Response to the valsalva maneuver after the fontan procedure for tricuspid valve atresia, single ventricle or pulmonic valve atresia

The Valsalva maneuver was performed during cardiac catheterization in 9 patients who had undergone a Fontan operation (Fontan group) and in 10 control subjects. The Fontan group had higher right atrial (RA) pressure (16 +/- 1 vs 4 +/- 0.5 mm Hg, p less than 0.001), lower cardiac index (2.5 +/- 0.1 vs 3.7 +/- 0.2 liters/min/m2, p less than 0.05), lower stroke index (32 +/- 2 vs 44 +/- 2 ml/beat/m2, p less than 0.05), and higher systemic vascular resistance (31 +/- 1 vs 24 +/- 1 units, p less than 0.05) than the control group. Four patients in the Fontan group had a normal 4-phase Valsalva response, and 5 did not (p less than 0.05). RA pressure was similar in those who responded normally and those who did not (16 +/- 0.5 vs 17 +/- 1 mm Hg), whereas in those who responded normally cardiac index was higher (2.9 +/- 0.2 vs 2.2 +/- 0.1 liters/min/m2, p less than 0.05), stroke index was higher (36 +/- 1 vs 28 +/- 1 ml/beat/m2, p less than 0.05), and systemic vascular resistance was lower (28 +/- 1 vs 31 +/- 1, p less than 0.05). It is concluded that cardiac output is a better predictor of a normal response to the Valsalva maneuver than RA pressure in patients after the Fontan procedure. A normal response to the supine Valsalva maneuver suggests a cardiac index greater than 2.4 liters/min/m2 and stroke index greater than 31 ml/beat/m2.