Heart Rhythms, Part 5: Premature Beats

There are 3 main types of premature beats. PAC's, PJC's and PVC's.

PAC

PAC's are Premature Atrial Contractions. While the SA node normally regulates the heartbeat during a sinus rhythm, PACs occur when another region of the atria depolarizes before the sinoatrial node and thus triggers a premature heartbeat. 

Clear as mud? In English, another part of the upper chambers of the heart prematurely fire off an electrical impulse causing an early beat. On the EKG it will have a deformed P wave (because it's not originating in the SA node), will have a narrow QRS complex, and be earlier than the other beats. After the PAC there were be a compensatory pause, a delay, after the premature complex, before the next regular complex. 


What does it mean? Nothing. Lots of perfectly healthy people have PAC's. Don't stress about it. I don't.

PJC

PJC are Premature Junctional Contractions. While the SA node normally regulates the heartbeat during a sinus rhythm, PJCs occur when AV node depolarizes before the sinoatrial node and thus triggers a premature heartbeat. 

Yes, it sounds a lot like a PAC. Very similar, just with a different origin. On the EKG they will look like a PAC except that there may not be a P wave, the P wave may be inverted, or after the QRS complex. Just like with a junctional rhythm.


Once again, these can happen with healthy hearts. Not too much to worry about.

PVC

PVC is a Premature Ventricular Contraction. While the SA node normally regulates the heartbeat during a sinus rhythm, PVCs occur when ventricles depolarize before the sinoatrial node or the AV node and thus triggers a premature heartbeat. At times PVCs can be felt as chest palpitations or a "missed heart beat" but they also occur in healthy hearts. Since the ventricles are contracting before they have time to fill with blood a PVC is not as efficient at pumping blood.

When PVCs happen more that once they can fall into a number of categories.  If every other beat is abnormal, you can describe it as bigeminal. If every third beat is aberrant, it is trigeminal; every fourth would be quadrigeminal. 


If you have 2 PVCs back to back they are considered couplets. 3 are considered triplets. More than 3 PVCs in a row is considered a run of V-Tach. Unlike PACs, PJCs and the occasional PVC, runs of V-Tach is something to be concerned about.


Some possible causes of PVCs include:

• Ischemia
• Certain medicines such as digoxin, which increases heart contraction
• Myocarditis
• Cardiomyopathy, hypertrophic or dilated
• Myocardial contusion
• Hypoxia
• Hypercapnia (CO2 poisoning)
• Smoking
• Alcohol
• Drugs such as cocaine
• Caffeine
• Tricyclic antidepressants
• Magnesium and potassium deficiency
• Calcium excess
• Thyroid problems
• Chemical (electrolyte) problems in the blood
• Heart attack
• Adrenaline excess
• Lack of sleep/exhaustion
• Stress

When PVCs all look the same on the EKG they are considered monomorphic or unifocal. This happens because the PVCs are all origintaing in the same location. If the PVCs have more than one look to them they are considered polymorphic or multifocal. This means they are stemming from multiple focal points in the ventricles.

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

Heart Rhythms Part 4: Ventricular Rhythms

As we learned in Part 3 the AV node will initiate an electrical impulse if it fails to receive one from the atria in a timely manner. This is also true for the ventricles. If they fail to receive an electrical impulse from the AV node they will fire on their own, albeit at a much slower rate (20 to 40 beats a minute). On the heart monitor a ventricular rhythm is characterized by a wide QRS complex. In other words, if it has a wide QRS complex, it's a ventricular rhythm of some sort.

There are several ventricular heart rhythms/arythmias and all of them have the potential to be lethal. Some of them are always deadly.

I'll start with ventricular rhythms. The ventricles have an intrinsic rate between 20 and 40 beats per minute. Clearly, if you're at this point, you are having some major issues medically speaking. So now that you can recognize a ventricular rhythm (by the wide QRS complex) the rate becomes important.

• <20 - Recheck for a pulse, I bet they're dead.
• 20 to 40 - Ideoventricular rhythm
• 40 to 100 - Accelerated ventricular rhythm
• 100+ Ventricular tachycardia (V-Tach), again, check for pulses. Often a lethal heart rhythm.

An ideoventricular rhythm. Note the wide QRS complexes.

A sinus rhythm going into V-Tach. This photo demonstrates how much wider the QRS complexes really are from a sinus thythm.

Ventricular fibrillation I think is best described as your heart having a seizure. The entire muscle just spasms and ceases to pump blood. This is always a lethal heart rhythm.

