1. EKG Interpretation: Arrhythmias Humayun J. Chaudhry, D.O., FACP, FACOI Assistant Dean for Pre-Clinical Education and Chairman, Department of Medicine N.Y. College of Osteopathic Medicine November 18, 2004

2. Today is Answer Now 1. Monday 2. Tuesday 3. Wednesday 4. Thursday 5. Friday

3. Arrhythmia Definition: Any rhythm other than a normal sinus rhythm (NSR) Definition: Any rhythm other than a normal sinus rhythm (NSR) Many arrhythmias are harmless Many arrhythmias are harmless Some arrhythmias are life-threatening Some arrhythmias are life-threatening

4. Analyzing Rhythms Step 1: Search for the P waves Step 1: Search for the P waves  Best seen in the inferior leads or chest leads Step 2: Look at the QRS complex Step 2: Look at the QRS complex Step 3: Look at rate, regularity, configuration and relation of P to QRS to determine the rhythm Step 3: Look at rate, regularity, configuration and relation of P to QRS to determine the rhythm

5. Pacemaker Sites SA node typically fires 60-100 bpm SA node typically fires 60-100 bpm Junctional area (surrounding the AV node) has an intrinsic rate of 40-60 bpm in adults (junctional escape rhythm) Junctional area (surrounding the AV node) has an intrinsic rate of 40-60 bpm in adults (junctional escape rhythm) Lower ectopic pacemaker sites have an even slower intrinsic rate (e.g., ventricular escape rhythm of 15-40 bpm) Lower ectopic pacemaker sites have an even slower intrinsic rate (e.g., ventricular escape rhythm of 15-40 bpm)

6. Arrhythmias Supraventricular Supraventricular  Pacemaker impulses originate above the ventricles (e.g., SA node, atria, AV node, bundle of His)  Hallmark: narrow, normal-appearing QRS complex (some exceptions)

7. Arrhythmias Ventricular Ventricular  Pacemaker impulses originate in the ventricles  Abnormal, slow, random (muscle cell to muscle cell) depolarization produces a wide QRS complex  Hallmark: wide bizarre QRS complex

8. The AV Node Junctional Rate is 1. >100 bpm 2. 60-100 bpm 3. 40-60 bpm 4. 20-40 bpm 5. < 20 bpm Answer Now

9. Atrial Premature Contractions An ectopic, supraventricular impulse that originates in the atria outside the SA node An ectopic, supraventricular impulse that originates in the atria outside the SA node Because atrial depolarization does not proceed through normal atrial conduction, see a bizarre or inverted p wave Because atrial depolarization does not proceed through normal atrial conduction, see a bizarre or inverted p wave Important clue: an abnormal or notched T wave preceding an early QRS complex Important clue: an abnormal or notched T wave preceding an early QRS complex

10. Multifocal Atrial Tachycardia An SVT that originates from three or more different ectopic atrial foci at a rate between 100 and 250 bpm An SVT that originates from three or more different ectopic atrial foci at a rate between 100 and 250 bpm Seen in patients with COPD and acute respiratory distress with resultant hypoxemia Seen in patients with COPD and acute respiratory distress with resultant hypoxemia

11. Paroxysmal Atrial Tachycardia An SVT derived from impulses that follow a re-entry circuit (a closed loop or circular path through which an impulse continuously follows itself) in the atria or AV node area An SVT derived from impulses that follow a re-entry circuit (a closed loop or circular path through which an impulse continuously follows itself) in the atria or AV node area Starts abruptly, ends abruptly, conducting at 150-250 bpm Starts abruptly, ends abruptly, conducting at 150-250 bpm Tx: carotid sinus massage, valsalva, diving reflex, calcium blockers, digoxin, ß-blockers Tx: carotid sinus massage, valsalva, diving reflex, calcium blockers, digoxin, ß-blockers

12. Atrial Flutter An SVT that originates in the atria An SVT that originates in the atria See flutter (F) waves (250-350 bpm) that look like a saw-tooth See flutter (F) waves (250-350 bpm) that look like a saw-tooth Rapid, regular rhythm Rapid, regular rhythm Determine A:V ratio Determine A:V ratio

13. Atrial Fibrillation An SVT characterized by An SVT characterized by  Absent P waves  Irregularly irregular R-R intervals with a variable ventricular rate Atrial impulses firing at 350-600 bpm Atrial impulses firing at 350-600 bpm See irregular, coarse, or fine undulations of the EKG baseline called fibrillation (f) waves See irregular, coarse, or fine undulations of the EKG baseline called fibrillation (f) waves

14. Ventricular Premature Contraction An abnormal QRS complex that originates from an ectopic focus in the ventricles An abnormal QRS complex that originates from an ectopic focus in the ventricles Depolariation proceeds slowly and abnormally producing a wide, bizarre QRS complex and an abnormal ventricular repolarization Depolariation proceeds slowly and abnormally producing a wide, bizarre QRS complex and an abnormal ventricular repolarization See a compensatory pause because sinus P wave after the PVC is blocked See a compensatory pause because sinus P wave after the PVC is blocked

15. Ventricular Tachycardia A ventricular rhythm of 3 or more PVCs in a row at a rate faster than 100 bpm A ventricular rhythm of 3 or more PVCs in a row at a rate faster than 100 bpm Wide, bizarre QRS complex in the absence of pre-existing BBB or other abnormality Wide, bizarre QRS complex in the absence of pre-existing BBB or other abnormality May be sustained (can degenerate into ventricular fibrillation) or nonsustained May be sustained (can degenerate into ventricular fibrillation) or nonsustained Tx: drugs, synchronized cardioversion, surgery, catheter ablation Tx: drugs, synchronized cardioversion, surgery, catheter ablation

16. Torsade de Pointes Most common predisposing cause is prolongation of QT interval Most common predisposing cause is prolongation of QT interval  Acquired (Type I antiarrhythmics, psychotropic drugs, low magnesium, low potassium, low calcium, liquid protein diets)  Congenital

17. What is the heart rate in the Day 6, EKG 6 12-lead tracing? 1. 350 bpm 2. 250 bpm 3. 98 bpm 4. 82 bpm 5. 68 bpm Answer Now

18. What is the mean QRS axis in the Day 6, EKG 6 12-lead tracing? 1. 30 degrees 2. 60 degrees 3. 90 degrees 4. 120 degrees 5. 150 degrees Answer Now

19. What is the rhythm depicted in Day 6, EKG 6 12-lead tracing? 1. Normal sinus rhythm 2. Atrial flutter 3. Atrial fibrillation 4. Ventricular flutter 5. Ventricular tachycardia Answer Now

20. What is the A:V conduction rate in the Day 6, EKG 6 12-lead tracing? 1. 1:1 2. 2:1 3. 3:1 4. 4:1 5. 5:1 Answer Now

21. What is the heart rate in the Day 6, EKG 10 12-lead tracing? Answer Now 1. 100 bpm 2. 110 bpm 3. 120 bpm 4. 130 bpm 5. 140 bpm

22. What is the mean QRS axis in the Day 6, EKG 10 12-lead tracing? Answer Now 1. -60 degrees 2. -30 degrees 3. 0 degrees 4. 30 degrees 5. 60 degrees

23. What is the rhythm depicted in the Day 6, EKG 10 12-lead tracing? Answer Now 1. Normal sinus rhythm 2. Supraventricular tachycardia 3. Ventricular tachycardia 4. Atrial flutter 5. Sinus tachycardia