Echocardiographic evidence of the Brockenbrough-Braunwald-Morrow sign after mitral valve repair.

The Brockenbrough–Braunwald–Morrow sign was first described in 1961 (1) in individuals with hypertrophic cardiomyopathy and dynamic left ventricular (LV) outflow tract (LVOT) obstruction worsened by conditions associated with increased myocardial contractility. The sign was characterized by an increase in peak-systolic gradient combined with a decrease in pulse pressure after an extrasystolic beat (2). The increased contractile performance in the postextrasystolic beat was explained by postextrasystolic potentiation from 1) persistence of the positive inotropic effect and 2) rest potentiation from an increased strength of contractility immediately after a period of rest (3). The pathophysiology underscoring the Brockenbrough– Braunwald–Morrow sign was demonstrated echocardiographically after repair of the mitral valve. A 58-yr-old female patient with severe mitral regurgitation from myxomatous degeneration underwent mitral valve repair that included a sliding quadrangular resection of the P2 (middle) segment of the posterior mitral valve leaflet and a 34-mm mitral ring annuloplasty (Model 4450, Edwards Life Sciences). Preprocedural transesophageal echocardiography (TEE) revealed a mitral valve with advanced myxomatous degeneration, redundant tissue of both leaflets and severe, central mitral regurgitation. After repair, color flow Doppler in the TEE midesophageal-aortic valvelong axis view demonstrated turbulent flow in the LVOT and mild mitral regurgitation consistent with systolic anterior motion (SAM) of the mitral valve (Fig. 1; also please see video loop available at www.anesthesiaanalgesia.org). Continuous-wave Doppler examination in the TEE transgastric mid-LV-long axis view measured a LVOT peak gradient of 60 mm Hg in the absence of aortic stenosis or septal hypertrophy. The presence of SAM ultimately led to a return to cardiopulmonary bypass and revision of the mitral valve repair (please see video loop available at www.anesthesiaanalgesia.org). In addition to SAM, further evidence for dynamic LVOT obstruction was captured on continuous-wave Doppler examination (Fig. 2). In this image, a premature complex led to a poor ejection and a reduced gradient. However, the postextrasystolic beat led to an increased LVOT gradient (VMAX 4.2 m/s; peak gradient 67.2 mm Hg; mean gradient 33.2 mm Hg). Continuouswave Doppler-derived measurements, taken immediately before the premature complex, demonstrated a consistent This article has supplementary material on the Web site: www.anesthesia-analgesia.org.