NationMaster - Encyclopedia: First degree AV block

First degree AV block or PR prolongation is a disease of the electrical conduction system of the heart in which the PR interval is lengthened. In first degree heart block, the disease is almost always at the level of the atrioventricular node (AV node). It has a prevalence in the normal (young adult) population of 0.65-1.1% and the incidence is 0.13 per 1000 persons. The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10) is a coding of diseases and signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or diseases, as classified by the World Health Organization (WHO). ... // I00-I99 - Diseases of the circulatory system (I00-I02) Acute rheumatic fever (I00) Rheumatic fever without mention of heart involvement (I01) Rheumatic fever with heart involvement (I02) Rheumatic chorea (I05-I09) Chronic rheumatic heart diseases (I05) Rheumatic mitral valve diseases (I050) Mitral stenosis (I051) Rheumatic mitral insufficiency (I06) Rheumatic aortic... The Disease Bold textDatabase is a free website that provides information about the relationships between medical conditions, symptoms, and medications. ... eMedicine is an online clinical medical knowledge base that was founded in 1996. ... The normal electrical conduction in the heart allows the impulse that is generated by the sinoatrial node (SA node) of the heart to be propagated to (and stimulate) the myocardium (Cardiac muscle). ... The heart and lungs, from an older edition of Grays Anatomy. ... The atrioventricular node (abbreviated AV node) is an area of specialized tissue between the atria and the ventricles of the heart, which conducts the normal electrical impulse from the atria to the ventricles. ... In epidemiology, the prevalence of a disease in a statistical population is defined as the ratio of the number of cases of a disease present in a statistical population at a specified time and the number of individuals in the population at that specified time. ... In optics one considers angles of incidence. ...

Causes

First degree AV block may be due to conduction delay in the AV node, in the His-Purkinje system (made up by the bundle of His and the Purkinje fibers), or a combination of the two. The majority of cases are due to a dysfuction of the AV node; however, when first degree heart block coexists with a bundle-branch block, the cause is more likely to be a conduction delay in the His-Purkinje system. The atrioventricular node (abbreviated AV node) is the tissue between the atria and the ventricles of the heart, which conducts the normal electrical impulse from the atria to the ventricles. ... The bundle of His is a collection of heart muscle cells specialized for electrical conduction that transmits the electrical impulses from the AV node (located between the atria and the ventricles) to the point of the apex of the fascicular branches. ... Purkinje fibers (or Purkyne tissue) are located in the inner ventricular walls of the heart, just beneath the endocardium. ... The atrioventricular node (abbreviated AV node) is the tissue between the atria and the ventricles of the heart, which conducts the normal electrical impulse from the atria to the ventricles. ... Bundle branch block refers to a disorder of the hearts electrical conducting system. ...

The most common causes of first degree heart block are an AV nodal disease, enhanced vagal tone (for example in athletes), myocarditis, acute myocardial infarction (especially acute inferior MI), electrolyte disturbances and medication. The drugs that most commonly cause first degree heart block are those that increase the refractory time of the AV node, thereby slowing AV conduction. These include calcium channel blockers, beta-blockers, digitalis cardiac glycosides and anything that increases cholinergic activity such as cholinesterase inhibitors. In medicine (cardiology), myocarditis is inflammation of the myocardium, the muscular part of the heart. ... Acute myocardial infarction (AMI or MI), commonly known as a heart attack, is a disease state that occurs when the blood supply to a part of the heart is interrupted. ... The atrioventricular node (abbreviated AV node) is the tissue between the atria and the ventricles of the heart, which conducts the normal electrical impulse from the atria to the ventricles. ... Calcium channel blockers are a class of drugs with effects on the muscle of the heart and the muscles of the rest of the body. ... Beta blockers or beta-adrenergic blocking agents are a class of drugs used to treat a variety of cardiovascular conditions and some other diseases. ... Species About 20 species, including: Digitalis cariensis Digitalis ciliata Digitalis davisiana Digitalis dubia Digitalis ferruginea Digitalis grandiflora Digitalis laevigata Digitalis lanata Digitalis leucophaea Digitalis lutea Digitalis obscura Digitalis parviflora Digitalis purpurea Digitalis thapsi Digitalis trojana Digitalis viridiflora Digitalis is a genus of about 20 species of herbaceous biennials, perennials and... Cardiac glycosides are drugs used in the treatment of congestive heart failure and cardiac arrhythmia. ... A cholinesterase inhibitor or anticholinesterase is a chemical that inhibits a cholinesterase enzyme from breaking down acetylcholine, so increasing both the level and duration of action of the neurotransmitter acetylcholine. ...

