Beta blocker

Skeletal formula of propranolol, the first clinically successful beta blocker
Dichloroisoprenaline, the first beta blocker

Beta blockers, also spelled β-blockers, are a class of medications that are predominantly used to manage abnormal heart rhythms, and to protect the heart from a second heart attack (myocardial infarction) after a first heart attack (secondary prevention).

- Beta blocker
Skeletal formula of propranolol, the first clinically successful beta blocker

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Alpha

An 80 mg capsule of extended-release propranolol

Propranolol

An 80 mg capsule of extended-release propranolol
A mixture of 20 mg and 10 mg propranolol tablets
Propranolol

Propranolol, sold under the brand name Inderal among others, is a medication of the beta blocker class.

A man with congestive heart failure and marked jugular venous distension. External jugular vein marked by an arrow.

Heart failure

Set of manifestations caused by the failure of the heart's function as a pump supporting the blood flow through the body; its signs and symptoms result from a structural and/or functional abnormality of the heart, that disrupts its filling with blood or its ejecting of it during each heart beat.

Set of manifestations caused by the failure of the heart's function as a pump supporting the blood flow through the body; its signs and symptoms result from a structural and/or functional abnormality of the heart, that disrupts its filling with blood or its ejecting of it during each heart beat.

A man with congestive heart failure and marked jugular venous distension. External jugular vein marked by an arrow.
Signs and symptoms of severe heart failure
Severe peripheral pitting edema
Kerley B lines in acute cardiac decompensation. The short, horizontal lines can be found everywhere in the right lung.
Model of a normal heart (left); and a weakened heart, with over-stretched muscle and dilation of left ventricle (right); both during diastole
Chest radiograph of a lung with distinct Kerley B lines, as well as an enlarged heart (as shown by an increased cardiothoracic ratio, cephalization of pulmonary veins, and minor pleural effusion as seen for example in the right horizontal fissure. Yet, no obvious lung edema is seen. Overall, this indicates intermediate severity (stage II) heart failure.
Siderophages (one indicated by white arrow) and pulmonary congestion, indicating left congestive heart failure
Ultrasound showing severe systolic heart failure
Congestive heart failure with small bilateral effusions
Kerley B lines

In those with heart failure due to left ventricular dysfunction, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, or valsartan/sacubitril along with beta blockers are recommended.

A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, causing catastrophic thrombus formation, totally occluding the artery and preventing blood flow downstream.

Myocardial infarction

A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle.

A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle.

A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, causing catastrophic thrombus formation, totally occluding the artery and preventing blood flow downstream.
Cross section showing anterior left ventricle wall infarction
Diagram showing the blood supply to the heart by the two major blood vessels, the left and right coronary arteries (labelled LCA and RCA). A myocardial infarction (2) has occurred with blockage of a branch of the left coronary artery (1).
A 12-lead ECG showing an inferior STEMI due to reduced perfusion through the right coronary artery. Elevation of the ST segment can be seen in leads II, III and aVF.
ECG : AMI with ST elevation in V2-4
Inserting a stent to widen the artery.

After an MI, lifestyle modifications, along with long-term treatment with aspirin, beta blockers and statins, are typically recommended.

Leads aVL and aVF of an electrocardiogram showing atrial fibrillation. There are irregular intervals between heart beats. No P waves are seen and there is an erratic baseline between QRS complexes. The heart rate is about 125 beats per minute.

Atrial fibrillation

Abnormal heart rhythm (arrhythmia) characterized by rapid and irregular beating of the atrial chambers of the heart.

Abnormal heart rhythm (arrhythmia) characterized by rapid and irregular beating of the atrial chambers of the heart.

Leads aVL and aVF of an electrocardiogram showing atrial fibrillation. There are irregular intervals between heart beats. No P waves are seen and there is an erratic baseline between QRS complexes. The heart rate is about 125 beats per minute.
Normal rhythm tracing (top) Atrial fibrillation (bottom)
How a stroke can occur during atrial fibrillation
Non-modifiable risk factors (top left box) and modifiable risk factors (bottom left box) for atrial fibrillation. The main outcomes of atrial fibrillation are in the right box. BMI=Body Mass Index.
A 12-lead ECG showing atrial fibrillation at approximately 132 beats per minute
Diagram of normal sinus rhythm as seen on ECG. In atrial fibrillation the P waves, which represent depolarization of the top of the heart, are absent.
ECG of atrial fibrillation (top) and normal sinus rhythm (bottom). The purple arrow indicates a P wave, which is lost in atrial fibrillation.
3D Medical Animation still shot of Left Atrial Appendage Occlusion

Beta blockers (preferably the "cardioselective" beta blockers such as metoprolol, bisoprolol, or nebivolol)

CT scan of the brain showing a prior right-sided ischemic stroke from blockage of an artery. Changes on a CT may not be visible early on.

