Our goal was to develop and experimentally validate a polarization-interference method for phase scanning of laser speckle fields generated by diffuse layers of birefringent biological tissues. This method isolates and uses new diagnostic parameters related to the “phase waves of local depolarization”. We combined polarization-interference registration with phase scanning of complex amplitude distributions in diffuse laser speckle fields to detect phase waves of local depolarization in birefringent fibrillar networks of biological tissue and measure their modulation depth. This approach led to the discovery of new criteria for differentiating various necrotic changes in diffuse histological samples of myocardial tissue from deceased individuals with “ischemic heart disease (IHD) — acute coronary insufficiency (ACI)”, even in the presence of a high level of depolarized background. To evaluate the degree of necrotic changes in the optical anisotropy of diffuse myocardial layers, a new quantitative parameter — modulation depth of local depolarization wave fluctuations — has been proposed. Using this approach, for the first time, differentiation of diffuse myocardial samples from deceased individuals with IHD and ACI was achieved with a very good 90.45% and outstanding accuracy of 95.2%.