ECG's Chapter 4
heart rate calculation method that can only be used when the heart rate is regular. It is considered the most accurate way to calculate heart rate from the ECG
6 Second Method
Heart rate calculation method used when the RR intervals are irregular
the increase in ventricular end diastolic volume before ventricular systole
Determination used to assess the direction of ventricular depolarization in the frontal panal
Dark Line Method
Heart rate determination method that can only be used when the heart rate is regular, this method can be a very accurate way to determine heart rate or to garnet a close estimate
an imaginary equailateral triangle formed by the right arm, left arm, and left leg electrodes. It represents the development of the three bipolar limb leads of the electrocardiogram.
a nonivasive test that records the heart's electrical activity.
Hexaxial reference system
diagram that shows the relationship of the dix limb leads in the frontal plane and helps to determine the hearts's electrical axis.
Left axis deviation (LAD)
represented by a negative lead aVL and positive lead I. The two forms are nonpathologica and patholigic.
Mean QRS axis (vector)
represents the flow of depolarization in the frontal plane.
Normal Sinus rhythm
A rhythm that has the following characteristics
Regular, heart rate 60-99bpm......
PR Interval (PRI)
Distance measured from the beginning of the P wave to the beginning of the QRS complex.
the actual electrodes that are placed on the chest wall to produce the chest leads.
Represents depolarization of the atria
Generated by ventricular depolarization
the time period between the start of the QRS complex and the end of the T wave. Represents the start of ventricular depolarization to the end of ventricular repolarization.
Right Axis Deviation (RAD)
spread of the depolarization moves towards the right ventricle. The mean electrical axis is between 105 and 180 degrees.
period between the end of the S wave and the start of the T wave. The ST segment should be isoelectric or at the baseline.
represents ventricular depolarization of the heart and the end of ventricular systole.
rarely seen in a normal ECG. Represents the last stages of ventricular repolarization.
Unipolar Limb leads
leads aVr, aVL, and aVf also called augmented vector leads. Developed from a combination of the right arm, left arm and left leg electrodes.