Okay, welcome to the forum and I've read your posting and concerns.

Firstly, you need to take a breath and relax. The events you are describing, although understandably frightening, are entirely incapable of inducing any type of cardiac event or otherwise place your life in jeopardy.

Also, it would be presumptuous of your doctor to state that having an irregular heartbeat "like that" is dangerous in the absence of knowing precisely what "that" actually represented. From the description you've provided, it merely sounds as though you experienced a run of vagus nerve-induced palpitation events and subsequent to becoming frightened induced a run of PAT, or paroxysmal atrial tachycardia, which is completely harmless and usually lasts for a minute or two before the heart returns to normal sinus rhythm. PAT tends to produce a breathless effect and other odd sensorium but is actually a casual occurrence among otherwise healthy persons.

Your symptoms would be inconsistent with either atrial or ventricular fibrillation and I'll refrain from further comment here since it is not applicable.

In order to understand how bending over can induce palpitation events, we need to briefly touch on simple human anatomy. One of the largest nerves in the body is cranial nerve 10, or the vagus nerve. It constitutes the largest mixed nerve and not only innervates regions such as the spleen, the lungs, the heart and the larynx, but also provides parasympathetic nerve function to the GI tract and is termed the pneumogastric nerve at that level.

When the body comes under stress, the central nervous system in general rises to an elevated state, affording the opportunity for wayward or inappropriate evoked potentials, or nerve impulses, to arise and travel along the affected nerve where upon reaching the terminal endpoints, various organs or tissue regions respond just as a twitching eyelid muscle is responding to a similar wayward impulse.

Likewise, the heart in such instances of palpitations of the type you and countless others experience is simply responding to wayward nerve impulses which travel along the vagus nerve at irregular intervals as a consequence of stress upon the nervous system. These events occur elsewhere as well, but due to the heart's very dynamic nature and anatomical design, the effects are felt most prominently. Remember that your heart is as much a muscle as it is an organ and like any other muscle, its tissues readily respond to stimulation whether intentionally invoked by the heart's normal pacers or from outside the heart by stimulation of the vagus nerve.

The actual role of the vagus nerve is to provide parasympathetic regulation to the heart, which balances sympathetic tone and nerve activity, sort of like the gas pedal and the brakes so to speak, with sympathetic tone generally accelerating things and parasympathetic tone slowing things down. The wayward nerve impulses which produce the palpitation events is not a normal course of the vagus nerve and its ability to influence the heart in this manner is purely by the pathway that the nerve provides throughout several areas of the body, the most important here of course is the heart.

When you bend over or strike a certain body position, certain factors such as abdominal gas or air trapped in the lumen of the intestines creates upward pressure against the diaphragm. Bending over further compresses the space and as increased pressure is induced upon the diaphragmatic musculature, it greatly increases the potential for wayward nerve impulses to arise and travel along the vagus nerve until they reach the terminal endings, one of which is naturally the heart.

Depending upon precisely when these events enter the heart's electrical corridor, the sensation can be experienced in a variety of ways. If during atrial depolarization, the sensation feels more like a light fluttering effect that some patients say they can feel up in their throat.

If the event arrives during ventricular depolarization, the sensation is more strong and forceful due to the size and strength of the ventricles, with patients describing the events as hard thumps, thuds or kicks or that the heart is jumping all around inside their chest.

If the event arrives during ventricular repolarization, then the sensation can seem like a very long pause as if the heart has stopped altogether and this occurs because repolarization at this stage of the cardiac cycle is the only brief instant when the heart is actually motionless before the next cycle begins. The palpitation event merely generates what seems to be an extended pause, which is not actually the case.

Magnesium is only required by the body in very discrete amounts and deficiency is extremely rare in industrialized nations. Many people subscribe to the use of supplements like magnesium with the claim that it can reduce benign palpitation events. This is, of course, entirely inaccurate and any brief respite from the events as a consequence of magnesium intake is purely due to a placebo effect. Furthermore, excess magnesium can sometimes produce bradycardia if taken in sufficient quantity, resulting in secondary orthostatic hypotension which causes lightheadedness and tachycardia upon standing too quickly from a seated or lying position. Magnesium is not going to resolve the circumstances and like your doctor, I too suggest that you discontinue use.

Lastly, it's always important to remember that the only negative consequence of the presence of vagus nerve-induced palpitations is the sensation itself. Again, the origin of these events is extra-cardiac in nature, meaning that they arise from outside the heart and do not constitute any type of classical arrhythmia that would warrant clinical concern. Additionally, if you are experiencing any type of GI discomfort as a consequence of increased stress and anxiety, ie gas or abdominal bloating, then symptomatic treatment and reduction of these symptoms will directly correspond with a reduction in palpitation events as well.

You're going to be just fine. Borrow one of your husband's credit cards with the highest limit, go buy a new outfit and have him take you dancing.

You have a long life ahead and it's critical not to spend those moments in apprehension that is based in irrational fears rather than medical fact.

Best regards,

Rutheford Rane, MD (ret.)