ECG - basic principle

ECG - Measurement

ECG - Lying vs. Sitting When you sit up, now heart has to pump against the gravity for circulation to the head; heart rate (BPM) increases; as BPM increases (63 vs. 81), cardiac cycles become shorter (0.9 vs. 0.73) When you are lying down, the entire body is at the same level; heart does not have to pump hard - low heart rate (BPM) and longer cardiac cycles (delta T)

ECG - deep breathing Exhalation after a deep inhalation relieves the pressure on thoracic veins; cardiac blood output returns to the baseline; heart rate decreases (88 vs. 67); duration of cardiac cycle increases (0.61 vs. 0.89) Deep inhalation causes temporary compression of thoracic veins that momentarily decreases cardiac blood output; to compensate, heart rate increases (75 vs. 88); the duration of cardiac cycle decreases (0.8 vs. 0.61) Under normal breathing condition, heart rate is 75 and duration of the cardiac cycle is 0.8 seconds

ECG - exercising During 10 minutes after exercise, the herat rate starts to go down towards the rset rate; cardiac cycle also starts increasing towards the baseline Immediately after ashort exercise, heart rate goes up (95 vs. 75); cardiac cycle shortens (0.62 vs. 0.8) At rest, heart rate (BPM) is about 75 and cardiac cycle is about 0.8 seconds Exhalation after a deep inhalation relieves the pressure on thoracic veins; cardiac blood output returns to the baseline; heart rate decreases (88 vs. 67); duration of cardiac cycle increases (0.61 vs. 0.89) Deep inhalation causes temporary compression of thoracic veins that momentarily decreases cardiac blood output; to compensate, heart rate increases (75 vs. 88); the duration of cardiac cycle decreases (0.8 vs. 0.61) Under normal breathing condition, heart rate is 75 and duration of the cardiac cycle is 0.8 seconds