Exercise unmasks impaired vascular and cardiac hemodynamic in patients with hypertrophic cardiomyopathy. (3rd October 2022)

• Record Type: Journal Article
• Authors: Tamargo, M; Martinez-Legazpi, P; Gutierrez, E; Espinosa, M A; Mendez, I; Fernandez, A I; Prieto-Arevalo, R; Gonzalez-Mansilla, A; Mombiela, T; Sanz-Ruiz, R; Elizaga, J; Yotti, R; Fernandez-Aviles, F; Bermejo, J
• Is Part Of: European heart journal. Volume 43(2022)Supplement 2
• Publication Date: 2022-10-03
• Subjects: Cardiology -- Periodicals; Heart -- Diseases -- Periodicals; 616.12005
• DOI: 10.1093/eurheartj/ehac544.1709
• Languages: English
• ISSNs: 0195-668X

Abstract

Abstract: Background/Introduction: Exertional dyspnea is a common finding in patients with Hypertrophic Cardiomyopathy (HCM), yet little data is available regarding the hemodynamic disturbances that lead to symptom development in this population. Purpose: To investigate the mechanisms involved in the functional limitation of patients with HCM. Methods: We prospectively studied 20 symptomatic patients with confirmed diagnosis of HCM. Assessment included NT-pro BNP levels, echocardiogram, and invasive characterization, where subjects also underwent invasive cardiopulmonary exercise testing. Results: Median patient age was 57 (48–66) years old and 15 (75%) were male. Basal NT-pro BNP was elevated (748 pg/mL [406–1082]) and 8 (40%) subjects had NYHA functional Class III despite optimal medical treatment. Sarcomeric abnormal mutations were identified in 12 subjects (60%), most frequently in MYBPC3. Ultrasound imaging showed marked left ventricle (LV) hypertrophy (LV Mass Index 140 g/m 2 [109–161]), with signs of LV outflow obstruction in 13 (65%) subjects. All patients displayed preserved ejection fraction (68% [61–73]). Significant mitral regurgitation was present in 5 subjects and median E/e' was 9.87 [6.43–13.14]. At rest, biventricular filling pressures were relatively normal, with upper limit mean Pulmonary Pressure (Table). Patients exercised for 6.4 (95% CI: 5.6–7.2) min, achieving a respiratory exchange ratio of 1.11 (1.02–1.17). All subjects displayed normal cardiac output at rest (5.6 L/min (3.7–7.5)), that increased during exertion, due mostly to a rise in heart rate (p<0.0001). Exercise doubled LV End-Diastolic Pressure from 15.3 (11.5–19.1) mmHg at baseline to 30.4 (26.6–34.3) mmHg at peak VO2 (p<0.0001), whereas mean pulmonary pressure increased from 21 (14–29) mmHg to 40 (33–47) mmHg (p<0.0001). Remarkably, although arterial hemodynamics were relatively normal at baseline, exercise induced significant increases both in the continuous (systemic vascular resistance) and pulsatile components of vascular load (Impedances, p<0.05; Table 1) (Figure 1). This increase in afterload during exertion has not been previously documented in HCM. The decreased compliance derived, can also play a role in the elevated filling pressures documented on exertion. Conclusion: Exercise unmasks adverse hemodynamics in HCM, severely increasing LV filling pressures and showing systemic arterial dysfunction. Funding Acknowledgement: Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Instituto de Salud Carlos III, Spain.