A is course V-Fib, B is fine V-Fib

The last ventricular arrhythmia is Torsades De Puentes which means twisting of points. This is a form of V-Tach with some specific characteristics on the EKG:

• Rotation of the heart's electrical axis by at least 180º
• Prolonged QT interval
• Preceded by long and short RR-intervals
• Triggered by an early premature ventricular contraction (R-on-T PVC)

You can actually see the "twisting of the points" best in leads II, III, and aVR.

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

Hydration And LODD

There appears to be some interesting findings about hydration levels and Line Of Duty Deaths in the wildland environment. It seems that reducing the workload of wildland firefighting crews during high ambient temperatures will do more to prevent a LODD than just making sure your crew is drinking water.

Read the article here on Wildfire Today.

Assault With A Deadly Weapon

The tones interrupted my morning workout. And for the second time that morning we were dispatched to a stabbing.

This call was again in district 52 at one of the local hotels. One of the nicer ones actually. As we approached we could see the sea of police vehicles (most of which were at our last call) and the AMR unit. For once they had beat us on scene.

As the air brakes set I jumped off the truck and walked over to the victim. The AMR medic gave me a quick run down. The patient appeared to be in his 20's and had been robbed. Or at least someone attempted to rob him. I don't know if they got anything. The poor guy had a defensive stab wound on one of his hands and another minor wound on his arm. The cut that we were worried about was the one in his chest.

He had about a on inch laceration about 3 ribs down from the middle of his clavicle. The puncture was bleeding slowly but steadily. The patient denied any trouble breathing and his lung sounds were equal bilaterally. He would be closely monitored all the way to the ER. With his vitals stable we bandaged him up and sent him on his way to the trauma center.


As we were leaving we were joking about the poor people trying to check into the hotel. They would be met at the front by several police cars, crime scene tape blocking the entrance and bloody clothes on the sidewalk. I can hear it now, "Honey, let's get another hotel."

Fillet Knife

Engine 52 was off at training and that left us covering their district. First think in the morning the tones went off. We were being dispatched to a stabbing in 52's district.

When we arrived on scene the Barney Fife patrol was already there. They directed me to the top of the stairs in the apartment where, just inside his bedroom, I found my patient.

According to his son the old man was in the late stages of dementia and had been hallucinating. That's when he took a knife and stabbed himself about 3 inches to the left of his belly button. It was very obvious where he had stabbed himself because the fillet knife was still embedded in his abdomen.

While the officers held the hands of my patient I carefully stabilized the knife with bulky dressings and a lot of 2 inch tape. The bleeding had been minimal, at least on the outside, and had already stopped. After taking care of the wound we decided to get a quick check of his vitals. They were all within normal limits.

By that time AMR was there and we packaged him up. On the gurney he was placed into restraints. This was as much for his own protection as for ours. He was obviously willing to stab himself once and we weren't going to take a chance since the knife was well within his reach.

The patient was lucky that he didn't hit anything vital or this call would have been a little more intense.

Not Breaking But Entering

The radio chirped, "Truck 51, respond for a lock out. The RP states they locked themselves out of their apartment and they may have left something on the stove."

 Photo borrowed from: http://report-on-conditions.blogspot.com

Hearing that reminded me of a Friends (I think) episode where one of them did the same thing. I remember the firefighter say to that to discourage people from calling to often for this they just chop down the door with an axe. I bet that would be effective.

When we arrived on the dark street we were met by a couple. The man said he had locked the door when they stepped out assuming that his girlfriend had the keys. Well, she didn't. Luckily the windows on their second floor apartment were unlocked.

I went back to the truck and grabbed one of our ground ladders. I went over to one of the larger windows and threw the ladder up to it. My captain footed the ladder while I scampered up to the window. I gently removed the screen and raised the blinds. I tried to move as much of the stuff in my way as I could. I really didn't want to break anything while entering.

Once inside I walked through to the kitchen. Just as we thought, nothing on the stove. I opened the front door and bid the tenants farewell.

By this time the neighborhood kids had heard our rig and were all out watching. They knew that we, like all good firemen, would have stickers. While my engineer put away the ladder I made sure each of the kids got their junior firefighter badge.

What Are Fire Lanes For?

Recently an Orange County Fire Authority (OCFA) crew took their HAZMAT unit to a neighboring city to watch one of their kids play in a Pop Warner football game. The incident made the local paper. You can read the article here.

