Ann Parker Cardiology Pharmacist Frimley Health Cardiac Medication Ann Parker Cardiology Pharmacist Frimley Health

Aims Overview of: Anti-arrhythmic medication Anticoagulation in AF Medication in heart failure And an opportunity for you to ask questions

Electrical conduction system of the heart Inherent rate – rate at which cells spontaneously initiate impulses. Atria 60-100 beats/min. AV node 40-60 beats. Vetricles 20-40 beats. Depolarisation ( the movement of charged ions across a cell membrane ) results in myocardial contraction. At resting state K+ in the cell and Na+ and Ca+ outside When an electrical impulse spreads through the muscle from the SA node the Na+ pump channels open and the K+ closes, electrolytes change place across the cell membrane

Arrhythmia When the electrical impulses that coordinate heartbeats are not working properly, making the heart beat too fast/slow or inconsistently. Many heart arrhythmias are harmless. Some may cause troublesome and even potentially fatal symptoms. We all occasionally experience irregular heartbeats, which may feel like a racing heart or fluttering.

Digoxin Works by inhibiting the sodium- potassium pump Helps to control heart rate, particularly in the irregular atrial fibrillation Increases cardiac contractility Medical use first described in 1785

Vaughan -Williams Classification Class I - sodium channel blockers eg Disopyramide, Flecainide, Mexilitine Class II- Betablockers Class III- potassium channel blockers eg Amiodarone Class IV- calcium channel blockers eg Verapamil, Diltiazem

Sodium channel blockers eg mexilitene, flecainide slows conduction in the heart makes the heart tissue less sensitive (reduce ventricular response) Side effects -dizziness, heartburn, nausea, nervousness, trembling, unsteadiness usually reversible and dose-related.

Betablockers Reduce the effect of adrenaline on the heart (sympathetic nervous system blockade) Slow the heart by depressing sinus node function and AV node conduction Can help maintain sinus rhythm Protective of the heart as reduce oxygen demand depression of sinus node (natural pacemaker) function and atrioventricular node (electrical relay station between the upper and lower chambers of the heart conduction

Potassium channel blockers eg amiodarone increases the refractory period via sodium and potassium channel effects has beta blocker like and calcium channel blocker like actions on the SA and AV node slows intra-cardiac conduction These electrophysiologic effects are reflected in a decreased sinus rate of 15 to 20%, increased PR and QT intervals of about 10%, the development of U-waves, and changes in T-wave contour. These changes should not require discontinuation of Amiodarone as they are evidence of its pharmacological action, although Amiodarone can cause marked sinus bradycardia or sinus arrest and heart block. On rare occasions, QT prolongation has been associated with worsening of arrhythmia

Act in the AV node to prolong conduction time and refractory period

Anticoagulation in AF, why? Risk of stroke assesses usings CHADsVASc score

Congestive heart failure CHADS2VASc Risk Factor Score Congestive heart failure 1 Hypertension Age >75years 2 Diabetes Stroke Vascular disease Age 65-74 years Sex category (female)

HASBLED Hypertension Abnormal renal and liver function Stroke Bleeding Labile INRs Elderly Drugs or alcohol

Anticoagulation Warfarin NOACs (or DOACs) eg. apixaban, dabigatran, rivaroxaban

Warfarin affects the body’s ability to synthesise vitamin K which is used in production of factors 2, 7, 9 and 10.

Heart failure treatment Type – LVSD of HFPEF Angiotensin converting enzyme inhibitors (ACEI) Betablockers Aldosterone antagonists Angiotensin receptor neprilysin inhibitor (ARNI) Natriuretic peptides (NPs) are a family of hormones that help maintain sodium and fluid balance. Natriuretic peptides (NPs) are a family of hormones that help maintain sodium and fluid balance.

References https://www.pinterest.com/pin/404338872771327665/ https://www.studyblue.com/notes/note/n/antiarrhythmic-drugs/deck/775590 https://uk.pinterest.com/pin/329536897715737090/ http://en.wikipedia.org/wiki/File:ConductionsystemoftheheartwithouttheHeart.png http://pmj.bmj.com/content/90/1067/520.abstract http://www.medicines.org.uk/emc/medicine/25742 https://www.pinterest.com/pin/404338872771546154/