What Causes Tachycardia?
Discussion Tachycardia is a rapid heart rate that is above normal for age and level of exertion. Tachycardia is common, particularly sinus tachycardia due to normally encountered circumstances such as pain, fever or exercise. It is usually a normal physiologic process but sustained tachycardia often indicates a potentially abnormal underlying cause. Sinus tachycardia has a rapid heart rate with normal P waves and P-R intervals and variations from moment to moment and respiration. Generally it is not over 200 beats/minute. Vagal stimulation can slow the heart rate; this is a gradual slowing, not an abrupt slowing seen in supraventricular tachycardia. A supraventricular tachycardia has rapid fixed rates, and normal QRS complexes with no discernable P waves or P waves on top of T waves. Vagal stimulation causes no change or an abrupt change to sinus rhythm. Rates are usually 180-300 beats/minute. Wide QRS complexes with usually a fixed rapid rate is a ventricular tachycardia but can also be a supraventricular tachycardia with ventricular aberration. History always provides the primary context for evaluating tachycardia including recent illness, feeding problems, exercise or syncope, emotional state and especially medication use. Physical examination should include evaluation of all vital signs with comparison to normal for age. Fever is commonly noted as can be dehydration when compared to previous weights. Four point blood pressures should be done if possible (congenital...
Source: PediatricEducation.org - Category: Pediatrics Authors: Pediatric Education Tags: Uncategorized Source Type: news
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