From the Guidelines
Class 2 anti-arrhythmics (beta blockers) are contraindicated in several conditions including severe bradycardia, high-degree heart block (second or third degree) without a pacemaker, cardiogenic shock, decompensated heart failure, and severe bronchospastic disease such as uncontrolled asthma or COPD. According to the 2015 ESC guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death 1, beta blockers should be avoided in patients with severe sinus bradycardia and sinus node disease (unless a pacemaker is present), AV conduction disturbances (unless a pacemaker is present), severe HF, Prinzmetal’s angina, inherited LQTS, and concomitant treatments associated with QT interval prolongation.
The contraindications exist because beta blockers work by blocking beta-adrenergic receptors, which slows heart rate and reduces cardiac contractility. In conditions like bradycardia or heart block, this further slowing of heart rate can be dangerous. Similarly, in cardiogenic shock or decompensated heart failure, the negative inotropic effects can worsen cardiac output. In bronchospastic diseases, non-selective beta blockers can block beta-2 receptors in the lungs, potentially triggering bronchospasm.
Some key points to consider when prescribing beta blockers include:
- Using beta blockers without intrinsic sympathomimetic activity, as recommended by the 2017 AHA/ACC clinical performance and quality measures for adults with ST-elevation and non-ST-elevation myocardial infarction 1
- Avoiding beta blockers in patients with Prinzmetal's angina, as they can worsen coronary vasospasm
- Using beta blockers with extreme caution in patients with diabetes mellitus, as they can mask hypoglycemic symptoms
- Selecting beta blockers that are proven to be effective in secondary prevention after MI, such as carvedilol, sustained-release metoprolol succinate, or bisoprolol, as recommended by the 2017 AHA/ACC clinical performance and quality measures for adults with ST-elevation and non-ST-elevation myocardial infarction 1.
From the FDA Drug Label
CONTRAINDICATIONS Propranolol is contraindicated in 1) cardiogenic shock; 2) sinus bradycardia and greater than first-degree block; 3) bronchial asthma; and 4) in patients with known hypersensitivity to propranolol hydrochloride. CONTRAINDICATIONS Hypersensitivity to metoprolol and related derivatives, or to any of the excipients; hypersensitivity to other beta-blockers (cross sensitivity between beta-blockers can occur). Myocardial Infarction Metoprolol is contraindicated in patients with a heart rate < 45 beats/min; second- and third-degree heart block; significant first-degree heart block (P-R interval ≥ 0.24 sec); systolic blood pressure < 100 mmHg; or moderate-to-severe cardiac failure PATIENTS WITH BRONCHOSPASTIC DISEASE SHOULD, IN GENERAL, NOT RECEIVE BETA-BLOCKERS.
Class 2 anti-arrhythmics (beta blockers) are contraindicated in:
- Cardiogenic shock
- Sinus bradycardia and greater than first-degree block
- Bronchial asthma
- Hypersensitivity to the medication
- Heart rate < 45 beats/min
- Second- and third-degree heart block
- Significant first-degree heart block (P-R interval ≥ 0.24 sec)
- Systolic blood pressure < 100 mmHg
- Moderate-to-severe cardiac failure 2, 3, 4
From the Research
Class 2 Anti-Arrhythmics Contraindications
- Class 2 anti-arrhythmics, also known as beta blockers, are generally not contraindicated in most cases, but rather are preferred for certain indications, such as heart failure or prior myocardial infarction 5, 6.
- However, the use of antiarrhythmic agents, including beta blockers, may be contraindicated in certain scenarios, such as ventricular arrhythmias, except for the use of beta blockers 5.
- In patients with structural heart disease, certain antiarrhythmic agents like amiodarone, dofetilide, or dl sotalol are preferred over beta blockers 5.
- The choice of beta blocker may depend on specific patient characteristics, such as the presence of heart failure or atrial fibrillation 6, 7.
- There is no clear evidence to suggest that Class 2 anti-arrhythmics are contraindicated in specific patient populations, but rather that the choice of agent should be individualized based on patient characteristics and clinical status 8, 9.