Hello. Severe vertigo in an elderly person most commonly arises due to inadequate supply to the brain. Common causes are either postural i.e. dizziness on standing up or due to any clot in the brain disrupting the blood supply sometimes temporarily. The second cause is more likely in your patient as he has a history of heart disease and blockage of the blood vessels. Hence, I am of the opinion that he might have suffered a TIA or transient ischemic attack. It is a kind of mini-stroke which recovers completely within a day. It cannot always be picked uo on a CT or MRI but an MR angiogram of the blood vessels supolying the brain might help. Postural dizziness is also a possibility if he is on multiple medications for his blood pressure. A sudden drop in the blood pressure on standing makes one dizzy. If this is the case then a review of his medications and adjustment of dosage is all that is needed. Another common cause for vertigo is benign paroxysmal positional vertigo or BPPV which is basically due to a stone in the inner ear. It will cause multiole episodes of severe vertigo accomoanied by vomiting on sudden movements of the head. It is a possibility but unlikely here. Of the above the most serious possibility is a TIA which increases the possibility of him having a full blown stroke later during the coming days. Hence, I would recommend visit to his physician, an MRI of the brain and of the blood vessels supplying yhe brain. If there is any clot or plaque there, the physician might prescribe either a pill or injection to dissolve it or it might need to be removed surgically by passing a wire. However, considering his age I would go for conservative management. Hooe this helps. Regards, Dr Geeta