Thursday, April 26, 2012

Wilderness SVT

I was lying on my back on a narrow stone ledge. A bandana was draped over my face, my legs in a Trendelenburg position, and my wife was trying to drown me by pouring ice water onto my face. It was at about this point that I was contemplating the next logical step in breaking a run of supraventricular tachycardia (SVT). I had tried the valsalva maneuver over and over, nearly to the point of popping out an eye like an excited Chihuahua. I also struggled with the carotid massage, locating the carotid bulb and rubbing my neck to conjure a genie. I even attempted to do both at the same time, bearing down with the image of birthing twins and burying two fingers into my neck like I was looking for change between the cushions of my sofa. No good.

My personal history of palpitations and tachycardia started years ago, in 1991, during a dehydrated mountain bike ride up the face of a legendary local Boise hill, where my heart rate hit 204. At the bottom of the downhill side my heart rate monitor was still showing a rate of 160. A few simple deep coughs broke the cycle and I was on my way - and my SVT has followed me intermittently for the rest of my years.

In the mid 1990’s, near the top of the Grand Teton, I again felt the pressure of a runaway heart. “Not good,” I thought, climbing at a slower pace. I tried the usual valsalva moves, anything that would increase my intrathoracic pressure and trigger my vagus nerve. However, all that accomplished was to redirect my concentration from climbing to my tachycardia. I needed to pay attention to climbing. To my benefit, my climbing partner that day was Mark, a cardiologist. I slowed, then stopped, and waited for him to climb up to me.  I am sure he was wondering why it appeared as if I was trying to force a spirited bowel movement, but within seconds he realized my plight, palpated my indiscernible pulse, and said, “Do you know where we are?”

Like a well-rehearsed magic trick, a few seconds of Marks experienced kneading to my lateral neck instantly broke the reentry cycle and I was symptom-free. In fact, I felt so good that we climbed on to the summit. I was grateful, and also quite pleased that my vessels didn’t yet have enough plaque in them to replace the SVT with a cerebral vascular accident.

Incidents involving your heart seem to be quite clear in your memory, like they were inscribed with a soldering iron. So, after mining the history of my rare episodes of SVT, the perpetrator of my rapid rate seemed to be a cruel combination of caffeine and dehydration.

Since that day I have monitored my hydration status closely during any outdoor adventure, as well as my coffee intake. I contemplated a visit with an electrophysiologist for a possible ablation, but decided instead to avoid the ‘burn’ and the rate-limiting medications that were suggested by various well-intentioned associates. Instead I decided to live normally, although more thoughtfully, and have only had a few repeat instances of SVT, all of which were vanquished without any more than a protracted valsalva - until Nepal.

We had just passed the village of Pangboche when palpitations and a rapid heartrate beat me into submission. Even though I was drinking three liters of water a day, I had discovered Starbucks Singles, which I had shamefully abused. I attempted the usual - cough, valsalva, cough, and valsalva again - but tachycardic I remained. I hiked further and then threw in the carotid massage for luck. Nothing. My pace was slowing. “I wonder if I could just hike in short bursts until we got to the Pheriche clinic? Surely they have some Adenosine there,” I thought.

 It’s a strange feeling, a runaway heart; like you are moving against an invisible force, as if someone has thrown the weight of ten quilts over your legs and arms. Your head becomes disturbingly light; enjoyment of the world melts away and clouds of negative thoughts replace reason.

Once I was stopped and supine (I would like to add here that to continue any stressful activity involving a strained electrical system will undermine any conversion tactics) my trekking friend, and ER physician, proposed the solution -ice water immersion. I had never tried the diving reflex myself, but at this point it was my only option.

I hoped the embarrassing display of my impromptu waterboarding wouldn’t raise the attention of every medical person on the trail, creating a Gore-Tex funded rugby scrum, but thankfully no one seemed to mind the spectacle. Within seconds of the icewater plunge, my pulse was radially palpable at a rate of 65 bpm, and my symptoms of fatigue and lightheadedness instantly resolved. So immediate was my relief that I was able to sit up, stand, and hit the trail within thirty seconds of conversion. I swore off caffeine for the remainder of the trek and began drinking water nearly to the point of obsession – to ensure a reoccurrence was less likely.

I found out later, the Pheriche clinic does not carry Adenosine, has no defibrillator, and relies entirely on metoprolol for tachycardias. The only answer might have been a rescue helicopter back to Kathmandu. My solution for future adventures will have to be more than just traveling with a cardiologist. It will involve the potentially lethal combination of dehydration and caffeine.

Until then, my heart remains a jack-in-the-box, and I continue to turn the tiny handle, waiting for the thrilling moment when I am faced with another manifestation of the SVT jester.