥90 had a positive predictive value of 25% for failed DFT, and a PRAETORIAN score of <90 had a negative predictive value of 99% for successful DFT. A PRAETORIAN score of ≥90 was the strongest independent predictor for failed DFT (odds ratio 33.77; confidence interval 6.13-279.95; P < .001). CONCLUSION: A PRAETORIAN score of <90 serves as a reliable indicator for DFT success in patients with S-ICD, and a PRAETORIAN score of ≥90 is a strong predictor for DFT failure.

Dilated cardiomyopathy: the role of genetics, highlighted in a family with Filamin C (FLNC) variant.

Dilated cardiomyopathy (DCM) is a heterogenous group of disorders characterised by left ventricular dilatation and dysfunction, in the absence of factors affecting loading conditions such as hypertension or valvular disease, or significant coronary artery disease. The prevalence of idiopathic DCM is estimated between 1:250 and 1:500 individuals. Determining the aetiology of DCM can be challenging, particularly when evaluating an individual and index case with no classical history or investigations pointing towards an obvious acquired cause, or no clinical clues in the family history to suggest a genetic cause. We present a family affected by DCM associated with Filamin C variant, causing sudden cardiac death at a young age and heart failure due to severe left ventricular impairment and myocardial scarring. We review the diagnosis and treatment of DCM, its genetic associations and potential acquired causes. Thorough assessment is mandatory to risk stratify and identify patients who may benefit from primary prevention implantable cardioverter defibrillator therapy according to international guidelines. Genetic testing has some limitations, and is positive in only 20%-35% of DCM, but should be considered in specific cases to identify families who may benefit from cascade screening after appropriate counselling. The management of often complex familial cardiomyopathy requires specialist input for every case, and the appropriate infrastructure to coordinate investigations.