Response to cardiac resynchronization therapy predicts survival in heart failure: a single-center experience.
OBJECTIVE
To determine whether survival after cardiac resynchronization therapy (CRT) is related to improvement in clinical or echocardiographic parameters.


BACKGROUND
In clinical trials, CRT improved symptoms, left ventricular (LV) structure, function, and survival. In clinical practice, response to CRT is highly variable and whether survival benefit is confined to those patients who experience improvement in clinical status or cardiac structure and function is unclear.


METHODS
This is a single-center study of patients receiving clinically indicated CRT between January 2002 and December 2004.


RESULTS
Of 309 patients (age 68 +/- 11 years, 83% male) receiving CRT at our institution during the study period, 174 returned for follow-up and 127 had repeat echocardiography. Baseline clinical characteristics and survival were similar among those who did or did not return for follow-up. In paired analyses, New York Heart Association (NYHA) class (-0.56 +/- 0.07, p < 0.0001), ejection fraction (EF, 6.3 +/- 0.7%, P < 0.0001), LV dimension (-2.7 +/- 0.6 mm, P < 0.0001), pulmonary artery systolic pressure (PASP, -4.6 +/- 1.3 mm Hg, P = 0.0007), and MR severity grade (-0.20 +/- 0.05, P = 0.0002) improved after CRT. Survival after CRT was associated with decrease in NYHA class (risk ratio [RR]= 0.43, P = 0.0004), increase in EF (RR = 0.94, P = 0.02), and decrease in PASP (RR = 0.96, P = 0.03). Change in EF and NYHA class were correlated (r = -0.46, P < 0.0001) and, adjusting for this covariance, change in NYHA (P = 0.04) but not EF (P = 0.12) was associated with improved survival.


CONCLUSIONS
Patients who experience improved symptoms, ventricular function, and/or hemodynamics have better survival after CRT. These data enhance understanding of the relationship between CRT clinical response and survival benefit in clinical practice.
Cha
Yong-Mei
YM
Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA. cha.yongmei@mayo.edu
Rea
Robert F
RF
Wang
Ming
M
Shen
Win-Kuang
WK
Asirvatham
Samuel J
SJ
Friedman
Paul A
PA
Munger
Thomas M
TM
Espinosa
Raul E
RE
Hodge
David O
DO
Hayes
David L
DL
Redfield
Margaret M
MM
D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000401:mortality* / Q000639:trends; D004452:Echocardiography / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000401:mortality* / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015996:Survival Rate; D016896:Treatment Outcome