Fragmented QRS and mortality risk in patients with left ventricular dysfunction

Area of Science:

• Cardiology
• Electrophysiology
• Preventive Medicine

Background:

• Fragmented QRS (fQRS) is a marker associated with cardiac events in some populations.
• Its utility in selecting primary prevention patients for implantable cardioverter-defibrillator (ICD) therapy is not established.

Purpose of the Study:

• To investigate whether fQRS improves risk stratification for primary prevention patients with left ventricular dysfunction eligible for ICD therapy.

Main Methods:

• A prospective, multisite cohort study of 842 patients with ejection fraction <=35% was conducted.
• ECG assessment for fQRS was performed, and its association with all-cause and arrhythmic mortality was evaluated.
• Multivariable Cox regression models, adjusted for clinical variables, were used to analyze outcomes stratified by ICD status.

Main Results:

• Fragmented QRS was present in 32.5% of patients.
• No significant difference in all-cause mortality (19.7% vs 24.1%) or arrhythmic mortality (9.9% vs 12.7%) was observed between fQRS-positive and fQRS-negative groups.
• Subgroup analyses by ICD status, etiology, or QRS duration did not reveal an association between fQRS and mortality.

Conclusions:

• In primary prevention patients with left ventricular dysfunction, fQRS on ECG is not associated with increased all-cause or arrhythmic mortality.
• These results do not support the use of fQRS for risk stratification in primary prevention patients considered for ICD therapy.