Disorders of Cardiac Rhythm

Chapter 145 Disorders of Cardiac Rhythm

Cardiac arrhythmias include disorders of cardiac impulse formation, conduction, rate, and regularity. Terms such as dysrhythmia, ectopia, and ectopy also are used to identify arrhythmias. Cardiac arrhythmias can be benign and clinically insignificant, or they can cause clinical signs. They can even progress to malignant arrhythmias that lead to heart failure, syncope, or sudden death.

Causes of cardiac arrhythmias include heart disease and disorders involving the autonomic nervous system, endocrine system, electrolytes, and other body systems. Anesthetic agents and other drugs can precipitate rhythm disturbances. Cardiac arrhythmias are diagnosed and classified electrocardiographically; see Chapter 144 for additional pertinent information regarding electrocardiography. A summary of the clinical pharmacology of drugs used in the treatment of congestive heart failure (CHF) is found in Chapter 146.


Cardiac arrhythmias are classified in Table 145-1. They occur with congenital or acquired cardiac disease or systemic disorders (Table 145-2).


Adapted from Miller MS, Tilley LP: Treatment of arrhythmias and conduction disturbances. In Miller MS, Tilley LP, eds.: Manual of Canine and Feline Cardiology. Philadelphia: WB Saunders, 1995, with permission.



Sinus Bradycardia

Sinus Block and/or Sinus Arrest (Fig. 145-1)

Sinus Tachycardia

Atrial Premature Complexes (Fig. 145-2)

Atrial Tachycardia (Figs. 145-3 and 145-4)


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Aug 27, 2016 | Posted by in SMALL ANIMAL | Comments Off on Disorders of Cardiac Rhythm

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