Transmitral pulsed-wave and mitral annular tissue Doppler are routinely used in clinical practice to assess left ventricular (LV) diastolic function. Using these Doppler modalities, three classic diastolic filling patterns are commonly described: abnormal relaxation (type 1), pseudonormal (type 2), and restrictive (type 3). However, in routine clinical practice, not all filling patterns fit neatly into this tripartite classification. A number of patients demonstrate a Doppler filling pattern, sometimes referred to as type 1B, characterized by a reduced mitral E/A ratio, prolongation of E-wave deceleration time, and an increased E/e′ ratio ( Figure 1 ). This constellation of Doppler findings is thought to be consistent with elevated left atrial pressure, delayed LV relaxation, and a negligible abnormality of passive LV filling properties.
Skaluba et al. demonstrated that patients who display this filling pattern at rest have reduced exercise tolerance on treadmill testing, comparable to that seen in patients with higher grades of LV diastolic dysfunction. Bogaty et al. performed transmitral Doppler studies on patients presenting with acute pulmonary edema and found that although many demonstrated more advanced grades of diastolic dysfunction, more than half displayed delayed relaxation patterns. This likely represented an instance of type 1B filling, although elevated left atrial pressure was documented clinically, not by measuring the E/e′ ratio. The investigators attributed this unexpected finding to a phenomenon they termed “hyperabnormal relaxation,” characterized by profound prolongation of active relaxation such that LV pressure continues to fall through end-diastole ( Figure2 ). When Doppler studies were repeated after stabilization, these patients demonstrated a paradoxical rise in mitral E/A ratio ( Figure 3 ), presumably reflecting improved relaxation. In similar fashion, Labovitz et al. demonstrated that coronary artery occlusion during balloon angioplasty caused a reduction in mitral E/A ratio, with a return to baseline values after balloon deflation.