Purpose: The aim of our study is to determine if there is a natural progression of QRSd in ICD-only patients.
Methods and results: Retrospective study over a 7-year period of 86 consecutive patients who underwent ICD-only implantation in 2008 at the Liverpool Heart and Chest Hospital, UK. The mean age at ICD implantation was 62.3 (± 11.5) years, range 24-82 years. Mean length of follow-up ECGs available was 5.0 (± 1.6) years, total of 431 patient-years. We observed a progressive prolongation of QRSd over the 7-year study period. The linear mixed model found a statistically significant (p < 0.001) increase in QRSd over time, as measured in years. Clinically important progression of QRSd to ≥ 120 ms was observed in 30% of patients after 2.7 (± 1.5) years and progression of QRSd to ≥ 150 ms was observed in 10% of patients after 2.9 (± 1.2) years.
Conclusions: The natural progression of QRS duration in ICD patients may have serious implications for device implantation. Our study found that the QRS duration increased at a rate of 3.1 ms per year in ICD patients.
Keywords: Cardiac resynchronisation therapy; ICD implantation; Progression of QRS duration; QRSd prolongation.