Pseudo-Kussmaul's Sign in Atrioventricular Nodal Reentry Tachycardia: A Prospective, Cohort Study.

Aims: To study the respiratory variation of right atrial (RA) pressures at baseline and during atrioventricular nodal reentry tachycardia (AVNRT).

Methods: Of the 23 patients screened, 16 participants with typical AVNRT were included in the study. After ensuring adequate hydration, baseline RA pressures were measured as the height of 'a' and 'v' waves. The patients were asked to take deep breaths, and the measurements were taken in both inspiration and expiration.

Results: Of the 16 participants, 14(87.5%) showed a normal fall in the height of 'a' and 'v' waves with inspiration, 1(6.25%) showed no change and 1(6.25%) showed a rise in height at baseline, p <0.01. During induced AVNRT, the 'a' and 'v' wave heights increased in 8(50%), remained same in 6(37.5%) and showed a normal fall in 2(12.5%), p = 0.07 for 'a' waves and p = 0.09 for 'v' waves. When the magnitude and direction of change in 'a' and 'v' wave height at baseline was compared with AVNRT, it showed a significant difference with 13(81.25%) participants demonstrating positive Pseudo-Kussmaul's sign, p <0.01. Mean age was numerically higher in those with a more considerable inspiratory rise in RA pressures but was not statistically significant, χ²(2) = 3.1, p = 0.21.

Conclusions: Pseudo-Kussmaul's sign does occur in a substantial number of patients during AVNRT. Clinical appreciation of this phenomenon is possible in half to three-fourth of patients, provided the mean RA pressures are low enough for the variation to be visible in the neck.