Measuring your heart rate is now easier than ever before. Apps can even use a smartphone’s camera to measure tiny changes in your finger to study your heart, while sports watches with and without chest straps also do the job. But it’s electrocardiography (ECG) that is mostly used in the medical world.
An ECG detects and amplifies the changes in electrical impulses on your skin as your heart contracts. The ECG can record the changes in your heart as each heart cell muscle has a negative charge across its outer wall. When the organ contracts the charge alters; this is called depolarization.
The ECG’s electrodes pick up these changes as variations in voltage. Heart conditions alter the conductivity of your heart’s tissue in specific ways that the ECG can distinguish. An ECG can have up to 12 electrodes to view your heart from many angles to ensure an accurate result.