Takotsubo syndrome and coronary vasospasm: Two faces of the same coin?

Takotsubo syndrome is a coronary microvascular disease: experimental evidence

BACKGROUND AND AIMS

Takotsubo syndrome (TTS) is a conundrum without consensus about the cause. In a murine model of coronary microvascular dysfunction (CMD), abnormalities in myocardial perfusion played a key role in the development of TTS.

METHODS AND RESULTS

Vascular Kv1.5 channels connect coronary blood flow to myocardial metabolism and their deletion mimics the phenotype of CMD. To determine if TTS is related to CMD, wild-type (WT), Kv1.5-/-, and TgKv1.5-/- (Kv1.5-/- with smooth muscle-specific expression Kv1.5 channels) mice were studied following transaortic constriction (TAC). Measurements of left ventricular (LV) fractional shortening (FS) in base and apex, and myocardial blood flow (MBF) were completed with standard and contrast echocardiography. Ribonucleic Acid deep sequencing was performed on LV apex and base from WT and Kv1.5-/- (control and TAC). Changes in gene expression were confirmed by real-time-polymerase chain reaction. MBF was increased with chromonar or by smooth muscle expression of Kv1.5 channels in the TgKv1.5-/-. TAC-induced systolic apical ballooning in Kv1.5-/-, shown as negative FS (P < 0.05 vs. base), which was not observed in WT, Kv1.5-/- with chromonar, or TgKv1.5-/-. Following TAC in Kv1.5-/-, MBF was lower in LV apex than in base. Increasing MBF with either chromonar or in TgKv1.5-/- normalized perfusion and function between LV apex and base (P = NS). Some genetic changes during TTS were reversed by chromonar, suggesting these were independent of TAC and more related to TTS.

CONCLUSION

Abnormalities in flow regulation between the LV apex and base cause TTS. When perfusion is normalized between the two regions, normal ventricular function is restored.

A valuable cardiac magnetic resonance investigation after MINOCA/takotsubo Syndrome: a case report

Myocardial infarction with non-obstructive coronary arteries is a working diagnosis that includes takotsubo cardiomyopathy/syndrome (TTS). Cardiac magnetic resonance (CMR) is useful for establishing the underlying aetiology of myocardial infarction with non-obstructive coronary arteries during the acute phase, but its role in follow-up is less well established. A 35-year-old man with several cardiac risk factors presented 3 days after his sister's death with biochemical and clinical features of acute myocardial infarction without coronary artery obstruction on angiography but with diagnostic features of TTS on CMR, including oedema but no late gadolinium enhancement. Subsequent CMR 3 months later revealed left ventricular late gadolinium enhancement suggesting previous acute myocardial infarction. Although the initial diagnosis of TTS was robust according to established criteria, it remained uncertain whether the later ischaemic injury was related to an ischaemic event at presentation or occurred in the intervening period. Nevertheless, CMR may have an extended role in the follow-up of these patients and may reveal additional, actionable pathology.