I'm not going to try to defend them. It was, according to the OCFA official statement, against policy. So they are handling it. The part of the story that I thought was funny was that people were complaining that the rig was parked in the fire lane. Hello! It's a fire truck. If they can't park a fire truck in the fire lane then what is it for?!



Map of the route between the station and the stadium.


Oh well. Made me laugh and shake my head (at both the firefighters and the citizens) so I thought I'd share.

Burnt Out? Get Out!

If you hate your job, quit. Find something else. If you choose to stick around, you lose your right to complain. Especially in EMS.

Despair.com

We had a call in the middle of the afternoon. It was for an overweight woman that was walking home from the local carnival. She had been out in the sun all day and hadn't been drinking much. She also has diabetes and hadn't exactly been eating like someone that should be watching their sugar levels. She was in her mid 40's, had already had a heart attack, had high blood pressure and some obvious psychiatric issues.

When we arrived we found her talking to PD. They had found her sitting on the sidewalk. She said that she was feeling weak, dizzy and had some nausea. She had also vomited once. She was pale and sweaty. We checked her vitals. BP 98/66, pulse 116, respiratory rate 20, pulse ox 94%, sinus tach on the monitor, 12 lead was unremarkable, blood sugar 308. She lived just a block and a half away and was unsure if she wanted to go to the hospital.

Enter AMR and the burnt out medic. She took one look at the patient after hearing my report and decided that she was an AMA. The Burn Out then spent the next 5 minutes trying to talk her into not going to the hospital during which time the mother and neighbor of the patient showed up.

The mom and the medic now double teamed my patient trying to get her to just go home. My patient was still wishy washy and wouldn't make a choice either way. To me, she clearly thought that going to the hospital was the thing to do but she wanted someone else to back her up on the idea. I finally stepped in on the AMR medics toes. I simply asked if she still felt ill? When she said yes I asked her what it would hurt if she went and got checked out. At that point she happily walked over to the ambulance and climbed in. The last thing I saw was the transporting medic giving me a dirty look.

If you hate taking care of people that much, QUIT! We don't need you.

Contra Costa Fire Rescue

This is what we see and hear. There was moderate smoke in the house. The firefighter was still able to stand and see a little bit. A lot of the time we aren't able to see 3 inches in front of our face. Good save ConFire.

Thank You OSHA

So this last tour we went to a district quite a ways away for our annual infectious disease class. It's 3 hours long and can be summed up in one sentence. Use proper PPE and wash your hands, often. So the other 2 hours, 59 minutes and 45 seconds is used to go over data and trends across the country and in our county. We also went over what to do when we think (or know) that we've been exposed to some creepy crawly bad stuff. The entire class is meant as a review. In other words, BORING!

I've found over the years that it doesn't matter who is presenting the class. It's a dry subject. Throw in the fact that the AC unit was not working in our class room and you have a recipe for nodding heads. zzzzzzzzz

About half way through our class we were on a break. While we were milling about our radios crackled to life. We heard all the engine companies in the districts that borders ours (yes, the one we were not currently in) get toned out for an apartment structure fire, reports of black smoke coming from a second floor window. So those of us that were outside immediately switched our radios to the tactical channel. All of us from Station 51 kept our fingers crossed hoping it was "a pot on the stove."

As the first in engine company arrived on scene we heard them give the size up. "Engine 52 is on scene, we have a 2 story, garden style apartment with nothing showing. This is Main Street IC, engine 52 is investigating."

So far, so good. At least for us. We were expecting to hear that they had smoke and flames showing and that we'd miss our structure fire. About a minute later the IC reported that they had light smoke showing. They asked that the next in engine lay in a supply line. They then went into attack mode (sounds kinda like a guard dog going after a criminal).

Just about a minute after that the report came in that the fire was out and that it was just a pot on the stove. Hehehehe. We didn't miss "the big one."

In talking with the crew the next day we found out that the firefighter, after forcing open the security door, simply walked in, picked up the pot, and walked right back outside. All that was left for them to do was smoke removal. Oh yeah, and to find some way to secure the now really broken front door.

So thank you OSHA (or it may be Cal OSHA) for nearly making me miss a structure fire so I could learn how to wash my hands, again.

Privileges Revoked

The other night we were called for a 3 year old having a seizure. Fairly vanilla as far as medical calls go.

As I walked up to the house the dad opened the door. In his arms was his toddler and cradled between his shoulder and right ear was the phone connecting him to the only think keeping him from losing it, the 911 operator (I don't think they get enough credit). As I walked in the dad told the person on the other end that the fire department was there and dropped the phone. Thinking back I don't know if he even hung up. The dad then, in near panic, almost tossed his son into my arms. It was as if he had been able to hold things together until help arrived and now that we were there he could stop functioning.

