Hypertension: This is the most common cause of left ventricular hypertrophy (LVH) and can lead to a strain pattern on the electrocardiogram (ECG) due to increased afterload. The absence of left axis deviation does not rule out hypertension as the cause, as axis deviation is not a universal finding in hypertensive heart disease.

Aortic Stenosis: This valvular heart disease can cause LVH due to the increased resistance to outflow from the left ventricle. A strain pattern may be observed on the ECG. While aortic stenosis is a significant cause of LVH, it might not always present with left axis deviation.
Hypertrophic Cardiomyopathy: Although this condition often presents with left axis deviation, it is not a universal finding. The presence of LVH with strain pattern without axis deviation could still suggest hypertrophic cardiomyopathy, especially if there are other supporting clinical features or family history.

Cardiac Amyloidosis: This condition can cause LVH and a strain pattern on the ECG. It is crucial not to miss cardiac amyloidosis because it has a different management and prognosis compared to other causes of LVH. The absence of left axis deviation does not rule out amyloidosis.
Fabry Disease: A genetic disorder that can lead to LVH and may present with a strain pattern on the ECG. It's essential to consider Fabry disease, as early diagnosis can lead to specific treatment that improves outcomes.

Friedreich's Ataxia: A rare genetic disorder that can cause hypertrophic cardiomyopathy and thus LVH with strain pattern. While it is less common, considering it in the differential diagnosis is important, especially in younger patients with ataxia.
Other Infiltrative Cardiomyopathies: Conditions like sarcoidosis or hemochromatosis can lead to LVH and may present with a strain pattern on the ECG. These are less common causes but should be considered, especially if other systemic symptoms or signs are present.