This study is a randomized controlled trial designed to evaluate the effects of combined diaphragmatic and abdominal neuromuscular electrical stimulation (NMES) on arterial blood gases, pulmonary function, left ventricular ejection fraction, and functional capacity in patients following percutaneous coronary intervention (PCI). A total of 42 participants will be randomly allocated into two groups: an intervention group receiving NMES along with standard cardiac rehabilitation, and a control group receiving standard rehabilitation alone. The intervention will be administered for 30 minutes per session, five days per week, over a period of two weeks. Outcome measures will include arterial blood gas parameters (PaO₂, PaCO₂, SaO₂), spirometry indices (FVC, FEV₁, PEFR), ejection fraction assessed by echocardiography, and functional capacity measured using the 6-minute walk test. Assessments will be conducted at baseline and post-intervention. The study aims to determine whether NMES can serve as an effective adjunct to conventional cardiac rehabilitation in improving respiratory and functional outcomes in post-PCI patients.

Percutaneous coronary intervention (PCI) improves coronary blood flow in patients with coronary artery disease; however, many patients continue to experience reduced pulmonary function, impaired gas exchange, decreased cardiac performance, and limited functional capacity after the procedure. These issues are often related to respiratory muscle weakness, immobilization, and altered ventilatory mechanics. Conventional cardiac rehabilitation focuses mainly on aerobic and resistance training, with limited emphasis on respiratory muscle strengthening.

Neuromuscular electrical stimulation (NMES) is a non-invasive technique that induces muscle contractions and may enhance both inspiratory and expiratory muscle function when applied to the diaphragm and abdominal muscles. This study aims to evaluate the effectiveness of combined diaphragmatic and abdominal NMES as an adjunct to standard cardiac rehabilitation in post-PCI patients.

In this randomized controlled trial, 42 hemodynamically stable patients aged 40-75 years will be randomly assigned to either an intervention group (NMES plus standard rehabilitation) or a control group (standard rehabilitation alone). The NMES intervention will be applied for 30 minutes per session, five days per week, for two weeks.

Outcome measures will include arterial blood gases (PaO₂, PaCO₂, SaO₂), pulmonary function (FVC, FEV₁, PEFR), left ventricular ejection fraction, and functional capacity assessed by the 6-minute walk test. Assessments will be conducted at baseline and after the intervention.

This study aims to determine whether NMES can improve respiratory and functional outcomes and serve as an effective adjunct to conventional cardiac rehabilitation in post-PCI patients.

Inclusion Criteria:

• Patients aged 40-75 years
• Patients who have undergone successful percutaneous coronary intervention (PCI) for stable or acute coronary syndrome
• Hemodynamically stable (no inotropic support, no active arrhythmias)
• Left ventricular ejection fraction (LVEF) ≥ 35%
• Able to perform spirometry and 6-minute walk test (6MWT)
• Willing to participate and provide informed consent

Exclusion Criteria:

• Significant arrhythmias or pacemaker/implantable defibrillator not cleared for NMES
• Severe pulmonary disease (e.g., advanced COPD, pulmonary fibrosis) affecting lung function independently
• Neuromuscular disorders interfering with NMES application
• Recent stroke or severe cognitive impairment limiting participation
• Active infection, sepsis, or systemic inflammatory disease

Due to the nature of the intervention, participants and care providers cannot be blinded. However, outcome assessors will be blinded to group allocation to minimize assessment bias.