Background:  In the implantable cardiac device (CD) population, not only can clinically silent atrial tachyarrythmias (AT) be detected, but an associated AT burden can be documented.  There are two methods of determining stroke risk:  CHADS₂ and CHA₂DS₂-VASc.  It is not known in the CD patient which method may be more sensitive in calculating TE risk.  

Objective:  Aims of this study were to reveal the AT burden among CD patients, determine CHADS₂ and CHA₂DS₂-VASc scores among patients with an AT burden, and compare these scores with TE events.

Methods:  Records were reviewed from patients undergoing a new CD implant within the last three years from two device clinics. Continuous variables were expressed as mean with standard deviation (SD) and categorical variables were stated as numbers and percentages.  The categorical variables were compared using the Chi² Square test and the continuous variables were compared using the independent 2-sided t-test.

Results: There were 275 CD patients enrolled.  Eighty-seven had an AT burden and 188  patients did not have an AT burden.  CD patients with AT burden were older than those without AT burden [69 (11), p=0.007]. Patients with AT burden had more hypertension and previous history of stroke (p=0.038, p=0.005) compared to those without AT burden. Both the CHADS₂ and CHA₂DS₂-VASc mean scores were higher in patients with an AT burden (p=0.018 and p=0.041).  Only two patients had documented TE following the implant of their device.

Conclusions:  This was the first study to compare two TE risk methods in CD patients. Even though the CHA₂DS₂-VASc score can impact the number of patients requiring anticoagulation, it did not add further utility.  However, this study did demonstrate a significant AT burden is detected in patients with higher TE risk scores suggesting providers may need to be more aggressive in initiating anticoagulation for this population.