Dr. Nidhi Raka on Instagram: "The thumbs up rule is a simplified method to evaluate the QRS axis on an ECG by looking at the polarity (positive or negative) of the QRS complexes in leads I and aVF: 1. Normal Axis (0° to +90°): • Both Lead I and aVF are positive (both thumbs up). • Indicates a normal heart axis, where electrical activity is directed between 0° and +90°. 2. Left Axis Deviation (0° to -30° or -30° to -90°): • Lead I is positive, and aVF is negative (left thumb up, right thumb down)