…the difference between ECG leads and ECG electrodes . An electrode is a conductive pad that is attached to the skin and enables the recording of…

…Accessory pathways do not display the slow conduction that the atrioventricular node does, and this means that any impulse reaching the accessory pathways may travel…

…the conduction system, one must be familiar with the vascular supply to these components. Figure 1 presents all relevant parts of the conduction system and…

Conduction defects ECG Management and treatment of AV blocks (AV block 1, 2 & 3) Evaluation of patients with suspected AV blocks requires a thorough medical…

…aberrant ventricular conduction (aberration, aberrancy). In clinical practice aberration is commonly seen in patients with atrial fibrillation because these patients have rapid and irregular rhythms…

…digoxin. Increased Vagus activity diminishes the automaticity in the sinoatrial node (which lowers heart rate) and also slows conduction over the atrioventricular (AV) node. The…

Conduction defects ECG Lathundar Left Bundle Branch Block (LBBB) Electrocardiographic Criteria and Characteristics Left bundle branch block is characterized by a significant reorganization of the…

…will spread through the right ventricle partly or entirely outside of the conduction system which will be slow and therefore cause a wide QRS complex…

…conduction disorders. These include beta blockers, non dihydropyridine calcium channel blockers, antiarrhythmic drugs (amiodarone, dronedarone, sotalol, flecainide, propafenone, procainamide, disopyramide, adenosine, digoxin, ivabradine), psychoactive and…

…conduction failure. The pathophysiology of these events may stem from reversible causes, including hypovolemia, hypoxia, cardiac tamponade, tension pneumothorax, preexisting acidosis, drug overdose, hypothermia, and…

…710. Eschalier R et al. Heart Rhythm. 2015 May;12(5):1071 9. Nonspecific intraventricular conduction delay: Definitions, prognosis, and implications for cardiac resynchronization therapy.

…originates in the atria it will pass through the bundle of His and therefore produce a normal QRS complex (provided that intraventricular conduction is normal)…

…that cause these rhythms spread partially or entirely outside of the ventricular conduction system, and thus the ventricular depolarization is slow (yielding a wide QRS…

…atrioventricular (AV) conduction. Clinical Presentation and Symptoms Patients with atrial flutter typically present with symptoms related to high ventricular rates and the loss of the…

…decremental conduction properties. Furthermore, adenosine binds to four types of receptors. Binding to A2A receptors induces coronary vasodilation, whereas binding to the A1, A2B, and…

…echocardiography should receive information regarding the conduction of the examination. Some patient engagement is required to obtain all views and the best possible image quality…

…cells in the sinoatrial node. They may also induce conduction defects (e.g. AV block). Increased intracranial pressure (manifests with sinus bradycardia and hypertension). Hypothyroidism …

…intermittent failures to discharge impulses). Sinoatrial block (delayed or blocked impulse conduction between the sinoatrial node and the atrium). All these conditions have been discussed…

…thick muscular layer between the endocardium and the epicardium is called myocardium . It contains cardiac muscle fibers, connective tissue and a very high density of…

…myositis, mixed connective tissue disease, Sjögren syndrome, SLE and APS. Some patient groups have a two to three fold greater prevalence of asymptomatic atherosclerotic cardiovascular…

…His Purkinje system, and ventricle. It extends the A H interval, which serves as an index of AV nodal conduction, but does not significantly alter…

…is due to intraventricular conduction defects). Hypertrophy may also shift the electrical axis (to the right in right ventricular hypertrophy, and to the left in…

…250 and 350 beats per minute (which is slower than the atrial rate in atrial fibrillation). The atrioventricular node is not capable of conducting all…

…referred to as conduction cells). These cells form bundles of fibers that act as electrical cords that spread the action potential rapidly and sequentially to…

…tachycardia during physical activity, all tachycardias should be considered pathological and the task is to clarify the cause of the tachycardia. The cause may range…

…Junctional tachycardia is less common. Basic knowledge of arrhythmias and cardiac automaticity will facilitate understanding of this article. As discussed in Chapter 1 the atrioventricular…

…in the conduction from the sinoatrial node to the atrium and this delay increases gradually until one impulse is completely blocked and a loss of…

…The electrical conduction system of the heart The sinus node (sinoatrial node) and intrinsic automaticity The sinus node is a small oval structure located near…

…of the conduction system are much too small to be detected by skin electrodes; the ECG presents the electrical activity of the atrial and ventricular…

…laboratory and personnel Exercise stress testing may be conducted by physicians, nurses, biomedical analysts, or other professionals. A physician is always formally responsible for conducting…

…risk of arrhythmia and sudden cardiac death is most often determined by the presence and severity of underlying cardiovascular disease. Conduction disease and the need…

…supply of the conduction system. As seen, the sinoatrial node is supplied by the right coronary artery in 60% of individuals, and by the left…

…sudden cardiac death and ventricular arrhythmias. Figure 2. Fragmented QRS complex. These QRS configurations are also indicate of previous myocardial infarction. New conduction defect Myocardial…

ECG Myocardial ischemia and infarction Acute myocardial infarction (AMI) always affects the left ventricle Myocardial infarction is virtually synonymous with left ventricular infarction . All myocardial…

…such as heart failure, structural heart disease, fibrosis of the conduction system and acute myocardial infarction (particularly anterior STEMI). Hence, an acute myocardial infarction may…

Conduction defects ECG Third degree (complete) AV block: ECG criteria, clinical characteristics and management This chapter discusses third degree AV block, which is synonymous with…

…Effects of propafenone and flecainide on ECG, heart rhythm and conduction Effect on sinoatrial (SA) node Flecainide has no effect on the activity in the…

…impulse conduction through the ventricles. After passing the AV node, the electrical impulse travels through the His bundle, which bifurcates into the left and right…

…slower conduction results in a prolonged QRS duration. The defining features of LBBB include a QRS duration of ≥0.12 seconds, a deep and broad…

…in the ventricles it will spread partly or entirely outside of the conduction system and thus produce a wide QRS complex (QRS duration ≥0.12…

…rate related conduction abnormalities, pacing related repolarization changes, and inadequate coronary flow relative to myocardial oxygen demand. Consequently, an elevated cardiac troponin concentration and new…

…nor cardiac rhythm, or impulse conduction. 2. Calcium Hypercalcemia Causes of hypercalcaemia Primary hyperparathyroidism and malignancies cause 90% of all cases of hypercalcemia. Less common…

…myocarditis, and amyloidosis may all cause LAFB. Prognosis of left anterior fascicular block (LAFB) Isolated LAFB is considered a benign conduction defect. Roughly 7% of…

…AV block is rarely of clinical significance and typically does not require intervention. In most cases, the conduction delay is localized to the atrioventricular node…

…sinus and the inferior vena cava, as well as cells around the mitral and tricuspid valves, which possess automaticity. These cells are not conduction cells…

…the specialized conduction system. This slow propagation leads to a delayed and abnormal activation sequence of the right ventricle, resulting in a prolonged and abnormal…

…conduction will be slower than the previous and the PR interval becomes prolonged. The AV node becomes more and more exhausted (i.e more and…

…intraventricular conduction is normal). If the P wave is visible, it is retrograde in lead II (because of the reversed direction of atrial activation) and…

…impulse reaches the atrioventricular node when there are two pathways, one being refractory and the other capable of conducting the impulse, re entry may arise…

…parietal layer and a visceral layer. The parietal layer is 2 mm thick, rich in connective tissue and envelops the entire heart and the departures…

…calcium channel blocker. Clevidipine is highly selective for vascular smooth muscle cells and has little or no effect on myocardial contractility or conduction. Clevidipine reduces…

…heart failure, atrial fibrillation, and other arrhythmias or conduction abnormalities. CKD also worsens the prognosis of established CVD. Mechanisms linking CKD to cardiovascular disease The…

…Hypertension and oestrogen exposure. Emotional or chronic mental stress. Fibromuscular dysplasia (FMD), which may produce arterial wall abnormalities and intramural haematomas. Inherited connective tissue disorders…

…and vice versa. The pathophysiological explanation for this may be a general degeneration of the atrial conduction system. Individuals with atrial fibrillation and bradycardia have…

…attention should be paid to potentially reversible causes and associated cardiovascular conditions, including coronary syndromes, valvular disease, atrial fibrillation, ventricular arrhythmias, conduction disease and hypertension…

…Provoking and relieving factors. Associated symptoms. Similarity to previous documented angina or myocardial infarction. Atherosclerotic and thromboembolic risk factors. Relevant predispositions, such as connective tissue…

…R waves: R wave ≥0,04 s in V1 V2 and R/S ratio ≥1 with concordant positive T wave in absence of conduction defect…

…through the left and right bundle branch, which branches out into the Purkinje network (refer to Cardiac Electrophysiology: The Action Potential). Impulse conduction through the…

…myocytes that form the slow conducting isthmuses critical for re entry [6] . Non ischemic dilated cardiomyopathy (NICM), hypertrophic cardiomyopathy (HCM), and arrhythmogenic right ventricular cardiomyopathy…

…which may be due to dysfunction in the conduction system. The J point and the ST segment The ST segment corresponds to the plateau phase…