Narrow-QRS-complex tachycardia suggests that anterograde conduction and thus depolarisation of the ventricle occurs through the atrioventricular (AV) node and His-Purkinje system. A 1:1 atrial:ventricular relationship can occur with both atrial and ventricular arrhythmias.Ĭlassification can also be based on whether there is a narrow- (QRS interval 120 ms) complex tachycardia. If P waves are discernible, an atrial:ventricular relationship of 1 is highly suggestive of an atrial arrhythmia. Some overlap may occur when conduction occurs with aberrancy (left or right bundle branch block) and in the presence of anti-arrhythmic agents that may slow conduction (sodium channel blockers). Atrial arrhythmias usually conduct to the ventricle through the His-Purkinje system and result in a narrow QRS complex. Whether the arrhythmia originates from the atrium or the ventricle is usually dependent on whether the QRS complex is wide or narrow, and on the atrial:ventricular relationship. Sinus tachycardia can be mistaken for other supraventricular arrhythmias, including atrial flutter, particularly with rapid tachyarrhythmias (when P waves are difficult to distinguish or when ectopic atrial foci originate near the sino-atrial node, such as near the superior vena cava or upper crista terminalis). A careful assessment is important, to evaluate whether the sinus rate is appropriate for the clinical situation. In most cases, a secondary cause of sinus tachycardia can be identified. Because each impulse originates in the sinoatrial node, the ECG shows a P wave preceding each QRS interval with a normal P-wave axis. Diagnosis depends on the P-wave morphology and the setting in which it occurs. Sinus tachycardia is a common cause of tachycardia that can often be mistaken for an arrhythmia. 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. These include: sinus versus non-sinus causes atrial versus ventricular arrhythmias narrow- versus wide-complex tachycardias regular versus irregular arrhythmias and classification based on the site of origin of the arrhythmia. Several methods of classification of tachyarrhythmia are helpful in organising and assessing tachycardias. Mean 24 hour heart rate, minimal heart rate and pauses in healthy subjects 40-79 years of age. The normal sinus rate in infants is 110 to 150 bpm, which gradually slows with age. European Heart Rhythm Association (EHRA) consensus document on the management of supraventricular arrhythmias, endorsed by Heart Rhythm Society (HRS), Asia-Pacific Heart Rhythm Society (APHRS), and Sociedad Latinoamericana de Estimulación Cardiaca y Electrofisiologia (SOLAECE). Katritsis DG, Boriani G, Cosio FG, et al. An ECG is performed.Tachycardia, generally defined as a heart rate ≥100 bpm, can be a normal physiological response to a systemic process or a manifestation of underlying pathology. shortness of breath, chest pain, shock, confusion, syncope) he could be managed pharmaceutically in the first instance.Ī 40 year old lady comes to the emergency department from her husband’s funeral with a sensation of ‘fluttering’ in her chest. If there were no symptoms of decompensation (e.g. If acutely symptomatic urgent DC cardioversion is indicated. If the patient was conscious the ALS algorithm would not be necessary and management depends on symptoms. This is a shockable rhythm and should be treated using the ALS algorithm with DC cardioversion and adrenaline. He should be treated as per ALS guidelines with chest compressions beginning immediately. This is ventricular tachycardia (VT) and in this case the patient is in cardiac arrest as they have no central pulse.
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