[IV Pulmonary trunk reversible banding: analysis of right ventricle acute hypertrophy in an intermittent loading...

Adjustable pulmonary trunk (PT) banding device may induce a more physiologic ventricle retraining for the two-stage Jatene operation. This experimental study evaluates the acute hypertrophy (96 hours) of the right ventricle (RV) submitted to an intermittent pressure overload.

Five groups of seven young goats were distributed according to RV intermittent systolic overload duration (0, 24, 48, 72 and 96 hours). The zero-hour group served as a control group. Echocardiographic and hemodynamic evaluations were performed daily. After completing the training program for each group, the animals were sacrificed for water content and cardiac masses evaluation.

There was a significant increase in RV free wall thickness starting with the 48-hour group (p<0.05). However, a decreased RV ejection fraction, associated with an important RV dilation and a significant increase in the RV volume to mass ratio was observed at 24-hour training period, when compared to 96-hour period (p=0.003), with subsequent recovery throughout the protocol. A 104.7% increase in RV mass was observed in the 96-hour group, as compared to the control group, with no differences in water content between these two groups. The daily mean increase in RV mass during the study period was 21.6% +/- 26.8%. The rate of RV mass acquisition for the overall study period of intermittent systolic overload was 0.084 g/h +/- 0.035 g/h.

Intermittent PT banding has allowed a significant RV mass acquisition in the 96-hour trained group. No myocardial water content changes were observed in this group, suggesting an increased myocardial protein synthesis.