Table of Contents
What is a Class 1 antiarrhythmics?
Class I antiarrhythmics are fast sodium channel blockers. They are responsible for phase 0 of fast-response cardiac action potentials. The three subclasses differ in their efficacy for reducing the slope of phase 0, with Ic drugs having the greatest and Ib drugs having the smallest effect on phase 0.
What do you know about Class II antiarrhythmic drugs?
miscellaneous antiarrhythmics or unclassified antiarrhythmics. Class II antidysrhythmic drugs inhibit beta-adrenergic activation of adenylate cyclase and reduce sinoatrial node and atrioventricular node activity. They prolong atrioventricular node repolarization and increase the P-R interval.
What is a Class 1b drug?
Class IB antidysrhythmics are anesthetic drugs that show cardiac activity. They block inactivated sodium channels more than that of the open state and do not delay channel recovery time. This causes slow conduction of electrical impulse through cardiac tissue.
Are all beta-blockers Class 2 antiarrhythmics?
There are four main groups of antiarrhythmic medications: class I, sodium-channel blockers; class II, beta-blockers; class III, potassium-channel blockers; class IV, calcium-channel blockers; and miscellaneous antiarrhythmics, or unclassified antiarrhythmics.
How does class 1b shorten action potential?
Class Ib agents shorten the duration of the action potential, mainly by preventing late sustained sodium current. Class Ic agents have little effect on the duration of the action potential.
What does a sodium Blocker do?
A class of drugs that act by inhibition of sodium influx through cell membranes. Blockade of sodium channels slows the rate and amplitude of initial rapid depolarization, reduces cell excitability, and reduces conduction velocity. An anti-anginal drug used for the treatment of chronic angina.
How do you feel when you have arrhythmia?
An arrhythmia is an irregular heartbeat. It means your heart is out of its usual rhythm. It may feel like your heart skipped a beat, added a beat, or is “fluttering.” It might feel like it’s beating too fast (which doctors call tachycardia) or too slow (called bradycardia). Or you might not notice anything.
Is propranolol a Class 2?
Now, beta blockers that mainly target pacemaker cells are actually classified as class II antiarrhythmics and just like all beta blockers, they can be subdivided into selective beta-1 blockers, like atenolol, acebutolol, betaxolol, bisoprolol, esmolol, and metoprolol; or non-selective beta blockers, like timolol and …
Why is digoxin not used anymore?
The use of digoxin is limited because the drug has a narrow therapeutic index and requires close monitoring. Digoxin can cause many adverse events, is involved in multiple drug interactions, and can result in toxicity. Despite its limitations, however, digoxin has a place in therapy.
Can digoxin stop your heart?
The toxic effects of digoxin can lead to: Life-threatening cardiac arrhythmias in which the heart beats too quickly. Severe bradycardia in which the heart beats too slowly.
What are the side effects of sodium channel blockers?
The anticholinergic effects of IA drugs can produce tachycardia, dry mouth, urinary retention, blurred vision and constipation. Diarrhea, nausea, headache and dizziness are also common side effects of many Class I drugs.