TCM is a reversible cardiac impairment that predominantly affects post-menopausal women and patients with neurologic injuries [1]. Although the pathogenesis remains unclear, the condition is thought to be related to high catecholamine levels leading to sympathetic stimulation of the myocardium and cardiotoxicity [1]. Other hypotheses attribute the condition to microvascular dysfunction of the coronary arteries and/or abnormalities of cardiac fatty acid metabolism may play a role in the disease development [2].

Although previously a rare condition, there has been a notable increase in TCM cases over the last two decades with more than 1000 cases documented in the literature [2]. The incidence of TCM was estimated to be 1.5-1.8%, but there was a significant increase during the COVID-19 pandemic (March 1-April 30, 2020), 7.8% (5). Proposed triggers for this condition include sources of major emotional and/or physical stress. Minor stress is rarely associated with the onset of TCM and an estimated 30% of cases are idiopathic [6]. Examples of major stress include but are not limited to an accidental overdose of epinephrine, an adrenaline-producing tumor such as pheochromocytoma, surgery, the death of a loved one, domestic abuse, or natural disasters [7].

TCM typically manifests within 24 hours after surgery [4]. The case presented is unusual as TCM was diagnosed after undergoing mitral valve replacement, demonstrated by a gradual decline in cardiac function. In the literature, only two known cases of TCM have been diagnosed within 2-weeks of a surgical procedure [8, 9]. There are several reasons why invasive procedures may contribute to TCM as the anticipation and act of surgery are both emotionally and physically taxing. The withdrawal of anesthesia and shifts in intravascular fluid volume can also be sources of stress [4]. Prolonged operative times such as in the setting of a cardiac valve replacement are particularly stressful to the body as large amounts of catecholamines are released [4]. Additionally, mitral valve pathology is a well-established risk factor for TCM [3] but is unlikely to be the sole cause given the delayed onset of symptoms in this case. Other postoperative events in the presented case such as autonomic dysfunction during or after cardioversion, atrial fibrillation, sick sinus syndrome, and pacemaker placement [10, 11], may have played a role in the delayed onset of TCM during this timeframe.

It is estimated that 96% of TCM cases have a favorable prognosis and achieve a full recovery [12]. TCM, however, is not entirely benign. In a study of 136 patients, approximately 5% progressed to cardiac arrest or death despite appropriate aggressive treatment [13]. Complications are similar to acute MI and include acute heart failure, cardiogenic shock, acute kidney injury, ventricular and papillary muscle rupture, tamponade, and stroke. When compared to acute MI, TCM patients had higher rates of acute HF and stroke, but lower rates of other complications and in-hospital mortality [14].

Treatment for stress-induced cardiomyopathy is supportive and despite the complications above, the condition usually resolves on its own within several weeks. Hemodynamics may be stabilized with diuretics, angiotensin-converting enzyme inhibitors, and/or beta-blocker medications. Anticoagulation therapy should be initiated until the systolic function is recovered, unless there is a definite contraindication.

According to a study of 131 perioperative TCM cases, about 58% of patients experienced postoperative TCM. Of those postoperative cases, 63% occurred within the first 24 hours while 8% happened more than a week later [4]. There have been several theories regarding the association between TCM and atrioventricular valvular procedures (80% mitral, 11% tricuspid). Sudden correction of atrioventricular regurgitation causes abrupt changes in ventricular loading conditions which leads to an increase in endogenous catecholamines. Changes in protein expression, sarcomere arrangement, and myocyte contractility may play a role in causing the enlargement of the ventricle and atrium. In the setting of chronic severe atrioventricular repair, the sudden drop in ventricular preload red increase in afterload leads to a mismatch in myocardial mechanics, an increase in ventricular myocardial stress, and a transient increase in myocardial oxygen consumption. Finally, inflammation may also contribute to the development of this condition [3].

In a 5-year study of over 95,000 patients undergoing surgical procedures, the prevalence of post-operative TCM was 17.74 per 100,000 patients with a mortality rate of 23.5% [1]. This study identified three major risk factors for postoperative TCM development in adult patients: preoperative hyponatremia, obesity, and the American Society of Anesthesiologists (ASA) class 3 or greater [1]. ASA is a physical status classification system used to predict operative risk. Grade 3 refers to a patient with severe, non-life-threatening systemic disease such as morbid obesity, an implanted pacemaker, or poorly treated diabetes mellitus [15]. Grades 4 and above are used to describe life-threatening disease conditions [15]. In the presented case, the patient was a postmenopausal female with a preoperative BMI of 40 and a borderline-low sodium level of 135 mEq/l. These additional risk factors could have contributed to the development of this syndrome.

In conclusion, the initiation of open heart surgery, along with several stressful postoperative events and other identified risk factors, may collectively increase the likelihood of developing TCM in this patient.