Clinical Study to Evaluate the Possible Efficacy and Safety of L- Carnitine and Sildenafil in Children Having Beta Thalassemia With Increased Tricuspid Regurgitant Jet Velocity

Inclusion Criteria: * Children with Beta thalassemia major who have increased TRJV more than 2.5m/s. * Children age from 6-18 years Exclusion Criteria: * Others hemolytic anemia * Young age before 6 years of age * Allergy to Sildenafil or L-carnitine * Patient with documented causes of pulmonary hypertension rather than caused by Beta thalassemia. * Hepatic dysfunction: serum Alanine Aminotransferase (ALT) 3X. * Renal dysfunction: Creatinine level greater than or equal to 1.2 mg/dl.