Abstract
Trigeminocardiac reflexes (TCR) elicited from the intranasal, facial orbital, perinasal or forehead regions are known by a spectrum of respiratory and circulatory vegetative effects which are dominated by strong vagal reflex bradycardia that can be effectively used in the reversal of certain supraventricular tachyarrhythmias (SVTs). The present aim was to examine the effects of inspiratory (IA) and expiratory apneas (EA) (20-25s breath holding on TLC or FRC levels, respectively) and Valsalva manoeuvre (VM, 20s occl. pressure 35 mmHg) on the mechanism of reversal from SVTs by facial cold TCR (cold gel, 10°C for 60 s). AVNRT (15) and AVRT (2) (183±15 c min-1; M±SD) were induced by atrial electrical impulses (2-4mA, 1ms duration; 600 ms period) and/or by isoprenalin (1-5μg/min, i.v.) in 17 patients (18-62 y) while recording icECG, heart rate (HR) and blood pressure (BP). Data showed that TCR+EA and TCR+IA increased both bradycardic (26±3%, vs. 14±4%) as well as pressor effect (13±4% vs. 10±4%) of TCR. Moreover, TCR+IA and TCR+VM increased both the speed and success rate of SVTs reversal (by 11-15%, 45±2% vs. 33%). When applied alone IA, EA or VM decreased HR in SVTs (11,2±3,1%, n=19; 8,6±2,1%, n=9; 16,2±3,1 n=19, M±SD) and rised BP (6-19%). Occassionally, EA (18%) and IA (21%) reversed SVTs into the normal rhythm similar to TCR (27-45%) and VM (26%). The role of intrathoracic pressure changes and other reflex mechanisms underlying SVTs reversal by apnoeic manoeuvres and TCR are discussed.
Supported by the Agency of the Slovak Ministry of Education for the Structural Funds of the EU, under project ITMS: 26220120067; (30%)
- © 2011 ERS
