Impact of atrial fibrillation type during acute coronary syndromes: Clinical features and prognosis

IntroductionAtrial fibrillation (AF) is widely recognized as an adverse prognostic factor during acute myocardial infarction, although the impact of AF type – new-onset (nAF) or pre-existing (pAF) – is still controversial.ObjectivesTo identify the clinical differences and prognosis of nAF and pAF during acute coronary syndromes (ACS).MethodsWe performed a retrospective observational cohort study including 1373 consecutive patients (mean age 64 years, 77.3% male) admitted to a single center over a three-year period, with a six-month follow-up.ResultsAF rhythm was identified in 14.5% patients, of whom 71.4% presented nAF and 28.6% pAF. When AF types were compared, patients with nAF more frequently presented with ST-elevation ACS (p=0.003). Patients with pAF, in turn, were older (p=0.032), had greater left atrial diameter (p=0.001) and were less likely to have significant coronary lesions (p=0.034). Regarding therapeutic strategy, nAF patients were more often treated by rhythm control during hospital stay (p<0.001) and were less often anticoagulated at discharge (p=0.001). Compared with the population without AF, nAF was a predictor of death during hospital stay in univariate (p<0.001) and multivariate analysis (OR 2.67, p=0.047), but pAF was not. During follow-up, pAF was associated with higher mortality (p=0.014), while nAF patients presented only a trend towards worse prognosis.ConclusionsAF during the acute phase of ACS appears to have a negative prognostic impact only in patients with nAF and not in those with pAF.

ResumoIntroduçãoA fibrilhação auricular (FA) é um reconhecido fator de mau prognóstico no enfarte agudo do miocárdio, no entanto, o impacto do tipo de FA, de novo (FAn) ou pré-existente (FAp), é ainda controverso.ObjetivosIdentificar as diferenças clínicas e o prognóstico da FAn e da FAp nas síndromes coronárias agudas (SCA).MétodosEstudo retrospetivo observacional de coorte, incluindo 1373 doentes consecutivos (idade média 64 anos, 77,3% homens) com SCA, admitidos num hospital, ao longo de três anos, com follow-up de seis meses.ResultadosA FA foi identificada em 14,5% doentes, dos quais 71,4% tinham FAn e 28,6% FAp. Comparando os tipos de FA, verificou-se que os doentes com FAn apresentaram mais frequentemente SCA com elevação do segmento ST (p=0,003). Por sua vez, a FAp foi mais comum em doentes idosos (p=0,032), com diâmetro superior da aurícula esquerda (p=0,001) e ausência de doença coronária (p=0,034). Quanto à estratégia terapêutica, os doentes com FAn foram mais vezes submetidos a controlo de ritmo durante o internamento (p<0,001), mas menos hipocoagulados à alta (p=0,001). Quando comparada com a população sem FA, a FAn foi preditora de morte hospitalar na análise univariada (p<0,001) e multivariada (OR 2,67, p=0,047), enquanto a FAp não. Já no follow-up, a FAp associou-se a maior mortalidade (p=0,014), enquanto os doentes com FAn apresentaram apenas uma tendência para um pior prognóstico.ConclusõesO impacto prognóstico negativo da FA na fase aguda das SCA parece ocorrer apenas nos doentes que apresentam FAn e não naqueles com FAp.