Background. The increase in survival rate of Tetralogy of Fallot (TOF) patients lead to an increase in the number of post-op patients requiring critical follow-up. Abnormal Right Ventricular (RV) physiology is a significant long-term problem for these patients. Some studies show that RV restrictive physiology protects the development of RV dysfunction. This study aims to determine the association of Right Ventricular Restrictive Physiology with Right Ventricular Systolic Dysfunction in these patients.
Methods. We conducted a cross-sectional study involving 69 post-op TOF patients at Philippine Heart Center from June 2012 to December 2012. We determined the following: age and sex, weight, body surface area, history and frequency of phlebotomy, and prior surgical procedure (Blalock Taussig Shunt). We determined the presence of RV restrictive physiology based on antegrade pulmonary flow, TV dt, IVRT, EtA ratio and hepatic flow reversal. We also determined RV systolic dysfunction using the Tei index, TAPSE, resting QRS duration as well as the presence of arrhythmia. The results were analyzed using the Mann-Whitney, Fishers Exact Probability and Chi Square Test.
Results. We enrolled 26 subjects with restrictive physiology, majority of which belonged to the 7-12 year old age group and 43 with non-restrictive physiology, with majority belonging to the 13-19 year old age group. Most of the subjects were males. Among those who underwent trans-annular patching (TAP), nine (13%) had restrictive physiology post-op whereas six (9%) had non-restrictive physiology. Among those who had non-TAP surgery, majority had non restrictive physiology. The timing of the appearance of RV restrictive physiology was noted between 1-2 years in majority of the subjects. RV dysfunction was noted in 11 out of 26 subjects with restrictive physiology, whereas, RV dysfunction was present in 29 out of 43 subjects with non-restrictive physiology (p=0.042).
Conclusions. RV restrictive physiology occurs postoperatively in TOF patients who underwent total correction. TAP favors the development of RV restrictive physiology post-op versus non-restrictive physiology. RV systolic dysfunction is more evident in patients with non-restrictive physiology compared to those with restrictive physiology. The presence of RV restrictive physiology could offer a protective effect against RV systolic dysfunction.