Takotsubo Cardiomyopathy: A Recognizable Phenotype: Mid-Cavity Variant

Takotsubo Cardiomyopathy (TC) is a unique cardiomyopathy that is an important etiologic consideration in the differential diagnosis of acute coronary syndrome. The presenting symptoms and signs are similar to acute coronary syndrome after plaque rupture, but important distinctions include absence of coronary occlusion and wall motion abnormalities that do fit with a single vascular territory. TC usually has an emotional or physical stressor. The acute presentation of TC can include life-threatening hemodynamic compromise, but the long-term prognosis is better than the prognosis associated with acute coronary syndrome [1]. There are several morphological variants of TC that include apical segment, mid-ventricular, and basal involvement. Apical and mid segment involvement may occur together. Echocardiography is fundamental to identifying the various phenotypes of TC. The mid-ventricular variant of TC is characterized by transient hypokinesis, akinesis or dyskinesis of the left ventricular mid segments with normal to hyperkinesia of apical and basal segments. There is no acute plaque rupture. There are new electrocardiographic changes including: ST elevation and/or t wave inversion and modest elevation of cardiac biomarkers [2].

59 year-old female presents with chest tightness and dyspnea. Symptoms occurred after a stressful conversation about the custody of her disabled 37-year-old son. On arrival to the emergency room she had an immediate ECG revealing t wave inversion V1-6 (Figure 1). This was compared to a normal ECG one year earlier (Figure 2).

Figure 1: ECG revealing t wave inversion across the pericardium (Red arrows pointing to inverted t waves).


Figure 2: Normal ECG one year before when the patient was free of symptoms.

The initial troponin was elevated at 0.13ng/ml (< 0.05ng/ml). The patient was taken to the cardiac catheterization and found to have mild coronary artery disease manifest has a proximal 40% left anterior descending narrowing (Figure 3).


Figure 3: 40% LAD narrowing (red arrow pointing to the LAD lesion).

Contrast LV ventriculography did not reveal any segmental abnormalities (Figure 4). Post cardiac catheterization echocardiography revealed reduced Left Ventricular (LV) systolic function with mid LV cavity segment hypokinesis with normal thickening of the apical and basal segments (Figure 5). The troponin level peaked at 0.38ng/ml (< 0.05ng/ml). The patient recovered in the hospital without hemodynamic or electrical disturbance.


Figure 4: LV Gram: RAO.


Figure 5: Modified apical 4 chambers: Mid-ventricular segment hypokinesis.

The patient returned 6 weeks later and she was free of symptoms with robust activities. Echocardiography revealed normal LV systolic function with normal wall motion of all segments (Figure 6). A nuclear stress test revealed normal perfusion. The patient had all the classic features of mid-cavity variant of TS cardiomyopathy.

Figure 6: Modified apical 4 chamber: Recovery of LV function 6 weeks post acute presentation.

Presentation

Prevalence

Electrocardiography and coronary angiography

Cardiac biomarkers

Acute treatment

Sub-acute and long-term treatment

Mid-ventricular variant of takotsubo cardiomyopathy is a recognizable phenotype that requires a high index of clinical suspicion and meticulous echocardiographic imaging. Echocardiography is the imaging modality of choice to clearly delineate the mid cavity hypokinesis.

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