1. Abnormal Sinus Rhythms
Tachycardia means a fast heart rate usually greater than 100 beats /min.
Figure 13-1; Guyton & Hall

2. Abnormal Sinus Rhythms (cont’d)
Bradycardia means a slow heart rate usually less than 60 beats /min
Figure 13-2: Guyton & Hall

3. Note: no P waves and slow rate Figure 13-4; Guyton & Hall
Sinoatrial Block
In rare instances impulses from S-A node are blocked.
New pacemaker is region of heart with the fastest discharge rate, usually the A-V node.
Note: no P waves and slow rate Figure 13-4; Guyton & Hall

4. First Degree Heart Block
AV Node
SA Node H T
Delay
Prolonged
P-R Interval
Copyright © 2006 by Elsevier, Inc.

5. Second Degree Heart Block
AV Node
SA Node H T
Intermittent Block
Conducted
Blocked
Copyright © 2006 by Elsevier, Inc.

6. Third Degree Complete Block
Total block through the A-V node or A-V bundle
P waves are completely dissociated from QRST complexes
Ventricles escape and A-V nodal rhythm ensues
HR = 37
Figure 13-7; Guyton & Hall

7. Premature Atrial Contractions (cont’d)
Figure 13-9; Guyton & Hall

8. Premature Ventricular Contractions (PVC’s)
Figure 13-3; Guyton & Hall

9. Atrial Paroxysmal Tachycardia
Paroxysmal means a series of rapid heart beats suddenly start and then suddenly stop.
Can be stopped with a vagal reflex or quinidine or procainimide
P wave is inverted if origin is near A-V node
Occurs by re-entrant pathways
Figure 13-12; Guyton & Hall

10. Ventricular Paroxysmal Tachycardia
Usually does not occur unless there has been ischemic damage
Quinidine increases refractory period of cardiac muscle and can eliminate the problem
Figure 13-13; Guyton & Hall

11. Atrial Fibrillation
Figure 13-19; Guyton & Hall

12. Atrial Flutter
Figure 13-20; Guyton & Hall

13. Ventricular Fibrillation