Dobutamine stress echocardiography in the exploration of the pathophysiology of takotsubo syndrome

Abstract

The pathophysiology underlying takotsubo syndrome (TTS) remains elusive. TTS is triggered by emotional/physical stresses, administered catecholamines/sympathomimetics, and during dobutamine (DB) stress echocardiogram (ECHO) testing (DSE). DSE induces dynamic left ventricular outflow tract obstruction (LVOTO) and mid-cavitary obstruction (MCO), particularly in postmenopausal women with chest pain and normal coronaries. Some patients suffer TTS, or quasi/atypical TTS, with the vast majority recovering shortly after DSE, although troponins and serial ECHO with/without strain/strain rate ECHO have not been employed to evaluate whether a few of such patients have not developed a forme fruste TTS. This piece proposes that retrospective/prospective scrutiny of ECHOs may provide valuable insights about the pathophysiology of TTS. For cases of DSE-triggered TTS, the regional hyperdynamic myocardial responses (RHMR) to DB, which preceded the regional myocardial contraction abnormalities (RMCAs), LVOTO, MCO and mitral regurgitation (MR) of TTS, should be evaluated. The temporal relationship of RHMR to DB and LVOTO/ MCO/MR, in patients who did/did not suffer TTS should be studied. Evaluation of RHMR to DB in patients with normal DSE may also be contributory. Additionally, patients with positive DSE due to coronary artery disease with an associated TTS-like component (mixed phenotypes) should be scrutinized. ECHOs should be correlated with symptoms during DSE, dose of DB, age, gender, history of hypertension and chest pain, blood pressure and heart rate changes during testing, presence of septal hypertrophy and sigmoid septum in the baseline ECHO, response of chest pain and RHMR and other ECHO abnormalities to β-blockers, follow-up morbidity, and recurrence of TTS. "the search of truth always must trump hubris, bias, complacency, and the fear of new knowledge." Lee Goldman Pathophysiology insights of enigmatic diseases [e.g., takotsubo syndrome (TTS)] should be sought in every conceivable source (i.e., symptom/sign/comorbidity/laboratory test) that appear(s) to provide even an inkling that a cause and effect association may be at work.