Real-world behavior of CRT pacing using the AdaptivCRT algorithm on patient outcomes: Effect on mortality and atrial fibrillation incidence.

BACKGROUND: The AdaptivCRT (aCRT) algorithm continuously adjusts cardiac resynchronization therapy (CRT) according to intrinsic atrioventricular conduction, providing synchronized left ventricular pacing in patients with normal PR interval and adaptive BiV pacing in patients with prolonged PR interval. Previous analyses demonstrated an association between aCRT and clinical benefit. We evaluated the incidence of patient mortality and atrial fibrillation (AF) with aCRT compared with standard CRT in a real-world population. METHODS AND RESULTS: Patients enrolled in the Medtronic Personalized CRT Registry and implanted with a CRT from 2013-2018 were divided into aCRT ON or standard CRT groups based upon device-stored data. A Frailty survival model was used to evaluate the potential survival benefit of aCRT, accounting for patient heterogeneity and center variability. Daily AF burden and first device-detected AF episodes of various durations were recorded by the device during follow-up. A total of 1814 CRT patients with no reported long-standing AF history at implant were included. Mean follow-up time was 26.1 ± 16.5 months and 1162 patients (64.1%) had aCRT ON. Patient survival probability at 36 months was 88.3% for aCRT ON and 83.7% for standard CRT (covariate-adjusted hazard ratio [HR] = 0.71, 95% CI: 0.53-0.96, P = .028). Mean AF burden during follow-up was consistently lower in aCRT ON patients compared with standard CRT. At 36 months, the probability of AF was lower in patients with aCRT ON, regardless of which AF definition threshold was applied (6 minutes-30 days, all P < .001). CONCLUSION: Use of the AdaptivCRT algorithm was associated with improved patient survival and lower incidence of AF in a real-world, prospective, nonrandomized registry.

Efeitos da estimulação diafragmática transcutânea sincronizada em pacientes com doença pulmonar obstrutiva crônica (DPOC): um estudo piloto / Effects of transcutaneous diaphragmatic synchronized pacing in patients with chronic obstructive pulmonary disease (COPD)

A pesquisa descrita neste artigo teve por objetivo avaliar quali-quantitativamente os efeitos da estimulação diafragmática transcutânea sincronizada em portadores de DPOC. Para isso, desenvolveu-se um sistema de estimulação elétrica controlado pelo sinal respiratório, a partir das variações de temperatura durante os eventos de inspiração e expiração, medidas por meio de dois termistores do tipo NTC inseridos dos lados interno e externo de uma máscara de respirador. Seis voluntários portadores de DPOC, de ambos os sexos, com idade entre 56 e 71anos, foram submetidos a 10 sessões estimulatórias de 20 minutos. O padrão do sinal estimulatório continha pulsos com duração de 90μs e repouso de 400μs, gerados em intervalos regulares e modulados em bursts com período ativo de 1470μs e inativo de 600μs, apresentando perfil trapezoidal com tempos de subida, descida e platô de 500ms cada. Todos os pacientes foram submetidos a uma avaliação inicial contendo: teste de força muscular respiratória avaliada por meio de PImáx e PEmáx, teste de função pulmonar e aplicação do questionário de qualidade de vida SGRQ. Após 10 sessões, houve um aumento na força muscular inspiratória em todos os pacientes, onde a PImáx sofreu um incremento médio de 66,67± 12,11cmH2O para 91,67 ± 25,03 cmH2O, a PEmáx de 92,50 ± 10,84 cmH2O para 116,67 ± 8,16 cmH2O. Também observou-se melhora da qualidade de vida no domínio sintoma, de 49,10± 19,40 para 28,60± 25,20; no domínio atividade, de 83,40± 12,50 para 67,57± 18,80; no domínio impacto, de 54,10± 11,34 para 38,00± 27,07; e escore total, de 65,50± 7,60 para 44,47± 22,31. A partir desses resultados, concluiu-se que a estimulação elétrica diafragmática sincronizada pode promover resultados positivos em portadores de DPOC.

The research described in this paper has the goal of evaluating the effects of transcutaneous diaphragmatic synchronized pacing in patients with COPD. In order to achieve the experimental protocol, it has been developed a system for electrical stimulation triggered by the respiratory signal obtained from the temperature variations during inspiration and expiration events, using two NTC thermistors coupled inside and outside of a respirator mask. It was studied six volunteers with COPD, of both sexes, aged between 56 to 71 years, who were submitted to 10sessions of 20minutes. The stimulatory parameters were set to: active phase of the pulse of 90μs, and inactive phase of 400μs, generated at regular intervals and modulated in bursts with active and inactive periods of 1470μs and 600μs, respectively; presenting trapezoidal envelope with rise time, fall time and plateau of 500ms. All patients underwent an initial assessment including: test of respiratory muscle strength seen through the MIP and MEP tests, lung function test and application of SGRQ quality of life questionnaire. After 10 sessions, there is an increasing inspiratory muscle strength in all patients, where MIP has an average increase of 66.67± 12.11cmH2O to 91.67 ± 25.03 cmH2O, MEP from 92.50 ± 10.84 cmH2O to 116.67 ± 8.16 cmH2O, and also observed a better quality of life in the symptom domain of 49.10± 19.40 to 28.60± 25.20, in the activity domain of 83.40± 12.50 to 67.57± 18.80, and in the impact domain of 54.10± 11.34 to 38.00± 27.07 and total score of 65.50± 7.60 to 44.47± 22.31. Therefore, we concluded that the transcutaneous diaphragmatic synchronized pacing can promote positive outcomes in patients with COPD.