Ergometric Test in Total vs Partial Right Ventricular By-Pass

pp 517-522

Abstract

Using the modified Riopel protocol of exercise test-ing and pulse O₂ saturometry in patients with partial and total by-pass of the right ventricle, forty six patients were evaluated to determine their res-ponse to exercise.

Material and method

Thirty six patients had univentricular auriculoventricular connection, while 10 patients had complex congenital heart malformations in whom biventricular correction was not considered possible. Forty patients had pulmonary stenosis, while 4 patients had a previous pulmonary artery banding, and 2 patients had Ebstein disease.

Techniques

Total by-pass:25 patients, 18 of these had atriopulmonary anastomosis, 2 total cavopulmonary connections, 2 Kawashima's technique, and 3 cavo-atriopulmonary connection. Middle age in total by-pass was 13.6 ± 4.6 years and a middle follow-up time,6.8 ± 3.9 years.Partial by-pass: 21 patients. a) Cavopulmonary connections in 17; bidirectional cavopulmonary connections in 15 (pulsatil in 12 and 3 non pulsatil),and 2 patients had a classic Glenn shunt. Middle age was 9.8 ± 5.7 years and postoperative follow-up time: 2.1 ± 1.8 years. b) Biventricular partial: 4patients. Middle age was 2.6 ± 2.9 years and post-operative follow-up: 2.6 ±2.9 years. Results of both groups were compared one with the other, and with the normal values of our laboratory, using the "t" Student test.

Results

Middle functional capacity in total by-pass patients was 13.5 ± 2.2 mets (79% estimated functional capacity), higher than in partial by-pass, (8.26 ± 3.1 mets, 48% estimated functional capacity) (p >0.001). In biventricular partial patients, middle functional capacity was 9.8 ± 2.9 mets (57.9% estimate functional capacity). Oxigen saturation percent in total by-pass patients at rest (middle 93.3 ±4.1%) and at maximal effort (middle 85.17 ± 6.07%) was higher than in partial by-pass patients at rest(middle 86.2 ± 5.0%) and at maximal effort (middle:69.33 ± 8.87%) (p > 0.001). In biventricular partial bypass, middle saturation at rest was 97.3 ± 1.5%) and at maximal effort, 87.3 ± 7.0%. Heart rate and maximal effort were similar in the total by-pass (middle 166.4±20.6/min) and in the partial by-pass patients (middle 163.5 ± 20.9/min) (p: NS). Relating exercise done by both groups with the chronotropic response, it was less intense in the total by-pass patients than in the partial by-pass patients.

Conclusions

1) Functional capacity in the total by-pass group was subnormal (middle 79% of the estimated functional capacity), with slight systemic in saturation (middle 85.1%), and subnormal chronotropic response to maximal effort (middle 166.4/min for a middle 13.5 mets load). 2) Functional capacity in the pulsatile and non pulsatile partial by-pass was severely diminished (middle 48% of estimated), and related to an intense systemic in saturation at maximal effort (middle 69.3%), with a conserved heart rate chronotropic response (middle 163.5/min for a load of middle 8.26 mets). 3) Functional capacity in by-pass group was non homogeneous, depending upon the different anatomic functional situation of these patients (middle 57.9% of estimated), with slight systemic in saturation (middle87.3%) and conserved chronotropic response heart rate.