The Expanding Role of Stress Echocardiography in Hypertrophic Cardiomyopathy
Eszter Dalma Pálinkás1, Quirino Ciampi2, Eugenio Picano3
¹Albert Szent-Gyorgy University Medical School, Szeged, Hungary
²Cardiology Division, Fatebenefratelli Hospital, Benevento, Italy
³CNR Institute of Clinical Physiology, Pisa, Italy
In the European Society of Cardiology 2014 guidelines on hypertrophic cardiomyopathy (HCM), exercise stress echo (SE) is recommended in symptomatic patients if bedside manoeuvres fail to induce left ventricular outflow tract gradient (LVOTG) ≥50 mmHg and is rated as class I, level of evidence B. The recommendation is class II b, level of evidence C, in asymptomatic patients. This evidence-based approach uses one stress (exercise), one parameter (LVOTG), and one target (obstruction) in one HCM patient (symptomatic without obstruction at rest). However, the omnivorous versatility of contemporary SE appears ideally suited to unmask the functional heterogeneity underlying the similar morphology and clinical presentation of HCM. At least 7 parameters converge conceptually, logistically, and methodologically in the ABCDEFG-SE protocol in HCM. They are: 1) regional wall motion abnormalities (step A); 2) B-lines by lung ultrasound (step B), possibly with other indices of diastolic function such as E/e’ and systolic pulmonary arterial pressure (from tricuspid regurgitant jet velocity or acceleration time of forward systolic pulmonary flow); 3) left ventricular contractile and preload reserve (step C) based respectively on force (systolic arterial pressure by cuff sphygmomanometer/end-systolic volume from 2-D) and end-diastolic volume; 4) coronary flow velocity reserve (step D) in left anterior descending coronary artery (with pulsed wave-Doppler); 5) heart rate reserve (peak/rest heart rate) from EKG (step E); 6) mitral valve regurgitate flow (step F); and 7) LVOTG (step G). ABCDEFG-SE allows a comprehensive assessment of inducible ischemia (A), lung water (B), myocardial systolic and diastolic function (C), coronary microcirculation (D), autonomic function (E), mitral regurgitation (F) and intraventricular obstruction (G). Yesterday SE used LVOTG for HCM with a one-fits-all approach. SE Today, SE may exploit its unsurpassed versatility to unmask different pathophysiological mechanisms and potential therapeutic targets in a personalized and comprehensive approach to HCM.