cardiologist said everything is good/ok
One condition that you must rule in or rule out is obstructive sleep apnea. This could be a good reasons why you wake up at the same time, with palpitations and pulsing in your head. If you just stopped breathing for 30 seconds and woke up from deep sleep, what you describe can happen. Longer periods of deeper sleep or REM sleep occurs later in the night. This is also when your muscles relax the most, making you more susceptible to breathing problems.
thanks going to cardiologist this wed. thanks for info