[The functional and hemodynamic benefits of automatic atrioventricular interval delay in permanent atrial synchronized pacing].
OBJECTIVE
In order to assess possible functional and hemodynamic benefits of different programming of atrioventricular (AV) delay--156 ms fixed vs 156 to 63 adaptive--two maximal exercise tests (cyclette) were performed in 8 patients (6 males, 2 females; 69 +/- 6 years) implanted with Chorus 6003 (Ela Medical, France) DDD pacemakers for complete AV block with normal sinus node function.


METHODS
The measured parameters were: pacing rate, cardiac output (thermodilution method), oxygen consumption (2001 gas-exchange analyser), arterial-venous difference (derived from pulmonary oxygen saturation, through an optical-fibers Swan-Ganz catheter coupled to an Oximetric3-Abbott oximeter), human atrial natriuretic factor and lactate plasmatic levels, anaerobic threshold.


RESULTS
A better cardiac output (11.4 +/- 1.7 vs 10.1 +/- 1.8 l/min) and oxygen consumption (1521 +/- 425 vs 1408 +/- 465 ml/min) were observed at maximal exercise with adaptive rather than with fixed AV delay programming (p < 0.05); moreover anaerobic threshold point was reached later during exercise test with adaptive AV delay (242 +/- 92 vs 216 +/- 109 sec, p = 0.05). On the contrary, with adaptive and fixed AV delay, there were not statistically different values of maximal heart rate (139 +/- 9 vs 139 +/- 9), levels at maximal exercise of arterial-venous difference (12.5 +/- 2 vs 12.8 +/- 1.4 Vol%O2), human atrial natriuretic factor (63 +/- 17 vs 78 +/- 48 pg/ml), lactate (29 +/- 15 vs 29 +/- 18 mg/dl), and oxygen consumption at anaerobic threshold point (772 +/- 164 vs 786 +/- 229 ml/min).


CONCLUSIONS
In DDD pacing adaptive AV delay causes aerobic and hemodynamic benefits.
Occhetta
E
E
Divisione di Cardiologia, Ospedale Maggiore, USSL 51, Novara.
Rognoni
G
G
Perucca
A
A
Aina
F
F
Magnani
A
A
Francalacci
G
G
Rossi
P
P
D000368:Aged; D004311:Double-Blind Method; D004867:Equipment Design; D005080:Exercise Test; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006327:Heart Block / Q000503:physiopathology / Q000628:therapy; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial
Benefici funzionali ed emodinamici dell'accorciamento automatico dell'intervallo atrio-ventricolare nella stimolazione cardiaca permanente di tipo atrio-sincronizzato.