A Pediatric Chronic lung disease (CLD) is an abroad term that encompasses a heterogeneous group of different clinicopathological disorders that advance slowly over months or years. They can broadly be divided into two groups: those with a known cause and those without. Cystic fibrosis, broncho-pulmonary dysplasia or lung of prematurity, asthma, chronic gastro esophageal reflux/aspiration pneumonitis, and constrictive obliterative bronchiolitis, chronic infection, and hypersensitivity pneumonitis are all included in the first group. The second group is subdivided into primary pulmonary diseases (idiopathic interstitial pneumonia, persistent tachypnea of infancy associated with neuroendocrine cell hyperplasia, pulmonary lymphatic and vascular disorders, etc.) and systemic diseases with a pulmonary manifestation (e.g., Langerhans cell histio- cytosis, vasculities, and granulomatosis) Asthma is a chronic inflammatory disease of the airways which is related to airway obstruction, hyper responsiveness and characterized recurrent wheezing, coughing and breathlessness Asthma, recurrent hypoxemia, and hypercarbia, together with various mediators and cytokines released due to chronic inflammation, lead to pulmonary vasoconstriction Exaggerated respiratory efforts in asthmatic patients may increase intrathoracic pressure, which may increase right-ventricular (RV) afterload. Consequently, pulmonary hypertension may develop, which could then lead to RV hypertrophy and/or dilatation There are lacks of information's about right ventricular (RV) function in children with chronic lung diseases so in this study the RV systolic function will be evaluated. Systolic right ventricular (RV) function is an important predictor in the course of heart disease such as in pulmonary hypertension .The European Society of Cardiology and the American Society of Echocardiography recommend the use of tissue Doppler imaging for the evaluation of both diastolic and systolic functions .

A Pediatric Chronic lung disease (CLD) is an abroad term that encompasses a heterogeneous group of different clinicopathological disorders that advance slowly over months or years . They can broadly be divided into two groups: those with a known cause and those without. Cystic fibrosis, bronchopulmonary dysplasia or lung of prematurity, asthma, chronic gastro esophageal reflux/aspiration pneumonitis, and constrictive obliterative bronchiolitis, chronic infection, and hypersensitivity pneumonitis are all included in the first group. The second group is subdivided into primary pulmonary diseases (idiopathic interstitial pneumonia, persistent tachypnea of infancy associated with neuroendocrine cell hyperplasia, pulmonary lymphatic and vascular disorders, etc.) and systemic diseases with a pulmonary manifestation (e.g., Langerhans cell histiocytosis, vasculitis's, and granulomatosis) .

Asthma is a chronic inflammatory disease of the airways which is related to airway obstruction, hyper responsiveness and characterized recurrent wheezing, coughing and breathlessness .

Asthma, recurrent hypoxemia, and hypercarbia, together with various mediators and cytokines released due to chronic inflammation, lead to pulmonary vasoconstriction . Exaggerated respiratory efforts in asthmatic patients may increase intrathoracic pressure, which may increase right-ventricular (RV) afterload. Consequently, pulmonary hypertension may develop, which could then lead to RV hypertrophy and/or dilatation .

Blood viscosity from polycythemia secondary to hypoxia also plays a role in the development of pulmonary hypertension.

Patients with chronic lung diseases develop pulmonary hypertension (and core-pulmonal in severe cases) because of the recurrent hypoxia and chronic inflammation this results in right heart enlargement and ventricular hypertrophy .

The initial insult in congenital diaphragmatic hernia (CDH) occurs during embryogenesis, resulting in aberrant bilateral pulmonary parenchymal and cardiovascular development, followed by ongoing inhibition of growth secondary to compression by abdominal contents. These developmental abnormalities contribute to the clinical phenotypes in CDH, with evidence of pulmonary hypoplasia, pulmonary hypertension, and ventricular dysfunction all contributing to morbidity and mortality .

According to the Cystic Fibrosis Foundation Patient Registry (CFFPR), the United States has over 30,000 people living with CF (> 70,000 worldwide) with roughly 1,000 new cases of CF diagnosed every year.

This disease primarily affects the respiratory system and the gastrointestinal system. However, recent studies suggest a direct or indirect involvement of the cardiovascular system. The destruction of lung parenchyma and pulmonary vasoconstriction due to chronic hypoxemia may result in pulmonary hypertension causing cor pulmonale. Some studies imply that the CFTR protein is also expressed in cardiac myocytes, including both atrial and ventricular myocytes .

The European Society of Cardiology and the American Society of Echocardiography recommend the use of tissue Doppler imaging for the evaluation of both diastolic and systolic functions .

However, irregular shape of the right ventricle, its retrosternal location, and the frequent coexistence of lung hyperinflation make standard "gray-scale" imaging suboptimal for routine assessment of the right ventricle .

There are lacks of information's about right ventricular (RV) function in children with chronic lung diseases so in this study the investigator will evaluate of the RV systolic function.

Systolic right ventricular (RV) function is an important predictor in the course of heart disease such as in pulmonary hypertension and RV infarction. However, one of its widely used parameters, RV ejection fraction (EF), is difficult to assess both with accuracy and ease. This is due to the complex geometrical shape of the RV.

Traditionally, RV fractional area or long-axis change measurements (FAC and FLC) by two-dimensional (2D) echocardiography have been employed, also lD parameters such as the tricuspid annular peak systolic excursion (TAPSE) . The advent of tissue Doppler imaging (TDI) has initiated long-axis function analysis of both ventricles difficult to obtain by conventional echocardiograph, whereby pulsed-wave TDI at the lateral tricuspid annulus allows the recording of RV peak myocardial contraction velocity (v)

Inclusion Criteria:

• Children have aged from 7 years to 18 years.
• Patients diagnosed with chronic lung disease at pediatric pulmonology unit by chest radiograph, computerized topography (CT) chest finding, sweat chloride test and pulmonary function tests.

A total of seventy - five participants will be selected to be included at the study (group A=75 patients as case group (children with Chronic Respiratory Disease) , group B=75 children as control group (children with no Chronic Respiratory Disease).

Including:

31 patients with bronchial asthma. 22 patients with interstitial pulmonary fibrosis. 22 patients with cystic fibrosis.

Exclusion Criteria:

• Congenital heart disease and Acquired heart diseases.

Sample Size Calculation:

The sample size will be determined using epi-infoVersion 7 based on the following prerequisites:

• Confidence level = 95%
• Expected frequency of Chronic Respiratory Disease = 4.9%.
• Confidence limit =5%
• Population size = 10000.
• Sample size (n) =75 patients as case group A total of seventy - five participants will be selected to be included at the study (group A=75 patients as case group (children with Chronic Respiratory Disease) , group B=75 children as control group (children with no Chronic Respiratory Disease).

Including:

31 patients with bronchial asthma. 22 patients with interstitial pulmonary fibrosis. 22 patients with cystic fibrosis.