Stroke

Medical condition in which poor blood flow to the brain causes cell death.

Medical condition in which poor blood flow to the brain causes cell death.

CT scan of the brain showing a prior right-sided ischemic stroke from blockage of an artery. Changes on a CT may not be visible early on.
There are two main categories of strokes. Ischemic (top), typically caused by a blood clot in an artery (1a) resulting in brain death to the affected area (2a). Hemorrhagic (bottom), caused by blood leaking into or around the brain from a ruptured blood vessel (1b) allowing blood to pool in the affected area (2b) thus increasing the pressure on the brain.
A slice of brain from the autopsy of a person who had an acute middle cerebral artery (MCA) stroke
CT scan of an intraparenchymal bleed (bottom arrow) with surrounding edema (top arrow)
Illustration of an embolic stroke, showing a blockage lodged in a blood vessel.
Histopathology at high magnification of a normal neuron, and an ischemic stroke at approximately 24 hours on H&E stain: The neurons become hypereosinophilic and there is an infiltrate of neutrophils. There is slight edema and loss of normal architecture in the surrounding neuropil.
A CT showing early signs of a middle cerebral artery stroke with loss of definition of the gyri and grey white boundary
Dens media sign in a patient with middle cerebral artery infarction shown on the left. Right image after 7 hours.
12-lead ECG of a patient with a stroke, showing large deeply inverted T-waves. Various ECG changes may occur in people with strokes and other brain disorders.
Walking with an orthosis after a stroke
Stroke deaths per million persons in 2012
Hippocrates first described the sudden paralysis that is often associated with stroke.

The routine use of beta-blockers following a stroke or TIA has not been shown to result in benefits.

Ventricular fibrillation (VF) showing disorganized electrical activity producing a spiked tracing on an electrocardiogram (ECG)

Arrhythmia

Too fast or too slow.

Too fast or too slow.

Ventricular fibrillation (VF) showing disorganized electrical activity producing a spiked tracing on an electrocardiogram (ECG)
Broad classification of arrhythmias according to region of heart required to sustain the rhythm
Normal sinus rhythm, with solid black arrows pointing to normal P waves representative of normal sinus node function, followed by a pause in sinus node activity (resulting in a transient loss of heartbeats). Note that the P wave that disrupts the pause (indicated by the dashed arrow) does not look like the previous (normal) P waves – this last P wave is arising from a different part of the atrium, representing an escape rhythm.

Medications for a fast heart rate may include beta blockers, or antiarrhythmic agents such as procainamide, which attempt to restore a normal heart rhythm.

Triiodothyronine (T3, pictured) and thyroxine (T4) are both forms of thyroid hormone.

Hyperthyroidism

Condition that occurs due to excessive production of thyroid hormones by the thyroid gland.

Condition that occurs due to excessive production of thyroid hormones by the thyroid gland.

Triiodothyronine (T3, pictured) and thyroxine (T4) are both forms of thyroid hormone.
Illustration depicting enlarged thyroid that may be associated with hyperthyroidism
Most common causes of hyperthyroidism by age.

Medications such as beta blockers may control the symptoms, and anti-thyroid medications such as methimazole may temporarily help people while other treatments are having an effect.

Heart

Muscular organ in most animals that pumps blood through the blood vessels of the circulatory system.

Muscular organ in most animals that pumps blood through the blood vessels of the circulatory system.

Human heart during an autopsy
Computer-generated animation of a beating human heart
The human heart is in the middle of the thorax, with its apex pointing to the left.
Heart being dissected showing right and left ventricles, from above
Frontal section showing papillary muscles attached to the tricuspid valve on the right and to the mitral valve on the left via chordae tendineae.
Layers of the heart wall, including visceral and parietal pericardium
The swirling pattern of myocardium helps the heart pump effectively
Arterial supply to the heart (red), with other areas labelled (blue).
Autonomic innervation of the heart
Development of the human heart during the first eight weeks (top) and the formation of the heart chambers (bottom). In this figure, the blue and red colors represent blood inflow and outflow (not venous and arterial blood). Initially, all venous blood flows from the tail/atria to the ventricles/head, a very different pattern from that of an adult.
Blood flow through the valves
The cardiac cycle as correlated to the ECG
The x-axis reflects time with a recording of the heart sounds. The y-axis represents pressure.
Transmission of a cardiac action potential through the heart's conduction system
Conduction system of the heart
The prepotential is due to a slow influx of sodium ions until the threshold is reached followed by a rapid depolarization and repolarization. The prepotential accounts for the membrane reaching threshold and initiates the spontaneous depolarization and contraction of the cell; there is no resting potential.
3D echocardiogram showing the mitral valve (right), tricuspid and mitral valves (top left) and aortic valve (top right).
The closure of the heart valves causes the heart sounds.
Cardiac cycle shown against ECG
Heart and its blood vessels, by Leonardo da Vinci, 15th century
Animated heart
Elize Ryd making a heart sign at a concert in 2018
The tube-like heart (green) of the mosquito Anopheles gambiae extends horizontally across the body, interlinked with the diamond-shaped wing muscles (also green) and surrounded by pericardial cells (red). Blue depicts cell nuclei.
Basic arthropod body structure – heart shown in red
The human heart viewed from the front
The human heart viewed from behind
The coronary circulation
The human heart viewed from the front and from behind
Frontal section of the human heart
An anatomical specimen of the heart
Heart illustration with circulatory system
Animated Heart 3d Model Rendered in Computer

