Résumé
The involvement of the right ventricle in acute myocardial infarction [AMI] has been shown to be associated with an increased risk of life-threatening arrhythmias and sudden cardiac death. The study aimed at investigating the right ventricular function in AMI and the interaction between left and right ventricles using Doppler tissue imaging [DTI]. The study included 125 patients admitted to coronary care units and diagnosed as AMI at all sites [anterior and inferior] [100 males and 25 females] with age ranging from 36 to 82 years. They were classified according to clinical, ECG and angiographic data into: group I included 52 patients with RV myocardial infarction [RVMI], group II: included 73 AMI patients without RVMI. They were compared to 25 age and sex matched healthy individuals as a control group. Conventional Doppler mitral and tricuspid inflow velocities and tricuspid annulus systolic excursion using 2D echocardiography were used to evaluate LV and RV functions. Also, Peak systolic and peak early and late diastolic velocities [S,E,A, E/A], contraction time [CT], pre-contraction [PCT], acceleration [AT] and deceleration time [DT] of S velocity were acquired from the apical four-chamber view at the lateral side of tricuspid annulus[ta], the septal, lateral, anterior and inferior sides of the mitral annulus [ma] using DTI. RV function using DTI; S[ta] PCT[ta] IRT[ta] were significantly impaired in group I compared to group II and control [9.2 +/- 1.4 vs 12.3 +/- 1.96 vs 14.6 +/- 2.2], [103.5 +/- 16.5, vs 84.6 +/- 24.3 vs 78.4 +/- 16] and [110.6 +/- 18.7 vs 84.9 +/- 30.2 vs 56 +/- 18.9] respectively. [P< 0.001]. Similarly, TASE was significantly lower in group I vs II and group II vs control [7.2 +/- 2.6 vs 12.4 +/- 4.9 vs 15.7 +/- 5.3 respectively [P<0.001]. LV functions S[ma], PCT[ma], CT[ma], E[ma], E[ma]/A[ma], were significantly decreased in group I and II compared to control [P< 0.001] but no significant difference of LV functions between patients with or without RV infarction. Almost all DTI parameters used in evaluation of systolic and diastolic RV functions showed strong direct correlation to the corresponding LV parameters [P<0.001]. RV end diastolic pressure was passively correlated to S[ta] but not E/E[ta] of the RV in all AMI patients. The interaction between the two ventricles can be identified using DTI which now plays a relevant role in clinical scenarios. In AMI, despite the proved increased risk of morbidity and mortality in RVMI, LV dysfunction adversely affects RV function even in absence of RV infarction