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Ventricular-Arterial Coupling in Stress-Induced Cardiac Events: Hemodynamic Mechanisms and Clinical Implications

Year: 2025
Type: article
Abstract: INTRODUCTION A comprehensive hemodynamic assessment, based on ventricular-arterial coupling, can improve our understanding of unexplained pathophysiological phenomena, particularly those triggered by mental stress.[1] Among the relevant indices, total arterial compliance (TAC), defined as the change in volume per change in pressure (ΔV/ΔP), offers unique insights. Traditionally viewed as a marker of arterial stiffening, TAC is also a key determinant of left ventricular (LV) afterload.[2,3] Although the relative contributions of aortic stiffness and LV ejection to TAC remain uncertain, the LV component may be especially important, as it is potentially more responsive to therapeutic intervention than the fixed structural properties of the aortic wall. This manuscript explores the hemodynamic mechanisms by which mental stress may reduce TAC and elevate systolic intraventricular pressure, thereby contributing to myocardial ischemia and regional wall motion abnormalities. INTERPRETING BLOOD PRESSURE IN TERMS OF VENTRICULAR-VASCULAR COUPLING Arterial blood pressure arises from the dynamic interplay between LV contraction and both central and peripheral vascular resistances, a relationship fundamental to the concept of ventricular-vascular coupling. Pulse pressure widens in the presence of stiffer arteries, earlier wave reflections, larger stroke volume and more rapid LV ejection. These relationships illustrate that pulse pressure is modulated by both vascular and cardiac components. Given the close association between pulse pressure and TAC, the latter may provide a more integrative measure of hemodynamic load, particularly in mental stress-induced syndromes such as white coat hypertension and Takotsubo cardiomyopathy.[4,5] MODELING AORTIC FLOW PROPAGATION While the Windkessel model remains fundamental in estimating TAC,[2,3] modern methods based on wave propagation and frequency-domain analysis enhance physiological fidelity but are impractical for routine use. Simpler metrics like stroke volume-to-pulse pressure ratio (SV/PP) are increasingly employed as surrogates for TAC and correlate well with more sophisticated methods.[6,7] MEASUREMENT CHALLENGES AND CLINICAL FEASIBILITY Although simultaneous measurements of pressure and flow in the ascending aorta provide the most accurate assessment of arterial load, they require invasive methods.[8] Noninvasive alternatives[9] often suffer from timing inaccuracies, particularly affecting estimates of aortic characteristic impedance (Zc).[10] In contrast, TAC is a more robust and reliable parameter under such conditions, making it better suited for investigating hemodynamic mechanisms in stress-related settings. Accordingly, TAC serves as the principal framework for assessing ventricular-arterial coupling in this study, rather than using the ratio of arterial elastance to end-systolic elastance (Ea/Ees).[11] Nevertheless, these approaches are conceptually and physiologically interrelated. PHARMACOLOGICAL INSIGHTS INTO VENTRICULAR-ARTERIAL COUPLING In studies comparing atenolol with captopril, atenolol paradoxically increased TAC due to prolonged LV ejection time rather than vascular relaxation.[12] Nitroglycerin failed to increase TAC despite lowering mean arterial pressure, likely due to reflex adrenergic stimulation of the LV.[10] These findings challenge earlier assumptions and support the view that TAC is influenced more by cardiac dynamics than vascular tone. PSYCHOPHYSIOLOGICAL MODULATION OF TAC Psychocardiological phenomena, such as white coat hypertension, illustrate the impact of mental stress on TAC.[4] In such situations, TAC was significantly reduced, likely reflecting transient increases in sympathetic activity and myocardial contractility, rather than alterations in vascular tone. Importantly, these hemodynamic measurements are typically obtained under resting conditions, which differ markedly from those during physical exertion. At rest, the aortic blood column is relatively stationary at the onset of LV contraction. As a result, enhanced myocardial contractility produces a disproportionately greater rise in pressure compared to flow, leading to a decrease in TAC, a phenomenon reminiscent of the “water hammer” effect in fluid dynamics.[13] This mechanism may help explain how mental stress potentially exerts more deleterious cardiovascular effects than physical stress. LV CONTRACTION AND SELF-GENERATED AFTERLOAD: IMPLICATIONS FOR TAKOTSUBO CARDIOMYOPATHY It was recognized decades ago that LV contraction can increase outflow resistance independently of vascular tone,[14] a concept now gaining broader acceptance among physiologists.[13,15-17] This self-generated afterload may be especially important during acute emotional stress in older adults, where vigorous LV contraction against a stiffened aorta can lead to excessive intraventricular pressure. Experimental animal studies implicate increased afterload in the development of Takotsubo-like myocardial dysfunction.[18] In humans, particularly postmenopausal women, structural and functional cardiac changes may heighten susceptibility to stress-induced regional wall motion abnormalities. These findings suggest a multifactorial pathophysiology in Takotsubo syndrome.[19] From a therapeutic perspective, beta-blockers may help mitigate stress-induced sympathetic activation and LV strain in high-risk individuals, though prospective studies are needed to confirm their preventive value.[20,21]Key question Are hemodynamic mechanisms involved in stress-related cardiac events, particularly in Takotsubo cardiomyopathy? Key finding LV afterload may increase excessively with the combination of a forceful ventricular contraction and a narrow, stiff aorta. Message for readers Exaggerated ventricular contraction against a narrow, stiff aorta may lead to excessive rise in intraventricular pressure and regional wall motion abnormalities in elderly people who experience intense mental stress. Central Illustration: Exaggerated LV contraction against a narrow, stiff aorta. LV = Left ventricular Soma J. Ventricular-arterial coupling in stress-induced cardiac events: Hemodynamic mechanisms and clinical implications. Heart Mind. Published online 2025 Aug 22. doi: 10.4103/hm.HM-D-25-00059CONCLUSION Integrating ventricular-arterial coupling into hemodynamic assessment offers a valuable framework for understanding stress-induced cardiac events. In older adults, acute emotional stress may trigger forceful left ventricular contraction against a stiff aorta, elevating systolic intraventricular pressure and potentially leading to Takotsubo cardiomyopathy. These mechanisms may also underlie more common syndromes such as myocardial ischemia and sudden cardiac death, supporting the potential role of beta-blockers in prevention for high-risk individuals. Ethical Statement Ethical approval was not required for this article as it is a review of existing literature. Declaration of patient consent Patient consent is not applicable for this article. Data Availability Statement Data sharing is not applicable to this article as no new datasets were generated or analyzed during the current study. Financial support and sponsorship None. Conflicts of Interest The author declares no conflicts of interest.
DOI: 10.4103/hm.hm-d-25-00059
Language: English
Field: Medicine
Open Access status: diamond
OpenAlex ID: W4413478297
FWCI:
Cites: 21
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Related to: 10