Diagnosis

In normal individuals, the AV node slows the conduction of electrical impulse through the heart. This is manifest on a surface EKG as the PR interval. The normal PR interval is from 120 ms to 200 ms in length. This is measured from the initial deflection of the P wave to the beginning of the QRS complex. The atrioventricular node (abbreviated AV node) is the tissue between the atria and the ventricles of the heart, which conducts the normal electrical impulse from the atria to the ventricles. ... ECG may also refer to the East Coast Greenway Lead II An Electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which records the electrical voltage in the heart in the form of a continuous strip graph. ... A millisecond is an SI-derived unit of time, equal to one thousandth of a second. ... A millisecond is an SI-derived unit of time, equal to one thousandth of a second. ...

In first degree heart block, the diseased AV node conducts the electrical activity slower. This is seen as a PR interval greater than 200 ms in length on the surface EKG. It is usually an incidental finding on a routine EKG. A millisecond is an SI-derived unit of time, equal to one thousandth of a second. ... ECG may also refer to the East Coast Greenway Lead II An Electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which records the electrical voltage in the heart in the form of a continuous strip graph. ... ECG may also refer to the East Coast Greenway Lead II An Electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which records the electrical voltage in the heart in the form of a continuous strip graph. ...

First degree heart block does not require any particular investigations except for electrolyte and drug screens especially if an overdose is suspected.

Treatment

The management includes identifying and correcting electrolyte imbalances and withholding any offending medications. This condition does not require admission unless there is an associated myocardial infarction. Even though it usually does not progress to higher forms of heart block, it may require outpatient follow up and monitoring of the EKG especially if there is a comorbid bundle branch block. If there is a need for treatment of an unrelated condition care should be taken not to introduce any medication that may slow AV conduction. If this is not feasible clinicians should be very cautious when introducing any drug that may slow conduction and regular monitoring of the EKG is indicated. Acute myocardial infarction (AMI or MI), commonly known as a heart attack, is a disease state that occurs when the blood supply to a part of the heart is interrupted. ... ECG may also refer to the East Coast Greenway Lead II An Electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which records the electrical voltage in the heart in the form of a continuous strip graph. ... Bundle branch block refers to a disorder of the hearts electrical conducting system. ... ECG may also refer to the East Coast Greenway Lead II An Electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which records the electrical voltage in the heart in the form of a continuous strip graph. ...

Prognosis

Isolated first degree heart block has no clinical consequences. There are no symptoms or signs associated with it, and there is no danger of progression to complete heart block. There is also no increased morbidity or mortality associated with it. Third degree heart block, also known as complete heart block, is a disease of the electrical system of the heart, in which the impulse generated in the top half of the heart (typically the SA node in the right atrium) does not propagate to the left or right ventricles. ...

In a subset of individuals with the triad of first degree heart block, right bundle branch block, and either left anterior fascicular block or left posterior fascicular block (known as trifascicular block) may be at an increased risk of progression to complete heart block. Right bundle branch block (RBBB) is a cardiac conduction abnormality seen on electrocardiogram (EKG). ... Trifascicular heart block is the triad of first degree heart block, right bundle branch block, and either left anterior or left posterior hemi block seen on an electrocardiogram (EKG). ... Third degree heart block, also known as complete heart block, is a disease of the electrical system of the heart, in which the impulse generated in the top half of the heart (typically the SA node in the right atrium) does not propagate to the left or right ventricles. ...

See also

Category: Cardiac electrophysiology The atrioventricular node (abbreviated AV node) is an area of specialized tissue between the atria and the ventricles of the heart, which conducts the normal electrical impulse from the atria to the ventricles. ... The normal electrical conduction in the heart allows the impulse that is generated by the sinoatrial node (SA node) of the heart to be propagated to (and stimulate) the myocardium (Cardiac muscle). ... â€œQRSâ€ redirects here. ... Second degree AV block is a disease of the electrical conduction system of the heart. ... Trifascicular heart block is the triad of first degree heart block, right bundle branch block, and either left anterior or left posterior hemi block seen on an electrocardiogram (EKG). ... Third degree AV block, also known as complete heart block, is a defect of the electrical system of the heart, in which the impulse generated in the atria (typically the SA node on top of the right atrium) does not propagate to the ventricles. ... Diagram of the human circulatory system. ... Pathology (from Greek pathos, feeling, pain, suffering; and logos, study of; see also -ology) is the study of the processes underlying disease and other forms of illness, harmful abnormality, or dysfunction. ... This article or section does not cite any references or sources. ... In kidney, as a result of benign arterial hypertension, hyaline (pink, amorphous, homogeneous material) accumulates in the wall of small arteries and arterioles, producing the thickening of their walls and the narrowing of the lumens - hyaline arteriolosclerosis. ... While most forms of hypertension have no known underlying cause (and are thus known as essential hypertension or primary hypertension), in about 10% of the cases, there is a known cause, and thus the hypertension is secondary hypertension (or, less commonly, inessential hypertension). ... Renovascular hypertension (or renal hypertension) is a form of secondary hypertension. ... It has been suggested that this article or section be merged with Coronary heart disease. ... Prinzmetals angina, also known as variant angina or angina inversa, is a syndrome typically consisting of angina (cardiac chest pain) at rest that occurs in cycles. ... Acute myocardial infarction (AMI or MI), commonly known as a heart attack, is a disease state that occurs when the blood supply to a part of the heart is interrupted. ... Dresslers syndrome is a form of pericarditis that occurs in the setting of injury to the heart or the pericardium (the outer lining of the heart). ... Pulmonary circulation is the portion of the cardiovascular system which carries oxygen-depleted blood away from the heart, to the lungs, and returns oxygenated blood back to the heart. ... Cor pulmonale is a medical term used to describe a change in structure and function of the right ventricle of the heart as a result of a respiratory disorder. ... The pericardium is a double-walled sac that contains the heart and the roots of the great vessels. ... Pericarditis is inflammation of the sac surrounding the heart, the pericardium. ... Cardiac tamponade, also known as pericardial tamponade, is a medical emergency condition where liquid accumulates in the pericardium in a relatively short time. ... In the heart, the endocardium is the innermost layer of tissue that lines the chambers of the heart. ... Grays Fig. ... Endocarditis is an inflammation of the inner layer of the heart, the endocardium. ... Mitral regurgitation (MR), also known as mitral insufficiency, is the abnormal leaking of blood through the mitral valve, from the left ventricle into the left atrium of the heart. ... Mitral valve prolapse (MVP) is a heart valve condition marked by the displacement of an abnormally thickened mitral valve leaflet into the left atrium during systole. ... Mitral stenosis is a narrowing of the orifice of the mitral valve of the heart. ... Aortic valve stenosis (AS) is a heart condition caused by the incomplete opening of the aortic valve. ... Aortic insufficiency (AI), also known as aortic regurgitation (AR), is the leaking of the aortic valve of the heart that causes blood to flow in the reverse direction during ventricular diastole, from the aorta into the left ventricle. ... Pulmonary valve stenosis is a medical condition in which outflow of blood from the right ventricle of the heart is obstructed at the level of the pulmonic valve. ... Myocardium is the muscular tissue of the heart. ... In medicine (cardiology), myocarditis is inflammation of the myocardium, the muscular part of the heart. ... Dilated cardiomyopathy or DCM (also known as congestive cardiomyopathy), is a disease of the myocardium (the muscle of the heart) in which a portion of the myocardium is dilated, often without any obvious cause. ... Hypertrophic cardiomyopathy, or HCM, is a disease of the myocardium (the muscle of the heart) in which a portion of the myocardium is hypertrophied (thickened) without any obvious cause. ... Restrictive cardiomyopathy (RCM) is the least common cardiomyopathy. ... Arrhythmogenic right ventricular dysplasia (ARVD, also known as arrhythmogenic right ventricular cardiomyopathy or ARVC) is a type of nonischemic cardiomyopathy that involves primarily the right ventricle. ... The normal electrical conduction in the heart allows the impulse that is generated by the sinoatrial node (SA node) of the heart to be propagated to (and stimulate) the myocardium (Cardiac muscle). ... Second degree AV block is a disease of the electrical conduction system of the heart. ... Third degree AV block, also known as complete heart block, is a defect of the electrical system of the heart, in which the impulse generated in the atria (typically the SA node on top of the right atrium) does not propagate to the ventricles. ... Bundle branch block refers to a disorder of the hearts electrical conducting system. ... ECG characteristics of a typical LBBB showing wide