3.30.25
There is something quite fascinating about the human body. I don’t mean what is on the outside, rather what is on the inside. After being an EMT as well as an instructor for nigh on 27 years, one tends to get a fair handle on what makes us tick you might say. Teaching has encouraged me to study and delve even deeper into the mystique of the body human. Being prepared for the questions I may receive while teaching is important to me which is why I research the subjects I teach as deeply as I can. The more one learns, the more one discovers how much more there is yet to learn!
One of the topics I love to share and teach other EMT’s about, is the human heart. This incredible organ is one which we all take so very much for granted, until it starts having issues that is! Every second of the day it is diligently working away. In conjunction with other organ systems, its pumping action supplies each cell in our body with oxygen and nutrients while facilitating the removal of waste products. When under stress, such as when we exercise, it quickly accelerates to meet the demand working muscles need for more oxygenated blood. While sleeping or meditating, our heart rate can drop to well below our normal levels. Of course, factors such as illness and disease can throw a kink in the works, messing with the optimal functioning of our heart to sometimes very detrimental effect.
The heart is amazing! Not only is it an incredible, hardworking pumping machine, but it has a fascinating electrical system that powers that pumping action. As an EMT it is important to understand both systems to better help our patients with cardiac complaints in the back of an ambulance. One tool available to us is cardiac monitoring. Sometimes the art of interpreting cardiac rhythm strips can be quite daunting. As an instructor I feel it is my job to help make deciphering all those little squiggles and F.L.B.’s – Funny Little Beats – as easy as possible for my students and fellow EMT’s. So, although I talk a lot about the SA and AV nodes, Bundle of His and Purkinje Fibers as well as intervals, segments, waves, blocks and such, all of which are very important to know, I try to make learning the heart’s electrical system as easy as possible. For that I turn to pirates and ships.
“Pirates and ships?” you may ask? What on earth does the heart’s electrical system have to do with that! Ah ha! More than one might imagine my friends! For you see, just like any lowly sailor on a pirate ship who aspires to take over and be called Captain, each cell in the heart can beat entirely on its own, separate from all its fellows. That means any heart cell can try to become captain and get to yell the ultimate command “Fire!” if it so chooses! This is called automaticity. However, despite what they may think, not all pirate swabbies are cut out to be a captain! So, bear with me a moment while we look at each sailor’s job on a pirate ship as it relates to the functioning of the heart.
In the heart, the main “pacemaker” that establishes our regular heartbeat is the sinoatrial (SA) node, let’s call him the Captain of the Ship. He sends the order to “Fire!” down electrical pathways to tell the heart’s muscles to contract (or fire) thus activating the pumping of blood from the top chambers of the heart (the atria) to the bottom ones (the ventricles), which in turn send blood zooming around the body. At the junction between the top of the heart and the bottom, is the atrioventricular (AV) node, this be the First Mate! He hears the captain shout “Fire!” and in turn yells to the Bosun’s Mate (anatomically known as the Bundle of His), a stout fellow, who loudly relays the order to the crew below deck (the Purkinje Fibers). Their job is to fire off the ship’s multitude of cannons simultaneously thus making the heart smoothly contract and pump a full complement of blood throughout the body. Are you still with me?
Now the good thing about this system is that if for example, the captain has drunk a wee bit too much rum and falls asleep on the job, the First Mate can effortlessly step in. He can announce the order to “Fire!” down to the Bosun’s Mate and crew below. Similarly, if both the captain and First Mate have been overly tippling at the rum and forget they are on duty, the good old Bosun’s Mate takes over although slowly enough that the crew, sensing weakness, might decide to mutiny! Not a good thing!
A strong Captain keeps his crew in line and brooking no interference from his subordinates, ensures the ship sails fast and true on its course. Yet as with any pirate ship, there are always those waiting to challenge the skipper! Now and then, an unwary Captain may find his First Mate deciding to slip in commands of his own! The poor crew, hearing multiple orders coming down from above, tries to satisfy them all and chaos results. Instead of the cannons firing in unison, we see them firing willy nilly! Ah, ha! Lo and behold, we have an arrythmia!
This my friends perfectly describes what is happening in my heart at the moment. I have two pirates vying for position of Captain of the ship. Instead of one strong leader calling out “Fire!” and the command smoothly being passed down to the crew below deck, so the cannons can be set off in an organized fashion, I have two would be Captains issuing orders! One yells on top of the other, but both are bossy and loud enough to be obeyed, thus the second order to “Fire!” comes before all the cannons and crew are fully reloaded and ready! Needless to say, this makes for rather inefficient running of the pump which causes the vessel – me! – to significantly slow down to a crawl!
Tomorrow, I will see a cardiac electrophysiologist. Hopefully he will sort things out by acting as mediator, ultimately deciding who shall be Captain of the Ship. Maybe he might just sack the pair of them and see fit to set up a better replacement. If his solution fixes my dicky heart, allowing me to get back to my old energetic self, I will graciously accept the outcome. For like so many things in life, there can only be one Captain of the Ship!
