DK2985_C000 1..28 - AlSharqia Echo Club

Cardiomyopathy 225Figure 10.10 Flow acceleration in the left ventricular outflow tract in a 63-year-old hemodynamically unstable woman after coronaryrevascularisation. (A–C) Immediately after cardiopulmonary bypass (CPB). (D–F) Clinical improvement after administration of anintravenous bolus of metoprolol (Ao, aorta; AoV, aortic valve; LA, left atrium; LV, left ventricle; SAM, systolic anterior motion).The first case of septal ablation with coronary ethanolinjection was described in 1995. Selective injection ofalcohol in one or two septal branches of the left anteriordescending artery is performed to induce a localizedseptal myocardial infarction at the site of the SAMseptalcontact. The proximal septal branch is selectivelycannulated and an angioplasty balloon is initially positionedand inflated; angiographic contrast media is theninjected through the distal lumen to identify unwantedpotential of spillage back into the left anterior descending(LAD) or in another coronary bed by way of collaterals,before the definitive ethanol injection. At our institution,myocardial contrast echocardiography is routinely usedbefore definitive alcohol injection to define the distributionof each potential septal branch and appropriatelyselect the one(s) supplying the target myocardium(Fig. 10.11). This method minimizes the risk of majorcomplications, such as papillary muscle, anterior orinferior wall extension of the infarct zone, and maximizesthe success rate. Echocardiography together with continuoushemodynamic monitoring (aortic and apical left ventricularcatheters) is used to monitor the acute changes inLVOT gradient. An immediate drop in the LVOT systolicpressure gradient is typically obtained (Fig. 10.12). Proceduralsuccess is usually defined as a 50% reduction inresting LVOT gradient or abolition of provocable gradient(Fig. 10.12) (19). When patients are carefully selected(LVOT obstruction with SAM in the absence of mitralvalve structural anomaly), the procedure is successful in.90% of cases. Further improvement in LVOT gradientis expected during six- to twelve-month follow-up, asseptal thinning and fibrosis supervenes. The most frequentcomplication of alcohol septal ablation is complete atrioventricularblock, which occurs in 5–15% of cases. Ventricularseptal defect is another potential risk, but has notbeen reported when the dimension of the treated septalwall exceeds 18 mm at baseline. Echocardiographicmonitoring is done with TTE, but TEE can be used inpoorly echogenic patients, to improve delineation of themechanism of obstruction.3. Surgical Septal MyectomyThe surgical septal myectomy was first described by Brockin 1957 and is still in use today. The procedure involvesthe removal of a rectangular portion of the hypertrophiedseptum by a transaortic approach. The surgery is veryeffective in relieving the obstruction and reducing thesymptoms (19), with a mortality rate ,2% in experiencedcenters (4). Although nonsurgical septal reduction hasrecently gained popularity, surgical septal myectomyremains the procedure of choice for patients with severesymptoms despite optimal medical therapy, or in patientswho have concomitant surgical valvular or coronaryartery disease warranting surgical correction.The success of the procedure depends on excising theappropriate amount of septum in order to enlarge significantlythe LVOT. This is believed to reduce the flowacceleration in the LVOT, alleviate the concomitantSAM and by doing so, relieve the obstruction and possiblythe MR (4).