Case report: Pulmonary arterial hypertension in ENG-related hereditary hemorrhagic telangiectasia

What Happens When You Have A Heart Block?

Heart block is a delay or disruption within the heart's electrical conduction system that controls the rhythm and beats, causing the heart to beat slowly or skip beats. Several possible causes of heart block exist. It may stem from aging of the conduction system, a prior heart attack, heart surgery, medication, or an infection.

There are three main types of heart block, and depending on the type, symptoms and treatment vary. First-degree heart block is the mildest type and often requires no treatment. Third-degree heart block is potentially life-threatening, and most people need the placement of a pacemaker (a small electronic device placed underneath the skin to help the heart beat normally).

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Types and Their Symptoms To best understand heart block, you must first understand what occurs when the heart beats with an intact electrical system. The heart is a muscle with two upper chambers (right and left atria) and two lower chambers (right and left ventricles). It normally beats between 60 and 100 beats per minute (bpm). Heart block can result in a slow heart rate (less than 60 bpm), which is known as bradycardia. During a heartbeat, an electrical impulse (signal) spreads through the heart, triggering the chambers to contract (push blood) or relax (fill with blood) in a coordinated manner. Each heartbeat starts with an electrical impulse fired by a cluster of cells (called the sinoatrial node) in the right atrium. The following steps then occur: The fired impulse from the right atrium stimulates both atria to contract simultaneously, pushing blood into the ventricles. Next, the impulse travels to the atrioventricular (AV) node located between the upper and lower chambers. The impulse pauses for a split second before spreading down the bundle of His into the left and right branches within each ventricle. Once in the ventricles, the impulses stimulate them to contract, pushing blood out to the lungs and the rest of the body. There are three types of heart block, and symptoms depend on the type. First-Degree Heart Block First-degree heart block is technically not a block. Instead, the electrical impulse is delayed or slowed as it spreads from the atria to the ventricles via the AV node. This is the mildest type of heart block and usually causes no symptoms. Second-Degree (Incomplete) Heart Block Second-degree heart block occurs when some of the heart's electrical impulses from the atria reach the ventricles, and some are entirely blocked. Second-degree heart block can be further classified into the following: Mobitz type 1 (also called Wenckebach) means that the heart's electrical signals travel slowly from the atria to the ventricle until a heartbeat is eventually "dropped" or "skipped." Mobitz type 2 is more severe than Mobitz type 1. It reflects an all-or-nothing scenario, where the atria's impulses either reach the ventricles without delay or do not reach them at all. Mobitz type 1 is generally considered a benign (harmless) form of second-degree heart block, although it can progress to a higher degree of heart block. Symptoms are usually absent with Mobitz type 1. Symptoms of Mobitz type 2 include: Third-Degree (Complete) Heart Block Third-degree heart block is the most severe type because it means that no electrical impulses reach the ventricles from the atria. Because no impulses reach the ventricles, the heartbeat slows significantly or, most dangerously, becomes absent. Symptoms of third-degree heart block are the same ones as those seen with second-degree Mobitz type 2, although they are more severe and potentially life-threatening. Bundle Branch Block: Another Conduction Disorder Unlike the above heart blocks (which involve a delay or block via the AV node), a bundle branch block reflects a slowing of the heart's electrical impulse through one of the ventricles, causing them to contract at slightly different times. The two types of bundle branch blocks are: Common Causes and Risk Factors Heart block has many possible causes. Common causes include: Certain infections—for example, Lyme disease or bacterial endocarditis with abscess (collection of pus)—may lead to heart block. Complications of heart procedures or operations like catheter ablation or heart valve surgery may produce heart block. Congenital heart block occurs in the fetus or a newborn up to 28 days of life. It's usually caused by an autoimmune disease (when the body attacks itself) in the pregnant person, like lupus or Sjögren's syndrome. Electrolyte disturbances are imbalances of charged minerals in the bloodstream—for example, high potassium levels in the blood (hyperkalemia). Heart attack (myocardial infarction) is a complication of coronary artery disease (CAD) in which a part of the heart muscle dies or is damaged due to its blood supply being interrupted. High vagal tone, perhaps secondary to obstructive sleep apnea or vigorous athletic conditioning may lead to heart block. Lenegre disease occurs when the heart's conduction system scars slowly over time. It affects people under age 60 and may be inherited. Lev disease refers to the thickening or calcification of the heart muscle's tissues and, eventually, the conduction system. It affects people over the age of 70. Secondary restrictive cardiomyopathy is the deposition of abnormal substances within the heart muscle due to an underlying disease, such as sarcoidosis or amyloidosis. Thyroid dysfunction, either underactive thyroid gland (hypothyroidism) or overactive thyroid gland (hyperthyroidism), may lead to heart block. Medications Certain heart medications can also cause heart block by slowing or inhibiting impulse conduction from the atria to the ventricles via the AV node. Examples of such medications include: Beta-blockers can treat high blood pressure, angina, heart failure, and some cases of irregular heart rhythms (arrhythmias). They can also help prevent recurrent heart attacks. Calcium channel blockers can treat high blood pressure (hypertension), angina, and arrhythmia. Digoxin is sometimes used to treat heart failure and atrial fibrillation (a type of irregular heartbeat). Normal Variant In some individuals, first-degree heart block or Mobitz type 1 second-degree heart block are a normal variant, meaning there is no underlying health problem. This is typically seen in young athletes. Risk Factors Factors that increase a person's chance of developing heart block include: Being biologically male Being of older age Having a higher body mass index (BMI) Having a history of heart attack or heart failure Having an elevated fasting blood glucose (sugar) Having high blood pressure How Serious Is a Heart Block? Heart block may not be serious and may not require treatment, as in most cases of first-degree block. In contrast, in some instances, heart block can be serious, if not life-threatening. Specifically, chronic bradycardia may result in heart failure, and third-degree heart block can lead to sudden cardiac death. Diagnosis The primary test for diagnosing heart block is an electrocardiogram (ECG). An ECG is a tool for visualizing the electrical impulse traveling through the heart as it beats. What Happens During an ECG? An ECG entails placing 12 electrodes on a person's chest, arms, and legs. The electrodes are connected to a machine via wires. The machine records the heart's electrical signals, translating them as a pattern of wavy, spiky lines on paper that a provider can read. The lines of an ECG reading consist of these three components: The P wave reflects atria contracting (or pumping blood into the ventricles). The QRS complex consists of three waves and reflects the ventricles contracting, pumping blood from the heart to the lungs or the rest of the body. The T wave reflects the ventricles relaxing and filling with blood before the above cycle repeats itself. Normally, the PR interval (the distance between the P and R waves) on the ECG paper is 200 milliseconds (or five small boxes). ECG abnormalities seen with heart block include: First-degree heart block: The PR interval is longer than 200 milliseconds, consistent with a slowing of the impulse through the AV node. Mobitz type 1 second-degree heart block: The PR interval gradually gets longer and longer until the heart drops a beat. Mobitz type 2 second-degree heart block: The PR interval is normal, but eventually, it's followed by a dropped heartbeat. Third-degree heart block: No pattern or coordination exists between the P waves and the QRS complexes. If the ECG shows a heart block, a focused medical history, physical exam, and various diagnostic tests help providers determine the underlying cause. For instance, they may inquire about: The presence of other symptoms like chest pain or light-headedness The medications a person is taking Whether there is a personal history of heart problems, recent heart procedures, or other diseases (e.G., Lyme disease) Whether there is a family history of heart problems They will also listen to your heart and lungs with a stethoscope and check your heart rate. The following tests may also be performed: Ambulatory ECG monitoring, such as a Zio monitor worn for 14 to 30 days to record the heart's electrical activity Blood tests like a basic metabolic panel (BMP) to check for electrolyte imbalances or troponin (a marker of heart damage) An exercise stress test to evaluate the sufficiency of blood flow to the heart during exercise An echocardiogram using sound waves to visualize the structure and function of the heart, including its thickness, size, and pumping ability Referral Some individuals with a heart block are referred to an electrophysiologist—a cardiologist with special training in understanding the heart's electrical activity. An electrophysiologist can perform a study to help find the precise location of the block, which helps guide the treatment plan. Treatment Options The treatment of heart block depends primarily on the type and severity. First-degree heart block and Mobitz type 1 second-degree heart block do not require treatment, assuming a person has no symptoms and is hemodynamically stable (they have adequate blood flow throughout the body, signified typically by normal blood pressure). If they have symptoms or are hemodynamically unstable (inadequate blood flow throughout the body, signified by low blood pressure), a temporary pacemaker is indicated. In some cases of second-degree block, medication will also be given. The treatment of Mobitz type 2 second-degree and third-degree blocks depends on whether the person is hemodynamically unstable or stable. A hemodynamically unstable person requires immediate medication and/or a temporary pacemaker. A hemodynamically stable person does not require medication or a temporary pacemaker. However, they need to be monitored closely in a medical facility with pacemaker supplies nearby in the event they become suddenly unstable. Pacemaker A pacemaker is a device implanted underneath the skin near the heart muscle. It sends electrical impulses to the heart to prevent it from beating too slowly. For all cases of heart block, healthcare providers will work to determine the underlying cause and reverse it, if possible (e.G., medication toxicity or electrolyte imbalance). A permanent pacemaker is generally indicated in all symptomatic blocks, even if the cause is reversed. It's also indicated in people with Mobitz type 2 second-degree heart block or third-degree block who do not have a reversible cause. Prevention There is no surefire way to prevent heart block. However, certain lifestyle practices may help lower your chances of developing it. For example, adopting heart-healthy habits can help prevent heart attacks. Such habits include: Avoid smoking, secondhand smoke, vaping, and other tobacco products. Limit alcohol consumption. Lose weight if you are overweight or have obesity. Stay physically active. Eat a diet rich in fruits, vegetables, fish, and chicken. Avoid excess sugar and salt. Other proactive steps you can take to help prevent heart block include: Reviewing medications that may trigger or cause heart block Managing conditions that increase your vulnerability to heart block (e.G., Lyme disease or conditions associated with CAD like high cholesterol) Complications and Treatment Side Effects Potential complications or side effects of pacemaker placement include: Blood clots Heart injury Infection Lead (the wire that connects the pacing device to the heart) dislodgement Malfunctioning of the pacemaker (lead or device) Pneumothorax (collapsed lung) Pocket bleeding (when blood collects around the implanted pacemaker) Can You Live Normally With a Heart Block? Most people with heart block live normal, full lives as long as they follow their healthcare provider's care plan. If you have a pacemaker, you may have some restrictions, such as avoiding contact sports. Summary Heart block causes the heart to beat slowly or skip beats due to a delay or block in the heart's electrical system. Many possible causes of heart block exist, including a medication side effect, heart attack, infection of the heart's lining or valves, or an electrolyte imbalance (e.G., high potassium in the bloodstream). Heart block is diagnosed by an electrocardiogram (ECG) and is classified into three types that range in severity: first-degree, second-degree, and third-degree heart block.

