When I was getting exclusively activity-related palpitations my cardiologist assured me I was fine. The scary stats you're concerned about are typically about people with heart failure, coronary artery disease or some structural abnormality. In a normal healthy heart, PVCs at activity or rest are not significant. I know it's hard to believe (and REALLY annoying during sex) but it won't hurt you.
Please do NOT hold your breath during sexual activity. That can absolutely cause PVCs. Try very hard to keep breathing normally and evenly.
PVCs have not been shown to be a sign of increased risk of mortality. You're not going to die from them. Please do consider giving up smoking though. To put it in perspective, nobody dies from PVCs but 50% of smokers will die from smoking.
The sympathetic nervous system is involved in both exercise and sex (and PVCs). During exercise, it causes the heart rate to increase as needed. During sex, the sympathetic system is responsible for the physiological phenomenon of orgasm and/or ejaculation, The sympathetic nervous also can trigger PVCs. Frankly I think the autonomic nervous system (sympathetic and vagal nervous systems) goes ballistic during intercourse, so it doesn't surpirse me that the heart skips occasional beats (PVCs).
I googled around and found this statement in a paper describing a study of those with implantable ICDs (i.e., those susceptable to VT and Vfib): "Occurrence of life threatening arrhythmias and sudden death during or following sexual activity is infrequent." So, if death is rare in those susceptible to Vfib, I think it's safe to assume that if you have an otherwise normal heart you don't have to worry about dropping dead during intercourse.
Tony
Yeah, with a normal heart you shouldn't be worrying at all. I can't answer why you don't have any during exercises but some while having sex, but it's irrelevant anyway, since they're harmless. Sometimes it has something to do with the position or something.
There are not known damage caused by PVCs in normal structured heart, so having them doesn't mean you'll have arrhythmia.
Ps.: I ALWAYS get PACs when I lean forward. Always.
If in doubt,Seek a second opinion, I should have wrote.
I can't speak for you specifically but when I had my last dreaded episode of PVCs, sex would be a severe trigger, I consulted with my cardio who assured me it would pass and it was of no concern , just all the excitement and adrenaline rush during a bad episode only triggering more.Don't hold your breath you need oxygen during an activity such as this, sounds as though anxiety might have taken over, DON"T let this happen to you.If in doubt seek a seek opinion , also I'm not an MD, only speaking of my personal experiences.