Use of intravenous adenosine as a noninvasive diagnostic test for sick sinus syndrome

Background Testing for sick sinus syndrome (SSS) requires invasive stimulation protocols for sinus node recovery time (SNRT) and corrected sinus node recovery time (CSNRT). Methods and Results We compared the CSNRT with the lengthening of the sinus cycle length (ADO:SCL) corrected to the basic cycle length (ADO:CSNRT) after administration of an intravenous bolus of adenosine (0.15 mg/kg) in 10 patients with clinical SSS (group 1) and 67 control patients (group 2). With 550 ms as an abnormal result for the ADO:CSNRT (and for the CSNRT) as an indicator of sinus node dysfunction, the ADO:CSNRT had a sensitivity of 80% and specificity of 97% for detection of SSS compared with sensitivity and specificity of 70% and 95% for invasive CSNRT. When combined, the 2 tests had a sensitivity of 100%. There was significant difference in the CSNRT between group 1 (1848 ± 1825 ms) and group 2 (355 ± 169 ms, P < .0001) and a significant difference in ADO:CSNRT between group 1 (1168 ± 1002 ms) and group 2 (272 ± 592 ms, P < .0001). Conclusions We conclude that the ADO:CSNRT is a sensitive and specific test for SSS that equals invasive testing and should be considered as an alternative to invasive testing in patients with suspected SSS. (Am Heart J 1999;137:435-8.)