Heart rate variability monitored by the implanted device predicts response to CRT and long-term clinical outcome in patients with advanced heart failure.
BACKGROUND
Few data exist on the long-term changes and the prognostic value of heart rate variability (HRV) assessed by implanted devices in heart failure (HF) patients treated with resynchronization therapy (CRT).


OBJECTIVE
To analyze the long-term changes in the standard deviation of 5-minute median atrial-atrial sensed intervals (SDANN), and assess its role in predicting CRT efficacy and major cardiovascular events.


RESULTS
We included 509 consecutive patients implanted with CRT devices. At 12-month follow-up, 44 patients had died and 86 patients had at least one HF hospitalisation. A significant increase in SDANN occurred after 4 weeks of CRT (from 69+/-22 ms to 82+/-27 ms, p<0.001). A further increase in SDANN was observed 6 months after implantation. Multivariable analysis identified SDANN as the sole predictor of major cardiovascular events (p=0.03) among several baseline parameters. SDANN< or =65 ms at the first week and SDANN< or =76 ms after 4 weeks of CRT yielded the best prediction of all-cause mortality and urgent heart transplantation on Kaplan-Meier analysis (log-rank test p=0.015 and p=0.011, respectively for week 1 and 4 values). Moreover, relative reduction in LVESV after CRT significantly correlated with SDANN at week 1 (r=-0.596, p=0.012), and week 4 (r=-0.703, p=0.001).


CONCLUSIONS
Device-monitored HRV is a useful tool to identify, early after implantation, patients with a low likelihood of long-term benefits from CRT and at high risk for cardiovascular events.
Fondazione Policlinico S. Matteo IRCCS, Pavia, Italy. ellettrofisiologia@smatteo.pv.it
Maurizio
M
Landolina
Maurizio
M
Gasparini
Maurizio
M
Lunati
Massimo
M
Santini
Roberto
R
Rordorf
Antonio
A
Vincenti
Paolo
P
Diotallevi
Annibale S
AS
Montenero
Carlo
C
Bonanno
Tiziana
T
De Santo
Sergio
S
Valsecchi
Luigi
L
Padeletti
D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D020257:Ventricular Remodeling / Q000502:physiology