EP Lab Digest - May 2008 - (Page 28)

28 EP APPROACH MAY 2008 ALCOHOL SEPTAL ABLATION Continued from page 26 compliant contributing to diastolic dysfunction of the left ventricle. The combination of diastolic dysfunction, LVOT obstruction, mitral regurgitation and eventual secondary pulmonary hypertension results in the characteristic symptoms of dyspnea, chest pain, lightheadedness, and syncope. In addition, patients with HOCM are at increased risk of sudden cardiac death, at a rate of 1-2% per annum.1,6,19 A genetic disease inherited in autosomal dominant fashion, several echocardiographic studies have estimated the prevalence of HOCM in the general population to be 0.2% or 1 in 500 individuals, regardless of race or ethnicity. 2 Diagnosis is oftentimes difficult, due to the multiplicity of mutations in any of the 1-10 genes that can be involved, variable phenotypic penetrance, and variable age at presentation, even within a particular family. 1,3-4,17 However, morphology defined by echocardiographic data along with clinical symptoms often leads to a diagnosis of HOCM, regardless of the phenotype. Treatment of HOCM is aimed at alleviating symptoms, preventing disease progression, and reducing the risk of sudden death. The latter is treated primarily by ICD implantation in patients deemed to be at high risk, based on a variety of clinical, genetic, and anatomic factors. In particular, patients with prior resuscitated sudden arrest, a history of syncope, a family history of sudden premature death, extreme hypertrophy (maximal wall thickness >30 mm), evidence for sustained or non-sustained ventricular tachycardia, and/or hypotensive response to exercise may warrant prophylactic ICD implantation.1,5-10,13,15-16,18-19 Symptomatic patients are treated with negative chronotropic and inotropic agents like beta blockers (first-line agents) and calcium channel blockers to increase diastolic filling time and myocardial relaxation. Low-dose diuretics can be cautiously used in patients with evidence of significant volume overload. Patients with NYHA class III or IV symptoms refractory to medical management can be offered conventional surgical myectomy or the less invasive ASA of the hypertrophied septum. Younger patients ( 120 msec) or long HV interval and a with the anterior mitral valve leaflet. post-procedural retrograde AV block, This results in LBBB in about 36–46% rapid infusion of a large volume of of patients undergoing septal myecto- ethanol, and a higher number of septal my.11,20 ASA can have a more variable perforators treated.The positive predictive effect based on the course of the chosen value of these parameters was low, but septal perforator vessel. ASA produces a they had a negative predictive value of transmural region of tissue necrosis, >80%.22-23,29-30 usually in the basal septum and extending into the right ventricular portion of See ALCOHOL SEPTAL ABLATION page 30 the septum at mid ventricular level, which is the usual location of the right bundle branch; thus, it results in a RBBB in about 42–58% patients undergoing ASA.11,20,22 The frequency of developing complete heart block (CHB) requiring pacing after ASA has varied from 5% to 33%22-23,28-30 and after surgical myectomy has remained low, <1% in the absence of a preexisting RBBB. Based on a recent study by Lawrenz et al, Figure 2. On echocardiogram, there was asymmetric septal hypertrophy (septal measuring the changes in thickness 1.9 cm, posterior wall 0.9 cm), intra-cardiac conduction in systolic anterior motion (SAM) of the patients during ASA by simulanterior mitral valve leaflet, mild mitral regurgitation, and a provocable subaortic taneously recording electrogradient of 120 mmHg. physiological parameters improves the safety of ASA by Patients with NYHA class III or IV symptoms refractory to medical management can be offered conventional surgical myectomy or the less invasive ASA of the hypertrophied septum. Figure 3. After removing the wire, 3 cc of 98% ethanol was infused slowly through the balloon central lumen under vigilant fluoroscopic guidance, with resultant ablation of the septal tissue.

Table of Contents Feed for the Digital Edition of EP Lab Digest - May 2008

EP Lab Digest - May 2008 Is There an Under-Referral of Women for Atrial Fibrillation Ablation? A Hybrid Approach to the Cure of Atrial Fibrillation Contents Letter from the Editor Spotlight Interview: University of Michigan Health System 10-Minute Interview: Amit J. Shanker, MD Modular EP Units: Are They Possible? One Hospital’s Experience All About My Job: Technician Supervisor (New Column!) Alcohol Septal Ablation in the Cath Lab: What is it All About? About the Canadian Heart Rhythm Society: Interview with Martin J. Gardner, MD, FRCP(C), FACC Email Discussion Group: May 2008 Second Annual Salary Survey My First Year in Electrophysiology: What Have I Got Myself Into? Highlight on Technology: Video-Audio Integration for the EP Lab On the Horizon: A New Remote Catheter Manipulation System Striving for Excellence in the Care of Cardiac Patients Five Reasons to Participate with a Professional Organization Suspected Shunting of Defibrillation Energy in the EP Lab Can Digital Music Players Cause Interference with Implantable Devices? ECG 101: Ambulatory ECG Monitoring Events Calendar Industry News and Products Classifieds Advertisers Index

EP Lab Digest - May 2008

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