Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of Graph Search.
Concept
Sinus rhythm
Summary
A sinus rhythm is any cardiac rhythm in which depolarisation of the cardiac muscle begins at the sinus node. It is necessary, but not sufficient, for normal electrical activity within the heart. On the electrocardiogram (ECG), a sinus rhythm is characterised by the presence of P waves that are normal in morphology.
The term normal sinus rhythm (NSR) is sometimes used to denote a specific type of sinus rhythm where all other measurements on the ECG also fall within designated normal limits, giving rise to the characteristic appearance of the ECG when the electrical conduction system of the heart is functioning normally; however, other sinus rhythms can be entirely normal in particular patient groups and clinical contexts, so the term is sometimes considered a misnomer and its use is sometimes discouraged.
Other types of sinus rhythm that can be normal include sinus tachycardia, sinus bradycardia, and sinus arrhythmia. Sinus rhythms may be present together with various other cardiac arrhythmias on the same ECG.
In humans, for an ECG to be described as showing a sinus rhythm, the shape of the P wave in each of the 12 standard ECG leads should be consistent with a "typical P vector" of +50° to +80°. This means that the P wave should be:
always positive in lead I, lead II, and aVF
always negative in lead aVR
any of biphasic (-/+), positive or negative in lead aVL
positive in all chest leads, except for V1 which may be biphasic (+/-)
If the P waves do not meet these criteria, they must be originating from an abnormal site elsewhere in the atria and not from the sinus node; the ECG cannot, therefore, be classed as showing a sinus rhythm.
In general, each P wave in a sinus rhythm is followed by a QRS complex, and the sinus rhythm therefore gives rise to the whole heart's depolarization. Exceptions to this include complete heart block and certain ventricular artificial pacemaker rhythms, where the P waves may be completely normal in shape, but ventricular depolarization bears no relation to them; in these cases, the speed of the "sinus rhythm of the atria" and the speed of the ventricular rhythm must be calculated separately.
Official source
About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.
Ontological neighbourhood
Related courses (4)
EE-511: Sensors in medical instrumentation
Fundamental principles and methods used for physiological signal conditioning. Electrode, optical, resistive, capacitive, inductive, and piezoelectric sensor techniques used to detect and convert phys
BIO-378: Physiology lab I
Le TP de physiologie introduit les approches expérimentales du domaine biomédical, avec les montages de mesure, les capteurs, le conditionnement des signaux, l'acquisition et traitement de données.
Le
BIO-379: Physiology lab II
Le TP de physiologie introduit les approches expérimentales du domaine biomédical, avec les montages de mesure, les capteurs, le conditionnement des signaux, l'acquisition et traitement de données.
Le
Related lectures (14)
ECG: hemodynamics
Demonstrates measuring pressure wave in the radial artery using a Doppler device.
Surfaces with Variable Curvature
Explores surfaces with variable curvature, discussing their construction and properties.
ECG Measurement: Leads and Signal Generation
Explains ECG measurement, leads, and signal generation, including abnormal ECG examples.