How Hypertension Alters Heart Work: A Pressure-Strain Analysis

Hypertension is the leading risk factor for heart disease. The use of left ventricular (LV) pressure-strain loop (PSL) analysis has recently emerged for estimating myocardial work. This study sought to: i) derive accurate PSLs using invasive pressure and strain curves from three-dimensional (3D) LV geometry to calculate global work index (GWI), and ii) compare GWI between patients with controlled and uncontrolled hypertension. Invasive LV catheterisation and transthoracic 3D echocardiography (3DE) were performed in 84 patients with controlled (n=30) and uncontrolled (n=54) hypertension. Global longitudinal strain over one cardiac cycle was derived from 3DE using a previously validated algorithm. PSLs were created by matching R-R intervals and aligning pressure and strain curves, and GWI was computed as the area inside the loop. Paired-sample (Welch) t-tests were performed to identify statistically significant differences (p<0.05) between groups. The mean systolic/diastolic pressure was 113/71 mmHg and 135/85 mmHg in patients with controlled and uncontrolled hypertension, respectively. The GWI was significantly higher (p=0.012) in uncontrolled hypertension by 311 mmHg% (mean GWI of 1,521 mmHg% and 1,832 mmHg% in controlled and uncontrolled hypertension groups, respectively). Patients with uncontrolled hypertension exhibit greater myocardial work, likely as a compensatory mechanism to preserve cardiac output against an increased afterload. Pressure-strain loop analysis may provide further insight into the underlying mechanisms of hypertension, with potential implications for therapy and disease management. Future work will explore the incremental prognostic value of GWI for monitoring disease progression.