The prognosis for DCM (dilated cardiomyoptathy) depends on the underlying cause.
When the left ventricle (pumping chamber) initially enlarges (chamber size) this condition is compensatory to a degree (Frank/Starling phenomonon) and increases the left ventricle contractions and will pump out of the chamber a percentage greater than 70%. Untreated the left ventridfcle will remodel (pathologically enlarged heart) and that condition will impair contractions and the low output will eventually cause heart failure or an arrhythmia (irregular heart rate) and cardiac arrest.
To handle your DCM requires treatment to reduce the heart's workload that enables the heart to work with reduced afterload (usually high blood pressure0 and with time can reverse the remodeling returning the left ventricle to normal size and functionality. This condition has the highest probability, but you don't furnish much information.
Intensive, prolonged endurance and strength training produces many physiologic adaptations. Volume and pressure loads in the left ventricle (LV) increase, which, over time, increase LV muscle mass, wall thickness, and chamber size. increase LV muscle mass, wall thickness, and chamber size (DCM). This condition is medically termed an athlete's heart. No treatment is necessary. The syndrome is significant because it must be distinguished from serious cardiac disorders and the heart will return to normal size if and when there is a reduction in the vigorous activity (not patholgical). You should consult with a cardiologist to determine the underlying cause and receive treatment if necessary.
Dilated cardiomyopathy (DCM) is when the main chamber (Left ventricle) is enlarged and
weakened. If the cause is known then hopefully it can be treated but in most cases the cause is not known. This is a very risky condition and medication will be tried to hopefully reduce certain hormones and allow the heart to return to normal size. Certain
lifestyle changes will also be required. If medication is unsuccessful then there is a big
chance that the right ventricle and other chambers will also become affected. When the
chambers become enlarged they don't push out the correct volume of blood into the body
with each pump. Heart failure is a risk.
If the conditions worsens you may be required to have a CRT pacemaker installed or a
ICD. Sometimes surgery is available (depending of severity) to reform the ventricle.
When the condition worsens enough, transplant is offered.