One of the most common dysrhythmiasUsed interchangeably with arrhythmia, refers to any abnormal rhythm – not normal sinus rhythm or sinus tachycardia. 1. Six Second ECG Guidebook (2012), T Barill, p. 196, the atriaRight and left atria (1/3 volume and muscle mass of the ventricles) pump blood to the ventricles. Chambers and Layers of the Heart 1. Six Second ECG Guidebook (2012), T Barill, p. 190 have a host of sites that are concurrently firing at a combined rateHeart Rate; calculated by counting the number of QRS complexes in six seconds and multiplying by 10; rate is also determined by measuring the number of large squares between two R waves; i.e. –1 large square = heart rate of 300/minute. of 350-600/minute; since the junctionConnects the atria to the ventricle and slows the impulse conduction speed sufficiently to allow for atrial kick; the junction consists of the AV node and the bundle of His; the junction is a supraventricular structure. 1. Six Second ECG... allows maximum 240 impulses through per minute, the result is a chaotic rhythmOften refers to a discernible pattern in time or distance between QRS complexes and/or P waves. most often with a narrow QRSThe electrical representation of ventricular depolarization; the atrial repolarization is also a part of the QRS. ECG interpretation relies heavily on the QRS complex. The QRS complex represents the depolarization of the ventricles. The repolarization of the atria is also...; note that without effective pumping from the atria, atrial kickThe contraction of the atria prior to ventricular contraction causes an increased volume and stretch to the ventricles – resulting in increased force of contraction and increased stroke volume (Starling’s Law); this extra stroke volume increases cardiac output by 10-35%.... is lost and the risk of blood clotting in the atria is relatively high.
The most common supraventricularLocated above the ventricle – includes the bundle of His, AV node, atria and the SA node. 1. Six Second ECG Guidebook (2012), T Barill, p. 206 dysrhythmia is atrial fibrillation. About 1 in 5 people over the age of 50 will develop atrial fibrillation at some time in their lives. Mechanically, the atria are only quivering. Atrial kick is lost.
In an otherwise healthy population, atrial fibrillation is often symptom free. For the aged and those with cardiac illness, atrial fibrillation can be associated with hemodynamic compromise and cardiac ischemiaThe ability to identify cardiac ischemia, injury and infarction is vital in the management of the majority of cardiac emergencies. Most sudden cardiac deaths are associated with an ischemic episode. Patient deaths due to an acute myocardial infarction (MI) typically.... Generating further concern, the lack of an effective atrial contraction is associated with blood pooling and the potential development of a clot in the atria (particularly after 48 hours). The dislodging of this emboli can lead to a pulmonary embolism or a stroke.
Recognizing atrial fibrillation usually requires only the ability to distinguish that the rhythm is chaotic. There is no patternPattern refers to the repeating components of an ECG rhythm in a predicative order. An ECG rhythm that is initiated by one of several intrinsic pacemaker sites of a heart will often generate a regular, even rhythm pattern. This can... to this rhythm. If a rhythm has QRS complexes with no recognizable pattern and P wavesA wave generated from the depolarization of the atria; the P wave is upright when originating from the SA node. The P wave represents the depolarization of the right and left atria. The P wave begins with the first deviation... are indistinguishable, rhythm is probably atrial fibrillation.
A chaotic cardiac rhythm with QRS complexes (most often narrow) is most likely atrial fibrillation.
Note: fibrillation (atrial or ventricular) produces rates of 350-600/minute. With atrial rates this high, fortunately the AV junctionConducts the impulse through the fibrous plate that separates the atria and the ventricles; consists of the AV node and the bundle of His; functions also to slow the conduction speed to allow for atrial conduction prior to ventricular conduction... ensures that many of these atrial depolarizations do not make it through to the ventriclesThe larger chambers of the heart (3 times the volume and muscle thickness than the atria), responsible for the pumping of blood to the lungs and the rest of the body..
Atrial fibrillation with rates less than 60/minute is called atrial fibrillation with slow ventricular response. Atrial fibrillation with rates of 60-100/minute is called atrial fibrillation or atrial fibrillation with a controlled response. Atrial fibrillation with rates faster than 100/minute is called atrial fibrillation with rapid response.
1. Six Second ECG GuidebookA Practice Guide to Basic and 12 Lead ECG Interpretation, written by Tracy Barill, 2012 Introduction The ability to correctly interpret an electrocardiogram (ECG), be it a simple six second strip or a 12 lead ECG, is a vital skill... (2012), T Barill, p. 114, 122-123, 191