Objectives We sought to determine the yield of cardiac testing and to identify predictors of cardiac disease in infants with an apparent life-threatening event (ALTE).

Design Retrospective longitudinal cohort study.

Setting Paediatric hospital providing primary and tertiary care that is part of an integrated healthcare system.

Patients Infants hospitalised for an ALTE from 1999 to 2003.

Main exposures Cardiac testing used at time of ALTE and results, and clinical risk factors for cardiac disease.

Outcome measures Short-term (during hospitalisation) and long-term (through November 2009) follow-up for any diagnosis of significant cardiac anatomic or rhythm abnormality.

Results Study criteria were met by 485 infants (mean age 1.9, SD±2.2 months; 49% boys). Cardiac testing was performed on 219 (45%) patients during ALTE hospitalisation, identifying two patients with significant cardiac disease (cardiomyopathy, ventricular pre-excitation). During 7.7 years of follow-up, three additional significant cardiac diagnoses (ventricular pre-excitation, frequent ventricular ectopy, moderate aortic stenosis) were identified. All cardiac tests had low positive predictive value (PPV). Significant cardiac disease was associated with prematurity (22% vs 80%, p=0.002), but not age, gender, prior ALTE or rescue breaths.

Conclusions This longitudinal study of an ALTE cohort revealed significant cardiac disease in <1% of patients. Prematurity was the only clinical predictor identified. ECG was sensitive for identifying significant cardiac disease, but routine testing warrants further investigation because of the low PPV.