Hi all, I have had my biventricular pacer ICD since March 2006. It has been running very well, with it pacing my ventricles 98% of the time, but it has only needed to take over my pacing 40% of the time and the events have been minimal. In the past 6 months this has all changed, it is now pacing 89% of the time and I have had over 100 svt's each interrogation. I have also developed angina. (This is relieved by the patches and the spray) My main concern is that there may be a blockage in the lead that goes into the vein outside the left ventricle. Can this happen, and if so, does anyone know what they do about it. I am having an angiogram on Monday, and of course am stressing about it all. I have been into the er twice, (I do not like hospitals so this was because of severe angina) and when on the monitors I set them off regularly. I was amazed when watching the monitor, I didn't feel any physical changes but my heart rate was all over the place, from very fast to very slow and then back again. I do not take medication for arythmias, as this is just a new issue for me, I do take ace inhibitors and aspirin. I am allergic to beta blockers. I had the device inserted for lbbb and low ejection fraction. It is obviously working well, as it is kicking in nearly all the time now and regulating my heart rate. But what concerns me is why it has to do it now and what has caused this recent change in my heart. Hope someone will be able to help, I will have quite a few sleepless nights between now and Monday.