Clinical evidence of low cardiac output :pallor, sweating, cold,
clammy extremities(increasedsympathic activity), impaired consciousness
(reduced cerebral blood flow), and hypotension.•Excessive
tachycardia :Very highheart
rates reduce diastole critically, resulting in poor coronary bloodflow and myocardial ischaemia.
•Excessive bradycardia :may not be tolerated by patients with poor
antiarrhythmic treatments - physical manoeuvres, drugs, or electricaltreatment - can also be proarrhythmic, so
that clinical deterioration mayoccur as a
result of treatment.
multiple antiarrhythmic drugs or high dosesof a single drug can cause myocardial depression and hypotension.
•External pacing mostreliable method for treating symptomaticbradycardias
resistant to atropine.