Life-Threatening Cardiac Emergencies for the Small Animal Practitioner

Preface ix Acknowledgments xi Introduction xiii 1 Normal ECG 1 Before recording 1 ECG set up 2 Recording the ECG 2 What is measured 3 Normal ECG 3 Calculating the heart rate 3 Calculating the mean electrical axis 5 Measuring the complexes 5 2 Bradyarrhythmias 8 Sinus bradycardia 8 Sinus arrhythmia 9 Sinus arrest 10 Atrial standstill 10 AV block overview 12 First-degree AV block 12 Second-degree AV block 12 Third-degree AV block 13 Asystole 15 Cardiopulmonary arrest 16 Escape rhythms 20 3 Tachyarrhythmias 22 Atrial premature complexes 22 Ventricular premature complexes 23 Differentiating SVT from VT 25 Supraventricular tachycardia 27 Atrial fibrillation 29 Ventricular pre-excitation 32 Re-entrant tachycardia 33 Wolff-Parkinson-White syndrome 34 Ventricular tachycardia 36 Accelerated idioventricular rhythm 39 Ventricular flutter 40 Ventricular fibrillation 40 Torsade de pointes 41 4 Miscellaneous arrhythmias and cardiac conditions 42 Artifacts and anomalies 42 Arrhythmogenic right ventricular cardiomyopathy 42 AV junctional rhythms 45 Junctional escape beats 45 Junctional rhythm 46 Bradycardia-tachycardia syndrome (sick sinus syndrome) 47 Electrical alternans (pericardial effusion) 48 Left bundle branch block 50 Left anterior fascicular block 51 Right bundle branch block 52 ST segment abnormalities 52 T wave abnormalities 53 Canine congestive heart failure—mitral valve insufficiency 55 Canine dilated cardiomyopathy 58 Feline aortic thromboembolism (saddle thrombus) 61 Feline congestive heart failure 64 Heartworm—caval syndrome (CS) 68 Pericardial effusion 73 5 Electrolyte disturbance and the ECG 77 Hyperkalemia 77 Hypokalemia 78 Hypercalcemia 78 Hypocalcemia 79 6 Emergency algorithms 80 Bradycardia algorithm 80 Tachycardia algorithm 80 Asystole algorithm (CPR) 80 Arrhythmia drug chart 80 Further reading 86 Index 87