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The Brockenbrough-Braunwald-Morrow sign

Open ArchivePublished:April 30, 2018DOI:https://doi.org/10.1016/j.jtcvs.2018.04.095
      Figure thumbnail fx1
      The Brockenbrough-Braunwald-Morrow sign in a patient with obstructive HCM.
      The Brockenbrough-Braunwald-Morrow sign is characteristic of dynamic LV outflow tract obstruction, as is seen in obstructive HCM, but is uncommon in fixed valvular or subvalvular obstruction.
      See Editorial Commentary page 1616.
      The Brockenbrough-Braunwald-Morrow sign was first described in patients with obstructive hypertrophic cardiomyopathy (HCM) by Brockenbrough and colleagues
      • Brockenbrough E.C.
      • Braunwald E.
      • Morrow A.G.
      A hemodynamic technic for the detection of hypertrophic subaortic stenosis.
      in the 1960s. This sign is characterized by a decrease in arterial pulse pressure after a premature ventricular contraction (PVC), accompanied by a significant increase in peak left ventricular (LV) systolic pressure. In patients without dynamic outflow obstruction, the longer filling period after a PVC increases LV end-diastolic volume; this and postextrasystolic potentiation increase both stroke volume and arterial pulse pressure.
      • Brockenbrough E.C.
      • Braunwald E.
      • Morrow A.G.
      A hemodynamic technic for the detection of hypertrophic subaortic stenosis.
      • Cooper M.W.
      Postextrasystolic potentiation. Do we really know what it means and how to use it?.
      In patients with obstructive HCM, provocation with a PVC leads to a paradoxic decrease in pulse pressure. Maneuvers to elicit the Brockenbrough-Braunwald-Morrow sign are frequently used to establish the diagnosis of obstructive HCM during cardiac catheterization and to assess the adequacy of septal reduction after surgical myectomy or alcohol septal ablation.
      • Ashikhmina E.A.
      • Schaff H.V.
      • Ommen S.R.
      • Dearani J.A.
      • Nishimura R.A.
      • Abel M.D.
      Intraoperative direct measurement of left ventricular outflow tract gradients to guide surgical myectomy for hypertrophic cardiomyopathy.
      • Nishimura R.A.
      • Seggewiss H.
      • Schaff H.V.
      Hypertrophic obstructive cardiomyopathy: surgical myectomy and septal ablation.
      Figure 1 illustrates the Brockenbrough-Braunwald-Morrow sign in a 65-year-old man with obstructive HCM before and after transaortic septal myectomy. For comparison, we present intraoperative pressure tracings from 2 patients with fixed LV outflow tract obstruction. The patient in Figure 2 is a 69-year-old man with aortic valvular stenosis, and Figure 3 shows pressure tracings from a 64-year-old woman with membranous and tunnel subaortic stenosis not associated with systolic anterior motion of the mitral valve.
      Figure thumbnail gr1
      Figure 1Brockenbrough-Braunwald-Morrow sign in obstructive hypertrophic cardiomyopathy. A, Left ventricular pressure tracing superimposed on aortic pressure tracing shows a typical Brockenbrough-Braunwald-Morrow sign before septal myectomy, with significant decrease in pulse pressure after a premature ventricular contraction. B, In the postbypass tracing, after septal myectomy, it can be seen that the premature ventricular contraction did not trigger the Brockenbrough-Braunwald-Morrow sign. Red line indicates left ventricular pressure tracing; blue line indicates aortic pressure tracing; brackets indicate pulse pressure before and after premature ventricular contraction. ECG, Electrocardiogram.
      Figure thumbnail gr2
      Figure 2Left ventricular pressure tracing superimposed on aortic pressure tracing in a patient with valvular aortic stenosis. A, In this patient, pulse pressure did not change after a premature ventricular contraction. B, No post–premature ventricular contraction changes in pulse pressure are seen after aortic valve replacement. Red line indicates left ventricular pressure tracing; blue line indicates aortic pressure tracing; brackets indicate pulse pressure before and after premature ventricular contraction. ECG, Electrocardiogram.
      Figure thumbnail gr3
      Figure 3Left ventricular pressure tracing superimposed on aortic pressure tracing in a patient with membranous and tunnel subaortic stenosis. A, No post–premature ventricular contraction change in pulse pressure was seen before the operation. B, After membranectomy and myectomy, there was a slight widening of arterial pulse pressure after premature ventricular contraction. Red line indicates left ventricular pressure tracing; blue line indicates aortic pressure tracing; brackets indicate pulse pressure before and after premature ventricular contraction. ECG, Electrocardiogram.
      At operation, LV and aortic pressures were simultaneously traced with high-fidelity catheters before and after cardiopulmonary bypass. We observed the Brockenbrough-Braunwald-Morrow sign in the patient with obstructive HCM (Figure 1, A), with a significant decrease in arterial pulse pressure after a PVC. The sign disappeared after septal myectomy, and pulse pressure remained stable after provocation (Figure 1, B). In the 2 patients with aortic stenosis and subvalvular stenosis (Figures 2 and 3), prebypass arterial pulse pressure did not change after PVC. As expected, the Brockenbrough-Braunwald-Morrow sign could not be elicited in these patients.

      References

        • Brockenbrough E.C.
        • Braunwald E.
        • Morrow A.G.
        A hemodynamic technic for the detection of hypertrophic subaortic stenosis.
        Circulation. 1961; 23: 189-194
        • Cooper M.W.
        Postextrasystolic potentiation. Do we really know what it means and how to use it?.
        Circulation. 1993; 88: 2962-2971
        • Ashikhmina E.A.
        • Schaff H.V.
        • Ommen S.R.
        • Dearani J.A.
        • Nishimura R.A.
        • Abel M.D.
        Intraoperative direct measurement of left ventricular outflow tract gradients to guide surgical myectomy for hypertrophic cardiomyopathy.
        J Thorac Cardiovasc Surg. 2011; 142: 53-59
        • Nishimura R.A.
        • Seggewiss H.
        • Schaff H.V.
        Hypertrophic obstructive cardiomyopathy: surgical myectomy and septal ablation.
        Circ Res. 2017; 121: 771-783

      Linked Article

      • A lesson in the power of observation
        The Journal of Thoracic and Cardiovascular SurgeryVol. 156Issue 4
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          Teaching the skill of observation is often shortchanged in medical education.1 As William Osler famously noted, the whole art of medicine is in observation. In this issue of the Journal, Cui and colleagues2 from the Mayo Clinic provide an example of how the power of a simple observation can have enduring educational value in our approach to diagnosis and management of human disease. The Brockenbrough-Braunwald-Morrow sign was first described in 1961 by the eponymous clinicians3 in patients presenting with dynamic left ventricular outflow tract obstruction and is characterized by a decrease in arterial pulse after a premature ventricular contraction, along with a significant increase in peak left ventricular systolic pressure.
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