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Tachyarrhythmias

Clinical features
Investigations
Therapy
Prevention
Prognosis
Clinical features

Look for variable amplitude of the first heart sound c

Why?

A variable first heart sound makes a ventricular tachycardia more likely

Patient Target Disorder and
Reference Standard		 Diagnostic Test LR+
(95% CI) 		Post-test Probability LR-
(95% CI) 		Post-test Probability
tachycardia c
(pre-test probability: 50%) 		ventricular tachycardia
(induced rhythm) 		variable amplitude of first heart sound infinity
(4.0 to infinity) 		100% 0.45
(0.28 to 0.73) 		31%

Expiry date: July 2004
Levels of Evidence used in grading these guides

Author   CM   Ball
Reviewer   H   Oral
CAT Writers   CM   Ball , N   Shenker , CJ   Wotton