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

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

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

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

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

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)

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

The AV Node Junctional Rate is 1. >100 bpm bpm bpm bpm 5. < 20 bpm Answer Now

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

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

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 bpm Starts abruptly, ends abruptly, conducting at 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

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

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 bpm Atrial impulses firing at 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

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

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

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

What is the heart rate in the Day 6, EKG 6 12-lead tracing? bpm bpm bpm bpm bpm Answer Now

What is the mean QRS axis in the Day 6, EKG 6 12-lead tracing? degrees degrees degrees degrees degrees Answer Now

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

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

What is the heart rate in the Day 6, EKG lead tracing? Answer Now bpm bpm bpm bpm bpm

What is the mean QRS axis in the Day 6, EKG lead tracing? Answer Now degrees degrees 3. 0 degrees degrees degrees

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