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Positive inotropic medications
Class II antiarrhythmics: Beta blockers
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Antiarrhythmic medications help control arrhythmias or abnormal heartbeats.
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. Now, we’ll focus on class II antiarrhythmics in this video.
Pacemaker cells build the electrical conduction system of the heart, which consists of the sinoatrial node, or SA node; the atrioventricular node, or AV node; the bundle of His; and the Purkinje fibers.
The current through these channels is called pacemaker current or funny current (If), and it mainly consists of sodium ions.
These sodium ions cause the membrane potential to begin to spontaneously depolarize and as the membrane potential depolarizes, voltage-dependent T-type calcium channels open up, thereby further depolarizing the pacemaker cell.
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