Cardiac Glycosides – Some Points in Cardiac Glycosides for Dental Students are discussed in this article.
No specific dental modifications are necessary for well-compensated patients with heart failure, unless the underlying causes for the heart failure require modifications. In uncompensated heart failure, it is important to enquire about the patient’s ability to be placed in supine position because severe dyspnoea may develop while lying down in a dental chair.
Avoid use of gingival retraction cord impregnated with adrenaline in digitized patients to prevent development of cardiac arrhythmias. In such patients, use haemostatic retraction cords impregnated with astringents.
Congestive heart failure develops when cardiac output is insufficient to meet the demands of tissue perfusion. Severe anaemia, thyrotoxicosis, left-right or arteriovenous shunt causes high output failure which responds poorly to digitalis because scope of further increasing cardiac output is limited.
Increased impedence to ventricular outflow (due to hypertension, post- rheumatic valvular defects or congenital heart disease) or lowered myocardial work capacity (due to ischaemic heart disease, myocarditis, cardiomyopathies, or arrhythmias) may lead to low output failure which responds beneficially to digitalis.
Digoxin is the Cardiac Glycosides of choice due to its quick onset and short duration of action. A person is considered to be digitized when pulse rate becomes 60 per minute or there occurs nausea and vomiting. Afterwards the effect is maintained by a maintenance dose.
By prolonging the refractory period of the AV node, digitalis protects the ventricle from the continuous bombardment by irregular impulses originating from ectopic foci in atrium in the presence of atrial flutter and atrial fibrillation.
Other Cardiac Glycosides used in congestive heart failure are:
- Cardiac Glycosides (selective beta 1 agonists, pipyridines and glucagone)
- Those which cause reduction of preload (diuretics and nitrates)
- Those which cause reduction of after load (hydralazine beta 2 selective agonists) and
- Those which cause reduction of preload and after load (angiotensin converting enzyme inhibitors).
Glucagone is very useful Cardiac Glycosides used in treating congestive cardiac failure induced by or complicated by beta adrenergic blockage by activating adenylate cyclase.