…each ECG lead is computed by analyzing the electrical currents detected by several electrodes. The standard ECG – which is referred to as a 12 lead…

…to the heart where they contact the endocardium. Pacemaker battery The battery is used to deliver pacing pulses, sensing (analyzing electrical activity in the heart)…

…Diabetes, immunosuppression A risk of necrotising otitis externa Anticoagulant treatment Bleeding into the ear canal Previous radiotherapy to the head and neck Fragile skin, poor…

…ecstasy) or amphetamines. In either scenario, there is sustained muscle activation, leading to marked heat generation, acidosis, and the subsequent development of hyperkalemia. This condition…

…contraction. The direction of the depolarization (and thus the electrical axis) is generally alongside the heart's longitudinal axis (to the left and downwards). Figure…

…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

…single heart vector [3]. The orientation and intensity of this vector fluctuate throughout the cardiac cycle as depolarization and repolarization progress [3]. The mean electrical…

…fibrillation prior to the cardiac arrest. Most of these have atherosclerotic heart disease (coronary artery disease) as the underlying cause. Other common causes are cardiomyopathy…

Referensvärden A child's ECG changes continuously with age: the heart rate, the electrical axis and the waveform in the newborn differ markedly from adult…

Myocardial ischemia and infarction ECG Posterior (posterolateral) acute myocardial infarction (STEMI) The heart is rotated 30° to the left in the thorax. This positions the…

ECG Stimulation threshold As previously discussed, myocardium may be excited by external electrical stimuli that drive the cells to threshold. Stimulation threshold is the minimum…

…and fluids surrounding the heart have an abundance of ions, enabling them to function as electrical conductors. As a result, the electrical currents produced by…

Arrhythmias and arrhythmology Emergency medicine Pharmacology & dosing Definition and Pathophysiology Bradycardia encompasses a spectrum of rhythm disturbances characterized by an inappropriately slow heart rate. Within…

…causes & management Definition of sinus bradycardia Sinus bradycardia fulfills the criteria for sinus rhythm but the heart rate is slower than 50 beats per minute…

…instead as an ectopic atrial rhythm (EAR) . Ectopic atrial tachycardia (EAT) most commonly occurs in individuals with underlying structural or electrical heart disease. Less frequently…

…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…

…is a standardized assessment in which a patient performs progressively increasing external work, usually on a treadmill, while symptoms, a 12 lead ECG, heart rate…

…The contemporary understanding of AF has evolved significantly; it is no longer viewed merely as an electrical anomaly but as a progressive, complex atrial myopathy…

…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…

…automaticity) in the sinoatrial node. This simply means that the sinoatrial node discharges electrical impulses at a higher frequency than normal. Similar to sinus rhythm…

…sequence, before mechanical dysfunction ( i.e. left ventricular systolic or diastolic dysfunction) or electrical changes (ST T changes on ECG) become apparent. In contrast, modalities…

…cardiovascular medicine. As a primary driver of sudden cardiac death (SCD) and a major cause of morbidity in patients with structural heart disease, VT necessitates…

…by a sudden and random electrical event. An excerpt from the article follows: [...] Of every 10 such victims, the heart in 6 or 7 showed…

…is a clinical diagnosis supported by echocardiography: Finding Comment : : Hypotension, distended neck veins, muffled heart sounds Beck's triad; complete in a minority Tachycardia, tachypnoea…

…while awaiting the antidote and specific treatment. Bradyasystole during and after cardiac arrest with persisting electrical activity. Overdrive pacing in bradycardia dependent torsades de pointes…

…years 3–5 years 5–8 years 8–12 years 12–16 years 16 years Heart rate (beats per minute) 93–155 (122) 91–158 …

…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…

…coronary artery disease, arrhythmias, heart failure and alcohol related cardiomyopathy. The cardiovascular implications of lower alcohol intake remain controversial. Epidemiological studies have often described a…

…and hyperkalemia. When bradycardia occurs in the context of inflammatory heart disease, it often reflects myocardial pathology that may also reduce myocardial contractility and cause…

…not produce conventional ST segment elevation in the standard 12 lead ECG. Instead, the infarct related electrical changes may be recorded indirectly as reciprocal abnormalities…

