**8.2 Arrhythmias and conduction abnormalities**

	- male sex
	- age 70 years or older
	- significant valvular disease
	- history of supraventricular arrhythmia, asthma, congestive heart failure
	- premature atrial complexes on preoperative electrocardiography
	- Sinus tachycardia:- Sinus tachycardia is a rhythm abnormality, usually benign. Heart rate is between 100 and 160 beats/min, regular rhythm with a normal P wave before each QRS complex.
	- Reflex bradycardia.
	- Atrial premature contractions, atrial flutter and fibrillation.
	- Paroxysmal supraventricular tachycardia:- characterized by the sudden onset of a rapid regular rhythm with rates between 150 and 250 beats/min.
	- Multifocal atrial tachycardia (MAT):- is an automatic arrhythmia characterized by an atrial rate greater than 100 beats/min with organized, discrete, non-sinus P-waves with at least three different forms in the same electrocardiographic lead.
	- Ventricular premature contractions and non-sustained ventricular tachycardia.
	- Sustained ventricular tachycardia and ventricular Fibrillation.
	- Long QT syndrome:- is a heterogeneous group of disorders characterized by a prolonged QT interval when corrected for heart rate, malignant ventricular arrhythmias (classically the torsades de pointes form of ventricular tachycardia), and the risk of sudden death. Causes:- Antiarrhythmic drugs (Type IA agents (e.g., quinidine), Type III agents (Amiodarone), Tricyclic antidepressants, antibiotics (e.g., erythromycin, azithromycin, ketoconazole), Metabolic and electrolyte disorders (Hypokalemia, Hypomagnesemia),

Nutritional disorders (starvation, liquid protein diets), Subarachnoid hemorrhage, Intracerebral hemorrhage, Head trauma, Encephalitis.
