Left bundle-branch area pacing cut heart failure events against right ventricular pacing in AV block

The edition in brief

LEAP-Block, published in JAMA on 28 October, randomised 499 patients across 14 Chinese hospitals with atrioventricular block, LVEF of 50% or more and an expected ventricular pacing burden above 40% to left bundle-branch area pacing or conventional right ventricular pacing. At 24 months the composite of death, heart failure events or upgrade to biventricular pacing occurred in 2.4% against 12.5% (absolute difference -10.1%, 95% CI -16.8 to -3.4), driven by heart failure events; mortality, upgrades and complications did not differ. Left bundle-branch capture was confirmed in about 80%. A JACC review argues that high-sensitivity troponin has turned detection into a classification problem: non-ischaemic injury is often mislabelled as type 2 MI, while chronic injury, which carries substantial risk, is dismissed once infarction is excluded. A pooled European Heart Journal analysis of six heart failure cohorts and trials found that low-dose mineralocorticoid receptor antagonists raise aldosterone and that the association between MRA use and outcomes depended on pre-treatment aldosterone: HR 0.63 with high levels, HR 1.66 with low levels. The authors call this hypothesis-generating, and MRAs remain guideline therapy. The pearl covers reversible causes to exclude before pacing for heart block.