Concept
Heart rate
Related concepts (34)
Hemodynamics
Hemodynamics or haemodynamics are the dynamics of blood flow. The circulatory system is controlled by homeostatic mechanisms of autoregulation, just as hydraulic circuits are controlled by control systems. The hemodynamic response continuously monitors and adjusts to conditions in the body and its environment. Hemodynamics explains the physical laws that govern the flow of blood in the blood vessels.
Medulla oblongata
The medulla oblongata or simply medulla is a long stem-like structure which makes up the lower part of the brainstem. It is anterior and partially inferior to the cerebellum. It is a cone-shaped neuronal mass responsible for autonomic (involuntary) functions, ranging from vomiting to sneezing. The medulla contains the cardiac, respiratory, vomiting and vasomotor centers, and therefore deals with the autonomic functions of breathing, heart rate and blood pressure as well as the sleep–wake cycle.
Artificial cardiac pacemaker
An artificial cardiac pacemaker (artificial pacemaker, and sometimes just pacemaker, although the term is also used to refer to the body's natural cardiac pacemaker) is a medical device, nowadays always implanted, that generates electrical pulses delivered by electrodes to one or more of the chambers of the heart, the upper atria or lower ventricles. Each pulse causes the targeted chamber(s) to contract and pump blood, thus regulating the function of the electrical conduction system of the heart.
Heart block
Heart block (HB) is a disorder in the heart's rhythm due to a fault in the natural pacemaker. This is caused by an obstruction – a block – in the electrical conduction system of the heart. Sometimes a disorder can be inherited. Despite the severe-sounding name, heart block may cause no symptoms at all in some cases, or occasional missed heartbeats in other cases (which can cause light-headedness, syncope (fainting), and palpitations), or may require the implantation of an artificial pacemaker, depending upon exactly where in the heart conduction is being impaired and how significantly it is affected.
Catecholamine
A catecholamine (ˌkætəˈkoʊləmiːn; abbreviated CA) is a monoamine neurotransmitter, an organic compound that has a catechol (benzene with two hydroxyl side groups next to each other) and a side-chain amine. Catechol can be either a free molecule or a substituent of a larger molecule, where it represents a 1,2-dihydroxybenzene group. Catecholamines are derived from the amino acid tyrosine, which is derived from dietary sources as well as synthesis from phenylalanine.
Sinus rhythm
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.
Adrenal medulla
The adrenal medulla (medulla glandulae suprarenalis) is part of the adrenal gland. It is located at the center of the gland, being surrounded by the adrenal cortex. It is the innermost part of the adrenal gland, consisting of chromaffin cells that secrete catecholamines, including epinephrine (adrenaline), norepinephrine (noradrenaline), and a small amount of dopamine, in response to stimulation by sympathetic preganglionic neurons. The adrenal medulla consists of irregularly shaped cells grouped around blood vessels.
Diastole
Diastole (daɪˈæstəli ) is the relaxed phase of the cardiac cycle when the chambers of the heart are re-filling with blood. The contrasting phase is systole when the heart chambers are contracting. Atrial diastole is the relaxing of the atria, and ventricular diastole the relaxing of the ventricles. The term originates from the Greek word διαστολή (diastolē), meaning "dilation", from διά (diá, "apart") + στέλλειν (stéllein, "to send"). A typical heart rate is 75 beats per minute (bpm), which means that the cardiac cycle that produces one heartbeat, lasts for less than one second.
QT interval
The QT interval is a measurement made on an electrocardiogram used to assess some of the electrical properties of the heart. It is calculated as the time from the start of the Q wave to the end of the T wave, and approximates to the time taken from when the cardiac ventricles start to contract to when they finish relaxing. An abnormally long or abnormally short QT interval is associated with an increased risk of developing abnormal heart rhythms and sudden cardiac death.
Bundle of His
The bundle of His (BH) or His bundle (HB) (hɪs "hiss") is a collection of heart muscle cells specialized for electrical conduction. As part of the electrical conduction system of the heart, it transmits the electrical impulses from the atrioventricular node (located between the atria and the ventricles) to the point of the apex of the fascicular branches via the bundle branches. The fascicular branches then lead to the Purkinje fibers, which provide electrical conduction to the ventricles, causing the cardiac muscle of the ventricles to contract at a paced interval.