Cardiac Arrhythmias: An Update Dr N.M.Gandhi Consultant Cardiologist Spire Gatwick Park Hospital, Horley East Surrey Hospital, Redhill Royal Sussex County Hospital, Brighton

Objectives Identify common arrhythmias encountered by the family physician Discuss initial Mg options AF and Ventricular arrhythmias case studies Which patients needs to be referred? ECG examples

THE CONDUCTION SYSTEM We use the term Conduction System to describe the electrical pathway of an electrical impulse that causes a heart beat.

Atrial Depolarization After the SA node fires, the resulting depolarization wave passes through the right and left atria, which produces the P-wave on the surface EKG and stimulates atrial contraction.

Ventricular Depolarization The impulse passes quickly through the bundle of His, the left and right bundle branches, and the Purkinje fibers, leading to depolarization and contraction of the ventricles. The QRS complex on the EKG represents the depolarization of the ventricular muscle mass.

CARDIAC ARRHYTHMIAS Disturbances of either : Impulse generation Impulse propagation

ELECTROPHYSIOLOGIC PRINCIPLES BRADYARRHYTHMIAS SINUS NODE DYSFUNCTION AV CONDUCTION DISTURBANCES TACHYARRHYTMIAS ATRIAL TACHYCARDIAS VENTRICULAR TACHYCARDIA A R H Y T M I S

Bradyarrhythmias Impulse formation: Impulse conduction: Decreased automaticity: Sinus bradycardia Impulse conduction: Conduction blocks: 1º, 2º, 3º AV blocks

Tachyarrythmias Impulse formation Impulse conduction Enhanced automaticity: Sinus node: sinus tachycardia Ectopic focus: Ectopic atrial tachycardia Triggered activity Early afterdepolarization: torsades de pointes Digitalis-induced SVT Impulse conduction Reentry: Paroxysmal SVT, atrial flutter and fibrilation, ventricular tachycardia and fibrillation.

Normal Sinus Rhythm www.uptodate.com Implies normal sequence of conduction, originating in the sinus node and proceeding to the ventricles via the AV node and His-Purkinje system. EKG Characteristics: Regular narrow-complex rhythm Rate 60-100 bpm Each QRS complex is proceeded by a P wave P wave is upright in lead II & downgoing in lead aVR

PAC Benign, common cause of perceived irregular rhythm Can cause sxs: “skipping” beats, palpitations No treatment, reassurance With sxs, may advise to stop smoking, decrease caffeine and ETOH Can use beta-blockers to reduce frequency

PVC Extremely common throughout the population, both with and without heart disease Usually asymptomatic, except rarely dizziness or fatigue in patients that have frequent PVCs and significant LV dysfunction

PVC Reassurance Optimize cardiac and pulmonary disease management Beta-blocker Ablation in a small number of cases

Bradyarrhythmias Impulse formation: Impulse conduction: Decreased automaticity: Sinus bradycardia Impulse conduction: Conduction blocks: 1º, 2º, 3º AV blocks

Sinus Bradycardia HR< 60 bpm; every QRS narrow, preceded by p wave Can be normal in well-conditioned athletes HR can be 30 bpm in adults during sleep, with up to 2 sec pauses

Sinus arrhythmia Usually respiratory--Increase in heart rate during inspiration Exaggerated in children, young adults and athletes—decreases with age Usually asymptomatic, no treatment or referral Can be non-respiratory, often in normal or diseased heart, seen in digitalis toxicity Referral may be necessary if not clearly respiratory, history of heart disease

Sick Sinus Syndrome All result in bradycardia Sinus bradycardia with a sinus pause Often result of tachy-brady syndrome: where a burst of atrial tachycardia (such as afib) is then followed by a long, symptomatic sinus pause/arrest, with no breakthrough junctional rhythm.

1st Degree AV Block PR interval >200ms If accompanied by wide QRS, refer to cardiology, high risk of progression to 2nd and 3rd deg block Otherwise, benign if asymptomatic

2nd Degree AV Block Mobitz type I (Wenckebach) Progressive PR longation, with eventual non-conduction of a p wave May be in 2:1 or 3:1

2nd degree block Type II (Mobitz 2) Normal PR intervals with sudden failure of a p wave to conduct Usually below AV node and accompanied by BBB or fascicular block Often causes pre/syncope; exercise worsens sxs Generally need pacing, possibly urgently if symptomatic

3rd Degree AV Block Complete AV disassociation, HR is a ventricular rate Will often cause dizziness, syncope, angina, heart failure Can degenerate to Vtach and Vfib Will need pacing, urgent referral

Tachyarrythmias Impulse formation Impulse conduction Enhanced automaticity: Sinus node: sinus tachycardia Ectopic focus: Ectopic atrial tachycardia Triggered activity Early afterdepolarization: torsades de pointes Digitalis-induced SVT Impulse conduction Reentry: Paroxysmal SVT, atrial flutter and fibrilation, ventricular tachycardia and fibrillation.

SUPRAVENTRICULAR T. Sinus Tachycardia Atrial flutter Atrial fibrilation Paroxysmal Supraventricular Multifocal Atrial T. Preexcitation Syndrome (Wolff-Parkinson-white Sy.)

Sinus tachycardia HR > 100 bpm, regular Often difficult to distinguish p and t waves

Paroxysmal Supraventricular T. Sudden onset and termination Atrial rates of 140 to 250 /min Normal QRS complexes The mechanism is most often reentry.

