Cardiomyopathy, CHF, Low BP

I am an active 53 y.o. female in great health until last year. I am 5' tall and about 118 lbs. In May 2011 I was diagnosed with empyema and had a thoracotomy with decortication. In the OR, I had an echo that showed right atrium collapsed but nothing else remarkable. I had a pericardial window and chest tubes for 8 days. After 2 days with no response to antibiotics, infectious disease doc was consulted and extensive testing done, all negative. I was told that young healthy people without compromised immune systems didn't commonly get empyema. A second echo before discharge showed nothing abnormal. Anyway, recovery was unremarkable and I returned to work in August. In December, I became short of breath and went to the pulmonologist who had treated the empyema. Chest x-ray showed fluid around same lung and he sent me for echo that showed dilated left ventricle and EF of 25%, with regurgitation at all valves except aortic. He started me on Lasix and ramipril and referred me to a cardiologist. At that visit, my BP was 101/60, apparently not ideal for someone who needs an ACE inhibitor.

When I saw the cardiologist, he was surprised that I appear healthy, healthy weight, healthy diet and lifestyle, no edema, no distended neck veins, etc., still working and living normal life, but very sick heart. He added Coreg to the ramipril and lasix and increased the dosage of Coreg over the next months to 25 mg. twice a day. In February, I had a second echo that showed EF still 25% and no other changes. I also had a chemical stress test. After 90 seconds, my heart rate went from 70 to over 150 and the doc stopped the test.....I was about to call it quits myself. I had a cath in March and it showed no blockages and still the 25% EF. I wore a Zoll life vest for three months and had another echo in May, which showed the same. Last week I saw an EP who diagnosed LBBB and implanted a CRT-D. While in the hospital, nurses called him with every BP because it was lower than parameters. Since treatment began in December, my BP has consistently been upper 60s to low 70s over upper 40s to low 50s. The EP held my heart meds and wouldn't discharge me. He finally called my cardiologist who told him my BP had been consistently low and the EP finally gave me the heart meds and discharged me.

My BP has been low since starting on medication. Several months ago, my cardiologist suggested decreasing my meds. I was afraid to since improvement in heart function and mortality seems to be due to the meds. Instead, we decreased the Lasix to 10 mg. since I didn't have edema, with the hope that the increase in fluid volume would raise the BP. It didn't happen, so I did concede to decreasing the Coreg to 12.5 mg twice daily. There has been no rise in my BP with the decrease in the Coreg. I'm going to my cardiologist and need to understand what is happening with my BP. If anyone has any experience with treating heart failure and nonischemic dilated cardiomyopathy with low BP, I would appreciate some insight.

1. What is the low BP doing to my body? I still work and function but do sometimes get lightheaded. What is the physical danger of the low BP? If I'm not fainting, is there a danger?

2. Is there some threshold of effectiveness with the heart meds? Will a decrease be less effective? My doc did say that dosages are recommended based on average and I'm small. Is there some line where the increased dosage has no resulting advantage?

3. Does anyone have any experience in treating my heart condition along with low BP? Is there a way to increase my BP without decreasing the meds?

4. My CRT-D is pacing 99% of the time. Will this result in improved function, which will result in higher BP?

I want to make an informed decision about the medication dosage. Any experience or information would be greatly appreciated.