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Fragmented QRS and arrhythmic events in patients with implantable cardioverter-defibrillator.

BACKGROUND
Patients with implantable cardioverter-defibrillator (ICD) may experience recurrent arrhythmic events (AE). Identification of these subjects may help to plan further therapy. Fragmented QRS (fQRS) has been identified as a risk marker of AE in various populations but its predictive value in patients with ICD has not been established.


AIMS
To examine whether fQRS is a risk marker of future AE in patients with ICD.


METHODS
We retrospectively analyzed demographic, clinical, ECG, procedural and follow-up data of 367 consecutive patients who received ICD in a single tertiary center. A 12-lead ECG recorded at the time of implantation was analyzed for the presence of fQRS. The analyzed primary end-point was AE and total mortality was a secondary end point.


RESULTS
During follow-up lasting (SD) 34.5 (18) months, 146 (40%) patients had AE whereas total mortality was 18% (67 patients). Univariate analysis identified seven parameters significantly associated with AE of which two - ICD implantation for secondary prevention [HR 2.13; 95% CI 1.13 - 4.025; P = 0.02] and fQRS in inferior ECG leads in patients with QRS duration < 120 ms [HR 4.88; 95% CI 0.05 - 0.85; P = 0.03] remained significant in the multivariate analysis. Total mortality was associated with morbidity but not with fQRS.


CONCLUSION
Fragmented QRS in inferior ECG leads in patients with QRS duration < 120 ms is an independent parameter associated with AE in patients with ICD. Whether it could be helpful in deciding to perform early/prophylactic ablation in these patients needs to be prospectively studied.