Fragmented QRS (fQRS) Index Calculator

Fragmented QRS (fQRS) Index: Explanation and Clinical Context Fragmented QRS (fQRS) refers to additional R waves (R’) or notching in the nadir of the S wave in contiguous ECG leads, representing myocardial conduction delay due to fibrosis or scarring. The fQRS Index is calculated as the number of ECG leads showing fQRS divided by the total number of leads (usually 12-lead ECG), providing a quantitative measure of myocardial scarring burden. A higher fQRS Index is associated with increased risk of adverse cardiac events, including arrhythmias and sudden cardiac death, particularly in patients with ischemic or non-ischemic cardiomyopathy.

This tool allows clinicians to stratify risk and potentially guide closer monitoring or therapeutic interventions in high-risk patients.