Medications to improve angina symptoms include nitroglycerin, beta blockers, and calcium channel blockers, while preventative treatments include antiplatelets such as aspirin and statins, lifestyle measures such as stopping smoking and weight loss, and treatment of risk factors such as high blood pressure and diabetes.

Automated arm blood pressure meter showing arterial hypertension (shown by a systolic blood pressure 158 mmHg, diastolic blood pressure 99 mmHg and heart rate of 80 beats per minute)

Hypertension

Long-term medical condition in which the blood pressure in the arteries is persistently elevated.

Long-term medical condition in which the blood pressure in the arteries is persistently elevated.

Automated arm blood pressure meter showing arterial hypertension (shown by a systolic blood pressure 158 mmHg, diastolic blood pressure 99 mmHg and heart rate of 80 beats per minute)
Determinants of mean arterial pressure
Illustration depicting the effects of high blood pressure
Rates of hypertension in adult men in 2014.
Diagram illustrating the main complications of persistent high blood pressure
Image of veins from Harvey's Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus
Graph showing, prevalence of awareness, treatment and control of hypertension compared between the four studies of NHANES

Previously beta-blockers such as atenolol were thought to have similar beneficial effects when used as first-line therapy for hypertension.

Normal remnant adrenal gland (left) with a pheochromocytoma (right) involving the adrenal medulla

Pheochromocytoma

Closely related to, but not to be confused with Paraganglioma

Closely related to, but not to be confused with Paraganglioma

Normal remnant adrenal gland (left) with a pheochromocytoma (right) involving the adrenal medulla
Adrenal gland; the medulla (center, red) is the origin of the adrenal gland
There are two adrenal glands, highlighted in yellow, on top of each of the kidneys
Structure of epinephrine
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FDG PET – the tumor is appreciated as the dark structure in the patient's left chest. Darkened structures at head of patient is brain, in the abdomen are the kidneys, in the pelvis is the bladder. These are normal.
Histopathology on the resected tumor confirms the diagnosis, by typical features as shown.
Patient receiving radiation therapy to the region of the head and neck. Full facial mold is in-place to protect areas where they do not want exposure
Top: Purple lesions are metastatic disease detected with DOTATATE imaging. Bottom: Same patient. Purple lesions are metastatic disease detected with FDG PET
Likelihood of diagnosis when an adrenal-nodule is identified; pheochromocytoma is in yellow near the top-right corner
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The Zebra has become a powerful symbol in the pheochromocytoma advocacy community and represents the rare medical cases that are more likely to be misdiagnosed

2) Pharmaceutical Interference: Many prescription, over-the-counter, and illicit substances can interfere with the proper collection of plasma metanephrines and lead to false-positive results. Providers should review a patient's medication list in-detail and have a discussion if temporarily discontinuing any of the interfering medications is possible. The most reported medications to result in falsely elevated metanephrines include: β-adrenoceptor blockers, phenoxybenzamine, tricyclic antidepressants, monoamine oxidase inhibitors, serotonin norepinephrine reuptake inhibitors (SNRI), and methyldopa. As the majority of these medications are commonly prescribed for psychiatric conditions, a conversation with the prescriber may be necessary to facilitate alternative therapeutic options while the patient is undergoing evaluation for a pheochromocytoma. After any possible prescription medications have been held, it is important to review any over-the-counter medications/supplements as well as the commonly used acetaminophen and pseudoephedrine cause false elevations in metanephrine levels. Finally, it is important to have open, non-judgemental discussions about the patient's recreational substance use. Amphetamines, nicotine, and cocaine can result in marked plasma norepinephrine levels.