MADRID, 20 (EUROPA PRESS)
A new study of young adults (aged 20-45) with bipolar disorder has detected subtle (subclinical) abnormalities in heart muscle function and blood pumping before the onset of heart failure, using peak systolic blood pressure and myocardial workload.
The results, published in Elsevier's 'Biological Psychiatry,' point to new avenues for therapeutic development aimed at preventing progression to heart failure in this at-risk population.
Despite accumulating evidence indicating that the risk of cardiovascular disease increases during the early stages of bipolar disorder, few studies have investigated cardiac dysfunction in the early course of the illness. This study is the first to find that myocardial dysfunction is already evident in patients with bipolar disorder younger than 45 years of age before the onset of heart failure, suggesting a possible relationship with underlying coronary vascular dysfunction.
By using indicators sensitive to the early detection of subclinical cardiac dysfunction before the onset of heart failure, this study showed that both global and regional peak systolic strain (which measures how much the heart muscle deforms or shortens during a contraction (systole)) and myocardial work (which assesses the total work the heart muscle does in pumping blood, taking into account both how much it contracts and the pressure it has to pump against) were altered in left ventricular segments in young adults with bipolar disorder compared with age-matched individuals without psychiatric disorders.
Since the researchers measured regional peak systolic strain and regional myocardial work according to the American Heart Association (AHA) 17-segment model based on perfusion territories, the results of this study suggest altered cardiac function in association with abnormal coronary vascular perfusion in the early phase of bipolar disorder.
“Because no studies have previously assessed regional peak systolic strain and regional myocardial work in patients with bipolar disorder using the AHA 17-segment model, this hypothesis-generating study was designed to identify patterns and formulate potential hypotheses for further investigation of the relationship between the heart and bipolar disorder,” said lead investigator Pao-Huan Chen, MD, of the Department of Psychiatry, College of Medicine, Taipei Medical University, Taiwan.
“Although there is much evidence suggesting an elevated cardiovascular risk in individuals with bipolar disorder, we remain surprised by the finding that, even in this young population with bipolar disorder, myocardial dysfunction broadly affects the left ventricular segments in the perfusion territories of all three major coronary arteries,” added first author Cheng-Yi Hsiao, MD, of the Division of Cardiology, Department of Internal Medicine, and Cardiovascular Research Center, Taipei Medical University Hospital.
PATHWAYS LEADING TO DYSFUNCTION MUST BE EXPLORED
Bipolar disorder is a serious mental illness that typically manifests during adolescence and early adulthood. Population-based cohort studies and large-scale meta-analyses have revealed that, in addition to experiencing mood disorder symptoms throughout their lives, patients have an approximately twofold increased risk of heart failure, a leading cause of premature cardiovascular mortality in patients with bipolar disorder.
To clarify the pathophysiology of heart failure in patients with bipolar disorder, the researchers suggest that future studies should explore the mechanistic pathways leading to coronary vascular dysfunction in this population.
"After replication in future studies with different samples, peak systolic stress and myocardial work indexes should be incorporated into the cardiovascular assessment of patients with bipolar disorder. This assessment would provide the opportunity to identify and treat cardiac dysfunction as early as possible, before heart failure progresses, while laying a solid foundation for the development of new therapies to prevent heart failure and improve life expectancy," Chen advises.
