Volume overload modulates effects of cardiac resynchronization therapy independently of myocardial reperfusion: results of the RESYNC study.
OBJECTIVE
Cardiac resynchronization therapy (CRT) may induce significant changes in regional wall motion and perfusion. However, the link between these variables in patients with heart failure has not been investigated.


METHODS
Thirty-six patients with idiopathic (n = 22) or ischemic (n = 14) cardiomyopathy (mean age 70 +/- 8 years, 24 male) were studied by echocardiography and gated single-photon emission computed tomography (SPECT) before and within 2 months after CRT.


RESULTS
New York Heart Association class improved in all but four patients. The perfusion analysis indicated that, in all but three patients, there was a significant improvement of tracer uptake. Baseline end-diastolic volume index obtained by gated SPECT modulated increase of ejection fraction (P < 0.001), reduction of end-systolic volume index (P < 0.01) and improvement of motion (P < 0.001), as well as of left ventricular wall thickening (P < 0.002). Finally, despite CRT inducing significant reperfusion independently of volume overload (P < 0.05), extension of perfusion defect correlated with global improvement in the follow-up (P < 0.05).


CONCLUSIONS
Volume overload may identify responders to resynchronization therapy. CRT induced a significant 'reperfusion' both in ischemic and idiopathic cardiomyopathies, even if this is not sufficient to improve left ventricular function in patients with more severe volume overload. Finally, simultaneous evaluation of volume overload and perfusion defects may result useful in identifying CRT responders.
CNR Institute of Clinical Physiology, Pisa, Italy. gimelli@ifc.cnr.it
Alessia
A
Gimelli
Mario
M
Stanislao
Guido
G
Valle
Paolo
P
Frumento
Pierluigi
P
Zanco
Renato
R
Ometto
Eugenio
E
Inglese
Gaetano
G
Martino
Umberto
U
Startari
Paolo
P
Bertelli
Paolo
P
Marzullo
D000368:Aged; D002304:Cardiac Pacing, Artificial; D009202:Cardiomyopathies / Q000150:complications / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D003326:Coronary Circulation; D015150:Echocardiography, Doppler; D005260:Female; D015637:Gated Blood-Pool Imaging; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D017202:Myocardial Ischemia / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy; D018579:Patient Selection; D011446:Prospective Studies; D012107:Research Design; D012720:Severity of Illness Index; D013318:Stroke Volume; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon; D016896:Treatment Outcome; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling