Paced QT interval as a risk factor for new-onset left ventricular systolic dysfunction and cardiac death after...

Area of Science:

• Cardiology
• Electrophysiology
• Cardiac Pacing

Background:

• Prolonged corrected QT (QTc) interval is a known risk factor for fatal arrhythmias and cardiac death.
• The association between paced-QTc (p-QTc) interval and new-onset left ventricular systolic dysfunction (new-LVSD) or cardiac death post-pacemaker implantation is not well-established.

Purpose of the Study:

• To investigate the relationship between the p-QTc interval and the incidence of new-LVSD and cardiac death in patients receiving permanent pacemaker (PPM) implantation.
• To determine if p-QTc interval prolongation is an independent predictor of adverse cardiac events after PPM.

Main Methods:

• A cohort of 491 patients with preserved left ventricular ejection fraction undergoing PPM implantation were studied.
• The p-QTc interval was measured within two weeks post-implantation, and patients were followed for new-LVSD and cardiac death.
• Statistical analyses, including Cox regression, were used to assess the association between p-QTc interval and outcomes.

Main Results:

• During a median follow-up of 78 months, 10.8% developed new-LVSD and 5.3% experienced cardiac death.
• Patients with new-LVSD showed more frequent atrioventricular block, higher ventricular pacing percentage, longer p-QRS duration, and prolonged p-QTc intervals.
• A graded increase in new-LVSD and cardiac death rates was observed across tertiles of p-QTc interval, with independent association found in Cox regression.

Conclusions:

• Prolonged p-QTc interval is significantly associated with new-LVSD and cardiac death in patients with preserved LV function after PPM implantation.
• The risk of cardiac death is particularly elevated in patients with both new-LVSD and a wider p-QTc interval.