ECG Underwriting Puzzler Presented by: William Rooney, M.D.

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Week 13 in the “Case of the Week” series QUESTION???? What is the major abnormality on this ECG? 3 OK, fine. There are several abnormalities. So, how about rhythm abnormalities? 3

Week 13 in the “Case of the Week” series CLUE: Look for the p waves CLUE: Look for the p waves P waves are hard to find huh. Analysis 4 How about the regularity of the rhythm? Irregularly irregular….what could cause that appearance?

Week 13 in the “Case of the Week” series You are right if you said Atrial Fibrillation Notice that they have no identifiable repetitive pattern Reviewing the Disorder 5 The intervals are all different Measure the R-R interval Don’t get confused if you observe electrical activity in some leads suggestive of p waves but no distinct p waves are found such as is seen in V6. Baseline artifact is common and can be confusing. 5

Animation of the disorder 6 Here is a diagram of the normal conduction system of the heart This is animation trying to depict a normal SA node generated beat in the atrium This animation tries to depict atrial fibrillation competing with the normal SA node in the atrium The AV node is stimulated repeatedly from different focus. It irregularly allows an impulse through causing an irregularly, irregular heart rate Atrial fibrillation occurs when there are multiple irritable automaticity foci in the atria Ectopic foci Ectopic foci can develop anywhere in the atrium and can compete with the normal SA node When multiple ectopic foci are present it can get chaotic SA NODE AV NODE

Features Features of atrial fibrillation No discrete P waves F waves (fibrillatory) are present sometimes No repetitive pattern to the RR interval Ventricular rate typically between beats/min when untreated. QRS complexes are typically narrow (although they can be wider if other conditions are associated with it --such as bundle branch block) Features of atrial fibrillation No discrete P waves F waves (fibrillatory) are present sometimes No repetitive pattern to the RR interval Ventricular rate typically between beats/min when untreated. QRS complexes are typically narrow (although they can be wider if other conditions are associated with it --such as bundle branch block) ECG features of this disorder 7 7

Week13 in the “Case of the Week” series CAUTION: Other conditions which have irregularly irregular R-R intervals include: Multifocal atrial tachycardia Multifocal atrial premature beats Atrial tachycardia or atrial flutter with varying AV block CAUTION: Other conditions which have irregularly irregular R-R intervals include: Multifocal atrial tachycardia Multifocal atrial premature beats Atrial tachycardia or atrial flutter with varying AV block Final Thoughts - ECG Solved 8 This concludes this edition of the ECG puzzler. Contact me if you have questions! Other abnormalities on this ECG: (Just to be complete) Q waves in leads III and aVF suggestive of but not diagnostic of an inferior wall MI Extensive “minor” T wave changes with low/flat T waves noted in the inferior and lateral leads as well as leads V4-6. Leftward axis Other abnormalities on this ECG: (Just to be complete) Q waves in leads III and aVF suggestive of but not diagnostic of an inferior wall MI Extensive “minor” T wave changes with low/flat T waves noted in the inferior and lateral leads as well as leads V4-6. Leftward axis For further reading: Please see page 110 in Dale Dubin’s 6 th edition of Rapid Interpretation of EKG’s For further reading: Please see page 110 in Dale Dubin’s 6 th edition of Rapid Interpretation of EKG’s