Electrical and mechanical components of dyssynchrony in heart failure patients with normal QRS duration and left bundle-branch block. Impact of left and biventricular pacing*1
ACC Current Journal Review(2004)
Abstract
The benefits of cardiac resynchronization therapy (CRT) documented in heart failure (HF) may be influenced by atrial fibrillation (AF). We aimed to compare CRT response in patients in AF and in sinus rhythm (SR).We prospectively studied 101 HF patients treated by CRT. Rates of clinical, echocardiographic and functional response, baseline NYHA class and variation, left ventricular ejection fraction, volumes and mass, atrial volumes, cardiopulmonary exercise test (CPET) duration (CPET dur), peak oxygen consumption (VO2max) and ventilatory efficiency (VE/VCO2 slope) were compared between AF and SR patients, before and at three and six months after implantation of a CRT device.All patients achieved ≥95% biventricular pacing, and 5.7% underwent atrioventricular junction ablation. Patients were divided into AF (n=35) and SR (n=66) groups; AF patients were older, with larger atrial volumes and lower CPET dur and VO2max before CRT. The percentages of clinical and echocardiographic responders were similar in the two groups, but there were more functional responders in the AF group (71% vs. 39% in SR patients; p=0.012). In SR patients, left atrial volume and left ventricular mass were significantly reduced (p=0.015 and p=0.021, respectively), whereas in AF patients, CPET dur (p=0.003) and VO2max (p=0.001; 0.083 age-adjusted) showed larger increases.Clinical and echocardiographic response rates were similar in SR and AF patients, with a better functional response in AF. Improvement in left ventricular function and volumes occurred in both groups, but left ventricular mass reduction and left atrial reverse remodeling were seen exclusively in SR patients (ClinicalTrials.gov identifier: NCT02413151; FCT code: PTDC/DES/120249/2010).Os benefícios da terapêutica de ressincronização cardíaca (TRC), documentados na insuficiência cardíaca (IC), poderão ser influenciados pela fibrilhação auricular (FA). Pretendemos avaliar comparativamente efeitos TRC em doentes em FA e em ritmo sinusal (RS).Foram estudados prospetivamente 101 doentes submetidos a TRC. Percentagens de respondedores clínicos, ecocardiográficos e funcionais, valores basais e variação de classe NYHA, fração de ejeção, volumes e massa ventriculares esquerdos, volumes auriculares, duração da prova de esforço cardiorrespiratória (PECR dur), consumo pico de oxigénio (VO2p) e eficiência ventilatória de esforço (VE/VCO2) foram comparados entre grupos FA e RS, pré-implantação TRC e nos seis meses após implantação.Os doentes tiveram percentagens de pacing biventricular ≥95%, com 5,7% de ablação auriculoventricular juncional. Definimos grupo FA (n=35) e grupo RS (n=66), tendo os doentes com FA idade superior, maiores volumes auriculares, menores PECR dur e VO2p pré-CRT. Percentagens de respondedores clínicos e ecocardiográficos foram idênticas nos dois grupos, mas de respondedores funcionais foram superiores nos doentes FA (71 versus 39% no grupo RS; p=0,012). Nos doentes RS verificou-se a redução significativa do volume auricular esquerdo e da massa ventricular esquerda (p=0,015 e p=0,021, respetivamente) e nos doentes com FA maior aumento da PECR dur (p=0,003) e VO2p (p=0,001; p=0,083 ajustado para idade).As respostas clínica e ecocardiográfica à TRC foram semelhantes nos doentes FA e RS, com resposta funcional superior em FA. A melhoria de função e dimensões ventriculares esquerdas foi idêntica nos dois grupos, contudo redução de massa ventricular esquerda e remodelagem inversa auricular esquerda foram exclusivas de doentes RS (ClinicalTrials.gov Identifier: NCT02413151; FCT code: PTDC/DES/120249/2010).
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Key words
heart failure patients,heart failure,dyssynchrony,normal qrs duration,bundle-branch
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