1. ECG Part II

2. Rate-measure of frequency of occurrence of cardiac cycles(b/m) < 60 beats/min is a bradycardia 60-100 beats/min is normal >100 beats/min is a tachycardia

3. Rhythm Sinus-normal cardiac rhythm originating via impulse formation in the sinoatrial or sinus node Defined by p wave axis that is positive in the inferior leads Morphology is the same Cadence is regular NOT A P BEFORE EVERY QRS

4. Axis-direction of ECG waveform in the frontal plane measured in degrees Normal-frontal plane is directed leftward between -30 degrees and +90 degrees Leads I and AVF should both be positive Lead 1 is upright and AVF is negatively deflected (towards head) left axis deviation Lead 1 is negative and AVF is negative, indeterminate axis

5. Intervals-PR PR- 0.10-0.220 sec Time required for impulse to travel from the atrial myocardium(SA node) to ventricular myocardium Reflects conduction through the AV node

6. Intervals-QRS Depends on the lead Normally it is from the beginning of the Q wave to the end of the S wave 0.07-0.120 sec

7. Intervals- QTc Reflects duration of activation and recovery of the ventricular myocardium Varies inversly with heart rate QTc = QT + 1.75(vent rate – 60) Normal range is <.450 sec R-R interval and divide in half

13. Tachycardia's Wide vs. Narrow

15. ATRIAL FIBRILATION

20. Bundle Branch Blocks

23. Myocardial Ischemia Increase in myocardial demand due to decrease in blood flow, not cessation of flow Only changes seen are in repolarization, st-t changes away from involved segment of myocardium

25. Myocardial Infarction Results due to cessation of blood flow, or a decrease in demand, therefore causing primary changes in QRS complexes with changes in the ST segments This results in elevation of the J point