This study develops an ultrasensitive electrical device, the silicon nanowire-field effect transistor (SiNW-FET) for detection of cardiac troponin I (cTnI) in obesity induced myocardial injury. The biosensor device utilizes metal–oxide–semiconductor (MOS) compatible top-down methodology for the fabrication process. After fabrication, the surface of the SiNW is modified with the cTnI monoclonal antibody (Mab-cTnI) upon covalent immobilization to capture cTnI antigen. The sensitivity of the device is also examined using cTnI at different concentrations with the lowest detection limit of 0.016 ng/mL. The electrocardiogram (ECG), magnetic resonance imaging (MRI), and superior vena cave (SVC) provide more information about cardiac responses in a mouse model of acute myocardial infarction (AMI). Further, magnetic resonance imaging helps to evaluate the cardiac output of an obesity induced myocardial injury mouse model. These methods play an essential role in monitoring the obesity based cardiac injury and hence, these studies were carried out. This is the first report to use the ECG, MRI, and SVC sampling methods to study the obesity based cardiac injury involving Syrian hamsters as animal models. The proposed SiNW-FET in this study shows greater sensitivity than the previously developed devices and demonstrates great potential for future applications in point-of-care (POC) diagnosis.