Systematic ECG interpretation follows a fixed sequence of steps: verifying voltage calibration, determining rhythm (presence and relationship of P waves to QRS complexes), calculating heart rate, measuring timing intervals (PR interval, QRS duration, QT interval), determining the electrical axis, and assessing P-wave, QRS, ST-segment, and T-wave morphology. The standard 10 mm calibration defines each small box as 1 mV, and normal sinus rhythm is characterized by each QRS being preceded by an identical, upright P wave with no conduction block, while deviations in axis, interval duration, or segment morphology serve as the basis for diagnosing arrhythmias, conduction abnormalities, chamber enlargement, and ischemia.
Systematic ECG interpretation follows a fixed sequence of steps: verifying voltage calibration, determining rhythm (presence and relationship of P waves to QRS complexes), calculating heart rate, mea…