Key result
Abnormal maximum/mean SACT ratio isolates SN dysfunction and occurs in ~56% of syncope patients.
Why the study?
The diagnostic value of maximum corrected sinus node recovery time and sinoatrial conduction time in patients with sinus node dysfunction was assessed using a modified calculation method.
Does a modified method for calculating sinoatrial conduction time improve the diagnosis of sinus node dysfunction?
Case-Control (n=31)
Does a modified method for calculating sinoatrial conduction time improve the diagnosis of sinus node dysfunction?
Absolute Event Rate: 55.6% vs 33.3%
A modified method for calculating sinoatrial conduction time, combined with maximum corrected sinus node recovery time, can completely differentiate patients with sinus node dysfunction from normal subjects.
May aid SND diagnosis in syncope; hypothesis-generating in case-control data, needs prospective validation.
The diagnostic value of maximum corrected sinus node recovery time (CSNRT) and sinoatrial conduction time (SACT) was assessed in 15 patients with clinical evidence of sinus node (SN) dysfunction and 16 control subjects. The SACT was calculated by a modified method using only those sinus cycles with A1-A1 intervals falling within one standard deviation of the mean. We also obtained a maximum SACT and a ratio of maximum/mean SACT. We found that the maximum/mean SACT ratio being useful for identifying patients with sinus arrest or sinoatrial block. Abnormal value of the ratio (greater than or equal to 1.85) was also more frequently observed in patients with syncope or dizzy spells than those without (55.6% vs. 33.3%). By applying mean SACT and maximum/mean SACT ratio, calculated by the modified method, together with maximum CSNRT, all patients with SN dysfunction could be completely isolated from the normal subjects.
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Chen et al. (1980) conducted a case-control in Sinus node dysfunction (n=31). Modified method for calculating sinoatrial conduction time (SACT) and maximum CSNRT vs. Control subjects was evaluated on Abnormal maximum/mean SACT ratio (≥1.85) in patients with syncope or dizzy spells versus those without. An abnormal maximum/mean SACT ratio (≥1.85) was more frequent in patients with syncope (55.6% vs. 33.3%), and combining these metrics completely isolated SN dysfunction patients from normal subjects.
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