This aim focuses on :

Assessing how common RV dysfunction is post-procedure Evaluating RV function changes over time (e.g., TAPSE, FAC, RV strain if available) Identifying risk factors or predictors (e.g., high residual gradient, severe PR, age at intervention)

Pulmonary stenosis (PS) is a congenital or acquired narrowing of the right ventricular outflow tract (RVOT) at the level of the pulmonary valve, leading to obstruction of blood flow from the right ventricle (RV) to the pulmonary artery. It accounts for approximately 8-10% of all congenital heart diseases and occurs most commonly as an isolated valvular lesion. Valvular PS is characterized by thickened, fused, or dysplastic pulmonary valve leaflets, resulting in increased right ventricular pressure and compensatory hypertrophy. Over time, if untreated, this can progress to right ventricular dilation, dysfunction, and right-sided heart failure.

Pulmonary balloon valvuloplasty (PBV) is the treatment of choice for moderate to severe valvular pulmonary stenosis. It is a minimally invasive, catheter-based intervention that involves dilation of the stenotic pulmonary valve using an appropriately sized balloon. The goal is to relieve obstruction, reduce right ventricular pressure, and prevent long-term complications such as RV hypertrophy, dysfunction, and arrhythmias. The procedure has shown excellent immediate and long-term outcomes, particularly in patients with a pliable, doming pulmonary valve and no significant regurgitation or associated congenital lesions.

Despite the effectiveness and safety of PBV, complications can occur, and among them, right ventricular dysfunction is a critical concern. RV dysfunction post-valvuloplasty may result from several mechanisms, including longstanding pre-procedural pressure overload, myocardial fibrosis, sudden afterload reduction, procedural trauma, or development of significant pulmonary regurgitation. This dysfunction can be subtle or overt and may impact the long-term clinical outcome, exercise tolerance, and quality of life of patients.

Therefore, understanding the predictors of right ventricular dysfunction after pulmonary balloon valvuloplasty is essential. Identifying high-risk patients pre-intervention and monitoring RV function post-procedure using echocardiographic parameters such as TAPSE, fractional area change (FAC), RV strain, and tricuspid annular tissue Doppler velocity (S') can guide better management strategies.

Inclusion Criteria:

• Any age group(no age restriction) Diagnosis of isolated valvular pulmonary stenosis confirmed by echocardiographic evaluation.

Patients who have undergone or are scheduled to undergo successful pulmonary balloon valvuloplasty (PBV), defined as a post-procedural peak gradient <40 mmHg with no significant residual obstruction.

Normal or mildly dysplastic pulmonary valve morphology suitable for balloon valvuloplasty.

No history of prior cardiac surgery or transcatheter pulmonary valve intervention.

Exclusion Criteria:

• Presence of other congenital heart diseases (e.g., TOF, VSD, ASD) Previous surgical or catheter-based intervention on the pulmonary valve. Dysplastic pulmonary valve morphology not suitable for PBV Subvalvular or supravalvular pulmonary stenosis. Development of significant procedural complications, such as severe pulmonary regurgitation requiring urgent surgical intervention.

Patients in hemodynamic shock, with uncontrolled arrhythmias, or other unstable clinical conditions that may interfere with echocardiographic evaluation or follow-up.

Presence of major systemic illnesses (e.g., advanced hepatic, renal, or pulmonary disease) that could independently affect right heart function or limit follow-up.

The study will include patients with isolated valvular pulmonary stenosis undergoing pulmonary balloon valvuloplasty (PBV) at the Cardiovascular Department, Assiut University Hospitals over 3 years. All ages will be included.

Exclusion criteria: patients with subvalvular/supravalvular PS, other major congenital heart disease, previous valve intervention, hemodynamic shock, or poor echo windows.

A minimum of 60 patients will be recruited. Clinical data, ECG, echo (including speckle tracking), and procedural details will be collected. Patients will be followed at discharge, 1 month, and 6 months to assess RV function and outcomes.