Hello! Welcome and thank you for asking on HCM! I understand your concern and would explain that your heart rate is still high and metoprolol er doesn t seem to be very effective. What are your blood pressure values? I recommend you to consult with your GP for a careful physical examination, a resting ECG and some blood lab tests : -complete blood count -fasting glucose -thyroid hormone levels -blood electrolytes -kidney and liver function tests -cortisol plasma levels to exclude other possible causes of this persistent high heart rate. Anxiety could also mimic this situation. You should discuss with you doctor on the above tests and consider increasing the dose of metoprolol or switch into another drug. Hope to have been helpful! Best regards, Dr. Aida