Syncope or fainting episode requires immediate medical attention as it is associated with neurological responses in the body. Syncope episdoes are related to the malfunction or altered function of important physiological activities in the body. Syncope is categorized into cardiovascular and non-cardiovascular types depending on the underlying case of ischemia. Presyncope is a precursor to the onset of syncope as the patient begins to experience lightheadedness or dizziness.
Clinical manifestations of presyncope
Presyncope or dizziness is often related to vertigo during clinical evaluation of the patient. Vomiting and nausea are two classical signs indicating the onset of a presyncope episode. In most cases people travelling to higher altitudes and regions of low oxygen concentration experience this. In some cases these symptoms occur because of extreme physical activity, improper nutrition, underlying cardiac condition and also diabetes. Syncope or presyncope is associated with apnea as there is decreased oxygen supply to the brain. Patients experience abdominal discomfort, blurred vision and also headaches during the presyncope episode. Presyncope episodes can be very dangerous during driving as it may lead to accidents. Disorientation is also an important symptom in identifying the onset of presyncope which subsequently leads to syncope.
Diagnosis of presyncope
The diagnosis of presyncope-related episodes is dependent on the identification of underlying cardiac and neurological conditions. Thorough analysis of the heart functionality, respiratory parameters and neurological functions are conducted. In many cases presyncope and episodes of syncope are closely associated with ischemic heart disease. Carotid artery palpation and examination of left ventricular flow are done. Presyncope episode is a warning sign of an impending physiological transition or complication. Cerebral blood flow obstruction caused due to pulmonary embolism is also a major factor for the onset of syncope.
Treatment of presyncope
Presyncope diagnosis is associated with existing medical conditions. Studies indicate that presyncope is also caused due to psychological disorders such as anxiety and panic. The patient is initially examined for underlying cardiac or neurological disorders before treating presyncope. The most common methods of treatment are through diet counseling such as fluid and salt intake. Patients prone to presyncope episodes are advised to avoid sauna, steam showers and also highly populated areas. Medications such as beta blockers, ephedrine, pseudoephedrine, theophylline, sertraline and fluoxetine are suggested for presyncope and cardio-neurogenic syncope conditions.
Calcium Channel Blockers
Calcium channel blockers are one of the key drugs administered in cardiovascular conditions. In most cases they are used in case of hypertension and angina.They are classified depending upon their mode of action and their chemical composition. These chemicals when induced in the body block the calcium channels in the cell membrane.
They are selected for vascular sites rather than the myocardial region. These drugs facilitate good vasodilator effects with limited electro physiological effect on the cardiac conduction system pertaining to the AV and SA nodes. Thus the negative inotropic effects do not occur in these drugs.These drugs are more selective to the cerebral arteries than the systemic arteries. Eg: Nifedepine, Amlodipine, nimodipine.
These drugs cause peripheral vasodilation with a moderate inotropic effect. Subsequently they increase the coronary vasodilation. Cardiac rate may or may not increase as it causes a slight depression in the SA or AV nodal conduction route. Eg: Verapamil.
These drugs are also associated with peripheral vasodilation causing mild inotropic effect and minimum depression in the SA / AV node conduction. They increase coronary vasodilation. They also exhibit intermediate vaso-selectivity. Eg: Diltiazem.
The elimination route for most of these drugs is through the liver. In most cases the recommended dosage is twice a day for sustained release in the body. The limitation of calcium channel blockers administration for hypertension is often related to their functionality such as vasodilation. However, because of their mechanism of action and efficacy, they do not cause conditions such as reflex tachycardia.
Calcium channel blockers are given to children who have low renin levels. The drug is given with other drugs such as beta-blockers and diuretics to attain desired results of cardiac physiology. In most cases, calcium blocker administration requires investigative tests such as blood vessel abnormalities, liver and kidney function tests.
Side effects and precautions
Calcium channel blockers are known to have some side effects since they are closely associated with vascular physiology and cardiac conduction system. Syncope and presyncope episodes followed by dizziness are commonly-noticed side effects. This happens because of the decrease in blood pressure due to reduced heart rate. Arrhythmia is another potential side effect along with gastro-esophageal reflux and nausea.
Lower extremity swelling or edema is a complication of treatment with calcium channel blockers (especially with Felodipine and Amlodipine), Thioglitazones and Minoxidil. Transient Incontinence is another symptom noticed with Calcium Channel Blocker drugs.
The most common side effects of calcium channel blockers are peripheral edema, Bradycardia, headache and constipation in some cases. The dihydropyridine agents such as Nifedipine, Nicardipine, Isradipine, Felodipine, Nisoldipine and Amlodipine, can produce symptoms of vasodilation - specifically headaches, palpitations, flushing and peripheral edema or swelling in lower extremities.
Some studies indicate that juices such as grapefruit should be avoided during the administration of calcium channel blockers as they hinder with the drug absorption and breakdown in the system. Alcohol consumption must also be avoided as it may cause damage because of hepatic involvement in the respective drug.
Calcium channel blockers are taken as second line cardiac drugs with respect to anti-hypertensive drugs and beta-blockers. However careful examination of the patient drug history is performed before recommending these drugs because some studies also imply that prolonged usage of all three drugs may increase the incidence of diabetes and the risks associated with it. Drug evaluation is essential because recent studies indicate the involvement of clarithromycin along with calcium channel blockers causing kidney damage and prolonged usage of these drugs can also cause breast cancer in women.
Bibliography / Reference
Collection of Pages - Last revised Date: March 23, 2019