Israel PM Benjamin Netanyahu Gets Emergency Pacemaker, Here’s What AV Heart Block Is

When you hear that you need “urgent pacemaker implantation,” you should drop whatever you are doing—whether it’s getting ready to travel or running a country— and get to the hospital as soon as possible. That’s what just happened to Israel’s Prime Minister Benjamin Netanyahu. And on early Sunday morning, doctors at the Sheba Medical Center in Tel Aviv did place a cardiac pacemaker in his chest.

After Netanyahu had received the pacemaker, two of the cardiologists caring for Netanyahu at the Sheba Medical Center—Eyal Nof, MD, the Head of the Invasive Electrophysiology Service, and Roy Beinart, MD, the Director at the Davidai Arrhythmia Center—said that “all went well” with the procedure. They added that Netanyahu is “doing very well this morning,” as you can see in the following YouTube video posted by the Medical Center:

The 73-year-old Netanyahu will remain in the hospital for observation for at least the bulk of Sunday because getting a pacemaker implanted ain’t exactly like going for a car wash. A pacemaker is a device that has wires extending into the muscles of your heart. It emits electrical signals periodically to help coordinate how your heart beats. Doctors will have to check to make sure that the pacemaker is working correctly and that there are no complications such as pain or bleeding from the procedure.

How did doctors know that Netanyahu needed “urgent pacemaker implantation?” After all, despite the saying “What does your heart tell you,” your heart can’t actually talk because it doesn’t have a mouth. The warning came from the data generated by a heart monitor that was placed on Netanyahu’s chest about a week prior after signs of dehydration had brought him to the hospital. The heart monitor did exactly that, continuously monitor the electrical signals of his heart.

While an electrocardiogram (ECG or EKG) can show you what the electrical signals in your heart are doing at a given time, an EKG is more like a selfie on social media. You don’t know what happened before or after the picture was taken. This doesn’t give the full picture of what may be happening as the electrical signals in your heart can change throughout the day depending on what you are doing. For example, you may start seeing abnormalities when you are excited such as when you see some avocado toast or exerting yourself such as when you climbing a tree to get that toast.

A heart monitor is more like a livestream and allows doctors to see what’s happening throughout the day and night and quickly identify any concerning abnormalities. Apparently, at some point Netanyahu’s heart monitor had shown signs of an AV block. In this case, AV block doesn’t mean that an audiovisual technician is refusing to check out your equipment. Rather AV here stands for atrioventricular.

To understand what an AV block means, let’s pump in some facts about how your heart works. You may have heard the term “muscle head.” But, it’s your heart that is mostly muscle. Your heart is essentially a muscular pump that keeps blood circulating throughout your body. Blood returning to your heart from the rest of your body fill your right atrium, which is one of the four muscular chambers of your heart. Your right atrium then contracts, squeezing blood into your right ventricle, another muscular chamber. When your right ventricle then squeezed blood into your pulmonary circulatory system where blood courses through your lungs to pick up oxygen. The blood then return to the third muscular chamber of your heart, your left atrium. When the left atrium contracts, blood then moves into your left ventricle. Your ventricle is the biggest muscular heart chamber of them all. It then contracts to pump blood to the rest of your body.

Here’s a diagram that show this course:

Your entire body and all of your favorite body parts depend on your heart to deliver the oxygen being carried by red blood cells. If your heart can’t do this for even a short while, tissues throughout your body are starved of oxygen and cells may begin to die. When too many of your cells die, you can’t do important stuff like take selfies, scroll through social media, and live. Therefore, it is essential that your heart continues to beat in a coordinated matter.

Your heart is like your smartphone. It needs electricity to do its thing. The muscles in your heart have an electrical conduction system coursing through them. Your sinoatrial node—sinus node or SA node for short—is situated in your right atrium and is considered the natural pacemaker of your heart. Every second or potentially more or less than a second—depending on different characteristics such as your age and whether you’re exerting yourself or excited such as when you’re eating some avocado toast—the sinus node initiates an electrical signal. This signal then spread through both your atria getting them to contract simultaneously and squeeze blood forward into your ventricles.

