Assessment of global left ventricular function by tissue Doppler imaging

Oxidative stress is implicated in many organs pathophysiologies in Down syndrome. Scarce data exist concerning left ventricular (LV) performance in DS children with normal hearts. Tissue Doppler derived myocardial performance index (TDI-Tei index) is a reliable method for ventricular performance evaluation. Myeloperoxidase (MPO) enzyme plays a crucial role in oxidants production and is a marker of cardiovascular risk.

To evaluate LV myocardial performance in DS children with normal hearts using TDI-Tei index and correlate it with plasma MPO as a marker of oxidative stress.

This cross-sectional study included 120 DS children recruited from Children s Hospital, Ain Shams University. Out patients clinic and echocardiography unit (mean age, 8.35 ± 4.25 years) who were subjected to: history taking, clinical examination, laboratory investigations (Complete blood count, serum Alanine Transaminase, serum creatinine, Thyroid profile, 12 lead Electrocardiogram and conventional Doppler echocardiography). DS children with congenital or acquired heart diseases, dysrhythmias, anaemia, pulmonary hypertension, thyroid, renal disease, diabetes were excluded. The remaining 50 DS children with normal hearts (group I) were compared to 50 age. Sex matched healthy children as control (group II) Studied groups were subjected to: plasma MPO using ELISA technique and TDI LV-Tei index assessment using Vivid E9 Echocardiography machine (GE, Horton, Norway).

LV TDI-Tei was significantly increased in group I compared to group II (0.46 ± 0.02 vs 0.32 ± 0.08, p < 0.001). Plasma MPO was increased in group I than group II (64.4831 ± 0.6 ng/ml vs 50.4 ± 30.2 nglml, p < 0.001). A significant positive correlation was found between plasma MPO and LV TDI-Tei (r = 0.877, p = 0.001) in group I.

Subclinical Left ventricle dysfunction evidenced by increased TDI Tei index was detected in DS children with normal hearts. This dysfunction correlated with plasma MPO level which mandates antioxidants treatment and tissue Doppler myocardial performance regular evaluation for early identification, monitoring and early intervention.

Beta-blockers are frequently used in patients with mitral stenosis to control the heart rate and alleviate exercise-related symptoms. The objective of our study was to examine whether ivabradine was superior to atenolol for achieving higher exercise capacity in patients with moderate mitral stenosis in sinus rhythm. We also evaluated their effects on left ventricular myocardial performance index (MPI).

Eighty-two patients with moderate mitral stenosis in sinus rhythm were randomized to receive ivabradine (n = 42) 5 mg twice daily or atenolol (n = 40) 50 mg daily for 6 weeks. Transthoracic echocardiography and treadmill test were performed at baseline and after completion of 6 weeks of treatment. Mean total exercise duration in seconds markedly improved in both study groups at 6 weeks (298.57 ± 99.05 s vs. 349.12 ± 103.53 s; p = 0.0001 in ivabradine group, 290.90 ± 92.42 s vs. 339.90 ± 99.84 s; p = 0.0001 in atenolol group). On head-to-head comparison, there was no significant change in improvement of exercise time between ivabradine and atenolol group (p = 0.847). Left ventricular MPI did not show any significant change from baseline and at 6 weeks in both drug groups (49.8% ± 8% vs. 48.3% ± 7% in ivabradine group, 52.9% ± 10% vs. 50.9% ± 10% in atenolol groups; p = 0.602).

Ivabradine or atenolol can be used for heart rate control in patients with moderate mitral stenosis in sinus rhythm. Ivabradine is not superior to atenolol for controlling heart rate or exercise capacity. Left ventricular MPI was unaffected by either of the drugs.