Search results
Results From The WOW.Com Content Network
A sinus rhythm is any cardiac rhythm in which depolarisation of the cardiac muscle begins at the sinus node. [1] It is necessary, but not sufficient, for normal electrical activity within the heart. [2] On the electrocardiogram (ECG), a sinus rhythm is characterised by the presence of P waves that are normal in morphology. [2]
Schematic representation of a normal sinus rhythm ECG wave. Diagram showing how the polarity of the QRS complex in leads I, II, and III can be used to estimate the heart's electrical axis in the frontal plane. The QRS complex is the combination of three of the graphical deflections seen on a typical electrocardiogram (ECG or EKG). It is usually ...
When an individual is in normal sinus rhythm, the ECG characteristics of WPW are a short PR interval (less than 120 milliseconds in duration), widened QRS complex (greater than 120 milliseconds in duration) with slurred upstroke of the QRS complex, and secondary repolarization changes (reflected in ST segment-T wave changes). [citation needed]
The hexaxial reference system is a diagram that is used to determine the heart's electrical axis in the frontal plane.. In electrocardiography, left axis deviation (LAD) is a condition wherein the mean electrical axis of ventricular contraction of the heart lies in a frontal plane direction between −30° and −90°.
Sinus tachycardia is a sinus rhythm of the heart, with an increased rate of electrical discharge from the sinoatrial node, ... A 12 lead ECG showing sinus tachycardia.
The heart rhythm must originate above the ventricles (i.e., sinoatrial node, atria or atrioventricular node) to activate the conduction system at the correct point. The QRS duration must be more than 100 ms (incomplete block) or more than 120 ms (complete block). [9]
This is known as an escape rhythm. Since this accessory pacemaker also activates independently of the impulse generated at the SA node, two independent rhythms can be noted on the electrocardiogram (ECG). The P waves with a regular P-to-P interval (in other words, a sinus rhythm) represent the first rhythm.
If lead b is positive, the electrical heart axis can be estimated to lie within the quadrant between axis of lead a and lead b. A simple tool to quickly identify axis deviation (Figure 3) is the popular mnemonic; R eaching for R ight Axis Deviation and L eaving for L eft Axis Deviation.