title: Acute blood pressure changes after the onset of atrioventricular nodal reentrant tachycardia: a time-course analysis.
abstract: BACKGROUND
  We aimed to characterize blood pressure (BP) response at the beginning of atrioventricular nodal reentrant tachycardia (AVNRT) and its relationship to orthostatic challenge and variable atrioventricular interval.
  
  
  RESULTS
  In this prospective study of 17 consecutive patients with documented AVNRT, mean BP was analyzed in the supine and upright positions during sinus rhythm, AVNRT, and pacing with atrioventricular delay of 150 msec (AV150) and 0 msec (AV0). Mean BPs were compared at 3-5 seconds, 8-10 seconds, and 28-30 seconds after the onset of AVNRT or pacing. BP decreased immediately after AVNRT initiation, with gradual recovery during the first 30 seconds from 71.9 +/- 16.5 mmHg to 86 +/- 13.8 mmHg, P < 0.01. A similar pattern was observed during AV0, but not during AV150, pacing. While supine, mean BP decrease was more pronounced during AVNRT and AV0 pacing (-26.1% and -32.1%, respectively) than during AV150 pacing (-8%, P = 0.02 and P = 0.07, respectively). This difference subsided 30 seconds after the onset of AVNRT or pacing. When upright, the mean BP time course was similar, but mean BP recovery during AVNRT was slower, and the difference between mean BP during AVNRT and AV150 persisted at 30 seconds.
  
  
  CONCLUSIONS
  The initial mean BP decrease during AVNRT recovered gradually within 30 seconds. A short atrioventricular interval is associated with a greater mean BP decrease at the onset of tachycardia. These observations may explain clinical symptoms immediately after the onset of AVNRT.
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Razavi
authors.forename: David M
authors.initials: DM
authors.lastname: Luria
authors.forename: Arshad
authors.initials: A
authors.lastname: Jahangir
authors.forename: David O
authors.initials: DO
authors.lastname: Hodge
authors.forename: Phillip A
authors.initials: PA
authors.lastname: Low
authors.forename: Win-Kuang
authors.initials: WK
authors.lastname: Shen
mesh_terms: D000328:Adult; D001794:Blood Pressure; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011187:Posture; D011446:Prospective Studies; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000503:physiopathology*; D013997:Time Factors