Researchers have examined the relationship between different degrees of QRS prolongation and different QRS morphologies and clinical outcomes in patients with heart failure, reduced ejection fraction ( HF-rEF ), and mild symptoms in the Eplerenone in Mild Patients Hospitalization and SurvIval Study in Heart Failure trial ( EMPHASIS-HF ).
Researchers have also evaluated the effect of Eplerenone in these patients according to QRS duration / morphology.
Patients were categorized as: QRS duration (ms) (i) less than 120 ( n = 1375 ); (ii) 120-149 ( n = 517 ); and (iii) greater than or equal to 150 ( n = 383 ), and QRS morphology (i) normal ( n = 1252 ); (ii) left bundle branch block ( BBB ) ( n = 608 ); and (iii) right BBB / intraventricular conduction defect ( IVCD ) ( n = 415 ).
The outcomes examined were the composite of cardiovascular death or heart failure hospitalization and all-cause mortality. Both abnormal QRS duration and QRS morphology were associated with higher risk, e.g. the rates of the composite outcome were: 10.2, 17.6, and 15.5 per 100 patient-years in the less than 120, 120-149, and greater than or equal to 150 ms groups, respectively.
Eplerenone reduced the risk of the primary outcome and mortality, compared with placebo, consistently across the QRS duration / morphology subgroups.
In conclusion, researchers found that even moderate prolongation of QRS duration and right BBB/IVCD were associated with a high risk of adverse outcomes in HF-REF.
Eplerenone was similarly effective, irrespective of QRS duration / morphology. ( Xagena )
Cannon JA et al, Eur J Heart Fail 2015;17:707-716