Cardiac pacing in patients with hypertrophic obstructive cardiomyopathy

[first paragraph of article]About one-third of patients with hypertrophic cardiomyopathy (HCM) have resting left ventricular outflow tract obstruction (LVOTO). The presence of LVOTO in HCM facilitates the progression of heart failure and increases the risk of death. LVOTO is defined as a peak instantaneous Doppler LV outflow tract gradient ≥30 mmHg, but the threshold for invasive treatment is usually considered to be ≥50 mm Hg.