[Predictors of lack of clinical improvement at mid-term follow-up with cardiac resynchronization therapy].
BACKGROUND
About 30% of all patients do not respond to cardiac resynchronization therapy for heart failure. The objective of the study was to analyze the variables that may predict the lack of response.


METHODS
We analyzed the results in a series of 63 patients who received cardiac resynchronization with a biventricular device. Clinical and left ventricular function parameters were evaluated at the beginning of the study and at 6 months. Responders were defined as those who were alive, had not received a heart transplant, and who achieved more than a 10% increase in distance in the 6-minute walking test.


RESULTS
Mean age was 68.3 (8) years, 51 patients (81%) were men, and NYHA functional class was III-IV in 79.4%. Mean left ventricular ejection fraction was 22.4% (6)%, QRS width was 177 (25) ms, and 77.8% were in sinus rhythm. Almost half (46%, n=29) had ischemic heart disease. At 6-month follow-up, 69.8% of the patients were responders. Ischemic heart disease, sustained monomorphic ventricular tachycardia and a degree of mitral regurgitation >II/IV before implantation were associated with lack of response. No association was found for any of the other baseline variables. Logistic regression analysis identified all three of the aforementioned variables as independent predictors of lack of response: ischemic heart disease OR=4.8, 95% CI, 1.2-18.3, P=.023; ventricular tachycardia OR=8.7, 95% CI, 1.8-41.3, P=.007; and mitral regurgitation OR=8.03, 95% CI, 1.7-37.1, P=.008.


CONCLUSIONS
The likelihood of responding to resynchronization therapy is lower in patients with ischemic heart disease, significant mitral regurgitation, or sustained monomorphic ventricular tachycardia.
Díaz-Infante
Ernesto
E
Unidad de Arritmias, Instituto de Enfermedades Cardiovasculares, Hospital Clínico Universitario, Universidad de Barcelona, Barcelona, España.
Berruezo
Antonio
A
Mont
Lluís
L
Osorio
Paulo
P
García-Morán
Emilio
E
Marigliano
Alba
A
Sitges
Marta
M
Azqueta
Manel
M
Paré
Carles
C
Muxí
Africa
A
Paredes
Pilar
P
Fosch
Xavier
X
Ninot
Salvador
S
Roig
Eulalia
E
Brugada
Josep
J
D000368:Aged; D002304:Cardiac Pacing, Artificial; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000628:therapy; D006801:Humans; D008297:Male; D011379:Prognosis; D011446:Prospective Studies; D013997:Time Factors; D017211:Treatment Failure