Influence of aetiology on long-term effects of resynchronization on cardiac structure and function in patients treated with β-blockers.
OBJECTIVE
Cardiac resynchronization therapy (CRT) elicits more beneficial effects on left-ventricular (LV) structure and function, and long-term clinical outcomes in nonischemic heart failure patients. Rates of β-blocker use in recent heart failure trials are higher than in CRT trials and this may influence the response to CRT. This study examined the long-term effects of CRT on LV structure and function in New York Heart Association class III-IV β-blocker-treated patients.


METHODS
One hundred and four (41 ischemic and 63 nonischemic) CRT patients, who were receiving β-blockers before and throughout 12 months following device implantation, were retrospectively selected. Variations in echocardiographic parameters recorded before, and 6 and 12 months after CRT were analyzed.


RESULTS
Selected patients were all stable on β-blockers, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (97%) and diuretics (97%) before implantation. CRT was associated with significant improvements in LV morphological and systo-diastolic functional parameters at 6 months, with further improvements between 6 and 12 months seen in nonischemic patients only. Accordingly, rates of echocardiographic response to CRT were similar at 6 months but significantly higher in nonischemic patients after 1 year. The degree of reduction in LV diameters and volumes, and of increase in ejection fraction, was significantly larger in nonischemic patients at both 6 and 12 months. In addition, a significant reduction in LV mass and severity of mitral regurgitation was more evident in nonischemic patients both 6 and 12 months following CRT.


CONCLUSIONS
Ischemic aetiology of heart failure is associated with less favorable long-term effects of CRT on LV structure and function despite the systematic use of β-blockers.
Division of Cardiology, Cardiovascular and Thoracic Department, Santa Maria alle Scotte Hospital, Siena, Italy. valezeta@libero.it
Valerio
V
Zacà
Claudia
C
Baiocchi
Rosaria
R
Gaddi
Rodolfo
R
Gentilini
Stefano
S
Lunghetti
Margherita
M
Padeletti
Antonio
A
Pagliaro
Fabio
F
Furiozzi
Sergio
S
Mondillo
Roberto
R
Favilli
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000368:Aged; D000704:Analysis of Variance; D058406:Cardiac Resynchronization Therapy; D016009:Chi-Square Distribution; D015150:Echocardiography, Doppler; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications* / Q000503:physiopathology; D012189:Retrospective Studies; D013318:Stroke Volume; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000187:drug effects*; D020257:Ventricular Remodeling / Q000187:drug effects*
D000319:Adrenergic beta-Antagonists