Role of miR-204 in segmental cardiac effects of phenylephrine and pressure overload.

Cardiotoxicity caused by adrenergic receptor agonists overdosing or stress-induced catecholamine release promotes cardiomyopathy, resembling Takotsubo cardiomyopathy (TC). TC is characterized by transient regional systolic dysfunction of the left ventricle. The animal models of TC and modalities for assessing regional wall motion abnormalities in animal models are lacking. We previously reported the protective role of a small noncoding microRNA-204-5p (miR-204) in cardiomyopathies, but its role in TC remains unknown. Here we compared the impact of miR-204 absence on phenylephrine (PE)-induced and transaortic constriction (TAC)-induced changes in cardiac muscle motion in the posterior and anterior apical, mid, and basal segments of the left ventricle using 2-dimensional speckle-tracking echocardiography (2-STE). Wildtype and miR-204-/- mice were subjected to cardiac stress in the form of PE for four weeks or TAC-induced pressure overload for five weeks. PE treatment increased longitudinal and radial motion in the apex of the left ventricle and shortened the peak motion time of all left ventricle segments. The TAC led to decreased longitudinal and radial motion in the left ventricle segments, and there was no difference in the peak motion time. Compared to wildtype mice, PE-induced peak cardiac muscle motion time in the anterior base of the left ventricle was significantly earlier in the miR-204-/- mice. There was no difference in TAC-induced peak cardiac muscle motion time between wildtype and miR-204-/- mice. Our findings demonstrate that PE and TAC induce regional wall motion abnormalities that 2-STE can detect. It also highlights the role of miR-204 in regulating cardiac muscle motion during catecholamine-induced cardiotoxicity.

Delirium-Induced Takotsubo Cardiomyopathy.

An 85-year-old woman presented with altered mental status and appeared to be actively agitated due to her medications. During her hospitalization, troponins trended up and an electrocardiogram (ECG) showed diffuse ST elevation. Echocardiogram showed an estimated ejection fraction of 40% with hypokinesis of the apex, suggestive of Takotsubo cardiomyopathy. After several days of supportive care, the patient showed significant clinical improvement with normalization of ECG, cardiac enzymes, and echocardiographic findings. Although Takotsubo cardiomyopathy has been associated with diverse forms of physical or emotional stress, this report discusses a rare case of delirium state causing Takotsubo cardiomyopathy.

Complete Heart Block Causing Takotsubo Syndrome: A Case Report.

The association of complete atrioventricular (AV) block with Takotsubo syndrome (TTS) is well known, but the cause-and-effect relationship has not been determined. We present the case of a 91-year-old female with complete AV block who went untreated for over a year and later developed Takotsubo syndrome. Reversal of wall movement defects was seen after a permanent pacemaker was implanted, and routine follow-up showed that the implanted pacemaker worked normally.

Dynamic left ventricular outflow tract obstruction in a patient with acute coronary syndrome and without the apical akinesia: Potential alternative mechanisms causing a dynamic left ventricular outflow tract obstruction other than a compensatory basal hyperkinesis.

The mechanism for dynamic left ventricular outflow tract obstruction (LVOTO) after acute coronary syndromes (ACS) is thought to be apical infarction with compensatory hyperkinesia of the residual normally perfused basal segments of the myocardium. However, herein, we report a patient with ACS and dynamic LVOTO (peak gradient of 250 mm Hg at rest) that could not be secondary to apical akinesia. We propose a potential alternative mechanism leading to dynamic LVOTO in ACS, namely, the interplay between sigmoid septum, basal hyperkinesis, and outflow tract narrowing induced by afterload reduction due to acute myocardial ischemia itself.

Case report: spontaneous coronary artery dissection and suspicion of takotsubo cardiomyopathy in a patient presenting with T-wave inversions, severe QTc prolongation, elevated cardiac biomarkers, and apical akinesia.

BACKGROUND: In patients suspected of acute coronary syndrome, but where the coronary angiography (CAG) has shown unobstructed coronary arteries differential diagnoses include spontaneous coronary artery dissection and takotsubo cardiomyopathy. This case report presents a patient with spontaneous coronary artery dissection but diagnostic signs suspicious of takotsubo cardiomyopathy. Which leads to a consideration of the co-existence of the diseases. CASE SUMMARY: A 57-year-old woman was acutely admitted to the emergency ward with sudden development of chest discomfort, palpitations, and dyspnoea. At hospitalization, the electrocardiography showed T-wave inversions in I, aVL, and V2, and Troponin I was elevated. Initial echocardiography revealed apical akinesia consistent with takotsubo cardiomyopathy. Initially, a diagnosis of acute coronary syndrome or takotsubo cardiomyopathy was suspected. The patient was further diagnostically assessed with CAG including optical coherence tomography which showed spontaneous coronary artery dissection in the left anterior descending artery. At follow-up 3 months later, CAG showed a fully healed coronary artery, and repeated echocardiography showed normalization of the left ventricular function. DISCUSSION: In this case report, initially, acute coronary syndrome was suspected due to electrocardiography with T-wave inversions and elevated cardiac biomarkers. Takotsubo cardiomyopathy was suspected when echocardiography showed apical ballooning, but CAG with optical coherence tomography revealed a spontaneous coronary artery dissection. Interestingly no severe obstructions of coronary arteries were seen, and follow-up echocardiography showed fully regained myocardial function. This leads to the debate as to whether this might be a case of co-existing spontaneous coronary artery dissection and takotsubo cardiomyopathy.