…most frequent source of EMI, although radiofrequency procedures, nerve stimulators, and other electronic equipment may also interfere with device function. The clinical consequences depend on…

…Stimulation threshold is the minimum amount of energy required to reach threshold and evoke an action potential. The intensity of the electrical stimulus is described…

…K + [potassium] and Ca 2+ [calcium]) flow back and forth across the cell membrane. Because ions are electrically charged, their movement generates an electrical current…

…main principle behind artificial pacemakers; i.e applying an external electrical current that depolarizes cells in contact with the lead tip, and thus generate an…

…the P wave is a requirement for establishing a diagnosis of sinus tachycardia. On the contrary to many paroxysmal supraventricular tachyarrhythmias (e.g AVNRT, AV

…on surface ECG. Oversensing may also occur when electrical events in one chamber is sensed by the lead in the other chamber, resulting in inappropriate…

…at low heart rates. During vasovagal syncope (e.g during intense emotional stress) During vagal maneuvers (Valsalva maneuver, carotid sinus [baroreceptor] stimulation). It is common…

…the AV node and the His Purkinje system, which transmit electrical impulses from the atria to the ventricles. Conduction through the AV node is intentionally…

…negative T waves in V1 through V4. PVCs and ventricular tachycardia can be provoked by physical any adrenergic stimulation, e.g physical activity. Figure 1…

…region. Duration above the threshold or unknown: at least three weeks of adequate anticoagulation before cardioversion — an INR ≥ 2.0 checked weekly on warfarin, or…

…complex in lead I but negative in lead II. Extreme axis deviation (–90°to 180°) : Net negative QRS complex in leads I and II. Figure 2…

…range of normal heart axis. Figure 38. The electrical axis of the heart (heart axis). As evident from the figure, the normal heart axis is…

ECG Video lecture: Assessment of the electrical axis of the heart

…electrical axis is typically calculated for ventricular activation in the frontal plane using the hexaxial reference system. This system is constructed by superimposing the lead…

…chapter will focus on ventricular fibrillation and pulseless electrical activity (PEA). These are highly lethal arrhythmias that lead to death if cardiopulmonary resuscitation is not…

…safely restore sinus rhythm, obviating slow drug titration and rendering the supraventricular versus ventricular distinction less critical. Performance involves sedation (e.g., intravenous midazolam, propofol…

…12) 2–33 (14) 2–39 (15) Children, overview Rijnbeek et al. Median values with the 2nd and 98th percentiles. 0–1 month 1–3…

…children) Principles of ECG leads, lead anatomy and electrical vectors have been discussed in the chapter The ECG Leads. Acquisition of ECGs in pediatric patients…

…long has the fibrillation lasted, and does the patient need an anticoagulant? The unstable patient Immediate electrical cardioversion, without delay, in any of the following…

…organized, continuous atrial electrical activity. This activity most commonly presents as a characteristic saw tooth pattern at rates typically exceeding 200 beats per minute. While…

…produce conventional ST segment elevation in the standard 12 lead ECG. Instead, the infarct related electrical changes may be recorded indirectly as reciprocal abnormalities in…

…this score. A high HAS BLED score (≥3) indicates a need for closer clinical monitoring and aggressive modification of reversible risk factors (e.g., treating…

…e.g. pulmonary embolism, trauma, respiratory causes, drug overdoses, etc.). Among victims in whom the cardiac arrest was caused by VT or VF (e.g…

…medications and remove any remnants of allergens (e.g., insect residues). For patients on beta blocker therapy, consider administering 1 2 mg of glucagon intravenously…

…beats per minute in atrial tachycardia and less than 100 beats per minute in atrial rhythm. Refer to ECG examples in Figures 1, 2 and…

…which delivers the electrical impulse to the anterior wall of the left ventricle; (2) the posterior (posteroinferior) fascicle , which delivers the electrical impulse to the…

…100 ms at paperspeed 25 mm/s. Figure 2 shows 12 lead ECGs demonstrating right and left bundle branch blocks. Figure 2. 50 mm/s…

…anatomical or functional dysfunction in the right bundle branch, such that the electrical impulse is blocked. Figure 1 illustrates the components of the ventricular conduction…

…LVH) and right ventricular hypertrophy (RVH). The electrical vector of the left ventricle is enhanced in LVH, which results in large R waves in left…

…electrical events but from different angles. This means that ECG leads with similar angles must display similar ECG curves (diagrams). For some purposes (e.g…

