Assessment of Hemodynamic Changes During Acute Myocardial Ischemia and Infarction Using Intrinsic Frequency Method

A sudden decrease in left ventricle (LV) contractility, LV wall stiffening, and an increase in LV filling pressure are among the major hemodynamic abnormalities within seconds of a coronary artery occlusion. These changes, along with other regulatory responses, cause global hemodynamic changes in the systemic circulation. Intrinsic frequency (IF) is a systems-based approach for analyzing the hemodynamics of the cardiovascular system using a single pressure waveform. In this study, we examined the changes in cardiovascular system hemodynamics during acute myocardial ischemia and myocardial infarction (MI), utilizing a standard rat model of coronary occlusion (30 min) and reperfusion (3 hours). We used Female Sprague Dawley rats (n=45, body weight ≈200-250 g). Catheters were inserted into carotid artery for pressure waveform measurement. We computed IF parameters and their relative changes from carotid waveforms, comparing them at six distinct events before, during, or after the coronary occlusion and reperfusion. Our findings show that IF parameters can detect global hemodynamic changes during various phases of coronary occlusion and reperfusion, including ischemia and MI. This highlights the potential usage of the IF method for noninvasive detection of acute ischemia or MI.



Funding Acknowledgement: This study is funded by the American Heart Association (AHA) Award Number 20CDA35260167.