Brief Answer: Yes, heart palpitations may be due to thyroid dysfunction (hyperthyroidism), even though your heart arteriogram (coronarography), is normal. Detailed Answer: Hello, Thank you for using HCM. Yes, you may be right. Heart palpitations may occur in specific medical conditions such as hyperthyroidism, or anemia, low blood pressure, dehydration, abnormal electrolyte levels etc. In rare cases, palpitations can be a sign of a more serious heart condition. Thyroid parenchyma disorders, may be suggestive of hyperthyroidism, as the most probable cause of the symptoms such as in your case. A laboratory assessment of the thyroid hormones levels (TSH, fT3, fT4) is essential to make a right diagnosis. If hyperthyroidism is proven, you should see an endocrinologist for further treatment strategy and follow-up. Electrolyte levels assessment (Na, K, Cl, Ca) is essential, too and their correction (if deviations are noted) is necessary. Meanwhile, referring the fact that you are symptomatic (you still experience heart palpitations under Verapamil), i would suggest you to increase the dosage of Verapamil in 80 mg x 3, monitoring your blood pressure. Meanwhile you should take plenty of water (2 - 3 liters per day). You should take an equilibrated diet. Try to avoid getting stressed or anxious. Hope this is helpful. Let me know if you need more clarifications. Otherwise please close and rate the answer. Kind Regards, Dr. Juarda