Seeing Heart Valve Failure From All Sides

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Heart Disease Is A Silent Killer, But Knowing The Signs And Symptoms Can Save A Life

RHINELANDER, Wis. (WJFW) -- Heart disease is the leading cause of death in the U.S., killing 1 in 5 Americans according to the Centers for Disease Control and Prevention.

"Every decade that people age it increases the risk of the onset of heart disease," said Doctor Michael Zevitz who is a Cardiologist at Aspirus Cardiology - Rhinelander.

He says people should pay attention to their heart health at a young age.

"People should get their first cholesterol check at age 20, that's the recommendation," Dr. Zevitz said. "Hyperlipidemia should not be ignored for decades. If it's elevated it should be treated or certainly addressed. Starting in the mid-30s people should start looking at risk factors that lead to heart disease."

Those risk factors include obesity, smoking, drinking alcohol, sleep deprivation and stress.

"Physiologic or psychological stress can lead to vascular disease. It also can lead to elevations in blood pressure. It can also adversely affect cholesterol levels. Try to basically learn how to dissipate or relieve the stress."

Dr. Zevitz says there are a variety of heart disease symptoms that people should not ignore.

"The earliest symptoms of heart disease are shortness of breath on exertion. Also increased fluttering or palpitations that might indicate an arrhythmia," Dr. Zevitz said. "Likewise, the onset of chest pain either on exertion or certainly at rest. Chest pain that occurs at rest where there's a heaviness or tightness or squeezing sensation that occurs at rest and lasts for a few minutes."

To lower your risk, Dr. Zevitz says you should focus on eating lean protein, vegetables and fruits along with staying active.

"It doesn't have to be strenuous exercise, but it has to be something that is done at the very least three times a week. The recommendation is to be between 5 to 7 days a week, for about 20 to 30 minutes a day."

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