The boy was dressed in his underwear and a t-shirt. He was also hot to the touch. I asked the dad how long the boy had been sick to which I received a blank stare. Dad didn't know the kids was sick. I asked about any medications. Again, dad was lost. He then told me that he was watching the kids while mom was out. I guess mom did most of the day to day care of the kids. I had the dad get me a wet wash cloth which I used to lower the kids fever. Having something to do to helped him calm down.

Once AMR was there we asked what hospital he would like to go to. Again, the blank stare. I felt bad for the guy. He kept muttering that his wife took care of the kids. I bet his sitting privileges are going to be revoked for a while.

Heart Rhythms Part 3: Junctional Rhythms

The human heart has several redundant systems. If an electrical impulse is not started in the atria within a certain amount of time, the AV node starts one. This is a junctional beat. Picture the AV node as being the electrical junction box between the upper and lower sections of the heart.

The AV node has an intrinsic rate between 40 and 60 beats a minute. Since the sinus node cranks along at 60-100 the AV node normally does not have to do anything. But if the atria fails to send down an electrical impulse, the AV kicks in.

The are only a couple of real medical issues with this heart beat. First, it is indicative of something else going wrong. You should figure out why the sinus node is failing. Second, you lose the atrial kick. Basically the heart functions less efficiently.

On the ECG a junctional rhythm can have several different appearances. It will have a narrow QRS complex just like a sinus rhythm. The variation comes with the P wave. It can appear closer to the QRS complex, be missing, appear upside down or appear behind the QRS complex. Think of the heart as a long electrical line. If you add a charge to it in the middle, the electricity will flow to both ends. So when the AV node fires, the electrical impulse goes to the ventricles and the atria.

If it gets to the atria first, you'll see a P wave first (PR interval less than .12 sec).

If it gets to both areas of the heart simultaneously then the P wave will be buried behind the QRS complex.

If the the impulse gets to the ventricles first, the P wave will come after the QRS complex.

Also, depending on the route the electrical impulse takes through the atria, the P wave may be inverted.

So now that you recognize the rhythm as junctional the rate comes into play.

• Heart rates <40 - Junctional Bradycardia Rhythm
• Heart rates 40 to 60 - Ideojunctional Rythym
• Heart rates 60 to 100 - Accelerated Junctional Rhythm
• Heart rates 100 to 160 - Junctional Tachycardia Rhythm
• Heart rates 160 to 250 - SVT (I'll cover this in a later post)

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

Twitter Question Answered

Recently I was asked a question on Twitter (my account is mostly for people to follow my blog). Agent_M18 asked me to talk a little bit more about what it's like to work as a firefighter and a paramedic. He said that where he works medics are all on the private side of things.

I've been able to work as a medic in several different systems. I've been the transporting medic that responds with a BLS fire department. I've been the medic on a squad with a BLS private ambulance company that transports. For the last several years I've worked in systems where I function as a paramedic with the fire department and the private ambulance also is ALS. One system that I don't have much experience in is where the fire department is also the transporting agency.

I'll go through some of the pros and cons that I have seen having been there.

Private ALS Ambulance/BLS Fire Department

Pros-

• Reduced cost. It's simply cheaper to have a BLS fire department (even a volunteer one) than an ALS one.
• Ambulance medics have a higher call volume and tend to keep up their skills and knowledge base better. 

Cons-

• Ambulances generally cover a larger geographic location than do fire companies. This means longer response time. On the vast majority of calls having to wait an additional 5-10 minutes for a paramedic to arrive doesn't make much of a difference. But on those rare, super critical calls, it can mean the difference between life and death.
• Fire department personnel, at times, have a hard time taking instruction from private ambulance personnel.

ALS Fire Department/Private BLS ambulance

Pros-

• Faster response times for the paramedics.
• Lower cost for the contract with the private ambulance company.

Cons-

• It's more expensive to have an ALS fire department (the cost of supplies), especially if it's a career department.
• Firefighter paramedics are not required to go to the hospital with someone that doesn't "need" ALS interventions. This encourages some medics to turf ALS calls to the BLS crew so that the medics can go back to bed, dinner, a fire.....pick your excuse. Patient care suffers.

