Peripartum cardiomyopathy is diagnosed when features of dilated cardiomyopathy develops in the last one month of pregnancy or within five months of delivery. Clinically there are features of left ventricular dysfunction of varying severity. Sometimes they present with pulmonary edema or cardiogenic shock. The risk peripartum cardiomypathy increases with increasing maternal age. Echocardiography documents the severity of left ventricular dysfunction. Peripartum cardiomyopathy constitutes about 4% of all cardiomyopathies. The incidence varies from 1:3000-4000 pregnancies. It is a form of dilated cardiomyopathy and contributes to 9% of maternal mortality. Mortality estimates range from 25-50%. Future pregnancies are better avoided, though safe pregnancies in those who have fully recovered from the left ventricular dysfunction within six months have been reported. Residual left ventricular dysfunction is a definite risk factor for significant worsening in future pregnancies. Even those who have recovered have been shown to have a drop in ejection fraction during future pregnancies.
Genetic background for peripartum cardiomyopathy
There could be a genetic background for at least those cases of peripartum cardiomyopathy (PPCM) which do not resolve in the usual pattern in the post partum period. This has been suggested by a new study published in Circulation. 2010;121:2169-2175, Karin Y. van Spaendonck-Zwarts et al found first degree relatives with un diagnosed dilated cardiomyopathy for all the three peripartum cardiomyopathy in their database who did not show full recovery. Genetic analysis showed that there was as mutation in the gene encoding cardiac troponin C (TNNC1) in one of these families. In addition they also evaluated 90 of the families with dilated cardiomyopathy in their database and found that five families had peripartum cardiomyopathy patients. The authors conclude that in some patients, peripartum cardiomyopathy may be an initial manifestation of familial dilated cardiomyopathy and would benefit from family screening.
Another study [Ana Morales et al. Rare Variant Mutations in Pregnancy-Associated or Peripartum Cardiomyopathy. Circulation. 2010; 121: 2176-2182 ] in the same issue of the journal evaluated both peripartum cardiomyopathy (occurring in last month of pregnancy to 5 months post partum) and pregnancy associated cardiomyopathy (PACM) with onset of dilated cardiomyopathy earlier in pregnancy. They studied 4110 women from 520 pedigrees in their Familial Dilated Cardiomyopathy Research Project database and found 45 cases of PPCM/PACM. Three cases of PPCM were familial with mutations in MYH7, SCN5A and PSEN2. Two of the sporadic cases of PPCM had mutations in MYH6 and TNNT2. One case of PACM had a mutation in MYBPC3.