Effect of cardiac resynchronization therapy on left ventricular diastolic function: implications for clinical outcome.
BACKGROUND
The definition of response to cardiac resynchronization therapy (CRT) remains controversial, with variable rates of response depending on the criteria used. Our aim was to analyze the impact of CRT on diastolic function in different degrees of response, particularly in patients with positive clinical but no echocardiographic response.


RESULTS
In 250 CRT patients clinical evaluation and echocardiography were performed before and after CRT. Absolute response to CRT was defined as a reduction in left ventricular (LV) end-systolic volume of ≥15% at 1-year follow-up. Additionally, patients were classified into 4 subgroups according to their amount of response: extensive reverse remodeling (RR), slight RR, clinical response without RR, and neither clinical response nor RR. An improvement in estimates of LV filling pressure and a decrease in left atrial dimensions were observed only in responders to CRT. Patients with clinical but no echocardiographic response had significant improvement in E-wave and deceleration time and nonsignificant improvement in other parameters.


CONCLUSIONS
LV diastolic function improves with CRT. Clinical responders without echocardiographic response show improvement in parameters of diastolic function. That suggests that clinical-only response to CRT is secondary to a real effect of the therapy, rather than a placebo effect.
Thorax Institute, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Spain. Electronic address: adoltra@clinic.ub.es.
Adelina
A
Doltra
Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain.
Bart
B
Bijnens
Thorax Institute, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Spain.
José María
JM
Tolosana
Thorax Institute, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Spain; Cardiovascular Disease Division, Pontificia Universidad Católica de Chile, Santiago, Chile.
Luigi
L
Gabrielli
Thorax Institute, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Spain.
María Ángeles
MÁ
Castel
Thorax Institute, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Spain.
Antonio
A
Berruezo
Thorax Institute, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Spain.
Josep
J
Brugada
Thorax Institute, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Spain.
Lluís
L
Mont
Thorax Institute, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Spain.
Marta
M
Sitges
D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000639:trends*; D003971:Diastole / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D013318:Stroke Volume / Q000502:physiology; D016896:Treatment Outcome; D014463:Ultrasonography; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy*; D016277:Ventricular Function, Left / Q000502:physiology*
Resynchronization; clinical response; diastolic function; echocardiography