Anxiety or Panic Attack: This condition is often characterized by palpitations, dizziness, and chest discomfort, along with other symptoms like shortness of breath and fear of losing control. The symptoms presented by the patient could align closely with the manifestations of an anxiety or panic attack, especially given the broad and non-specific nature of the complaints.

Atrial Fibrillation: A common cardiac arrhythmia that can cause palpitations, dizziness due to reduced cardiac output, and chest discomfort. It's a likely consideration given the combination of symptoms.
Mitral Valve Prolapse: This condition can lead to palpitations, chest discomfort, and occasionally dizziness, especially if there's significant mitral regurgitation affecting cardiac output.
Hypertension: Uncontrolled high blood pressure can lead to palpitations, dizziness, and chest discomfort due to increased workload on the heart and potential effects on blood vessels.

Myocardial Infarction (MI): Although chest discomfort is a key symptom, MI can sometimes present atypically, especially in women, with symptoms like palpitations and dizziness being more prominent. Missing an MI can be fatal.
Pulmonary Embolism (PE): This condition can cause sudden onset of chest discomfort, palpitations due to right heart strain, and dizziness from decreased cardiac output. PE is a medical emergency that requires prompt diagnosis and treatment.
Cardiac Tamponade: Accumulation of fluid in the pericardial sac can compress the heart, leading to reduced cardiac output, which may cause palpitations, dizziness, and chest discomfort. It's a life-threatening condition that needs immediate attention.
Aortic Dissection: A tear in the aorta's inner layer can cause severe chest discomfort, palpitations, and dizziness due to potential involvement of the coronary arteries or aortic valve. It's a medical emergency with high mortality if not promptly treated.

Hyperthyroidism: Although more commonly associated with weight loss, exophthalmos, and heat intolerance, hyperthyroidism can also cause palpitations, dizziness, and chest discomfort due to increased sympathetic activity.
Pheochromocytoma: A rare tumor of the adrenal gland that secretes catecholamines, leading to episodes of palpitations, hypertension, chest discomfort, and dizziness.
Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC): A rare heart condition that can cause life-threatening arrhythmias, leading to palpitations, dizziness, and potentially chest discomfort, especially during exercise.