Do Nitrate Related Drugs Cause Heart Problems?

"|You can take viagra but be careful with drugs like nitrites that would enhance its effect and cause heart attack." I did reply but it disappeared. I asked about nitrites - I assume the Dr. was referring to the recreational drugs containing nitrites (or nitrates?), or 'poppers' etc; I do not take any drugs. A glass or two of red wine is as far I go! Bear in mind that my cardiac event was heart failure not heart attack. The weakness is in the left ventricaI although there are problems on the right as well. I measure my blood pressure regularly; at rest it is usually around 125/56 with heart rate of 60-80. The pacemaker maintains rate above 60bpm. After exertion the rate may go up to 145/70 and 75-90. I welcome your comments.
I have also read about some of the side effects of Viagra.