6 Metoprolol 100 mg/dL to 200 Metoprolol 200 mg/dL to 300 mg/dL Septal Myectomy
Note: Table made from line graph.
McCully et al suggested, in a series of 47 patients who underwent septal myectomy alone, that asymmetric hypertrophy, severe systolic anterior motion of the mitral leaflet(s) on preoperative echocardiography can identify patients who are most likely to benefit from septal myectomy (50).
Visualization is accessible only to the principal surgeon, and the anatomy of the empty heart can be ambiguous, leading to imprecision in the extent of myectomy that may result in either an inadequate small resection with persistent obstruction (51), or too large, and a ventricular septal defect (0% to 2%), or complete heart block (5, 38-45).
The intra-operative transesophageal echocardiography allows for the surgeon and the cardiologist to be sure that the septal myectomy and mitral valve surgery, if required, are adequate before the patient leaves the operating room.
The reported mortality with the procedure is higher than with a septal myectomy.
Results: Twenty-one patients underwent the full RPR procedure; thirteen received portions of the procedure and only seven underwent myectomy alone (including three with concomitant mitral valve replacement (MVR) for insufficiency unrelated to their obstructive pathology).
Durable long-term results can be achieved in all patients when the mitral valve pathology is appreciated and appropriately repaired, along with a properly located and adequately sized septal myectomy.
Key words: Hypertrophic obstructive cardiomyopathy, septal myectomy
Some HCM patients undergo surgical septal myectomy
to correct outflow obstruction.
A comparison of dual chamber pacing and septal myectomy
for patients with drug refractory symptoms was undertaken at the Mayo Clinic.
In patients who fail medical therapy, the gold standard for relieving LVOT obstruction is surgical septal myectomy
This is supported by echocardiographic and Doppler findings: 1) SAM begins at low Doppler outflow tract velocity even before onset of ejection; 2) LV flow strikes the underside of protruding leaflet with high angle of attack; 3) Mid-septal hypertrophy is usually necessary for resting gradient; 4) Posterior leaflet SAM which almost invariably accompanies anterior leaflet SAM can only be explained by the pushing force; 5) In animal models SAM occurs when the papillary muscles are elevated; 6) SAM can occur without asymmetric septal hypertrophy; 7) Myectomy
may improve SAM by redirecting the direction of flow away from the mitral leaflets (38,39,43,44).