Diagnostic Tests in Cardiology

Abstract

Background: Diagnostic tests use chemical (medication, dyes, radioactive material) and/or physical agents (radiation, ultrasound, magnetic fields) to produce certain reactions in vivo or in vitro. These reactions may be chemical (e.g., blood tests), pharmacological (e.g., HR acceleration under medication), or physical (e.g., X-ray absorption by tissues). The resulting signal (electrical, optical, etc.) differs in its characteristics (intensity, wave morphology, etc.) according to the type of tissue and to the presence or absence of disease. The normal or abnormal signals, recorded and displayed on an electronic or paper support, assess the presence, severity, localization, and reversibility of disease and help optimize therapy. Unfortunately, medical tests are often performed despite there being no reasonable chance of their influencing therapy (e.g., a nuclear scan in a terminal patient will not lead to angiography and revascularization).