First report of super-response after left bundle branch area pacing for cardiac resynchronization therapy utilizing a stylet-driven lead

The deleterious effects of electrical dyssynchrony on myocardial health and function have been firmly established, whether the dyssynchrony is caused by left bundle branch block (LBBB)1 or by right ventricular pacing.2 In patients with heart failure with reduced ejection fraction correction of electrical dyssynchrony with biventricular pacing to achieve cardiac resynchronization therapy (CRT) with the implantation of a left ventricular (LV) lead via the coronary sinus (CS) system is a class I guideline-directed therapy.