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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, RESULTS. Meshes: Aged, Bundle-Branch Block, Cardiac Pacing, Artificial, Cardiotonic Agents, Dopamine, Echocardiography, Stress, Female, Heart Failure, Humans, Magnetic Resonance Angiography, Male, Prospective Studies, Stroke Volume, Ventricular Dysfunction, Left, Ventricular Remodeling.
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Do low-dose dobutamine stress echo to quantify the degree of remodelling after cardiac resynchronization therapy? Context: Presence of contractile reserve during low-dose dobutamine stress echo (DSE) appears predictive of cardiac resynchronization therapy (CRT) outcome. We hypothesize that changes in left bundle branch block (LBBB)-induced dyssynchronous motion during low-dose DSE could be related to the extent of reverse remodelling. Fifty-two patients (69 +/- 2 years, EF: 24 +/- 7%, QRS > 120 ms) were studied pre- and post-CRT (7 +/- 1 months). Reduction in left ventricular end-systolic volume (LVESV) >/=10% defined response. A clinical improvement was sought additionally prior to implant and after CRT (NYHA class reduction >1), increase in 6 min walk test (>10%), and fall in BNP (>/=30%). To identify the presence of septal scar and its impact on our assessment during low-dose DSE, a cardiac magnetic resonance was performed pre-CRT. Presence of an abnormal short-lived septal motion occurring during the isovolumic contraction time [septal flash (SF)] identified LBBB-induced dyssynchrony. Septal flash extent was quantified from M-mode and radial velocity traces. At baseline, 31/52 patients had an SF. In all patients, DSE increased SF. Twenty-nine out of thirty-one patients responded with reverse remodelling post-CRT. The degree of peak low-dose stress SF correlated with the extent of reverse remodelling (R = 0.6, P < 0.0001). Additionally, SF increase correlated with greater fall in BNP post-CRT (R = 0.4, P = 0.01). Among patients with no SF at rest (21/52 patients), low-dose DSE induced an SF and a fall in stroke volume (SV) in five patients who all showed reverse remodelling after CRT. With low-dose DSE, the remaining 16 patients all failed to demonstrate a SF, and all but one patient with additional atrioventricular dyssynchrony were non-responders.
assistant
Low-dose DSE increases and unmasks LBBB-induced dyssynchronous motion, easing its detection. The degree of clinical and echocardiographic response correlated with the extent of peak SF seen during low-dose DSE. Final Decision: yes