RT Journal
A1 Cheng S, Wang TJ
T1 OUtcomes in patients with prolonged pr interval or first-degree atrioventricular block—reply
JF JAMA
JO JAMA
YR 2009
FD November 11
VO 302
IS 18
SP 1967
OP 1968
DO 10.1001/jama.2009.1605
UL http://dx.doi.org/10.1001/jama.2009.1605
AB 
In response to Dr Doraiswamy, we note that 89% of the pacemakers were implanted for a primary indication of high-grade AV block or sinus node dysfunction. The other 11% were attributed to a variety of indications, including postoperative changes or myocardial infarction, with high-grade AV block or sinus node dysfunction often noted as a secondary indication. Analyses examining the relationship of specific conduction abnormalities with outcomes were limited by inadequate power. With regard to nodal-blocking agents, we excluded individuals using medications at baseline that affect cardiac conduction times other than β-blockers or calcium-channel blockers. Overall, the prevalence of PR interval prolongation in the setting of nodal agents was very low (0.2% of the sample), a consequence of the generally healthy study cohort. The association of baseline PR interval with mortality in a subgroup analysis limited to those with a PR interval less than 200 milliseconds showed similar results (adjusted hazard ratio, 1.05; 95% confidence interval, 0.99-1.12; P = .10), but power was attenuated by the narrower range of PR interval values in this subgroup. Because our study sample was predominantly white and of European descent, we agree that further studies are warranted in more diverse populations.