C.P. Cannon

The electrocardiogram (ECG) is the ? rst test performed on most cardiac patients–one that helps make the ? rst part of the diagnosis and one that can frequently direct treatment decisions. Thus, for any phy- cian, a solid understanding of the ECG is critical. Learning the basics and subtleties of the ECG is a right of passage for all physicians and healthcare providers during their training. So, what would we want from a book on ECGs? Ideally, such a book would be comprehensive, yet concise, practically oriented, and explain pathophysiology and its application to practice. Dr. Khan has written such a book. Rapid ECG Interpretation is comprehensive, yet concise, and very practically oriented. More imp- tant, it takes a step-by-step approach, walking the reader through a thorough evaluation of the ECG. This, as many of us have been taught, is the “right” way to look at an ECG. This edition includes a new opening chapter that covers basic concepts. This quickly orients the reader to the physiology, anatomy, and geometry of the electrical system of the heart. After reviewing each component of the ECG, the next section describes the unique ECG patterns of speci? c cardiac conditions, including pulmonary embolism and long QT syndrome. This is f- lowed by a chapter with each of the arrhythmias. Finally, Dr. Khan includes an invaluable section—an ECG Board Review and Self- Assessment Quiz. With this, the reader can really see if the basic c- cepts and ECG fundamentals have been learned.

The electrocardiogram (ECG) is the ? rst test performed on most cardiac patients–one that helps make the ? rst part of the diagnosis and one that can frequently direct treatment decisions. Thus, for any phy- cian, a solid understanding of the ECG is critical. Learning the basics and subtleties of the ECG is a right of passage for all physicians and healthcare providers during their training. So, what would we want from a book on ECGs? Ideally, such a book would be comprehensive, yet concise, practically oriented, and explain pathophysiology and its application to practice. Dr. Khan has written such a book. Rapid ECG Interpretation is comprehensive, yet concise, and very practically oriented. More imp- tant, it takes a step-by-step approach, walking the reader through a thorough evaluation of the ECG. This, as many of us have been taught, is the “right” way to look at an ECG. This edition includes a new opening chapter that covers basic concepts. This quickly orients the reader to the physiology, anatomy, and geometry of the electrical system of the heart. After reviewing each component of the ECG, the next section describes the unique ECG patterns of speci? c cardiac conditions, including pulmonary embolism and long QT syndrome. This is f- lowed by a chapter with each of the arrhythmias. Finally, Dr. Khan includes an invaluable section—an ECG Board Review and Self- Assessment Quiz. With this, the reader can really see if the basic c- cepts and ECG fundamentals have been learned.

Introduction by Bernhard Meier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxxiii Theoretical Basics and Practical Approach Introduction and Concept of the Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 The Value of'the ECG' Today . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Limitations of the Pattern ECG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Concept of the Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Theoretical Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Anatomy of the Impulse Formation and Impulse Conduction Systems . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Normal Impulse Conduction . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3 Action Potential of a Single Cell ofWorking Myocardium and its Relation to Ion Flows . . . . . . . . . . 4 4 Atrial Depolarization and Repolarization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 5 Ventricular Depolarization and Repolarization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5. 1 Vectors and Vectorcardiogram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5. 2 Simplified QRS Vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6 Lead Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 7 'Magnifying Glass' and 'Proximity' Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 8 Refractory Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 9 Nomenclature of the ECG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Practical Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1 The Practical Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . 14 1. 1 Definitive ECG diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 xiii 2 Practical approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2. 1 Analysis of rhythm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2. 2 Detailed analysis of morphology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 References 18 Pattern ECG The Normal ECG and its (Normal) Variants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Components of the Normal ECG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 1. 1 Sinus Rhythm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 1. 1. 1 Atrial Vectors in Sinus Rhythm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 1. 2 PQ Interval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 1. 3 QRS complex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 1. 3. 1 QRS Axis in the Frontal Plane (ÄQRS ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 p 1. 3. 2 QRS Axis in the Horizontal Plane . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . 22 1. 3. 3 Two Special QRS Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 1. 3. 4 Other Normal Variants of the QRS Complex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 1. 4 ST Segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .