This case report described the history of a patient diagnosed with ABS who obtained good clinical outcome with supportive treatment, no specific medications or interventions was necessary to reverse the syndrome. This case report may be included in the differential diagnosis of patients with acute coronary syndrome apparent changes with regional wall motion and absence of obstructive coronary pathology [1].
The ABS is reversible and triggered by physical or emotional severe stress [6], predominant in women (9:1) with a mean age between 60 and 75 years old and less than 3% of patients have less than 50 years old [1, 3, 4] characteristics that were observed in this case. It is possible that, in women, estrogen has a protective role on the vascular system, and a relative deficiency of estrogen after menopause may predispose to the development of ABS [1, 3, 4, 7].
In this syndrome, the patients may present chest pain (CCS class III) in 50% to 60%, however, some of them present moderate to severe dyspnea (60%), shock or just electrocardiographic abnormalities, [4, 7]. Nonspecific T wave abnormalities, new bundle branch block, and in some cases, a normal ECG can be found [1]. This report showed a normal electrocardiogram at admission, but evolved with left bundle branch block during hospitalization.
The magnitude of the increase in biomarkers was lower than that observed in acute myocardial infarction and disproportionately low to the extensive and acute abnormality regional wall motion which characterizes the ABS [1].
Most patients with this syndrome present normal coronary arteries, which was evidenced in the case described, may also present mild atherosclerosis [1].
The ABS should be included in the differential diagnosis of patients with apparent acute coronary syndrome in the left ventricle in the absence of obstructive coronary artery disease, especially in the definition of a stressful trigger [1, 4]. According to Prasad et al. [1] there is a need to establish a registry to investigate ABS, its natural history and conduct of randomized trials of pharmacotherapy strategies aiming to promote myocardial recovery and prevent recurrence.
One important mechanism that is worth to be discussed as a triggering factor is the adrenergic system. Beta-adrenergic receptors are related to the GPCR family of heptahelical membrane sensors, one of the largest classes of cell-surface receptors, representing essentially the primary target of current pharmaceutical therapies. The function of beta-adrenergic receptors is regulated by several factors, such as blood catecholamines and non-catecholamine neurotransmitters and age [9]. In this context, we believe that this system is a strong candidate to be involved in ABS. Moreover, adrenergic receptors and GRK proteins (mostly GRK5 and GRK2), play a role in acute coronary syndromes [10–12]. Taken together, it is suggested that the interaction between the both systems are involved in the ABS.
Our case report present important data, since the ABS described in our study is a rare cardiac disorder poorly investigated in the literature. The ABS is a newly reported condition afflicting older women, characterized by acute left ventricular systolic dysfunction, triggered by emotionally and physically stressful events, and occurring without significant coronary obstruction [1]. Sympathetic nervous system hyperactivity has been implicated in the pathophysiology of ABS. Single nucleotide polymorphisms involving the adrenergic receptors might result in susceptibility to ABS [12]. In this context, the lifestyle may improve the sympatho-vagal balance [13] and, hence, it is indicated as an important factor to prevent the ABS.
Future studies should establish standardized criteria and guidelines for the diagnosis and clinical disease and, consequently, for their treatment and follow up [8].
