Clinical evidence points to the possibility that patients with hypertrophic cardiomyopathy may have disordered regulation of cytosolic calcium. One hypothesis is that these patients might have an increased number of calcium channels so that for a given signal, they have increased calcium influx. Such an increased number of calcium channels has recently been reported in the Syrian hamster model of cardiomyopathy. To study calcium channel density in human myocardium we have been using right atrial appendages isolated during cardiac surgery on patients with or without HCM. In a very few patients that have been studied as of this time, there may be some patients with HCM who have a greater number of calcium channels than a non-HCM heart disease control population. Studies are ongoing to confirm this observation.
