Irregular heartbeat. Computer-enhanced image of an electrocardiograph (ECG) trace showing an abnormal heartbeat. An ECG heart trace measures the pumping of the heart as a series of small and larger waves. These waves correspond to the electrical activity of heart muscle during contraction and relaxation. This measurement is an important means of diagnosing heart diseases like coronary artery disease, thrombosis, and cardiac arrhythmia.
Model release not required. Property release not required.