Cardiac Arrhythmia: Given the patient's history of coronary artery disease (CAD) and episodes of syncope over the last 2 months, a cardiac arrhythmia such as atrial fibrillation or ventricular tachycardia is a plausible cause. The patient's age and CAD history increase the likelihood of arrhythmic disturbances.

Orthostatic Hypotension: This condition is common in the elderly and can be exacerbated by medications, dehydration, or autonomic dysfunction. The patient's history of hypertension and hypothyroidism, managed with medications, could contribute to orthostatic changes.
Vasovagal Syncope: Although more common in younger individuals, vasovagal syncope can occur in the elderly, especially in response to stress, pain, or prolonged standing.
Hypertensive Crisis: Although less likely given the patient's managed hypertension, a sudden increase in blood pressure could lead to syncope due to hypertensive encephalopathy or cardiac complications.

Aortic Dissection: Although rare, an aortic dissection is a life-threatening condition that can present with syncope, especially if the dissection involves the ascending aorta and compromises cardiac output or cerebral blood flow.
Pulmonary Embolism: Syncope can be a presenting symptom of a large pulmonary embolism, which can be fatal if not promptly diagnosed and treated.
Cardiac Tamponade: Accumulation of fluid in the pericardial space can compress the heart, leading to reduced cardiac output and syncope. This condition requires immediate medical attention.

Subclavian Steal Syndrome: A rare condition where syncope occurs due to reversal of blood flow in the vertebral artery, typically associated with significant subclavian artery stenosis or occlusion.
Carotid Sinus Hypersensitivity: An exaggerated response to carotid sinus baroreceptor stimulation can lead to bradycardia and/or vasodilation, resulting in syncope. This condition is more common in older adults with cardiovascular disease.