Finally, the P-Q or P-R interval gives a value for the time taken for the electrical impulse to travel from the atria to the ventricle (normally less than 0.2 seconds).
normal interval, MARCH
rear march
"Close interval, dress right (or left), dress!"
p = r - c r - c = p r - c - r = p - r -(-c) = -(p) c = -p
Finally, the P-Q or P-R interval gives a value for the time taken for the electrical impulse to travel from the atria to the ventricle (normally less than 0.2 seconds).
Between 0.6 (100bpm) and 1 second (60bpm).
Use the R-R interval. Cardiac cycle time = heart rate. R wave marks the reliable point on the ECG of ventricular depolarisation thus unlike atrial depolarisation (P-wave) it is less susceptable to conduction delays etc / heart block which can alter the cycle time (for example 2nd degree heart block where the P-R interval increases then is missing then restarts). Even if there is complete heart block or irregularly irregular rhythms such as atrial fibrillation the R-R interval will show the heart rate. This is due to the intrinsic rhythmicity of the ventricles and its ability to become it's own pacemaker in times of need :D R-R interval / time = the electrical reflection of heart rate. NB: this tells you nothing about rhythm. for this you'd need to assess the P-R interval which tells you more about the relationship between the atria and the ventricles. also if you want to see HOW the electrical discharge spreads you'd have to look at the P-QRS-T components individually. The reason why you wouldn't use the P-T interval is because it varies so much even in normal individuals with sinus arrhythmia. also it does not take into account the refractory phase of the cardiac cycle. Hope this helps. Sources: Hampton's ECG made easy, Lecture notes on cardiology
Normal interval, close interval, and double interval
The electrical milestone event that occurs at the P wave of the cardiac cycle of the EKG is atrial depolarization. The upward stroke is right atrial depolarization, and the downward stroke is left atrial depolarization. Normally, this lasts for no more than 0.11 sec.
P-R interval
normal interval, MARCH
Normal interval, close interval, and double interval
normal interval, close interval, and double interval
Normal interval, close interval, and double interval
an s-p interval is the time that it takes for the secondary waves of an earthquake after the primary waves hit.
S-P interval means the integer minus the integer. The difference times nine.