In these cases, if the extrasystole are reduced or removed (for example, via ablation therapy) the cardiomyopathy usually regresses. Genetics
About 25–35% of affected individuals have familial forms of the disease, with most mutations affecting genes encoding cytoskeletal proteins, while some affect other proteins involved in contraction. The disease is genetically heterogeneous, but the most common form of its transmission is an autosomal dominant pattern.Autosomal recessive (as found, for example, in Alström syndrome), X-linked (as in Duchenne muscular dystrophy), and mitochondrial inheritance of the disease is also found. Some relatives of those affected by dilated cardiomyopathy have preclinical, asymptomatic heart-muscle changes.Other cytoskeletal proteins involved in DCM include α-cardiac actin, desmin, and the nuclear lamins A and C. Mitochondrial deletions and mutations presumably cause DCM by altering myocardial ATP generation.Kayvanpour et al. performed 2016 a meta-analysis with the largest dataset available on genotype-phenotype associations in DCM and mutations in lamin (LMNA), phospholamban (PLN), RNA Binding Motif Protein 20 (RBM20), Cardiac Myosin Binding Protein C (MYBPC3), Myosin Heavy Chain 7 (MYH7), Cardiac Troponin T 2 (TNNT2), and Cardiac Troponin I (TNNI3). They also reviewed recent studies investigating genotype-phenotype associations in DCM patients with titin (TTN) mutations. LMNA and PLN mutation carriers showed a high prevalence of cardiac transplantation and ventricular arrhythmia. Dysrhythmias and sudden cardiac death (SCD) was shown to occur even before the manifestation of DCM and heart failure symptoms in LMNA mutation carriers.
Secondary polycythemia resolves when the underlying cause is treated.Secondary polycythemia in which the production of erythropoietin increases appropriately is called physiologic polycythemia. Conditions which may result in a physiologically appropriate polycythemia include:

Altitude related – This physiologic polycythemia is a normal adaptation to living at high altitudes (see altitude sickness). Many athletes train at high altitude to take advantage of this effect, which can be considered a legal form of blood doping. Some individuals believe athletes with primary polycythemia may have a competitive advantage due to greater stamina. However, this has yet to be proven due to the multifaceted complications associated with this condition. Hypoxic disease-associated – for example in cyanotic heart disease where blood oxygen levels are reduced significantly, may also occur as a result of hypoxic lung disease such as COPD and as a result of chronic obstructive sleep apnea. Iatrogenic – Secondary polycythemia can be induced directly by phlebotomy (blood letting) to withdraw some blood, concentrate the erythrocytes, and return them to the body. Genetic – Heritable causes of secondary polycythemia also exist and are associated with abnormalities in hemoglobin oxygen release. This includes patients who have a special form of hemoglobin known as Hb Chesapeake, which has a greater inherent affinity for oxygen than normal adult hemoglobin. This reduces oxygen delivery to the kidneys, causing increased erythropoietin production and a resultant polycythemia. Hemoglobin Kempsey also produces a similar clinical picture.