OverviewPatrick J. Tchou, MD, talks about blocked impulses in the heartWhat is heart block?Heart block is a problem with your heart's electrical system, which makes your heart beat and controls your heart rate and rhythm. The condition is also called atrioventricular (AV) block or a conduction disorder. Show
What happen if I have heart block?Normally, electrical signals travel from the upper chambers of your heart (atria) to the lower chambers (ventricles). The AV node is a cluster of cells that connect the electrical activity – like a bridge – from the top chambers of your heart to the bottom chambers. If you have heart block, the electrical signal does not travel through the AV node to the ventricles. The result is a heart that doesn’t function effectively, meaning your heart beats slowly or skips beats and it can’t pump blood through its chambers and out to the body as a normal heart would. What are the types of heart block?Heart block can be first, second or third degree, depending on the extent of electrical signal impairment.
Is heart block serious or dangerous?It can be. Type of heart block, its location and severity, and symptoms vary from person to person. If left untreated, severe heart block can cause sudden cardiac arrest (your heart suddenly stops beating), but most commonly can cause either lightheadedness or fainting spells. Who is at risk of having heart block?You may be at increased risk of a heart block if:
Symptoms and CausesWhat causes heart block?The most common cause of heart block is heart attack. Other causes include heart muscle disease, usually called a cardiomyopathy, heart valve diseases and problems with the heart’s structure. Heart block can also be caused by damage to the heart during open heart surgery, as a side effect of some medications or exposure to toxins. Genetics can be another cause. What are the symptoms of heart block?Symptoms of heart block vary depending on the type of block. First-degree heart block:
First-degree block is common in athletes, teenagers, young adults and those with a highly active vagus nerve. Second-degree heart block symptoms:
Third-degree heart block symptoms:
Symptoms of third-degree heart block are more intense due to the slow heart rate. If you have severe symptoms, get medical attention right away. Diagnosis and TestsHow is heart block diagnosed?Your cardiologist will first review your medical history and family health history and ask questions about your overall health, your diet and activity level and your symptoms. You’ll also be asked about any medications you are taking (prescription or over-the-counter) and if you smoke or use illicit drugs. During your physical exam, your cardiologist will listen to your heart and check your heart rate. You’ll also be checked for signs of heart failure, such as fluid buildup in your feet, ankles an legs. Your cardiologist may refer you to an electrophysiologist. Electrophysiologists are physicians who specialize in the electrical activity of the heart. Tests you might undergo include:
What are the complications of heart block?The complications can be life-threatening and include:
Management and TreatmentHow is heart block treated?Your cardiologist will determine how heart block (its type, location and severity) is affecting your heart’s ability to function and consider your symptoms to determine how to manage your condition. Symptoms and treatment vary from person to person. Sometimes, making changes to medications or treatment for heart disease stops heart block.
If you need a pacemaker, your cardiologist/electrophysiologist will talk to you about the details, the type that is best for you, and what to expect before, during and after you get your pacemaker. PreventionCan heart block be prevented?Some cases of heart block may be congenital (present at birth). But most heart block develops after birth. Some causes can’t be prevented. We also know that the risk of heart block increases with age and so does heart disease. Some causes of heart disease are preventable. Steps you can take to keep your heart and body as healthy as possible include:
Outlook / PrognosisHow does heart block affect my life?If you have first-degree heart block, ask your cardiologist or electrophysiologist what – if any – changes you need to make to your lifestyle or medications. This type of heart block does not usually get in the way of your normal activities. If you have a pacemaker for second- or third-degree heart block, your cardiologist may recommend some restrictions about the types of exercise you can participate in (such as contact sports). However, in general, a pacemaker will not seriously restrict your ability to take part in sports and leisure activities. Your cardiologist will want to periodically check your pacemaker to make sure that it continues to meet your needs. Monitoring is done with both remote and in-person evaluations. The remote monitoring uses wireless cellular communication, often using blue tooth or Wifi as well. This allows your doctor’s office to monitor you almost continuously. You will also need to be seen in person to have your pacemaker fully evaluated and adjusted, usually once a year. It is important to follow your doctor’s instructions for pacemaker monitoring so they can ensure your pacemaker is correctly regulating your heartbeat. Living WithIf you have a pacemaker:
When should I call my healthcare professional?Call your healthcare provider if you feel:
Is 1st degree AV block serious?First-degree heart block is not usually serious, and people can lead a usual life, providing the condition does not progress. However, people will require regular monitoring. If the heart block worsens, complications can include: injury as a result of fainting.
What is firstFirst-degree atrioventricular (AV) block is a condition of abnormally slow conduction through the AV node. It is defined by ECG changes that include a PR interval of greater than 0.20 without disruption of atrial to ventricular conduction. This condition is generally asymptomatic and discovered only on routine ECG.
What is sinus bradycardia with AV block?Sinus bradycardia occurs on an ECG when there is a normal upright P wave in lead II (sinus P wave) preceding every QRS complex with a ventricular rate of less than 60 beats per minute. Causes of sinus bradycardia include: AV blocking medications (beta-blockers, non-dihydropyridine calcium channel blockers, digoxin).
What is the treatment for firstIn general, no treatment is required for first-degree AV block unless prolongation of the PR interval is extreme (>400 ms) or rapidly evolving, in which case pacing is indicated. Prophylactic antiarrhythmic drug therapy is best avoided in patients with marked first-degree AV block.
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