Figure 5: CHEST XRAY WITH PULMONARY CONGESTION
DISCUSSION
Primary percutaneous intervention (pPCI) has revolutionized the
treatment in ST-elevation myocardial infarction (STEMI) and tremendously
decreased the rate of mechanical complications. In the pre-fibrinolytic
period, the rate of mechanical complications was 6%, while it has been
reduced to <0.5% in the revascularization era. In an analysis
of 4 million hospitalized STEMI patients from 2003 to 2015, mechanical
complications have been reported in only 0.27% of patients with PMR
incidence as low as 0.05%.2
The optimal timing of papillary muscle rupture is 2 to 7 days
post-myocardial infarction. Mortality was reported 50% within 24 hrs
without surgical intervention. 82% of patients with first myocardial
infarction were reported to have papillary muscle
rupture.3,4
Echocardiography with Doppler is the cornerstone for the diagnosis of
this fatal complication. The sensitivity of TTE to visualize the
structural abnormalities has been estimated to be 65-85%, with
transesophageal echo sensitivity approaching 92-100%.
The rupture of the posteromedial papillary muscle is 6 to 12 times more
common than the anterolateral papillary muscle due to its single blood
supply from the posterior descending artery of the dominant right
coronary artery (RCA) or dominant left circumflex artery (LCX), causing
inferior wall myocardial infarction (IWMI).5 Most
cases of PMR occur after small areas of ischemia, usually less than 25%
of left ventricular with poor collaterals, and is thought to be due to
preserved ventricular function exhibiting increased shear stress to the
ischemic papillary muscle.
Our patient did not have an audible murmur of severe mitral
regurgitation, which could be explained by the rapid equalization of
pressures within the left ventricle and left atrium.
This case was unusual as he had successful thrombolytic reperfusion of
acute inferior infarction at presentation. Later he again developed
in-hospital re-infarction leading to PMR. Whether it is related to covid
19 infections is unknown to us with a lack of strong evidence.
There have been reports of increased coronary artery thrombus burden in
patients with STEMI in COVID 19 positive patients.6This is consistent with an increased frequency of thrombotic strokes,
particularly in young people, during the pandemic. Alterations in the
coagulation system, abnormal platelet function, or abnormal endothelial
function have been postulated.7
Early diagnosis, prompt hemodynamic support to reduce afterload with
appropriate medications as well as with devices like intra-aortic
balloon pump (IABP), extracorporeal membrane oxygenation (ECMO), and
Tandem heart, and immediate surgical intervention are required to reduce
morbidity and mortality due to papillary muscle rupture secondary to
Acute myocardial infarction.8
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