Anxiety or Stress-Related Palpitations: Given the patient's age and the fact that this is their first time experiencing palpitations, anxiety or stress could be a significant contributing factor. Palpitations are a common symptom of anxiety disorders.

Atrial Fibrillation: A common arrhythmia in older adults, atrial fibrillation can cause palpitations due to irregular heartbeats.
Hypertension: Uncontrolled high blood pressure can lead to palpitations.
Thyroid Disorders: Both hyperthyroidism and hypothyroidism can cause palpitations, though hyperthyroidism is more commonly associated with this symptom.
Dehydration or Electrolyte Imbalance: Dehydration and electrolyte imbalances, such as low potassium or magnesium levels, can lead to palpitations.

Myocardial Infarction (MI) or Acute Coronary Syndrome: Although less common as a primary cause of palpitations, MI or acute coronary syndrome must be considered, especially in a 62-year-old, as it can be life-threatening.
Pulmonary Embolism: This condition can cause palpitations among other symptoms like shortness of breath and chest pain, and is critical not to miss due to its high mortality rate.
Cardiac Tamponade: A life-threatening condition where fluid accumulates in the sac around the heart, leading to palpitations, shortness of breath, and potentially shock.

Pheochromocytoma: A rare tumor of the adrenal gland that can cause episodes of palpitations, hypertension, and sweating.
Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC): A rare heart condition where the muscle in the right ventricle is replaced by fat and scar tissue, leading to arrhythmias and palpitations.
Long QT Syndrome: A rare condition affecting the heart's electrical system, which can cause sudden, uncontrollable, dangerous arrhythmias and palpitations.