The term cardiomyopathy generally denotes a progressive disease in clinical cardiology.There was a time diagnosis of dilated cardiomyopathy (DCM ) was synonymous with a delayed death sentence ! Of course , the situation has vastly improved over the years with the availability of new medical , interventional and surgical management. Still , there is no denying the fact , DCM continues to have a grave outcome especially when it occurs without any identifiable cause .
While we have variety of aggressive DCMs , we also have patients with relatively benign forms of dilated and dysfunctional hearts which recover totally .
This reversible forms of DCM is observed in the following situations.
Hypertensive dilated cardiomyopathy . The left ventricle in some of the patients with severe SHT respond to the stress (Increased after load) by dilatation rather than hypertrophy. This is especially common after an episode of LVF. If we do an acute echocardiogram the LV function is severely impaired and the LV may also be dilated. With good control of BP and fluid management the ventricle promptly return to it’s baseline dimension. The recovery is complete in many . (The mechansim of LV dysfunction acute severe Hypertension is referred to as Pre-load /After load mismatch) Link to concept of Pre load mismatch .
* Note in the past these entities were not called as cardiomyopathy .
Peri partum cardiomyopathy.
This is a serious disorder of cardiac muscles that occur during pregnancy few months before or few months after delivery . There is correlation between PIH and this entity. Prognosis varies between very bad to excellent. Very few cardiac entities have a natural history like this one disease of women.Most of the pregnant women regain their original cardiac status within year or so. It should be recalled there is high chances of recurrence in next pregnancy.
The toxic response to alcohol or the additive cobalt can result in DCM .There is overlap between holiday heart syndrome and alcoholic DCM , where atrial fibrillation is the major problem. Wet Beri beri is the advamced form of clinical DCM that respond to vitamin B therapy.
This is also a common entity that occur during persistent sinus tachycardia or AF , thyrotoxicosis.Beta blockers are of great use here. Recovery is usual if the primary cause is correctable.
Toxic and drug related reversible LV dysfunction
Diabetes and chronic kidney disorders are known to have a reversible form of cardiomyopathy
Some rare toxins , scorpion envenomation , selenium deficiency can result in reversible DCM
**Ischemic DCM are partially correctable in many , still we don’t include it as cause for reversible DCM
*** Many episodes of acute myocarditis can have transient or short term LV dialtation and dysfunction.they are classified as myocarditis .But there is little difference (Except acadmeic . . .) between chronic myocarditis with LV dysfucntion and cardiomyopathy.