Closed loop stimulation is effective in improving heart rate and blood pressure response to mental stress: report of a single-chamber pacemaker study in patients with chronotropic incompetent atrial fibrillation.
BACKGROUND
Closed-loop stimulation (CLS) is a form of rate-adaptive pacing capable of providing an effective pacing rate profile not only during physical exercise but also during mental stress. To test its effectiveness, CLS and accelerometer sensor (AS) rate response were compared intraindividually during a mental stress test (MST).


METHODS
Thirty-six patients (mean age 78.9 ± 6.4 years) implanted with a pacemaker with the CLS algorithm (Cylos, Biotronik, Berlin, Germany) underwent MSTs in different pacing configurations: nonrate-adaptive mode (VVI), AS mode (VVIR), and CLS mode, respectively. A modified Stroop test was used in order to induce mental stress. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure, and pacing percentage burden were collected for 5 minutes before, during, and 5 minutes after the test.


RESULTS
Mean peak-HR during MST was significantly higher in CLS configuration than in VVIR and VVI modes (92.8 ± 12.6 vs 78.9 ± 6.5 vs 77.8 ± 7.5; P ≤ 0.001). The average HR increase during MST was also higher in CLS configuration than in VVIR and VVI modes (22.7 ± 16.7 vs 8.2 ± 8.6 vs 6.6 ± 6.3; P ≤ 0.001). The percentage of pacing beats during MST was higher in CLS configuration than with the other two algorithms (48.4 ± 17.9 vs 27.4 ± 17.5 vs 25.8 ± 17.6; P ≤ 0.001). The average peak-SBP was significantly higher during MST in CLS mode than in VVIR and VVI configurations (172.6 ± 15.5 vs 156.7 ± 12.2 vs 145.5 ± 13.7; P ≤ 0.001). The mean SBP increase showed a similar behavior (51.8 ± 24.7 vs 18.4 ± 13.7 vs 16.4 ± 10.3; P ≤ 0.001).


CONCLUSIONS
CLS algorithm in a single-chamber device is more effective than AS in detecting an hemodynamic demand due to an emotional stress and supplying a proper HR increase. These results are even more surprising compared to previous data in dual-chamber pacemakers, because they imply that CLS algorithm can provide an appropriate rate-modulation in patients with AF and chronotropic incompetence.
Cardiac Electrophysiology Laboratory, Luigi Sacco Hospital, Milan, Italy. riccardoproietti6@gmail.com
Riccardo
R
Proietti
Gianmauro
G
Manzoni
Luigi
L
Di Biase
Gianluca
G
Castelnuovo
Leonida
L
Lombardi
Camilla
C
Fundarò
Nadia
N
Vegliante
Giada
G
Pietrabissa
Pasquale
P
Santangeli
Robert A
RA
Canby
Antonio
A
Sagone
Maurizio
M
Viecca
Andrea
A
Natale
D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000628:therapy*; D001794:Blood Pressure / Q000502:physiology*; D017147:Defibrillators, Implantable; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial; D013315:Stress, Psychological / Q000503:physiopathology*