Prevalence, clinical profile and prognostic implications of interatrial block in patients admitted for heart failure

Abstract Introduction and objectives To describe the prevalence, clinical profile, and prognostic significance of interatrial block (IAB) in heart failure (HF) inpatients. Methods We included prospectively 557 hospitalized HF patients with sinus rhythm from nationwide registry. Partial IAB was defined as a P wave duration ≥120 ms, and advanced IAB as a P wave duration ≥120 ms with biphasic morphology in inferior electrocardiogram (ECG) leads. Clinical, blood test, and echocardiographic data were analyzed in a Cox regression to determine the impact of IAB at discharge on prognosis. The primary outcome was a composite of mortality or readmission for HF at 1-, 6-, and 12-month. Results Normal P wave, partial, and advanced IAB were identified in the discharge ECG in 336 (60.3%), 118 (21.1%), and 103 (18.5%) patients, respectively. The independent factors related to IAB at discharge were previous history of HF (OR, 1.78; 95%CI, 1.23–2.57), valvular HF etiology (OR, 1.88; 95%CI, 1.18–3.00), heart rate at admission (OR, 1.10 per 10 beats; 95%CI, 1.03–1.17) and left atrial diameter (OR, 1.24 per 5 mm; 95%CI, 1.11–1.38). The incidence of 1-, 6-, and 12-month mortality/readmission for HF was 4.8%, 7.7%, and 33.0% in normal P wave, 1.7%, 7.6%, and 33.2% in partial IAB, and 3.9%, 9.7%, and 36.9% in advanced IAB. Multivariable analysis showed no significant effect of IAB in major acute cardiovascular events. Conclusions IAB is found in 40% of patients in sinus rhythm discharged after a HF hospitalization. This ECG pattern at discharge does not imply a greater risk of readmission or death during the first year.