What is the significance of an ECG in medical assessments?

The significance of an ECG (electrocardiogram) in medical assessments lies primarily in its ability to measure heart rhythms. An ECG provides valuable information about the electrical activity of the heart, allowing healthcare professionals to identify various types of arrhythmias, abnormalities in heart function, and overall cardiac health. The graphical representation generated by the ECG reveals critical insights into how well the heart is beating, whether it is beating too fast, too slow, or exhibiting irregular patterns. This information is essential for diagnosing conditions such as atrial fibrillation, heart attacks, and other heart-related issues, making the ECG a crucial tool in cardiology and emergency medicine. The other options do not accurately describe the primary function of an ECG, as it is not designed to assess blood pressure, lung capacity, or kidney function.