Atrioventricular junction
An AV-junctional rhythm, or atrioventricular nodal bradycardia, is usually caused by the absence of the electrical impulse from the sinus node. This usually appears on an electrocardiogram (ECG) with a normal QRS complex accompanied with an inverted P wave either before, during, or after the QRS complex.An AV-junctional escape beat is a delayed heartbeat originating from an ectopic focus somewhere in the AV junction. It occurs when the rate of depolarization of the SA node falls below the rate of the AV node. This dysrhythmia also may occur when the electrical impulses from the SA node fail to reach the AV node because of SA or AV block. This is a protective mechanism for the heart, to compensate for an SA node that is no longer handling the pacemaking activity and is one of a series of backup sites that can take over pacemaker function when the SA node fails to do so. This would present with a longer PR interval. An AV-junctional escape complex is a normal response that may result from excessive vagal tone on the SA node. Pathological causes include sinus bradycardia, sinus arrest, sinus exit block, or AV block. Ventricular
Idioventricular rhythm, also known as atrioventricular bradycardia or ventricular escape rhythm, is a heart rate of less than 50 BPM. This is a safety mechanism when a lack of electrical impulse or stimuli from the atrium occurs.
Nonetheless, skin-whitening creams containing this ingredient can sometimes be found in beauty supply stores in New York City and on the internet. It is also sold internationally, and does not require a prescription in some countries. Whitening creams with clobetasol propionate, such as Hyprogel, can make skin thin and easily bruised, with visible capillaries, and acne. It can also lead to hypertension, elevated blood sugar, suppression of the bodys natural steroids, and stretch marks, which may be permanent.Clobetasol propionate is, along with mercury and hydroquinone, "amongst the most toxic and most used agents in lightening products." Many products sold illegally have higher concentrations of clobetasol propionate than is permitted for prescription drugs. Contraindications
According to the California Environmental Protection Agency, clobetasol propionate should not be used by pregnant women, or women expecting to become pregnant soon, as studies with rats shows a risk of birth defects:
"Studies in the rat following oral administration at dosage levels up to 50 mcg/kg per day revealed that the females exhibited an increase in the number of resorbed embryos and a decrease in the number of living fetuses at the highest dose. Pregnancy: Teratogenic Effects (i.e., possibility of causing abnormalities in fetuses): Pregnancy Category C: Clobetasol propionate has not been tested for teratogenicity when applied topically; however, it is absorbed percutaneously, and when administered subcutaneously it was a significant teratogen in both the rabbit and mouse. Clobetasol propionate has greater teratogenic potential than steroids that are less potent.