QRS ≥ 120 ms and LVEF ≤ 35% and appearance typical block left arm and NYHA III and IV in sinus rhythm, QRS ≥ 150 ms and LVEF ≤ 35 % non- appearance block left leg NYHA III and IV in sinus rhythm, QRS ≥ 130 ms and LVEF ≤ 30% and appearance typical of LBBB NYHA II