AF Association Australia Tel: 1800 050 267 or (02) 61084602 info@atrialfi brillation-au.org www.atrialfi brillation-au.org AF A www.atrialfibrillation-au.org Rate Limiting Calcium Channel Blockers

Introduction Rate Reduction: Some patients with Atrial Fibrillation fi nd that their heart races which can The calcium channel blockers are a type of cause unpleasant symptoms and reduce their medication which aff ect many cells within activity levels. Rate Limiting Calcium Channel Rate Limiting Calcium Channel Blockers - Patient Information the body. It is split into two families, the Blockers can be use alone or in combination Dihydropyridine which mainly have a role in with other medication such as beta-blockers the management of angina and high blood or digoxin. pressure and the rate limiting calcium channel blockers which share these properties but also Hypertension: The Rate Limiting Calcium have a use in changing the rate and rhythm of Channel Blockers are eff ective blood pressure the heart. The second group can be used either reducing medications. However their related alone or in conjunction with other medications medication, the Dihydropyradines, are more to help in the management of Atrial Fibrillation. commonly used in this setting. The two examples are Verapamil and Diltiazem. How do they work Side Effects and Problems

These medications aff ect the way that calcium Heart Failure: Due to their eff ect on the strength salts are moved into the muscular cells of the on heart muscle contraction the rate limiting body. In the arteries this leads to a widening calcium channel blockers should not be used in of the artery and this causes a drop in blood patients who have problems with the strength pressure. In the heart this leads to a less of their heart beat. These patients are classed contractual force of the muscle cells and as having heart failure also referred to as left reduces the overall force of the heart beat. This ventricular impairment. change to the fl ow of calcium also aff ects the conduction of the heart beat from the upper Lightheadedness: Due to their ability to drop the chambers of the heart to the lower chambers. blood pressure, in some people this may give In this way it has an eff ect of slowing the heart a sensation of lightheadedness or dizziness. beat. This is unlike beta-blocking medications Ankle Swelling: Due to their eff ect in widening that slow the heart beat by also having an the arteries and veins these medications can eff ect on the adrenalin receptors in the heart. occasionally cause ankle swelling. This will return to normal when the medication Clinical Use is discontinued.

Anti-arrhythmic: Rate limiting calcium channel Use with Beta-blockers: Diltiazem or Verapamil blockers can be used to try to maintain the should only be used in combination with a heart in its normal rhythm. Verapamil is the beta-blocker under specialist guidance. most frequently used drug for this purpose and Acknowledgements: Dr Matthew Fay, GP is often used in people who can not tolerate Endorsed by: Professor G Y H Lip, Cardiologist beta-blocker medication. Mrs Jayne Mudd, Arrhythmia Nurse Specialist

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AF-A Australia Medical Advisory Committee: Dr Michael Davis Professor Ben Freedman Dr Gerry Kaye Founder & CEO: Mrs Trudie Lobban MBE Deputy CEO: Mrs Jo Jerrome © AF Association Published January 2009, Reviewed August 2012, Planned Review Date August 2014 This factsheet has been adapted for AF Association Australia with kind permission from the AF Association www.afa.org.uk

Please remember that this publication provides general guidelines only. Individuals should always discuss their condition with a healthcare professional. If you would like further information or would like to provide feedback please contact AF-A.