Acute Coronary Syndrome Arrhythmias

Related Subjects: |Atherosclerosis |Ischaemic heart disease |Assessing Chest Pain |ACS - General |ACS - STEMI |ACS - NSTEMI |ACS - GRACE Score |ACS - ECG Changes |ACS -Cardiac Troponins |ACS - Post MI arrhythmias |ACS: Right Ventricular Infarction

Those with inferior infarcts usually do not need paced unless haemodynamically compromised. In these the conduciton issues resolve within 2 weeks and permanent pacing is rarely required. In those with MB2/CHB in Anterior STEMI conduction system damage is usually permanent and needs paced.

Indications for temporary Pacing Post MI

• Mobitz II heart block with anterior MI.
• Complete heart block (CHB) with inferior MI if hypotensive or cardiac failure
• Complete heart block with anterior MI.
• New Bifascicular block (RBBB with left or right axis deviation): usually Anterior MI and at risk of CHB.
• Trifascicular block (long PR interval and either LBBB or RBBB with axis deviation): usually anterior MI and at risk of CHB.
• Alternating LBBB and RBBB: suggests extensive myocardial injury and high risk of CHB.
• Avoid subclavian route after thrombolysis. Consider internal jugular or the femoral route because there is less risk of haemorrhagic complications

Managing Early ventricular arrhythmias

• Evidence seems to be to avoid treating unless forced to. Evidence that antiarrhythmics may be harmful post MI.
• Ventricular Ectopics and non-sustained VT are very common especially post reperfusion. They usually require no treatment. Correct K+, Mg2+ and Ca2+, and correct if needed.
• Sustained VT or after VF, standard practice is IV bolus Lignocaine 100 mg over 5 min, then infusion of 2–4 mg/min) for 24 h after cardioversion. Amiodarone is also used.
• Early use of IV beta-blockers, e.g. metoprolol, often reduces the incidence of ventricular arrhythmias.

Managing Early ventricular arrhythmias

• AF/SVT: seen with pericarditis or heart failure. Tends to settle with digoxin. Cardioversion if persists. Treat pericarditis/infection or cardiac failure actively.
• VT: as a late event carries a bad prognosis. Acutely consider IV amiodarone: if there is recurrent VT that has not settled with beta-blockers. Get Echo to check LV function. Consider criteria for AICD
• Beta-blockers: indicated in all those who can take them.
• Consider early inpatient angiography, appropriate EP investigations and management as necessary (AICD).
• Avoid other anti-arrhythmics, especially those that are negatively inotropic, e.g. flecainide.