Use of Disopyramide in Obstructive Hypertrophic Cardiomyopathy: A European Insight.

Background/Objectives: Guidelines for obstructive hypertrophic cardiomyopathy (HCM) recommend treatment with disopyramide as an add-on to beta-blockers or calcium-channel blockers when symptoms persist. Data pertaining to effective disopyramide use in practice beyond single-center experience are very limited. This study aimed to quantify disopyramide use in patients with obstructive HCM in England, France and Germany, before the availability of cardiac myosin inhibitors. Methods: This retrospective study used nationally representative databases from England (Clinical Practice Research Datalink and Hospital Episode Statistics, 2010-2019), France (National Healthcare Data System, 2012-2019) and Germany (German statutory health insurance, 2011-2019). Adults (18+) with obstructive HCM were included, based on diagnostic codes for obstructive HCM or any HCM with septal reduction therapy. Disopyramide usage was defined as ≥1 prescription for a patient in a calendar year. Results: Overall, 3730, 6823 and 1141 patients diagnosed with obstructive HCM were identified in the English, French and German databases, respectively. In England, disopyramide use ranged from 4.7% to 5.6% per year with use generally stable over time. The equivalent usage for France was 1.7% to 2.6% per year. As expected, no recorded reimbursed use was reported in Germany during the study period. Conclusions: Disopyramide use is very low in patients with obstructive HCM, possibly due to treatment-related issues, availability or lack of reimbursement. These barriers may drive the uptake of alternative guideline recommended therapies for obstructive HCM treatment.