[dbbolton]

Preface: I'm not trying to nitpick you to death. I wouldn't expect anyone outside the medical field to remember any of these terms.

Yes, a HR of 230 BPM is not normal. The terminology is confusing because tachycardia can be both physiologic ('normal') and pathological ('abnormal') depending on the context. What you are describing is not "just" tachycardia, but most likely a type of supraventricular tachycardia/tachyarrhythmia (not a cardiologist, but my best guess would be AV nodal reentrant tachycardia or AVNRT).

The maneuver is called valsalva, one of several vagal maneuvers that essentially work by increasing the parasympathetic input to the heart and negating some of the sympathetic (fight-or-flight) input.

[vanderZwan]

Oh no worries, I appreciate that you take the time to inform me! It'll be fun to google those terms and dive into wikipedia & co :)