756-1 Non Surgical Septum Reduction: A New Treatment for Hypertrophic Obstructive Cardiomyopathy (HOCM)

In patients with HOCM and marked intraventricular gradients resistant to conventional drug treatment with beta blockers and/or Verapamil surgical resection of the muscular septal bulge has been advocated. We have investigated a new catheter treatment in 5 patients with HOCM and significant LV ouflow tract gradients. All patients were in class 3 NYHA with angina and shortness of breath. Intraventricular gradients were measured with transeptally introduced Brockenbrough catheters in the LV inflow tract and arterial catheters in the aortic root. All patients were studied at rest, during the Valsalva manoeuvre, after nitrates and after Isoproterenol infusion. The measurements were repeated during balloon occlusion of the first major septal branch of the left anterior descending coronary artery. — In all patients the resting intraventricular gradient was reduced to less than 20mm/Hg and provocative testing (nitrates and post extrasystolic potentation) failed to create typical increments. The longest inflation time was 30 minutes. Three patients had Verapamil 0.5mg injected through the angioplasty balloon which resulted in a longer lasting gradient/reduction after deflation of the balloon.–After informed consent, 2 patient had 3–5ml of desiccated alcohol infused through the inflated balloon catheter in order to devitalise the offending myocardium. This resulted in a CK elevation up to 2,500 units and permanent abolition of the intraventricular gradient accompanied by marked clinical improvement.From these preliminary observations we conclude that non surgical septum ablation maybe a promising new technique for the treatment of HOCM. Further studies are warranted