A previously considered benign ECG finding – left anterior fascicular block – may be an ‘important predictor’ of subsequent cardiovascular disease or death, according to researchers.
US researchers looked at 1,664 individuals without overt cardiovascular disease, hypertension and diabetes and a diagnosis of LAFB. LAFB wasdefined as a QRS axis between -45 degrees and -90 degrees and QRS duration of less than 0.12 seconds in the absence of left ventricular hypertrophy, inferior myocardial infarction, and ventricular pre-excitation on the baseline ECG.
After adjusting for age, sex, race, BMI, systolic BP, smoking, alcohol consumption, income and study centre, individuals with LAFB had a 89% increased risk of atrial fibrillation, a 143% increased risk of congestive heart failure and a 57% increased risk of death, compared with those with a normal ECG.
LAFB was strongly linked to death from cardiovascular causes, with an adjusted hazard ratio of 2.02.
What does it mean for GPs?
The authors concluded: ‘Given previous histopathological studies, these findings suggest that LAFB may be a clinically relevant marker of an individual’s propensity to left heart fibrosis. Further research is needed to determine if LAFB is an important predictor of consequent adverse outcomes.’