Drugs that slow the conduction of the electrical signal through AV node, such as beta-blockers, digoxin, calcium channel blockers, and amiodarone, can cause heart block if they are taken in excessive amounts, or the levels in the blood get too high. Anatomy
The synchronized contraction of the heart occurs through a well-coordinated electrical signal pathway. The initial electrical signal originates from the SA node located in the upper portion of the right atrium. The electrical signal then travels through both the right and left atrium and causes the two atria to contract at the same time. This simultaneous contraction results in the P wave seen in an ECG tracing.The electrical signal then travels to the AV node located on the lower portion of the interatrial septum. At the AV node there is a delay in the electrical signal, which allows the atria to contract and blood to flow from the atria to the ventricles. This delay accounts for the ECG period between the P wave and the QRS complex, and creates the PR interval. From the AV nodes, the electrical signal travels through Bundle of His and divides into the right bundle and left bundle, which are located within the interventricular septum. Finally, the electrical signal travels into the Purkinje fibers. The division of the signal into a right and left bundle and then into the Purkinje fibers allows for a simultaneous depolarization and contraction of the right and left ventricles. The contraction of the ventricles results in the QRS complex seen on an ECG tracing.
The patient should minimize or preferably stop scratching LS-affected skin. Any scratching, stress or damage to the skin can worsen the disease. Scratching has been theorized to increase cancer risks. Furthermore, the patient should wear comfortable clothes and avoid tight clothing, as it is a major factor in the severity of symptoms in some cases.Topically applied corticosteroids to the LS-affected skin are the first-line treatment for lichen sclerosus in women and men, with strong evidence showing that they are "safe and effective" when appropriately applied, even over long courses of treatment, rarely causing serious adverse effects. They improve or suppress all symptoms for some time, which highly varies across patients, until it is required to use them again. Methylprednisolone aceponate has been used as a safe and effective corticosteroid for mild and moderate cases. For severe cases, it has been theorized that mometasone furoate might be safer and more effective than clobetasol. Recent studies have shown that topical calcineurin inhibitors such as tacrolimus can have an effect similar to corticosteroids, but its effects on cancer risks in LS are not conclusively known. Based on limited evidence, a 2011 Cochrane review concluded that clobetasol propionate, mometasone furoate, and pimecrolimus (calcineurin inhibitor) all are effective therapies in treating genital lichen sclerosus.