A new simplified electrocardiographic score predicts clinical outcome in patients treated with CRT

Aims Cardiac Resynchronization Therapy (CRT) reduces morbidity and mortality for patients with heart failure and wide QRS complex, but up to 1/3 of patients are "non-responders" to the therapy. This study examines the ability of a simple standard electrocardiogram (ECG)-based scoring system to predict clinical outcome. Methods and results Four hundred and ninety-one consecutive patients with CRT-implants (79% males, mean age 71 years, LVEF 24%, 59% with ischemic cardiomyopathy, 83% in NYHA class III) were included from a single large volume centre. All patients met standard indications for CRT, and were followed for 3 years after CRT implantation. Three ECG parameters were measured on the post-implant ECG, and compared to pre-implantation measurements: QRS duration, time to intrinsicoid deflection onset (ID) in V1 lead, amplitude change in V1 lead. Each positive ECG variable was given a numerical value of 1 to create the score (ranging 0–3). Clinical outcome was assessed as a composite of all-cause death, left ventricular assist device implantation, cardiac transplantation and HF hospitalization. Event-free survival was predicted by shortening of QRS duration ≥20 ms (HR 0.66 [95% CI 0.48–0.90] P = 0.009), ≥50% decreased summed R + S amplitude in V1 lead (HR 0.67 [0.49–0.90] P = 0.009) and ≤40 msec ID time in lead V1 during pacing (HR 0.63 [0.46–0.86] P = 0.004). The total score was an independent predictor for both event-free survival (HR 0.65 [0.54–0.77] P < 0.001) and for ≥10% left ventricular ejection fraction improvement (OR 1.7 [1.3–2.3] P < 0.001). Conclusions Composite data from 12-lead ECG during CRT-treatment can be used in a simple score to predict long-term clinical outcome.