Persistent atrial fibrillation worsens heart rate variability, activity and heart rate, as shown by a continuous monitoring by implantable biventricular pacemakers in heart failure patients.
BACKGROUND
Atrial fibrillation (AF) induces loss of atrial contribution, heart rate irregularity, and fast ventricular rate.


OBJECTIVE
The objectives of the study were to accurately measure AF incidence and to investigate the mutual temporal patterns of AF and heart failure (HF) in patients indicated to cardiac resynchronization therapy.


METHODS
Four hundred ten consecutive patients (70% male, age 69 +/- 11) with advanced HF (NYHA = 3.0 +/- 0.6), low ejection fraction (EF = 27 +/- 9%), and ventricular conduction delay (QRS = 165 +/- 29 ms) received a biventricular pacemaker. Enrolled patients were divided into two groups: G1 = 249 patients with no AF history, G2 = 161 patients with history of paroxysmal/persistent AF.


RESULTS
In a median follow-up of 13 months, AF episodes longer than 5 minutes occurred in 105 of 249 (42.2%) G1 patients and 76 of 161 (47.2%) G2 patients, while AF episodes longer than one day occurred in 14 of 249 (5.6%) G1 patients and in 36 of 161 (22.4%) G2 patients. Device diagnostics monitored daily values of patient activity, night heart rate (NHR), and heart rate variability (HRV). Comparing 30-day periods before AF onset and during persistent AF, significant (P < 0.0001) changes were observed in patient activity, which decreased from 221 +/- 13 to 162 +/- 12 minutes, and in NHR, which increased from 68 +/- 3 to 94 +/- 7 bpm. HRV significantly decreased (from 75 +/- 5 ms before AF onset to 60 +/- 6 ms after AF termination). NHR during AF was significantly (P < 0.01) and inversely correlated (R(2)= 0.73) with activity, with a significant lower activity associated with NHR >or= 88 bpm.


CONCLUSIONS
AF is frequent in HF patients. Persistent AF is associated with statistically significant decrease in patient activity and HRV and NHR increase.
Puglisi
Andrea
A
Institute of Cardiology, Fatebenefratelli Hospital, Rome, Italy. puglisiandrea@hotmail.com
Gasparini
Maurizio
M
Lunati
Maurizio
M
Sassara
Massimo
M
Padeletti
Luigi
L
Landolina
Maurizio
M
Botto
Giovanni Luca
GL
Vincenti
Antonio
A
Bianchi
Stefano
S
Denaro
Alessandra
A
Grammatico
Andrea
A
Boriani
Giuseppe
G
D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000453:epidemiology* / Q000517:prevention & control; D002908:Chronic Disease; D015716:Electrocardiography, Ambulatory / Q000706:statistics & numerical data*; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000453:epidemiology* / Q000517:prevention & control; D006339:Heart Rate; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D010138:Pacemaker, Artificial / Q000706:statistics & numerical data*; D015995:Prevalence; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors