title: Low-dose dobutamine test associated with interventricular dyssynchrony: a useful tool to identify cardiac resynchronization therapy responders: data from the LOw dose DObutamine stress-echo test in Cardiac Resynchronization Therapy (LODO-CRT) phase 2 study.
abstract: BACKGROUND
  Cardiac resynchronization therapy (CRT) is effective in patients with heart failure, but 30% to 50% of subjects are classified as nonresponders. Identifying responders remains a challenging task.
  
  
  OBJECTIVE
  The LODO-CRT trial investigated the association between left ventricular contractile reserve (LVCR) and clinical and echocardiographic long-term CRT response.
  
  
  METHODS
  This is a multicenter, prospective, observational study. Left ventricular contractile reserve was detected using a dobutamine stress echocardiography test, defined as an ejection fraction increase of >5 points. Clinical CRT response was defined as the absence of major cardiovascular events (ie, cardiovascular death or heart failure hospitalization). Echocardiographic response was defined as a left ventricle end-systolic volume reduction of >10%.
  
  
  RESULTS
  A total of 221 CRT-indicated patients were studied (80% presented LVCR). During a mean follow-up of 15 ± 5 months, 17 patients died and 16 were hospitalized due to heart failure. The proportion of clinical responders was 155 (88%) of 177 and 33 (75%) of 44 (P = .036) in the groups with and without LVCR, respectively. Kaplan-Meier analysis showed a significant difference in cardiac survival/hospitalization between patients with and without LVCR. The proportion of echocardiographic responders was 144 (87%) of 166 and 16 (42%) of 38 in the groups with and without LVCR (P < .001), respectively; LVCR showed 90% sensitivity and 87% positive predictive value to prefigure echocardiographic CRT responders. Multivariable analysis identified LVCR and interventricular dyssynchrony as independent predictors of CRT response. The concomitant presence of both factors showed 99% specificity and 83% sensitivity in detecting responders.
  
  
  CONCLUSIONS
  The presence of LVCR helps in predicting a clinical and echocardiographic CRT response. Concomitant assessment of LVCR and interventricular dyssynchrony accurately stratifies responder and nonresponder patients.
authors.affiliation: IRCCS Istituto Clinico Humanitas, Rozzano, Milan, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Gasparini
authors.forename: Carmine
authors.initials: C
authors.lastname: Muto
authors.forename: Saverio
authors.initials: S
authors.lastname: Iacopino
authors.forename: Francesco
authors.initials: F
authors.lastname: Zanon
authors.forename: Cosimo
authors.initials: C
authors.lastname: Dicandia
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Distefano
authors.forename: Stefano
authors.initials: S
authors.lastname: Favale
authors.forename: Carlo
authors.initials: C
authors.lastname: Peraldo Neja
authors.forename: Renato
authors.initials: R
authors.lastname: Bragato
authors.forename: Mario
authors.initials: M
authors.lastname: Davinelli
authors.forename: Lorenza
authors.initials: L
authors.lastname: Mangoni
authors.forename: Alessandra
authors.initials: A
authors.lastname: Denaro
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D002316:Cardiotonic Agents / Q000008:administration & dosage; D004280:Dobutamine; D004305:Dose-Response Relationship, Drug; D025401:Echocardiography, Stress / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013318:Stroke Volume / Q000502:physiology*; D017180:Tachycardia, Ventricular / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D013997:Time Factors; D020257:Ventricular Remodeling
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine