Cause
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| Progressive cardiac conduction defect | |
|---|---|
| Other names | Familial Lenègre disease, Familial Lev disease, Familial Lev-Lenègre disease, Familial PCCD, Familial progressive heart block, Progressive familial heart block, Hereditary bundle branch defect |
| Specialty | Cardiology |
Progressive cardiac conduction defect(PCCD) is a hereditary cardiac condition marked by a progressive delay in impulse conduction via the His-Purkinje system, resulting in right or left bundle branch block (RBBB or LBBB), syncope, and occasionally sudden cardiac death. [1]
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When progressive conduction abnormalities in people under 50 with structurally normal hearts are present but skeletal myopathies are absent, progressive cardiac conduction defect is primarily diagnosed, particularly if there is a family history of PCCD. [2]
At the moment, implanting an implantable pacemaker is the only proven treatment for PCCD, regardless of the underlying cause. [3]
Bradycardia, also called bradyarrhythmia, is a resting heart rate under 60 beats per minute (BPM). While bradycardia can result from various pathologic processes, it is commonly a physiologic response to cardiovascular conditioning or due to asymptomatic type 1 atrioventricular block.
An artificial cardiac pacemaker, commonly referred to as simply a pacemaker, is an implanted medical device that generates electrical pulses delivered by electrodes to one or more of the chambers of the heart. Each pulse causes the targeted chamber(s) to contract and pump blood, thus regulating the function of the electrical conduction system of the heart.
Sinus node dysfunction (SND), also known as sick sinus syndrome (SSS), is a group of abnormal heart rhythms (arrhythmias) usually caused by a malfunction of the sinus node, the heart's primary pacemaker. Tachycardia-bradycardia syndrome is a variant of sick sinus syndrome in which the arrhythmia alternates between fast and slow heart rates.
An implantable cardioverter-defibrillator (ICD) or automated implantable cardioverter defibrillator (AICD) is a device implantable inside the body, able to perform defibrillation, and depending on the type, cardioversion and pacing of the heart. The ICD is the first-line treatment and prophylactic therapy for patients at risk for sudden cardiac death due to ventricular fibrillation and ventricular tachycardia.
Third-degree atrioventricular block is a medical condition in which the electrical impulse generated in the sinoatrial node in the atrium of the heart can not propagate to the ventricles.
First-degree atrioventricular block is a disease of the electrical conduction system of the heart in which electrical impulses conduct from the cardiac atria to the ventricles through the atrioventricular node more slowly than normal. First degree AV block does not generally cause any symptoms, but may progress to more severe forms of heart block such as second- and third-degree atrioventricular block. It is diagnosed using an electrocardiogram, and is defined as a PR interval greater than 200 milliseconds. First degree AV block affects 0.65-1.1% of the population with 0.13 new cases per 1000 persons each year.
Second-degree atrioventricular block is a disease of the electrical conduction system of the heart. It is a conduction block between the atria and ventricles. The presence of second-degree AV block is diagnosed when one or more of the atrial impulses fail to conduct to the ventricles due to impaired conduction. It is classified as a block of the AV node, falling between first-degree and third degree blocks.
Lev's disease, also known as Lenegre disease, is an idiopathic disease that can result in a complete heart block, or an extremely slowed heart rate, in patients with this condition. It is thought that for certain patients, this impairment of heart's electrical conduction system is due to fibrosis and calcification of conduction cells. This disease is considered to be age related, with increasing decline seen in elderly patients.
Atrioventricular block is a type of heart block that occurs when the electrical signal traveling from the atria, or the upper chambers of the heart, to ventricles, or the lower chambers of the heart, is impaired. Normally, the sinoatrial node produces an electrical signal to control the heart rate. The signal travels from the SA node to the ventricles through the atrioventricular node. In an AV block, this electrical signal is either delayed or completely blocked. When the signal is completely blocked, the ventricles produce their own electrical signal to control the heart rate. The heart rate produced by the ventricles is much slower than that produced by the SA node.
In cardiology, a ventricular escape beat is a self-generated electrical discharge initiated by, and causing contraction of the ventricles of the heart; normally the heart rhythm is begun in the atria of the heart and is subsequently transmitted to the ventricles. The ventricular escape beat follows a long pause in ventricular rhythm and acts to prevent cardiac arrest. It indicates a failure of the electrical conduction system of the heart to stimulate the ventricles.
Inappropriate sinus tachycardia (IST) is defined as sinus tachycardia that is not caused by identifiable medical ailments, a physiological reaction, or pharmaceuticals (a diagnosis of exclusion) and is accompanied by symptoms, frequently invalidating and affecting quality of life. IST symptoms include palpitations, chest discomfort, exhaustion, shortness of breath, presyncope, and syncope.
Electrical alternans is an electrocardiographic phenomenon of alternation of QRS complex amplitude or axis between beats and a possible wandering base-line. It can be seen in cardiac tamponade and severe pericardial effusion and is thought to be related to changes in the ventricular electrical axis due to fluid in the pericardium, as the heart essentially wobbles in the fluid filled pericardial sac. It can also be found in other conditions, such as bidirectional ventricular tachycardia from digoxin toxicity and atrioventricular tachycardia.
Multifocal atrial tachycardia (MAT) is an abnormal heart rhythm, specifically a type of supraventricular tachycardia, that is particularly common in older people and is associated with exacerbations of chronic obstructive pulmonary disease (COPD). Normally, the heart rate is controlled by a cluster of cells called the sinoatrial node. When a number of different clusters of cells outside the SA node take over control of the heart rate, and the rate exceeds 100 beats per minute, this is called multifocal atrial tachycardia.
Bifascicular block is characterized by right bundle branch block with left anterior fascicular block, or right bundle branch block with left posterior fascicular block on electrocardiography. Complete heart block could be the cause of syncope that is otherwise unexplained if bifascicular block is seen on electrocardiography. It is estimated that less than 50% of patients with bifascicular block have high-degree atrioventricular block, although the exact incidence is unknown.
Pacemaker syndrome is a condition that represents the clinical consequences of suboptimal atrioventricular (AV) synchrony or AV dyssynchrony, regardless of the pacing mode, after pacemaker implantation. It is an iatrogenic disease—an adverse effect resulting from medical treatment—that is often underdiagnosed. In general, the symptoms of the syndrome are a combination of decreased cardiac output, loss of atrial contribution to ventricular filling, loss of total peripheral resistance response, and nonphysiologic pressure waves.
Cardiac resynchronisation therapy is the insertion of electrodes in the left and right ventricles of the heart, as well as on occasion the right atrium, to treat heart failure by coordinating the function of the left and right ventricles via a pacemaker, a small device inserted into the anterior chest wall.
EP Europace is a peer-reviewed medical journal published by Oxford University Press that publishes research articles about the study and management of cardiac arrhythmias, cardiac pacing, and cardiac cellular electrophysiology. It is 1 of 13 official journals of the European Society of Cardiology and is the official journal of the society's working groups on Cardiac Cellular Electrophysiology and e-Cardiology and of the European Heart Rhythm Association.
A frequent type of syncope, termed vasovagal syncope is originated by intense cardioinhibition, mediated by a sudden vagal reflex, that causes transitory cardiac arrest by asystole and/or transient total atrioventricular block. It is known as “Vaso-vagal Syncope”, “Neurocardiogenic Syncope” or “Neurally-mediated Reflex Syncope”. Although many different therapies have been tried in this condition, severe and refractory cases have been treated with pacemaker implantation despite great controversies about its benefit.
Twiddler's syndrome is a malfunction of a pacemaker due to manipulation of the device and the consequent dislodging of the leads from their intended location. As the leads move, they stop pacing the heart and can cause strange symptoms such as phrenic nerve stimulation resulting in abdominal pulsing or brachial plexus stimulation resulting in rhythmic arm twitching. Twiddler's syndrome in patients with an implanted defibrilator may lead to inadequate, painful defibrillation-shocks.
The congenital heart block (CHB) is the heart block that is diagnosed in fetus or within the first 28 days after birth, some studies also include the diagnosis during early childhood to the definition of CHB. It refers to the disorder in the electrical conduction system within the heart muscle, which leads to the failure in pumping the blood efficiently into the aorta and the pulmonary trunk. The result of CHB can be first, second, or third-degree (complete) atrioventricular block in which no electric signals move from the atrium to the ventricles