…The principal acute complications fall into two broad categories: Electrical complications , particularly ventricular arrhythmias. Mechanical or pump failure complications , including heart failure and cardiogenic shock…

…VF) and pulseless ventricular tachycardia (VT). The bradyarrhythmias include all bradyarrhythmias, pulse less electrical activity (PEA), and asystole. Bradyarrhythmias are discussed in the chapter Management…

…for up to 20% of sudden cardiac deaths in patients without structural heart disease and is the leading cause of SCD in men under the…

…air is substantial enough to compress the superior and inferior vena cava, impeding or halting venous return to the heart. In instances of tension pneumothorax…

…coordinate these two tasks, the heart has an electrical conduction system composed of specialized myocardial cells (henceforth referred to as conduction cells). These cells form…

…throughout this course. At the heart of ECG interpretation lies the ability to determine whether the ECG waves and intervals are normal. This chapter will…

…fashion which is rather easy to spot. The hallmark of fascicular blocks is the deviation of the electrical axis. The QRS duration is slightly prolonged…

…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…

…years 3–5 years 5–8 years 8–12 years 12–16 years 16 years Heart rate (beats per minute) 93–155 (122) 91–158 …

…its inner diameter, is strongly related to heart failure, ventricular tachyarrhythmias, and overall mortality. Ventricular dimensions are measured using an electronic caliper, with the tips…

…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…

…Importantly, for the ventricles to have any electrical (and thus pumping) activity at all, an escape rhythm must arise in an ectopic focus (located distal…

…cause of the arrhythmia already affects cellular function. This results in electrical instability which explains why ventricular tachycardia may progress to ventricular fibrillation. Left untreated…

…arteries or in heart muscle. In other words, the heart today is anatomically the same as it was yesterday except that an electrical charge developed…

…drug induced arrhythmias in patients receiving agents known to alter the electrical properties of the heart (inducing QRS or QT prolongation) or causing electrolyte abnormalities…

…changes occur during the first year of life. The electrocardiogram (ECG) evolves in parallel with the changing anatomy and physiology of the heart. ECG amplitudes…

…exercise tolerance Acute coronary syndrome Silent ischaemia Heart failure, particularly when left ventricular function is impaired Haemodynamic or electrical instability in advanced or acute presentations…

…risks of revascularization outweigh its expected benefits. Haemodynamic and electrical status Haemodynamic instability, cardiogenic shock, acute heart failure related to ongoing ischaemia, life threatening arrhythmias…

…Its relationship with cardiovascular risk is nonlinear: even light smoking carries a substantial proportion of the excess ischaemic heart disease risk associated with heavy smoking…

…blood supply. Stress increases myocardial oxygen requirements, principally through increased heart rate and contractility. In the presence of a flow limiting coronary stenosis, supply cannot…

…AF causing acute haemodynamic instability requires prompt treatment, with electrical cardioversion preferred. Evaluation and risk assessment The evaluation of a patient with AF who may…

…can cause tamponade. Post operative Complications : Post surgical complications following thoracic procedures can cause tamponade. Tamponade with swinging heart of the pericardium. Source. Rapid diagnosis…

…or other trauma. Drowning Cardiac arrest due to drowning Electrocution Cardiac arrest due to electrical current through the heart. Asphyxia Asphyxia as a result of…

…to the swinging back and forth of the heart in the pericardial space. Note that tachycardia, pulmonary embolism and ischemia may also cause electrical alternans…

…In the United States, more than 500,000 individuals (adults and children) experience a cardiac arrest (Heart Disease and Stroke Statistics). The CARES registry reported…

…changes occur during the first year of life. The electrocardiogram (ECG) evolves in parallel with the changing anatomy and physiology of the heart. ECG amplitudes…

…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…

…particularly with continuing ischaemia, heart failure, electrical instability or a large area of myocardium at risk. Over 48 hours: urgent PCI is still indicated with…

…Irregular, rapid ( 300 bpm) ventricular depolarizations, with very irregular waveforms (no visible QRS waveforms) VT/VF storm (electrical storm) ≥3 episodes of sustained VT, VF…