Paroxysmal Supraventricular Tachycardia Refers to supraventricular tachycardia other than afib, aflutter and MAT Usually due to reentry—AVNRT or AVRT

PSVT CSM or adenosine commonly terminate the arrhythmia, esp, AVRT or AVNRT Can also use CCB or beta blockers to terminate, if available Counsel to avoid triggers, caffeine, Etoh, pseudoephedrine, stress

Multifocal Atrial T. Is due to enchanced automaticity within the atria, resulting in abnormal discharges from several ectopic foci Most often occurs in the setting of severe pulmonary disease and hypoxemia. EKG: irregular rhythm with multiple (at leats 3) P waves morphologies

Atrial flutter Is caracterized by rapid coarse “sawtooth” appearing atrial activity, at rate of 250 to 350 x min. Many of these fast impulses reach the AV node during its refractory period, so that the ventricular rate is generally lower. Frequently it degenerates into atrial fibrilation The most expiditious therapy is electrical cardioversion, which is undertaken directly for highly symptomatic patients. (to revert chronic refractory atrial flutter that has not responded to other approaches)

Preexcitation Syndrome Wolff-Parkinson-White Syndrome EKG: Although different types of bypass tracts have been identified, the bundle of Kent, is the most common and can usually conduct in both the anterograde and retrograde directions.

Atrial Fibrillation Irregular rhythm Absence of definite p waves Narrow QRS Can be accompanied by rapid ventricular response

Atrial fibrillation--management Rhythm vs Rate control—if onset is within last 24-48 hours, may be able to arrange cardioversion—use heparin around procedure Need TEE if valvular disease (high risk of thrombus) If unable to definitely conclude onset in last 24-48 hours: need 4-6 weeks of anticoagulation prior to cardioversion, and warfarin for 4-12 weeks after

Atrial Fibrillation: Clinical Problems Embolism and stroke (presumably due to LA clot) Acute hospitalization with onset of symptoms Anticoagulation, especially in older patients (> 75 yr.) Congestive heart failure Loss of AV synchrony Loss of atrial “kick” Rate-related cardiomyopathy due to rapid ventricular response Rate-related atrial myopathy and dilatation Chronic symptoms and reduced sense of well-being

AF: Medical Management Treatment of underlying cause Ventricular rate control Anticoagulation Antiarrhythmics with a view to restore sinus rhythm

Control of Ventricular Rate in Atrial Fibrillation Betablockers Calcium channel blockers Verapamil, diltiazem Digoxin Amiodarone

Anticoagulation

Anticoagulation Assessment of bleeding risk should be part of the clinical assessment of AF patients prior to starting anticoagulation Antithrombotic benefits and potential bleeding risks of long-term coagulation should be explained and discussed with the patient Aim for a target INR of between 2.0 and 3.0 NICE 2006 NOTES FOR PRESENTERS Refer to NICE guideline – pages 22 and 23 In order to provide adequate thromboprophylaxis with minimal risk of bleeding, current clinical practice aims for a target INR of between 2.0 and 3.0; INRs higher than 3.0 are associated with increases in bleeding, and INRs lower than 2.0 are associated with increases in stroke risk.

CHADS 2 scoring CCF Hypertension Age > 75 Diabetes Stroke/TIA 1 point 1point 2 points Any patients with AF with a score of =/>2 would benefit from being on Warfarin

Cardioversion

Cardioversion Cardioversion results in SR in at least 90% of cases SR is only maintained in 30-50% at one year Class 1a, 1c and III agents increase likelihood of maintained SR from 30-50% to 50-70% at one year

Follow-up Reassess the need for anticoagulation at each review Follow-up after cardioversion should take place at 1 month, and the frequency of subsequent reviews should be tailored to the patient Reassess the need for anticoagulation at each review NOTES FOR PRESENTERS For further details, refer to the NICE guideline – page 25. The commonest reason for referral for specialist investigation or intervention is failed medical therapy

Catheter Ablation for AF

AF Ablation Success rates – approx 70% but may require repeat procedure Often increase in symptoms for first 3-6 months after procedure does not indicate failure Risks – damage to existing conduction mandating pacing Cardiac perforation/tamponade Bleeding Stroke/thromboembolism Death

Catheter Ablation: Indications Symptomatic patients Refractory to Antiarrhythmics Medical therapy contraindicated due to co-morbidities or intolerance NICE 2006

Which AF patients need Specialist Referral? Patients with: - WPW syndrome - Uncontrolled ventricular rate (> 200/min) - Tachy-brady syndrome - For rhythm control strategy - CCF - Intolerant to Drugs - Invasive options

VENTRICULAR ARRHYTHMIAS Ventricular tachycardia Torsades De Pointes Ventricular fibrillation

Ventricular tachycardia Is divided in 2 categories: If it persist for more than 30 seconds “sustained VT” Less than 30 seconds: “nonsustained VT” Symptoms vary depending on the duration. Major manifestations are hypotension and loss of consciousness.

Non-sustained ventricular tachycardia Need to exclude heart disease with Echo and stress testing May need anti-arrhythmia treatment if sxs In presence of heart disease, increased risk of sudden death Need referral for EPS and/or prolonged Holter monitoring ICD may be life saving

Torsades De Pointes Varying amplitudes of the QRS. It can be produced by afterdepolarizations (triggered activity). Particularly in prolonged QT interval. Occur with some drugs (quinidine), electrolite disturbances, and congenital prolongation of the QT interval.

Specialist Referral ECG Examples

Contact... * E-mail: nandkumar.gandhi@sash.nhs.uk drnmgandhi@hotmail.com * Fax: 01737 231938 * Phone: Spire - 01293 785511 ESH - 01737 768511, ext.6333