QRS complexes with abnormal morphology in leads V1 and V6. ... Right bundle branch block (RBBB) is a cardiac conduction abnormality seen on electrocardiogram (EKG). ... Bifascicular block is a conduction abnormality in the heart where two of the three main fascicles of the His/Purkinje system are blocked. ... Trifascicular heart block is the triad of first degree heart block, right bundle branch block, and either left anterior or left posterior hemi block seen on an electrocardiogram (EKG). ... Wolff-Parkinson-White syndrome (WPW) is a syndrome of pre-excitation of the ventricles of the heart due to an accessory pathway known as the Bundle of Kent. ... Lown-Ganong-Levine syndrome (LGL) is a syndrome of pre-excitation of the ventricles due to an accessory pathway providing an abnormal electrical communication from the atria to the ventricles. ... The long QT syndrome (LQTS) is a heart disease in which there is an abnormally long delay between the electrical excitation (or depolarization) and relaxation (repolarization) of the ventricles of the heart. ... This article or section does not cite any references or sources. ... A supraventricular tachycardia (SVT) is a rapid rhythm of the heart in which the origin of the electrical signal is either the atria or the AV node. ... AV nodal reentrant tachycardia (AVNRT) is a type of reentrant tachycardia (fast rhythm) of the heart. ... Ventricular tachycardia (V-tach or VT) is a fast rhythm that originates in one of the ventricles of the heart. ... Atrial fibrillation (AF or afib) is an abnormal heart rhythm (cardiac arrhythmia) which involves the two small, upper heart chambers (the atria). ... Atrial flutter is a rhythmic, fast rhythm that occurs in the atria of the heart. ... pac This page meets Wikipedias criteria for speedy deletion. ... Premature ventricular contraction (PVC), also known as ventricular premature beat (VPB) or extrasystole, is a form of irregular heartbeat in which the ventricle contracts prematurely. ... Sick sinus syndrome, also called Bradycardia-tachycardia syndrome is a group of abnormal heartbeats (arrhythmias) presumably caused by a malfunction of the sinus node, the hearts natural pacemaker. ... Cardiomegaly is a medical condition wherein the heart is enlarged. ... Although ventricular hypertrophy may occur in either the left or right or both ventricles of the heart , left ventricular hypertrophy (LVH) is more commonly encountered. ... Left ventricular hypertrophy (LVH) is the abnormal thickening of the myocardium (muscle) of the left ventricle of the heart. ... Right ventricular hypertrophy (RVH) is a form of ventricular hypertrophy affecting the right ventricle. ... Section of an artery An artery or arterial is also a class of highway. ... An arteriole is a blood vessel that extends and branchs out from an artery and leads to capillaries. ... The word capillary is used to describe any very narrow tube or channel through which a fluid can pass. ... Aortic dissection is a tear in the wall of the aorta (the largest artery of the body). ... Raynauds phenomenon (RAY-noz), in medicine, is a vasospastic disorder causing discoloration of the fingers, toes, and occasionally other extremities, named for French physician Maurice Raynaud (1834 - 1881). ... Raynauds disease (RAY-noz) is a condition that affects blood flow to the extremities which include the fingers, toes, nose and ears when exposed to temperature changes or stress. ... Buergers disease (also known as thromboangiitis obliterans) is an acute inflammation and thrombosis (clotting) of arteries and veins of the hands and feet. ... Intermittent claudication is a cramping sensation in the legs that is present during exercise or walking and occurs as a result of decreased oxygen supply. ... In medicine, hereditary hemorrhagic telangiectasia (HHT), also known as Rendu-Osler-Weber syndrome, is a genetic disorder that leads to vascular malformations. ... In the circulatory system, a vein is a blood vessel that carries blood toward the heart. ... Lymph originates as blood plasma lost from the circulatory system, which leaks out into the surrounding tissues. ... Lymph nodes are components of the lymphatic system. ... Thrombosis is the formation of a clot or thrombus inside a blood vessel, obstructing the flow of blood through the circulatory system. ... Phlebitis is an inflammation of a vein, usually in the legs. ... This article is about Deep-vein thrombosis. ... A venous thrombosis is a blood clot that forms within a vein. ... In medicine (gastroenterology and hepatology), Budd-Chiari syndrome is the clinical picture caused by occlusion of the hepatic vein. ... It has been suggested that this article or section be merged into deep vein thrombosis. ... Paget-Schroetter disease (also Paget-von SchrÃ¶tter disease) refers to deep vein thrombosis of an upper extremity vein, including the axillary vein or subclavian vein. ... Vein gymnastics in the barefoot park Dornstetten, Germany. ... Hemorrhoids (AmE), haemorrhoids (BrE), emerods, or piles) are varicosities or swelling and inflammation of veins in the rectum and anus. ... In medicine (gastroenterology), esophageal varices are extreme dilations of sub mucosal veins in the mucosa of the esophagus in diseases featuring portal hypertension, secondary to cirrhosis primarily. ... Cross section showing the pampiniform plexus Varicocele is an abnormal enlargement of the veins in the scrotum draining the testicles. ... Gastric varices are dilated submucosal veins in the stomach. ... Superior vena cava syndrome (SVCS) is a result of obstruction of the superior vena cava. ... Lymphadenopathy is swelling of one or more lymph nodes. ... Lymphedema (AmE), also known as Lymphoedema (BrE), or lymphatic obstruction, is a condition of localized fluid retention caused by a compromised lymphatic system. ...

Contents

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Diagnosis

Treatment

Prognosis

See also

Causes