NPPB and left ventricular hypertrophy: The approach also suggests that intervention should not be performed unless certain symptoms and clinical findings are present, such as severe left ventricular hypertrophy, a systolic pulmonary artery pressure of more than 60 mmHg, increases in pro-brain natriuretic peptide (BNP) by more than threefold its normal value on follow-up, the mean gradient increases by >20 mmHg with exercise, increasing size of the left atrium, and decreases in the indexed stroke volume, as well as decreases in the left ventricular global longitudinal strain by more than −14.7% (34).