A novel mathematical model explains bi-exponential left ventricular pressure decay by asynchronous myocardial relaxation, where the T2/T1 ratio reflects the synchronously relaxing fraction.
A new model for the pressure relaxation of the left ventricle is proposed. The model presumes that the myocardium relaxes asynchronously, but that when regions begin to relax, after a delay, the local wall stress decays as a mono-exponential process. This formulation results in an apparently bi-exponential process (two time constants) which has been previously reported. It is shown that the ratio of the two time constants (T2/T1) can be interpreted as the fraction of the myocardium which relaxes synchronously. Data are presented illustrating the Model during transient coronary occlusion in patients undergoing percutaneous transluminal coronary angioplasty.
Brower et al. (1983) studied this question.