Normal T-wave is positive in most leads, highest in V2-V3. Women have more symmetrical T-waves with lower amplitude. T-wave should be concordant with QRS complex. T-wave amplitude diminishes with age
Sinus rhythm begins at sinus node, necessary but not sufficient for normal heart activity. ECG shows normal P waves with typical P vector between +50° and +80°. Normal sinus rhythm includes tachycardia, bradycardia, and arrhythmia
Gallop rhythm is misleading term, better described as triple rhythm. Triple rhythm can be normal or abnormal. Common type occurs when third and fourth heart sounds sum with tachycardia
ECG records heart's electrical signals to check heartbeat. Available in medical offices, hospitals, ambulances and smartwatches. Holter monitor records heart activity for days, event monitor for 30 days
Heart rate can be calculated from ECG by measuring RR interval between R wave peaks. Ruler or caliper can be used to measure distance between R wave peaks. ECG paper speed is typically 25 mm/s (sometimes 50 mm/s). Normal adult resting heart rate is between 60-100 beats per minute
Heart is located between lungs and left of breastbone, beating 100,000 times daily. Heart has four chambers: two atria and two ventricles. Four valves prevent backward blood flow: mitral, tricuspid, aortic, and pulmonic