Strontium in atrioventricular conduction disorder: Is it a new target?

Introduction: Atrioventricular (AV) block is a common problem worldwide requiring permanent pacemaker implantation, which results in a huge economic burden on society. In our country, the major burden is noted in eastern India. The etiopathological correlation of degenerative conduction tissue disorder does o't explain the differential volume of disease. We speculate environmental link, particularly the influence of elevated trace metals in the pathogenesis of this condition. Purpose: The purpose of the study was to investigate and correlate the concentration of trace metals in blood of patients who have received a permanent pacemaker. Materials and Methods: The blood samples of 81 patients who had permanent pacemaker implantation in the past 3 years were collected and levels of various trace metals were evaluated. It was done using inductively coupled plasma mass spectrometry. The values were expressed in μg/l. Results: There were elevated trace metals in 21 patients and 4 among them had an overlap of more than one abnormal values. Strontium (Sr) surprisingly was elevated in a maximum of 11 patients. The most interesting observation was a trend of Sr being elevated in male sex with AV nodal disease. Conclusion: From this study we hypothesize, Sr affects ion channels in conduction tissue due to its close chemical similarity to calcium. In long run, it could have been inducing fibrosis causing AV blocks. Our observation suggests that trace metal screening may be considered in areas with a high prevalence of AV blocks requiring permanent pacemakers.