Analyzing The Event

Everything that happened yesterday is now known as The Event.
While I was talking with the nurse at 10:30 pm last night, the doctor walked in, Joshua G., a cheerful resident who sounded like Sherlock Holmes as he outlined the task of figuring out why Mom had fainted.
"We don't yet know why this event occurred, but after looking at her chest x-ray I ordered a CT scan that showed a mass near her heart: a first-order pulmonary embolism, somewhat significant, but subacute to chronic. It did not happen in the last 24 hours, but it was not on the scan done in June. It could have happened sometime in the last few weeks."
"So that isn't really why she fainted?"
"No--a blood clot can cause syncopy, but this probably was not the cause of The Event. We will observe her heart rate and other things for a few days, and we will give her Heparin followed by Coumadin."
"Okay," I said. "Thank you." I went home and to bed.
When I came back at 10:30 am, Dr. G. was still there. He had been up all night, and he had more to report.
"During the night her heart had a few pauses, about two seconds long, intermittently. Her heart rate dropped into the low 30s. Therefore, it's possible that she had a second-degree heart block yesterday. This could have caused her loss of consciousness. For this we usually recommend a demand pacemaker, which delivers a small jolt when the heart slows."
"Okay, fine" I said. But I was wondering how he could string two sentences together with no sleep. Nice guy, smiley, young--but I know how spacey I get when I'm sleep-deprived.
I called my brother Bill, who is a general surgeon in Washington state, to run this info by him.
"How could she get a blood clot, when she has a venal caval filter?" I asked.
He provided a background lecture on venal caval filters and why doctors don't use them as much now--"They can cause the vena cava to totally occlude."
He told me to ask: "Have they done a Dopplar duplex ultrasound of the great vessels?"
To remember this question, I wrote it down, trying to suppress the image in my mind of ocean-going vessels. Knowing a little bit of Medispeak is like knowing a little French. When you ask a question and sound fluent, you provoke a torrent of response that may be incomprehensible.
"Also ask if they know where the clot came from," he said. "The ultasound may show a bigger clot somewhere else, from which this clot broke off."
When I called my sister Emily, she reminded me of another possible cause of the fainting: an LBD-type of event. Lewy Body Dementia causes a fluctuating mental status--grogginess one day, alertness the next, agitation the next. But apparently these mental changes can include moments of totally checking out--and then returning.
To summarize: we don't know why The Event occurred. But several detectives are on the case.