…and ECG typically identify ischemia at later stages, when functional or electrical alterations are evident. Subjective symptoms (i.e. chest pain) appear as the last…

…in the lead in which it is longest, usually II or V5, and the U wave must not be included. Electrical axis Electrical axis Interpretation…

… one of the most useful signs Low voltage on the ECG, electrical alternans Supportive; it does not exclude Diastolic collapse of the right atrium and…

…Transcutaneous pacing takes seconds to start and can keep a patient alive until a transvenous lead is in place — but only if it is working…

…presented in the parenthesis). Values without confidence interval are simply the 98 th percentile (i.e the upper reference limit). Age <1 day 1–3…

…ranges from symptom free presentation to persistent chest discomfort, cardiac arrest, electrical or haemodynamic instability, and cardiogenic shock. ACS is distinct from myocardial infarction (MI…

…rate is extremely low—such as less than 40 to 50 beats per minute in the first 4 to 6 hours after an acute infarction…

…usually on a treadmill, while symptoms, a 12 lead ECG, heart rate and blood pressure are monitored. The test is generally symptom limited and is…

…mitigation of reperfusion injury are complementary objectives of initial STEMI management. The principal acute complications fall into two broad categories: Electrical complications , particularly ventricular arrhythmias…

…the cells' membrane potential (during phase 2), it engenders electrical potential difference in the myocardium. The electrical potential difference exists between ischemic and normal myocardium…

…LVH) and right ventricular hypertrophy (RVH). The electrical vector of the left ventricle is enhanced in LVH, which results in large R waves in left…

…Na}$) and are identified in 20% to 30% of probands [7] . Historically, expanded genetic panels implicated over 20 other genes (e.g., CACNA1C , GPD1L …

…Australia. Emerg Med 2013;30:3842. Luna GK, Pavlin EG, Kirkman T, Copass MK, Rice CL. Hemodynamic effects of external cardiac massage in trauma shock…

…Australia. Emerg Med 2013; 30:3842. Luna GK, Pavlin EG, Kirkman T, Copass MK, Rice CL. Hemodynamic effects of external cardiac massage in trauma shock…

…Note that the ECG rarely shows atrial recovery (repolarization) since it coincides with ventricular depolarization (i.e. QRS complex), which has much stronger electrical potentials…

…in use anymore because it has been shown that such ECG changes also occur in conditions where the left ventricle is not overloaded (e.g…

…The ECG in Brugada syndrome Brugada syndrome is a rare channelopathy (an electrical disorder caused by mutations in cardiac ion channels) which predisposes the individual…

…The LMCA supplies a large myocardial territory through the left anterior descending (LAD) and left circumflex (LCx) arteries (Figure 1). Acute obstruction can lead to…

…may even lead to compression of the ventricles during diastole; cardiac tamponade occurs if excess pericardial fluid causes hemodynamic effects. Electrical alternans – i.e the…

…the rhythm is non shockable, as seen in certain causes of cardiac arrest (e.g. pulmonary embolism) or in case of long no flow or…

…as it does not represent a true conduction block but rather a delay in the propagation of electrical impulses from the atria to the ventricles…

…of survival, cardiopulmonary resuscitation (CPR) should be started. If cardiac arrest is an expected consequence of a disease course (e.g. terminal cancer, terminal heart…

…two tasks, the heart has an intrinsic pacemaker–i.e. the sinus node–and an electrical conduction system composed of specialized myocardial cells. Conduction cells…

…presented in the parenthesis). Values without confidence interval are simply the 98 th percentile (i.e the upper reference limit). Age <1 day 1–3…

…be diagnosed using surface ECG (i.e. ECG recorded on the body surface). This is because the electrical potentials generated by the sinoatrial node are…

…cessation of tissue perfusion as a result of cardiac or vascular condition. May reverse spontaneously (e.g., vasovagal syncope) or with treatment (e.g., arrhythmias)…

…Table 1). Phase Period Optimal treatment Electrical phase 0 to 4 minutes Defibrillation Circulatory phase 4 to 10 minutes Compressions and ventilation, followed by defibrillation…

…Under normal circumstances the electrical impulse travels from the atria to the ventricle via the atrioventricular (AV) node. The electrical impulse cannot travel directly from…

…AV block is a very serious condition because escape rhythms may (1) not occur, (2) occur transiently, or (3) occur but generate insufficient cardiac output…