I am better now and can sleep for up to five or six hours without waking up. But i just went through a Hell of a time for the past five months, waking up (first) to a vibration or rumbling in my left chest, which grew in intensity over the next few weeks and became frightening enough for me to have a stress Echo, ECG, CPAP test including 3 weeks of CPAP therapy, etc. It all cost me at least $5000 and at the end of the day my Cardiologist could not help me. The vibration morphed into a 'flutter' which apparently doesn't show up on an ECG; but my Cardio refused to give me a Holter to check out what is waking me up at night. I do not have shortness of breath. Sometimes i do wake up with chest pain especially after sleeping on my left side; it may be my mild mitral and tricuspid leaks getting temporarily acute. One thing i noticed, is that i have mold in my apartment; i can smell it coming into the bathroom up the drain. Many years ago i went through a very similar experience and got an allergy test and was diagnosed severely allergic to dust mites and mould. I suspect i have had an acute reaction to the mould which caused the sleep apnea (AHI of 21) primarily central sleep apnea, which now appears to be disappearing (but it took four months staying in my girlfriend's place in another country); i can now sleep without the CPAP which i have done without for the past ten days. But there is still a low level 'flutter' sensation or pulsation, which has diminished significantly. In 2005 i was prescribed propranalol at 120 mg a day for the 'palpitation' by doctor number 17 in the UK, after i had travelled to Canada and in the UK saw several specialists, had an Echo (normal but with trivial mitral leak) and saw many doctors and went to the hospital Emergency a few times. Nobody could help me; but the propranalol (i got it after more than a year existing on nothing) eliminated the vibration. In fact, in 2007 i was able to come off the medication altogether. I am now back on the propranalol as the 'symptoms' started again; but i am only taking 40 mg a day because i am convinced that propranalol has given me bradycardia and that could be causing me more problems! Does anyone have any idea what could be causing the 'pulsation' in my left chest. I can get by now on very little medicine because the pulsation has diminished so much; but it comes back especially when i am resting and my heart rate drops a lot. During my July 2011 sleep study, my heart rate dropped to 38 but my O2 was still above 90% (i was off the propranalol i think for the study). I have noticed when i sleep, sometimes i have a 'shock' and my entire body jerks. It is very brief but feels almost like an epileptic shock. I have two questions: can anyone help me discover what might be causing the vibration/pulsation? Is this possibly caused by my dental amalgams (I have eleven amalgams and one crown with amalgam underneath); also, could the propranalol have caused the vibration?