Echocardiographic variables predictive of appropriate therapies for ventricular tachyarrhythmia in patients undergoing combined cardiac resynchronization therapy.
BACKGROUND
The significant risk of sudden arrhythmic death in patients with congestive heart failure and electromechanical ventricular dyssynchrony has led to increased use of combined cardiac resynchronization therapy defibrillator (CRT-D) devices.


OBJECTIVE
To evaluate the echocardiographic variables in patients undergoing CRT-D that predict the occurrence of appropriate therapies (AT) for ventricular tachyarrhythmia.


METHODS
We analyzed 38 consecutive patients (mean age 60 +/- 12 years, 63% male) with echocardiographic evaluation before and 6 months after CRT-D implantation. Patients with AT were identified in a mean follow-up of 471 +/- 323 days. A standard echocardiographic study was performed including tissue Doppler imaging (TDI). Responders were defined as patients with improvement in NYHA class of < or = 1 in the first six months, and reverse remodeling as a decrease in left ventricular end-systolic volume of < or = 15% and/or an increase in left ventricular ejection fraction of > 25%.


RESULTS
The responder rate was 74%, and the reverse remodeling rate was 55%. AT occurred in 21% of patients, who presented with greater left ventricular end-diastolic internal diameter (LVEDD) before implantation (86 +/- 8 vs. 76 +/- 11 mm, p = 0.03) and at 6 months (81 +/- 8 vs. 72 +/- 14 mm, p = 0.08), and increased left ventricular end-systolic internal diameter (66 +/- 14 vs. 56 +/- 14 mm, p = 0.03) and lower ejection fraction (24 +/- 6 vs. 34 +/- 14%, p = 0.08) at 6 months. In the group with AT, the responder rate was lower (38 vs. 83%, p = 0.03), without significant differences in reverse remodeling (38% for the AT group vs. 60%, p = 0.426) or in the other variables. By univariate analysis, predictors of AT were LVEDD before implantation and E' after implantation. Age, gender, ischemic etiology, use of antiarrhythmic drugs, reverse remodeling and the other echocardiographic parameters did not predict AT. In multivariate logistic regression analysis, both LVEDD before implantation (OR 1.24, 95% CI 1.04-1.48, p = 0.019) and postimplantation E' (OR 0.27, 95% CI 0.09-0.76, p = 0.014) remained as independent predictors of AT.


CONCLUSIONS
In patients undergoing CRT-D, episodes of ventricular tachyarrhythmia occur with high incidence, independently of echocardiographic response, with LVEDD before implantation and E' after implantation as the only independent predictors of AT in the medium-term. These results highlight the importance of combined devices with defibrillation capability.
Timóteo
Ana Teresa
AT
Serviço Cardiologia, Hospital de Santa Marta, Centro Hospitalar de Lisboa Central, Lisboa, Portugal. ana_timoteo@yahoo.com
Galrinho
Ana
A
Branco
Luísa Moura
LM
Oliveira
Mário Martins
MM
da Silva
Manuel Nogueira
MN
Feliciano
Joana
J
Soares
Rui
R
Cunha
Pedro Silva
PS
Leal
Ana
A
Santos
Sofia
S
Ferreira
Rui Cruz
RC
D058406:Cardiac Resynchronization Therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D017180:Tachycardia, Ventricular / Q000000981:diagnostic imaging* / Q000628:therapy*; D014463:Ultrasonography