[Adequacy of of pacemakers responsive to the volume-minute ventilation rate in heart transplantation patients].
OBJECTIVE
To evaluate in the late post-operative period (PO) the chronotropic response to exercise of patients submitted to orthotopic cardiac transplantation (CT) and the implant of a cardiac pacemaker (PM).


METHODS
A rate response ventricular PM (VVI+R) which uses minute ventilation (MV) as a sensor was implanted in five patients in the early PO of CT due to chronotropic incompetence. The patients were 31 to 64 years old and the indication to implant of PM was low ventricular escape rhythm following atrial taquicardia/bradycardia (one case) or sinus bradycardia (4 cases). The study was performed by means of paired exercise tests using Naughton protocol in order to compare the heart rate in VVI (prefixed heart rate) and VVIR+MV (rate response) mode. The duration of the exercise was compared between the two modes of stimulation.


RESULTS
In VVI mode the heart rate was significantly lower than in VVIR+MV mode for comparable periods of exercise (101 +/- 12 ppm vs 132 +/- 4 ppm; p < 0.05); in VVIR+MV mode the patients had a prolonged time of exercise as compared to VVI mode (15 +/- 7 min vs 12 +/- 7 min; NS).


CONCLUSIONS
The MV rate response PM provided patients with satisfactory heart during exercise and may be an adequate option to patients submitted to CT who present chronotropic incompetence.
Sant'Anna
J R
JR
Instituto de Cardiologia do Rio Grande do Sul/Fundação Universitária de Cardiologia, Porto Alegre.
Castro
I
I
Lima
L L
LL
Reis
A
A
Kalil
R A
RA
Prates
P R
PR
Lucchese
F A
FA
Halperin
C
C
Pereira
E
E
Rodrigues
R
R
D000328:Adult; D001919:Bradycardia / Q000209:etiology* / Q000503:physiopathology / Q000628:therapy; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D016027:Heart Transplantation / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D011446:Prospective Studies
Adequação de marcapasso com resposta de freqüência por volume-minuto respiratório em pacientes submetidos a transplante cardíaco.