Left Ventricular Hypertrophy (LVH): This condition is characterized by thickening of the left ventricle wall, which can lead to delayed R wave progression on an ECG. It's a common finding in the elderly population, especially in those with hypertension.

Anterior Myocardial Infarction (MI) or Ischemia: Although the patient has no cardiac history, an MI can sometimes present subtly, especially in the elderly. Delayed R wave progression can be a sign of anterior wall ischemia or infarction.
Left Bundle Branch Block (LBBB): This is a conduction abnormality that affects the left bundle branch, leading to delayed activation of the left ventricle, which can manifest as delayed R wave progression on an ECG.
Cardiomyopathy: Various forms of cardiomyopathy, such as dilated cardiomyopathy, can lead to changes in the ECG, including delayed R wave progression due to alterations in ventricular structure and function.

Acute Coronary Syndrome (ACS): It's crucial not to miss ACS, as timely intervention is critical. Although the patient has no cardiac history, ACS can occur without prior symptoms, and delayed R wave progression could be an early sign.
Pulmonary Embolism (PE): A large PE can cause right ventricular strain, leading to ECG changes, including delayed R wave progression in some cases. Given the potential lethality of PE, it's essential to consider it in the differential diagnosis.

Wolff-Parkinson-White (WPW) Syndrome: This is a rare condition characterized by an accessory electrical pathway in the heart, which can lead to various ECG abnormalities, including altered R wave progression.
Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC): A rare form of cardiomyopathy that primarily affects the right ventricle, potentially leading to ECG changes, including those that might mimic delayed R wave progression.
Cardiac Sarcoidosis: A rare condition where granulomatous inflammation affects the heart, potentially leading to conduction abnormalities and ECG changes, including delayed R wave progression.