Predictors of Exercise-Induced Pulmonary Hypertension in Patients with Asymptomatic Degenerative Mitral Regurgitation: Mechanistic Insights from 2D Speckle-Tracking Echocardiography

Figure 1. (a) Four-chamber left atrial strains (LASs). (b) Four-chamber LAS rates (LASRs). The white dotted line represents the mean value of the tracked LA segments. Reservoir (r), conduit (e), and contractile (a) strains are represented by color-coded arrows (yellow, pink, and blue, respectively). Measurements were averaged over 4- and 2-chamber views. In this patient, reservoir, conduit, and contractile strains and strain rates were 41.1%, −25.6%, and −15.5%, and 1.68 s−1, −2.0 s−1, and −2.2 s−1, respectively.

Figure 2. Correlations of left atrial strain (LAS)-s with LA diameter (LAD) and LA volume index (LAVI). LAS-s ≤26.9% (associated with estimated exercise-induced pulmonary hypertension) was present in 44 and 29% of patients despite LAD <55 mm and LAVI <60 mL/m2, respectively (pink squares).

Figure 3. Although cases 1 and 2 had a similar left atrial volume index (LAVI, approximately 55 mL/m2), LA function, as indicated by 2D speckle-tracking echocardiography, was significantly different. In case 1, reservoir (r), conduit (e), and contractile (a) strains and strain rates were 41.1%, −25.6%, and −15.5%, and 1.68 s−1, −2.0 s−1, and −2.2 s−1, respectively. On the other hand, case 2 had lower reservoir, conduit, and contractile strains and strain rates (22.1%, −13.9%, and −8.2%, and 1.02 s−1, −0.70 s−1, and −0.82 s−1, respectively). Abbreviations: LAS, left atrial strain; LASR, left atrial strain rate.

Figure 4. In receiver operating characteristic analysis, left atrial strain (LAS)-s, an index of reservoir function, had an area under the curve (AUC) of 0.85 and could predict exercise-induced pulmonary hypertension with higher accuracy than age at a cut-off value of 26.9% (sensitivity, 80%; specificity, 74%).

Figure 5. Symptom-free survival according to left atrial strain (LAS)-s, an index of reservoir function.