The electrical signal also travels from your sinus node down to your atrioventricular (AV) node, which is located in the tissue wall dividing your atria and ventricles. The signal slows down for a tiny bit while traveling through your AV node. This is by design. It’s a bit like a club bouncer telling you to hold on for second before entering a club that’s a bit too crowded. The delay gives time for the ventricles to fill with blood first before contracting. Once the signal gets past the AV node it goes through the two branches of bundle of His-Purkinje fibers into your ventricles. The right branch of the bundle of His goes to your right ventricle. And the left branch goes to, you guessed it, your left ventricle. There the electrical signal stimulates your ventricles to contract after your atria has squeezed blood into them. All of this results in your heart beating in a coordinated “lub-dub, lub-dub” fashion. At least, it’s supposed to do so.

Problems arise when something goes awry with this electrical conduction systems. An AV block is when electrical signals get delayed for too long at the AV node or the His-Purkinje system. This can occur when scar tissue forms in the AV node area thus disrupting the structure of the area. Certain medications such as beta-blockers, calcium channel blockers, digoxin, and amiodarone can lead to AV block as well. Other possible causes include abnormalities of the neighboring heart valves and various congenital and genetic disorders.

Now, not all AV blocks are the same. And not all require pacemakers. There are three general degrees of AV block of increasing severity. A first degree AV block is when the electrical signal is simply slowed a bit more than usual but not to the point that you end up skipping any heart beats. You can see in the following EKG that the distance between the initial P-wave (the small upward bump that represents the signal from the sinus node) and the QRS complex (the larger structure that starts with a sharp tall pointed upwards triangle-shape and then is followed by a sharp less deep downwards triangle-shape representing the signal traveling through the AV node and the bundle of His) is a longer than normal:

Typically, such AV blocks won’t cause any symptoms and are detected incidentally on an EKG. This is considered a partial AV block because your sinus node is still able to send signals through the whole system. This is sort of like ordering a Merrycolor Nicolas Cage Pillow on Amazon and having it delivered a little later than expected. There’s no real consequence but it bears periodic checks.

Second degree AV blocks are also partial AV blocks. Here the electrical signal is delayed to the point that heart beats end up being periodically skipped. You can see in the following EKG that every now and then an entire electrical signal complex is missing:

This is like having a subscription to Rainbow Unicorn toilet paper and having some orders completely dropped. Dropped heart beats may then mean that your heart isn’t pumping quite as regularly and efficiently. As a result, you may experience symptoms of your body and brain not getting as much blood and oxygen as they are used to such as weakness, fatigue, shortness of breath, difficulty exercising, or fainting. Medications may help overcome such blocks. Depending on the cause, severity, and consequences of the block, a pacemaker may be needed.

The third degree of AV block is a complete AV block. This is where the electrical signals aren’t getting through the AV node at all. As you can see in the following EKG, there’s no coordination between the signals in the atria and the signals in the ventricles:

This is akin to Amazon trying to send you your Umbrella Hat or Thanos swimsuit and not even being able to get through to you at all. Your ventricles may continue to contract and pump blood because separate electrical signals can originate in your ventricles. But this is a very dangerous unstable situation. Having your ventricles and atria generate and respond to different and uncoordinated electrical signals can be like having Prince Harry and Prince William trying to steer a kayak together. With too many different electrical signals going, your heart can easily go haywire and everything shut down, which could mean death. A pacemaker is certainly needed when there is complete AV block.

The pacemaker that’s now in Netanyahu’s chest will presumably monitor the electrical signals in his heart and deliver its own electrical signals accordingly via wires that are connected to his heart. This is a reminder that amidst all hustle, bustle, and politics of daily life, what’s in your heart really matters. And to keep up with the pace of being a Prime Minister, Netanyahu is now going to have to make pace with his heart.