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A premature ventricular contraction (PVC) is a common event where the heartbeat is initiated by Purkinje fibers in the ventricles rather than by the sinoatrial node. PVCs may cause no symptoms or may be perceived as a "skipped beat" or felt as palpitations in the chest. PVCs do not usually pose any danger. [1]
Ectopic beats are considered normal and are not indicative of cardiac pathology. Ectopic beats often remain undetected and occur as part of minor errors in the heart conduction system. They are rarely indicative of cardiac pathology, although may occur more frequently or be more noticeable in those with existing cardiac abnormalities.
The height of AC component of the photoplethysmogram is proportional to the pulse pressure, the difference between the systolic and diastolic pressure in the arteries. As seen in the figure showing premature ventricular contractions (PVCs), the PPG pulse for the cardiac cycle with the PVC results in lower amplitude blood pressure and a PPG.
A premature heart beat or extrasystole [1] is a heart rhythm disorder corresponding to a premature contraction of one of the chambers of the heart. Premature heart beats come in two different types: premature atrial contractions and premature ventricular contractions. Often they cause no symptoms but may present with fluttering in the chest or ...
This results in the heart being less able to pump blood effectively and also may cause electrical conduction problems. [3] Specifically, within the bundle branches that conduct impulses through the interventricular septum and into the Purkinje fibers , as these are responsible for the depolarization of contractile cells of both ventricles.
Bigeminy is a cardiac arrhythmia in which there is a single ectopic beat, or irregular heartbeat, following each regular heartbeat.Most often this is due to ectopic beats occurring so frequently that there is one after each sinus beat, or normal heartbeat.
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°.
This is complemented by gastro-coronary reflexes [12] whereby the coronary arteries constrict with "functional cardiovascular symptoms" similar to chest-pain on the left side and radiation to the left shoulder, dyspnea, sweating, up to angina pectoris-like attacks with extrasystoles, drop of blood pressure, and tachycardia (high heart rate) or ...