Authors:

N Kuznetsova¹ , C Borguezan Daros² , H Zanella³ , Q Ciampi⁴ , L Cortigiani⁵ , N Gaibazzi⁶ , A Zagatina⁷ , JL De Castro E Silva Pretto⁸ , A Djordjevic-Dikic⁹ , I Simova¹⁰ , M Amor¹¹ , PM Merlo¹² , J Lowenstein¹² , MAR Torres¹³ , E Picano¹⁴ , ¹Moscow University Medical School, Cardiology - moscow - Russian Federation , ²Hospital San Josè, Cardiology - Criciuma - Brazil , ³National Institute of Cardiology Ignacio Chavez, Cardiology - Mexico City - Mexico , ⁴Fatebenefratelli Hospital, Division of Cardiology - Benevento - Italy , ⁵San Luca Hospital, Cardiology - Lucca - Italy , ⁶University Hospital of Parma, Cardiology - Parma - Italy , ⁷Saint Petersburg Pavlov State Medical University, Cardiology - Saint Petersburg - Russian Federation , ⁸Hospital Sao Vicente, Cardiology - Passo Fundo - Brazil , ⁹Clinical center of Serbia, Cardiology - Belgrade - Serbia , ¹⁰City Clinic, Cardiology - Sofia - Bulgaria , ¹¹Ramos Mejia Hospital, Cardiology - buenos aires - Argentina , ¹²Cardiodiagnosticos, Investigaciones Medicas, Cardiology - buenos aires - Argentina , ¹³Federal University of Rio Grande do Sul, Cardiology - Porto Alegre - Brazil , ¹⁴Institute of Clinical Physiology, CNR, Biomedicine Department - Pisa - Italy ,

Background:  ABCDE-stress echocardiography (SE) may explore different aspects in the heterogeneous  entity of known or suspected heart failure (HF).
Aim: To assess ABCDE-vasodilator SE in non-ischemic  HF
Methods: In a prospective, observational, multicenter study, we recruited 428 patients with angiographically normal coronary arteries: 148 patients with  HF and preserved (>50%) ejection fraction (HFpEF, Group 1); 100 with HF and mid-range (40-50%) ejection fraction (HFmrEF, Group 2); 180 with HF and reduced (<40%) ejection fraction (HFrEF, Group 3). A group of 75 healthy asymptomatic patients (30 male, 40%, age 57±14 years) referred to testing for screening  was also selected (Controls). All patients underwent vasodilator SE with dipyridamole (0.84 mg/kg) in 14 accredited laboratories of 5 countries (Argentina, Brasil, Russian Federation, Serbia and Italy). The ABCDE-SE protocol was adopted: A for regional wall motion abnormalities; B for B-lines (positivity criterion: stress = rest for = 2 points in a 4-site simplified scan available in 181 pts and 10 controls); C for left ventricular contractile reserve (LVCR) based on force (systolic blood pressure/end-systolic volume, positivity criterion: peak/ rest =1.1); D for pulsed wave Doppler-based assessment of coronary flow velocity reserve (CFVR) in left anterior descending coronary artery (positivity criterion: peak/rest =2.0); E for EKG-based assessment of heart rate reserve (positivity criterion: peak/rest =1.22).
Results: All positivity criteria, except A,  were more prevalent (p<.01) in Group 3 compared to Group 2, in Group 2 compared to Group 1, and Group 1 compared  to controls: see figure.  In particular, a blunted heart rate reserve was found in 4/75 controls (5%), 27/148 pts of Group 1 (18%), 28/100 of Group 2 (28%) and 98/180 of Group 3 (54%).
Conclusions: ABCDE-vasodilator SE can help to identify the profound pathophysiological heterogeneity underlying a similar  clinical presentation in patients with known or suspected HF with angiographically normal coronary arteries. These patients rarely show stress-induced regional wall motion abnormalities (A), but may exhibit pulmonary congestion (B), reduced myocardial functional reserve (C), altered coronary microcirculation (D) and cardiac autonomic dysfunction (E).