EVALUATION OF BARORECEPTORS SENSITIVITY IN YOUNG ADULTS WITH VASOVAGAL SYNCOPE IN LONG TERM FOLLOW-UP AFTER CORRECTION OF D-TRANSPOSITION OF GREAT ARTERIES BY SENNING ATRIAL SWITCH.
The aim of study: evaluation of baroreceptors sensitivity in relation to presence of reflex syncope in young adults with benign forms of sinus node dysfunction (SND) in near-asymptomatic young adults after reparation of d-transposition of great arteries d-TGA by Senning atrial switch (SAS) .
Study population: we observed 21 pts (14 men) aged 18-21 yrs with d-TGA, with electrocardiographic signs of SND and history of presyncope and 21 sex and age matched healthy volunteers.
Methods: All pts underwent head-up tilt test (HUTT) and transoesophageal atrial stimulation for evaluation of corrected sinus node recovery times (CNRT) before and after pharmacological blockade (PHB). CNRT>525 ms was assumed as abnormal. Non-invasive evaluation of baroreceptor sensitivity (BRS) during HUTT was evaluated in dTGA patients and healthy control group using NEXFIN analyser.
Results: HUTT was positive in 6 pts (28,6%), negative in 7 pts, and doubtful (presence of bradycardia and/or hipotonia with aggravated prodroms) in 8 pts.
Mean CNRT value was 698,2ms; SACT- 124,4ms and shorten significantely after PHB (CNRT to 362,8; SACT to 116,5ms). Mild prolongation of CNRT (<850 ms) with normalization after PHB was observed in 12 pts (57,1%). Reduction of BRS was observed in dTGA pts. in comparison to healthy controls. Significant depletion of BRS was also observed in pts. with negative HUTT in relation to non-fainter, both in dTGA(systolic BP: 11,4 vs 16,9 ms/mmHg; diastolic BP 18,4 vs 21,1 mmHg;p<0,03) and control groups(systolic BP: 12,6 vs 19,4 ms/mmHg; diastolic BP 13,3 vs 16,6 mmHg;p<0,02).
Conclusions: Reflex vasovagal syncope frequently occurs after physiological correction of d-TGA. Electrocardiographic signs of sinus node dysfunction rather then abnormal electrophysiological parameters were noticed in near-asymptomatic young adults after reparation of d-transposition of great arteries by Senning atrial switch Significant reduction of baroreceptor sensitivity was observed after dTGA correction by atrial switch both in pts. with positive and negative HUTT.