Effects of Incentive Spirometry Versus Diaphragmatic Breathing on Oxygen Saturation and Heart-rate Variability in Post Percutaneous Coronary Intervention Patients

This study is a two-arm randomized parallel group trial designed to compare the effects of Incentive spirometry vs diaphragmatic breathing on oxygen saturation and Heart-rate variability in hemodynamically stable post-PCI patients. Participants will be randomly allocated to either the incentive spirometry group or the diaphragmatic breathing group and will receive the allocated intervention for 2 consecutive days with three supervised sessions per day in addition to routine post-PCI care. Oxygen saturation will be assessed using a pulse oximeter and heart-rate variability will be assessed using a Polar H10 sensor at baseline and after the intervention. The study will determine whether there is a difference between two interventions in the prescribed outcome measures.

Inclusion Criteria: * Adults aged 44-75 years * Hemodynamically stable post-PCI patients with systolic blood pressure\>90 mmHg, diastolic BP 50-100mmHg Heart-rate 60-100 beats/min and no ongoing chest pain or signs of acute clinical instability. * Oxygen saturation \>92% on room air * Able to follow simple verbal instructions and perform the breathing exercises. * Ejection Fraction \>35% Exclusion Criteria: * Ongoing myocardial ischemia, unstable angina, significant arrythmia or requirement for inotropic/vasopressor support. * Cardiogenic shock or severe heart failure (NYHA class IV) * Recent thoracic surgery or chest wall injury limiting rib expansion or deep breathing. * Cardiac implantable electronic device (pacemaker/ICD) with pacing dependency or an implanted ventricular assist device. * Severe cognitive impairment * Uncontrolled hypertension(SBP\>180 mmHg or DBP\>110 mmHg) or bradycardia\