Right Ventricle Recovery After ST Segment Elevation Myocardial Infarction Treated by Primary PCI as Assessed by 2D Speckle Tracking Echocardiography

Background
The right ventricle (RV) shows good long term recovery in STEMI patients treated by primary PCI (PPCI), but, in the short term, RV involvement has a worse prognosis. Acute cardiogenic shock due to acute RV failure is equal in mortality to that due to acute left ventricular failure. The assessment of RV structure and function by echocardiography improved by advances including tissue doppler, strain, and three-dimensional (3D) imaging techniques.

Methods
In PPCI treated patients, the early recovery of the RV was studied using 2D speckle tracking Echocardiography.

Results
The study enrolled 120 patients, 40 anterior STEMI patients, 40 inferior STEMI patients and 40 adult healthy controls. All patients presented to Ainshams university hospitals cath. lab for PPCI as per guidelines. We excluded patients with known history of any disease affecting the RV. 102 males (85%) and 18 females (15%) were studied. The mean age of the anterior group was (53 ± 9 years) and of the inferior group was (54 ± 10 years). Full transthoracic echocardiography (TTE) examination including assessment of the RV systolic function by fractional area change(FAC), tricuspid annulus plane systolic excursion(TAPSE), Systolic TV annular velocity (S’) and RV free wall longitudinal strain. All echocardiographic measures were repeated after 3-6 months. Nine patients died during the follow up period. 54 (67.5%) patients had an impaired left evntricular ejection fraction (LVEEF) in the baseline study which significantly improved in the follow up (39.4%), (p value 0.001). A significant deterioration of the diastolic function was detected, (p value 0.002). A significant reduction of the Left atrial volume index (LAVI) was detected (p value 0.006). Also, a significant improvement of the RV FAC (p value 0.01) and TAPSE (p value 0.047). There was a significant deterioration of the apical RV free wall strain (P value 0.018).

Conclusions
Right ventricular systolic function may be normal after acute STEMI treated by PPCI, but with 2D strain echocardiography, subclinical RV systolic dysfunction can be detected. So, it’s recommended to assess the global & segmental RV functions after acute MI with the conventional parameters as well as by 2D speckle tracking derived strain.