ALS Fire Department/ALS Private Ambulance

Pros-

• Faster response times for paramedics.
• Second medic on critical calls once the ambulance shows up.
• Ambulance medics have a higher call volume and have an easier time keeping up their knowledge and skills.
• Better patient care. Every patient has a medic in attendance from beginning to end.

Cons-

• Cost. It's more expensive to have a medic on every responding piece of equipment.
• There can be a compatibility issue with varying equipment used at the FD and the ambulance company.
• Differences in opinions on patient care can lead to conflicts.

Fire Based ALS Ambulances

Pros-

• The same pros would apply here as with the private ALS ambulance and the ALS fire department.
• EMS training is all done the same so everyone is on one page.
• All equipment is the same.
• No confusion with the command structure.

Cons-

• Again, cost. Especially at career departments. Although this is somewhat offset by fees received for transporting the patient.

Because of my own experiences in each of these systems I am very much for having a paramedic on each responding apparatus. This way the patient gets the care they need with the arrival of the first unit and they will remain with a paramedic until they reach the hospital.

I have also found that the skill sets of a paramedic riding on an engine or truck differ slightly from those riding on a box. The engine medics usually arrive first on scene and tend to be better at sorting out the initial chaos found in an emergency situation. Transporting medics tend to be better at longer term patient care and patient destination decisions. I personally love being first in. I'll leave transporting to someone else, unless it's a critical patient. Then I'll go the the ER too.

For you medics out there. Which system do you work in? Which do you prefer? If you work within an EMS system that's different from the four I described, tell me about it.

What's That Smell

I grabbed my bowl of ice cream and just as a sank the spoon to get my first taste the tones went off. After a quick run to the freezer I made it to the engine and slipped into my bunker pants. As the bay doors opened up I jumped into the rig and belted in.

We were responding for an odor investigation. The RP said that there was a smell of methane in the area. We thought that it was strange that they said methane and not propane or natural gas. It was a warm night and we figured that it was probably going to be a skunk call.

As we pulled into the cul-de-sac my engineer and I simultaneously smelled it. The, what I thought was unmistakeable, smell of a skunk. At the end of the circle we found the address. The family was all in garage which had been converted into a man cave complete with pool table and couch. The wife met us and asked if we could smell that? Her husband stood back shaking his head.

My captain, assuming that they were new to this smell, asked how long they had lived in California. Anyone that has lived in the Golden State for any amount of time has probably smelled Pepe Le Pew. When they said they grew up here he then asked if they had ever smelled a skunk before. The wife became defensive. she said that her dog had been sprayed by a skunk just 6 months before and that there was no way this was a skunk.

After assuring her that it was definitely a skunk (and a few I told you so's from her husband) we told her we would happily check the house and back yard for anything else that my be leaking. We checked the propane tanks on the backyard BBQ and the RV. Everything was good except for the exceptional strong odor of a skunk.

By the time we were getting ready to leave most of the neighbors had come out to find out what was going on. I'm sure they all had a good laugh.

If you think that was bad, the previous week we had an entire first alarm assignment responding for a gas leak that turned out to be a skunk. Dang trouble causing critters.

No More Ambulances

So what happens when the agency that has contracted with the county to provide emergency ambulance service fails to staff even half of the required rigs?

I'll tell you. The Chief gets a phone call and is asked if my department can staff ambulances for them! And then the firefighter paramedics get phone calls saying that they have to come into work. Even if they were on their way home from a 96 hour shift and an hour away from the nearest station.

I ended up staffing one of our ambulances. I think there was a plan to actually place our paramedics onto AMR's ambulances. I don't know if this happened. Thankfully my shift was boring. For the most part I got to watch football. It still wasn't where I wanted to be.

Forked Driver

Engine 52, truck 51, you're responding for a water flow alarm at 4582 Main St.

A water flow alarm is an alarm in the fire protection sprinkler system that goes off when water flows past it. If the alarm system is monitored, such as the case with this call, the fire department is dispatched and the alarm warns people to get out of the building. In reality, most water flow alarms are false alarms. Not this one.

We pulled up the the warehouse and were met by the supervisor. He said that one of his guys sheared off a sprinkler head with a forklift. Unfortunately for them they were a distribution warehouse for cardboard boxes so they had pallets of folded cardboard getting soaked.

We went around and found the PIV closest to the sounding alarm and turned it off. Once that was done we went to the main drain to get all the water out of the system. Thankfully the employees were already hard at work with forklifts (to move the pallets) and squeegees. They even tried using a 50 gallon trash can. Once we had the shower turned off we left them to clean up the mess.