Three Hot Line trials from ESC Congress 2026 – ASPIRED, DANISH-CRT, and His-Alternative II – test 14-day ECG monitoring in patients with unexplained syncope, compare cardiac resynchronization therapy (CRT) modalities, and assess targeted left ventricular lead placement at the site of latest electrical activation in patients with heart failure and prolonged QRS.

ASPIRED
In the ASPIRED trial, which was simultaneously published in NEJM, 14-day ambulatory ECG monitoring in patients with unexplained syncope after evaluation in the emergency department did not significantly decrease the number of patient-reported syncope episodes at one year, compared with standard care.

Matthew J. Reed, MD, et al., randomly assigned 2,234 patients (average age 58 years; 52% men) from 45 hospitals in the UK to either 14-day ambulatory ECG monitoring or standard care. The mean(±SD) number of patient-reported syncope episodes at one year was similar across both groups (1.37±5.10 in the ECG monitoring group vs. 1.58±8.56 in the standard-care group). In other findings, more adverse events (n=49) were reported in the ECG monitoring group, compared with the standard care group (n=8).

“Early ECG monitoring did not lead to lower recurrence of syncope than standard care,” said Reed and colleagues. “This finding probably reflects the multifactorial nature of syncope, with a clinically important arrhythmia identified in only 22.0% of the intervention group, a result that limited the effects of rhythm-directed therapy.”

DANISH-CRT
Results from the DANISH-CRT trial, published in the Lancet, showed targeted left ventricular lead placement at the site of latest electrical activation in patients with heart failure and prolonged QRS, did not reduce the composite endpoint of death or unplanned hospitalization for heart failure compared with conventional lead placement in a posterolateral, non-apical position.

Jens Cosedis Nielsen, DMSc, et al. enrolled approximately 1,000 patients with heart failure and wide QRS who were on guideline-directed medication and eligible for biventricular pacing. The primary endpoint occurred in 28% of patients (139/499) in the intervention group vs. 26% of patients (128/501) receiving conventional lead placement. Researchers noted no significant differences in overall complication risks between the two groups, but lead-related complications were more frequent among those receiving targeted left ventricular lead placement.

In a related editorial comment, Matthew Shun-Shin, MD, PhD, and Zachary Whinnett, MD, write that while “targeting the area of latest electrical activation did not produce a significant reduction in activation time, other approaches for delivering [CRT], such as directly targeting the conduction system with His-bundle or left-bundle approaches, have the potential to produce more notable effects on the electrical activation pattern, time and acute hemodynamics.”

They add, “Whether these techniques produce improvements in longer term outcomes needs to be established in prospective randomized controlled trials.”

His Alternative II
In the His Alternative II trial, simultaneously published in JACC: Clinical Electrophysiology, researchers found that CRT with conduction system pacing (CSP-CRT) in heart failure patients with left bundle branch block was noninferior to biventricular pacing (BiV-CRT) in the relative reduction of left ventricular end-systolic volume (LVESV) with six months of follow-up. In addition, both treatment modalities provided “excellent improvements” in left ventricular ejection fraction, QRS duration, heart failure symptoms and functional capacity.

“Our findings are in concordance with most of the randomized studies comparing CSP with BiV over the past years,” said Michael Vinther, MD, PhD, et al. “These studies have shown excellent and similar or even better responses with CSP-CRT compared to BiV-CRT and comparing our results to some of the latest European studies (CSP-Sync and Left Bundle CRT) the improvements in the patients randomized to CSP-CRT were almost identical regarding LVEF and LVESV. This suggests that the effect of CSP-CRT is reproducible among European centers.”

Visit ACC’s ESC Congress 2026 coverage page to explore the latest science and key takeaways shaping cardiovascular care.

Clinical Topics: Arrhythmias and Clinical EP, Cardiovascular Care Team, Heart Failure and Cardiomyopathies, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure

Keywords: ESC Congress, ESC26, Syncope, Electrocardiography, Ambulatory, Monitoring, Physiologic, Heart Failure, Pacemaker, Artificial, Cardiac Pacing, Artificial, Cardiac Resynchronization Therapy, Bundle-Branch Block