“Heart Block” Is Not a Blocked Heart

 

A pharmacist friend of mine in our WhatsApp chat group wrote to me this letter:

 

Dear Prof Dr Lim, 

I'm writing to provide a brief update on my brother-in-law. He was hospitalized at Serdang Hospital for two months following heart surgery and has now been fitted with a pacemaker. Currently, he is at Cheras Rehabilitation Hospital undergoing physiotherapy and occupational therapy to regain his strength, especially in his legs.

 

Regarding the chat group, I would prefer to join at a later time. As I am listed as one of the emergency contacts, I must now keep my phone on at all times, including overnight. To ensure I can receive an emergency call, I need to avoid being disturbed by general WhatsApp message notifications during the night, as they would disrupt my sleep. Thank you for your understanding and consideration. Best regards.

 

Here's my reply:

 

I am unsure why your brother-in-law needs a pacemaker if he underwent a Coronary Artery Bypass Grafting (heart bypass) due to a heart blockage from a stenosis in the coronary blood vessels from cholesterol, calcium and other atherosclerotic plagues  causing narrowing of the heart vessels. This is entirely different from "heart block" due to  partial blockage of electric transmission through the heart muscles which will then require a pacemaker. The term "heart block" and blockage due to atherosclerotic plagues are two entirely different conditions

 

Electrical heart block and partial stenosis from atherosclerosis can be managed by a cardiologist using angioplasty, stents and medication, whereas heart attacks due to severe atherosclerosis require a cardiothoracic or a heart surgeon to treat surgically. It is an open heart surgery.  

 

My friend then replied: 

 

Prof Dr Lim, you're correct that he did not have a heart bypass. His situation was specifically related to an electrical heart block. His path to the pacemaker was quite a surprise. He was in and out of Serdang Hospital frequently until the doctors decided to run a trial with an external pacemaker, which was inserted through the groin. Once that trial confirmed a pacemaker was necessary, they proceeded with the standard procedure.

 

The first attempt was to create a small pocket under the skin near the collarbone to house a traditional pacemaker generator. However, this was unsuccessful because my elderly brother-in-law is very thin. During this procedure, they accidentally nicked a lung, causing it to collapse (a pneumothorax).

 

Given that he wasn't a candidate for the standard device due to his frail build, the team opted for a different solution: a micro, leadless pacemaker. It was inserted through the groin, directly under the heart muscle, to manage the electrical block and regulate his heartbeat. Thanks for your clarification.

 

Having read that, I thought I should write a simple explanation  in blue below , the meaning of "heart block" and a coronary blood vessel or vessels block or a stenosis in one of the coronary blood vessels to the heart - a coronary heart disease. Even some doctors do not know the difference, let alone patients and ordinary people.  Allow me to explain below in blue: 

When “Heart Block” Is Not a Blocked Heart: Understanding Two Very Different Heart Conditions

People are often alarmed when they hear that someone has undergone a “heart procedure,” especially when words such as bypass surgery, heart block, and pacemaker are mentioned together. This confusion is understandable because the same word “block” is used to describe two entirely different heart conditions. In reality, these conditions affect completely different systems within the heart and are treated in very different ways.

One type of heart problem involves the heart’s electrical system, while the other involves the blood vessels that supply the heart muscle. Although both occur in the same organ, they are fundamentally distinct in cause, mechanism, severity, and treatment.

A heart block refers to a disorder of the heart’s electrical conduction system. The heart beats rhythmically because electrical impulses originate from specialized pacemaker cells and travel through defined pathways to coordinate the contraction of the heart chambers. When these electrical signals are delayed, partially interrupted, or completely blocked, the heart is unable to beat in a normal and coordinated manner. As a result, the heart rate may become abnormally slow or irregular, leading to symptoms such as fatigue, dizziness, shortness of breath, fainting, or even sudden collapse in severe cases.

Electrical heart block most commonly occurs because of degeneration or fibrosis of the conduction pathways as part of the aging process. It may also result from damage caused by previous heart attacks, other structural heart diseases, inflammation, or scarring of heart tissue. Certain medications that slow electrical conduction through the heart, such as beta-blockers, calcium channel blockers, or digoxin, can also precipitate or worsen heart block.

Heart block is classified according to its severity. In mild forms, electrical signals are merely slowed but still reach the heart chambers, and affected individuals may have no symptoms at all. These cases often require nothing more than observation and regular monitoring. In more advanced forms, some or all electrical impulses fail to reach the ventricles, causing dangerous slowing of the heart rate. In second-degree Mobitz type II heart block and in third-degree (complete) heart block, treatment almost always requires the implantation of a permanent pacemaker.

A pacemaker is a small electronic device placed under the skin, usually below the collarbone, with leads that deliver controlled electrical impulses to the heart. Its purpose is to maintain an adequate heart rate and rhythm when the heart’s natural electrical system fails. Importantly, pacemaker implantation is a medical procedure and not a major open-heart surgery. It does not involve opening the chest cavity or stopping the heart, and recovery is usually relatively quick.

In contrast, coronary heart disease is not an electrical problem at all, but a “plumbing” problem involving the blood vessels that supply the heart muscle. This condition occurs when the coronary arteries become narrowed or blocked due to the buildup of atherosclerotic plaques. These plaques consist of cholesterol, fats, calcium, and inflammatory cells that accumulate gradually along the inner walls of the arteries. As the arteries narrow, blood flow to the heart98 muscle is reduced, particularly during exertion, resulting in chest pain (angina). If a coronary artery becomes suddenly or completely blocked, a heart attack may occur due to irreversible damage to the heart muscle.

The treatment of coronary heart disease depends on the extent and severity of the arterial blockage. In mild to moderate cases, management may begin with lifestyle changes such as dietary modification, regular exercise, smoking cessation, and weight control, combined with medications to lower cholesterol, control blood pressure, prevent clot formation, and reduce cardiac workload.

When arterial narrowing is more significant but localized, coronary angioplasty and stenting, also known as percutaneous coronary intervention (PCI), may be performed. This minimally invasive procedure involves threading a catheter through the blood vessels to the heart, inflating a balloon to open the narrowed artery, and inserting a small metal mesh stent to keep the vessel open. PCI is generally suitable when the blockage is limited in number and severity, often less than about seventy percent narrowing.

However, when there are multiple severely narrowed arteries, total occlusions, or disease involving major coronary vessels, medical therapy or stenting alone is insufficient. In such cases, open-heart surgery known as coronary artery bypass grafting (CABG) is required. During this major surgical procedure, a cardiothoracic surgeon creates new pathways for blood to flow to the heart muscle by using healthy blood vessels taken from the chest wall, leg, or arm to bypass the blocked coronary arteries. CABG involves opening the chest and is a major operation with a longer recovery period.

In short, the key to understanding these commonly confused conditions lies in recognizing which system of the heart is affected. A heart block is an electrical conduction problem and is most often treated with a pacemaker, whereas coronary heart disease is a vascular blockage problem and is treated with medical therapy, angioplasty and stenting, or bypass surgery, depending on its severity. Although both conditions may coexist in the same patient, they are distinct diseases, and confusing one for the other can lead to unnecessary fear or misunderstanding.