Cardioversion

detail discussion about cardioversion

1. Cardioversion Dr Kifayat khan Resident Cardiac Surgeon

2. cardioversion Learning Objectives Difference between cardioversion and defebrilation Types of cardioversion Electrical Elective Emergency Chemical or pharmacological

3. Cardioversion : A procedure by which an abnormal heart rate (arrhythmia) is converted to a normal rhythm using electricity or drugs. therapeutic dose of electric current is used at a specific moment in the cardiac cycle ( R wave ) it can be performed safely in pregnant women with fetal heart rate monitoring. uses a therapeutic dose of electric current to the heart at a random moment in the cardiac cycle. is the most effective resuscitation measure for cardiac arrest associated with ventricular fibrillation and pulseless ventricular tachycardia. Defibrilators may be External 2.internal. 3. ICD( implantable cardioversion defeb ) 4:AED

4. Cardioversion vs defebrilation Sync on R wave For peri arest tachyarhtmias Usually elective Low energy Escalate for next shock ( 100,200,300,360) Done for A Feb A flutters V tach with pulse Not sync For arrest Always emergency High energy No escalate for next shock Done for Vent feb V tach + pluseless

5. Types of cardioversion Electric cardioversion It is a procedure in which a synchronized electrical shock is delivered through the chest wall to the heart through special electrodes or paddles that are applied to the skin of the chest and back . Basic principles is During defibrillation and cardioversion , electrical current travels from the negative to the positive electrode by traversing myocardium. It causes all of the heart cells to contract simultaneously. This interrupts and terminates abnormal electrical rhythm. This, in turn, allows the sinus node to resume normal pacemaker activity. Elective: For elective cardioversion , patient should be anti coagulated 3-4 weeks before and after cardioversion Exclude Thromboembolism through TEE Emergency: It is used in emergency situations to correct a rapid abnormal rhythm associated with faintness, low blood pressure, chest pain, difficulty breathing, or loss of consciousness.

6. Indications & Contraindications Indications: V. tachycardia with pulse ( ventricular rate >150) who is unstable (chest pain, pulmonary edema, lightheadedness, hypotension) Atrial fibrillation Atrial flutter Atrial tachycardia Contraindications • Presence of left atrial thrombus. Digitalis toxicity or hypokalemia. Sinus tachycardia caused by various clinical conditions and catecholamine-induced arrhythmia.

7. Recommendations for Direct-current Cardioversion of Atrial Fibrillation Class I: When a rapid ventricular response does not respond promptly to pharmacological measures for patients with AF with ongoing myocardial ischemia, symptomatic hypotension, angina or hear faliure , immediate R-wave synchronized direct-current cardioversion is recommended. (Level of Evidence: C) AF involving preexcitation when very rapid tachycardia or hemodynamic instability occurs. (Level of Evidence: B ). Cardioversion is recommended in patients without hemodynamic instability when symptoms of AF are unacceptable to the patient. In case of early relapse of AF after cardioversion , repeated cardioversion attempts may be made following administration of antiarrhythmic medication. (Level of Evidence: C) Class IIa : Direct -current cardioversion can be useful to restore sinus rhythm as part of a long-term management strategy for patients with AF. (Level of Evidence: B ). Patient preference is a reasonable consideration in the selection of infrequently repeated cardioversions for the management of symptomatic or recurrent AF. (Level of Evidence: C )

8. Equipment: Defibrillator with a synchronising button . Emergency trolley with emergency drugs; ( lignocaine, atropine, and adrenaline ) . Oxygen mask, intubation equipment, airway . Monitor and continuous recording facilities (BP,ECG, SpO2) . Intravenous access • Suction device

9. Antero-posterior placement of paddles(1,1) single paddle is placed on the left fourth or fifth intercostal space on the midaxillary line the other paddle is placed just to the right of the sternal edge on the second or third intercostal space . Antero-lateral placement of paddles Positioning of Paddles (2,2 ) A single paddle is placed to the right of the sternum, as above. T he other paddle is placed between the tip of the left scapula and the spine. Conductive gel are commonly used to ensure good contact,

10. Preparing for a Cardioversion Do not eat or drink for at least eight hours prior to the procedure . Blood thining medicines may be given with electrical cardioversion to prevent clots Take your regularly scheduled medications the morning of the procedure unless your medical practitioner has told you. Stop digoxin 48 hours prior to the procedure Do not apply any lotions or ointments to chest or back as this may interfere with the adhesiveness of the shocking pads .

11. Procedure Steps Place paddles so that they do not touch pts clothing or bed linens Ensure monitor is attached. Do not charge the machine untill ready to shock. Exert 25 pound pressure on the paddle . Ensure you and every body is free of the pat . Inspect skin for burns . Record the delivered energy. Sedate patient with a short-acting agent such as midazolam or propofol and an opioid analgesic, such as fentanyl. Reversal agents, such as flumazenil and naloxone, should be available.

12. Complications uncommon but may include: Harmless arrhythmias, such as atrial, ventricular, and junctional premature beats. Serious complications include ventricular fibrillation (VF) severe bradycardia or asystole Thromboembolization Bruising , burning or pain where the paddles were used. Myocardial necrosis can result from high-energy shocks. ST segment elevation can be seen immediately and usually lasts for 1-2 minutes. ST segment elevation that lasts longer than 2 minutes usually indicates myocardial injury unrelated to the shock. Pulmonary edema is a rare complication of cardioversion. It is probably due to transient left atrial standstill and left ventricular systolic dysfunction .

13. Pharmacologic cardioversion Various antiarrhythmic agents can be used to return the heart to normal sinus rhythm specially in patients with fibrillation of recent onset. Drugs like amiodarone , diltiazem , verapamil and metoprolol are frequently given before cardioversion to decrease the heart rate, stabilize the patient and increase the chance that cardioversion is successful .

14. Class I They are sodium channel blockers (which slow conduction by blocking the Na+ channel ) Class Ia : Procainamide , quinidine and disopyramide Class 1b: drugs include lidocaine , mexiletine and phenytoin. Class Ic : Flecainide , moricizine and propafenone

15. Class II They are beta blockers which inhibit SA and AV node depolarization and slow heart rate. They also decrease cardiac oxygen demand and can prevent cardiac remodeling. some are cardio selective (affecting only beta 1 receptors, metoprolol,nebivolol ) while others are non-selective (affecting beta 1 and 2 receptors) .

16. Class III, Class IV agents (prolong repolarization by blocking outward K+ current ) . amiodarone and sotalol Class iv drugs are calcium ( Ca ) channel blockers. They work by inhibiting the action potential of the SA and AV nodes . Deltiazem