Some Time Off

For those of you that live in southern California or are planning a vacation Knotts Berry Farm is offering free admission for Police and Fire personnel plus a free admission for one other person. In addition they offer discounts for up to 6 more people.

Enjoy.

Heart Rhythms Part 6: Blocks

A heart block is a disease in the electrical system of the heart. This is different than coronary arterial disease. The muscle tissue and vascular system is ok but the electrical impulses are not traveling in a normal fashion through the heart.

There are 3 main types of blocks, conveniently, first, second and third degree blocks. Second degree blocks are then broken down into two subtypes. We'll get to those in a minute.

First Degree Blocks 

More correctly called a first degree atrioventricular block, it is a condition in which the PR interval (the length between the beginning  P wave and the beginning of the QRS complex) is lengthened beyond 0.20 seconds.

What that means is that the electrical impulse generated in the SA node is delayed by the AV node before going on to the ventricles. Management includes identifying and correcting any possible electrolyte imbalances or withholding any offending medications.

Second Degree Blocks

A second heart block is a conduction block between the atria and ventricles. A second-degree AV block is when one or more (but not all) of the atrial impulses fail to make it to the ventricles due to impaired conduction.

There are two types of second degree heart blocks, types 1 and 2. A type 2 heart block is considered to be a much more malignant block than a type 1.

Second Degree Heart Block Type 1

A second degree heart block type 1 is also known as a Mobitz 1 or a Wenckebach. 

A Wenckebach is characterized on the EKG by having an increased amount of time between the P wave and the QRS complex until a QRS complex is dropped, or missed. This is because of a diseased AV node.

The arrows point to the P waves. Not the increasing distance between the P waves and the QRS complexes.

Second Degree Heart Block Type 2

A second degree heart block type 2 is also called a Mobitz 2 block. A Mobitz 2 is characterized on the EKG by having intermittent QRS complexes dropped without a change in the PR interval. When this happens in a regular pattern the number of P waves to QRS complexes is stated as in 3:1, meaning 3 P waves for every QRS complex. 

A second degree type 2 block is caused by a a disease of the His-Purkinje System. It may also rapidly progress into a complete heart block.

Treatment may require an implanted pacemaker.

Third Degree Blocks

A third degree heart block is also known as a complete heart block. A complete heart block is a medical condition in which the electrical impulse generated in the SA node does not propagate to the ventricles. On the EKG this is characterized by having  regular P waves and regular QRS complexes but they are independent of one another. Essentially there are two separate heart rhythms on the EKG. One for the upper chambers of the heart and one for the lower ones. Usually the rate of the P waves will be higher than that of the QRS complexes. Some of the P waves will be buried behind the QRS complexes.

The most common cause is coronary ischemia. Treatment is an implanted pacemaker.

Heart Rhythms Part 1: Basic Anatomy
Heart Rhythms Part 2: Sinus Rhythms
Heart Rhythms Part 3: Junctional Rhythms
Heart Rhythms Part 4: Ventricular Rhythms
Heart Rhythms Part 5: Premature Beats
Heart Rhythms Part 6: Heart Blocks

Dose Of Humility

After one of our medical aids last tour I was getting some restock from our ambulance provider. As I leaned in to grab an IV catheter I cracked my dome on the ambulance. @#$%!!! So much for the smooth fireman to the rescue.

Not my actual skull

Two days later, it still hurts.

Repeat Customers

Over the last couple of shifts we've responded back to several of the patients that we saw a month ago (not always for the same problem). In the cases of a couple of the febrile kids that had seizures I'm happy to report that none of the parents were in a panic and no one tossed their kids to me. This is a major improvement.

A couple of the other calls involved people with major medical issues. You can tell that there is a sigh of relief when their local firefighters can walk in and call them by name. And that they know the history of what's going on.

On the other hand, I find that I have to be more vigilant in my assessment when I know the patient. Lest I assume something that may not be true. And while I hope that these patients won't have the need to call me again, I know it's only a matter of time.

TC Down The Street

The tones went off (insert sounds here...maybe I'll have to try that sometime). We were being dispatched for a TC just down the street from the station. We jumped into our turnouts and pulled out of the station.

As we approached the scene we could see a four door late model sedan in the middle of the side street. Along the curb was a late model mid size pickup. There was moderate damage to the front and sides of both vehicles that happens when to cars try to occupy the same space at the same time. Airbags had deployed and both occupants had self extricated.

As the air brakes set I jumped off the rig and went to see what we were dealing with. I first came upon the driver of the car. He said that other than the minor cut on his hand, he was fine. He didn't want any medical attention. I then walked over to the other driver who was talking on his cell phone.

After convincing him to hang up (repeatedly) I did a quick assessment. While my engineer held c-spine I did a neuro check to see if the patient warranted full spinal immobilization. Fortunately, he did not. While I questioned my patient I noticed that he was a bit slow in answering my questions. He would answer everything correctly but just seemed a little slow. He was also complaining of a burning sensation on his forearm. This was probably from the airbag. Once AMR showed up we loaded him on the gurney and sent him to the hospital. The poor guy was probably just shaken up from the accident.

Once he was taken care of we turned our attention to the debris field around the scene. My engineer grabbed the push broom and I grabbed the shovel. While we were tending to the patient the engine crew put absorbent down on the fluids in the roadway. Now, we cleaned everything up. While it may look like we are just being helpful it actually serves to prevent an accident later on at that same location. Once everything had been cleaned up we headed back to the barn, leaving PD to wait with the wrecks for the tow trucks.