Zhang et al report in this issue,1 in their comparison of quality of care and outcomes of patients with left anterior hemiblock (LAHB) hospitalised with acute coronary syndrome (ACS), lower rates of coronary revascularisation and reperfusion and higher rates of in-hospital and 6-month unadjusted mortality. They suggest that the more conservative approach to ACS care is due to the coexistence of comorbidities in patients with LAHB.

The notion of an ACS risk-treatment paradox is, however, not new. Fox and colleagues used data from the international GRACE registry to demonstrate inequalities in care and outcomes for patients hospitalised with ACS across different healthcare systems—higher-risk patients were less likely to receive evidence-based therapies.2 What is novel in the study from Zhang and colleagues are the findings that (1) LAHB in the context of ACS was associated with higher-risk features of mortality; (2) despite this, patients with LAHB were less likely to receive guideline recommended care; and (3) after consideration of comorbidities, LAHB was not an independent predictor of early or late mortality among the 692 patients with LAHB from the cohort of over 11 000 patients from the international GRACE ECG substudy and Canadian ACS registry.

Unlike the first prognostic studies of LAHB in the context of ACS undertaken in the 1970s, which suggested that LAHB did not confer higher mortality rates,3 more recent research has revealed an increased risk of cardiac death associated with LAHB. On the one hand, the study by Zhang and colleagues corroborates these earlier investigations describing …