Hi Mr. Pranab Sarkar, After going through your father s case, I want to know about 1) Presence of diabetes, high blood pressure problem, cholesterol problem if any along with heart problem. 2) Current medication going on. 3) Habits like smoking, alcohol. 4) Any recent illness like loose motions, vomiting, excessive sweating, high grade fever. 5) Any ear problem (pain, decreased hearing, tinnitus- abnormal sound in ear), throat problem. 6) Are symptoms increases after sudden neck movements. I would like to suggest following test for your father- 1) ECG electrocardiogram preferably during episode. 2) Holter s monitoring, electrophysiological study of heart. 3) 2DEcho (echocardiography) 4) Blood sugar level during episode, Complete blood count, hemoglobin, kidney function test, thyroid function test. 5) Blood pressure check in supine position and In standing position to know postural hypotension. 6) If all these tests are normal then there may be need of MRI brain with angiography and carotid artery doppler. In your Father s case there may be possibility of 1) Cardiac arrhythmia (abnormal electrical activity of heart) - it may be a caused by decreased blood supply to heart (vessel blockage) or metabolic abnormalities (abnormalities of kidney or liver function) 2) Postural hypotension. 3) Problems related to blood supply of brain. 4) Hypoglycemic episodes (low blood sugar level) more common in patients with diabetes on treatment. If symptoms increases with neck movement or sudden change position (posture) and there is no postural drop in blood pressure on clinical examination in that case postural vertigo is most likely in that case you should consult ENT specialist, otherwise you should consult your cardiologist, though neurological evaluation by neurologist may also required.