Hypertrophy and Cardiac Enlargement

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Cardiac Dilatation and Hypertrophy

Cardiac enlargement is compensatory response to persistent increased workload that are associated with cardiovascular disease.
Heart may respond by dilatation, hypertrophy or combination of both.

Cardiac hypertrophy:

Cardiac hypertrophy refers to increase in muscle mass of myocardium.
It is due to increase in size of cardiac muscle cells. These are generally secondary in nature and results as compensatory response to increased workload.
2 forms of hypertrophy are recognized; eccentric hypertrophy and concentric hypertrophy
Eccentric hypertrophy:
- Eccentric hypertrophy is generally regarded as healthy, or physiologic hypertrophy and is often termed “athlete’s heart.”
- Eccentric hypertrophy results in a heart having enlarged ventricular chambers and walls of normal or decreased thickness.
- It is produced by lesions that increase blood volume load, such as valvular insufficiencies and septal defects.
Concentric hypertrophy:
- Concentric hypertrophy is a hypertrophic growth of a hollow organ without overall enlargement in which the walls of the organ are thickened and its capacity or volume is diminished.
- In case of cardiac concentric hypertrophy, heart has small ventricular chambers that have thick walls.
- It occurs from lesion that increase pressure load such as valvular stenosis, systemic hypertension, and pulmonary disease.

Clinical Signs:

Diagnosis:

Based on clinical findings
ECG; irregular rhythm in heart
Echocardiography, Radiography
Physical examination: palpation of apex of heart, percussion of thoracic cavity, there is increase in apex beat of heart when heard through auscultation.

Treatment:

Treatment is only advised when animal’s heart starts to fail and animal loses its consciousness frequently.
Diuretics and ACE inhibitors are advised.
In case of arrhythmias, adrenergic blockers or calcium channel blockers are given
Low sodium diet should be given to affected animals.