From the Guidelines
Beta blockers are generally contraindicated in patients with heart block, especially in those with second-degree or third-degree (complete) heart block. These medications work by blocking beta-adrenergic receptors, which slows heart rate and reduces the conduction of electrical impulses through the heart. In patients who already have impaired electrical conduction (heart block), beta blockers can worsen the condition by further slowing conduction, potentially leading to severe bradycardia, complete heart block, or even cardiac arrest. According to the ACC/AHA guidelines 1, patients with marked first-degree AV block (i.e., ECG PR interval greater than 0.24 s), any form of second- or third-degree AV block in the absence of a functioning implanted pacemaker, should not receive beta blockers on an acute basis.
Some key points to consider when deciding on beta blocker therapy in patients with heart block include:
- The type and degree of heart block: patients with second-degree or third-degree heart block should avoid beta blockers altogether
- The presence of a functioning implanted pacemaker: patients with a pacemaker may be able to tolerate beta blockers, but this should be decided on a case-by-case basis
- Alternative medications for conditions typically managed with beta blockers: for patients with heart block who require treatment for hypertension or angina, alternative medications such as calcium channel blockers or nitrates may be considered
- Close monitoring: if a patient with heart block requires beta blocker therapy, they should be closely monitored for signs of worsening heart block or other adverse effects.
It's also important to note that the ACC/AHA guidelines 1 recommend that beta blockers be used with caution in patients with significant beta-blocker therapy in patients with ACS who were chronic obstructive pulmonary disease who may have a component of reactive airway disease. However, in the context of heart block, the risk of worsening conduction system disease generally outweighs any potential benefits of beta blocker therapy.
From the FDA Drug Label
Good clinical judgment suggests, however, that patients who are dependent on sympathetic stimulation for maintenance of adequate cardiac output and blood pressure are not good candidates for beta blockade.
The use of beta blockers is not indicated in patients with heart block, as they may be dependent on sympathetic stimulation to maintain adequate cardiac output and blood pressure.
- Contraindications to beta blockade include conditions where patients rely on sympathetic stimulation, such as heart block.
- The decision to use beta blockers should be based on good clinical judgment, considering the individual patient's condition and potential risks. 2
From the Research
Beta Blocker Therapy in Heart Block
- Beta blockers are not typically indicated as a primary treatment for heart block, as they can potentially worsen the condition by further reducing heart rate 3.
- However, beta blockers may be used in certain cases, such as in patients with heart failure or arrhythmias, under close medical supervision 4, 5.
- The use of beta blockers in patients with heart block requires careful consideration of the potential benefits and risks, and should be individualized based on the patient's specific condition and medical history 3, 6.
- In general, beta blockers are contraindicated in patients with severe bradycardia, preexisting sick sinus syndrome, second- and third-degree atrioventricular block, severe left ventricular dysfunction, active peripheral vascular disease with rest ischemia, or reactive airway disease so severe that airway support is required 3.
Specific Considerations
- In patients with heart failure and concomitant obstructive airway disease, cardioselective beta blockers may be safe and beneficial 6.
- In patients with heart failure with preserved ejection fraction and sinus rhythm, beta blocker use was not associated with improved clinical outcomes in one study 7.
- The choice of beta blocker, dose, and route of administration depends on the type of arrhythmia and clinical presentation, as well as the patient's demographics and medical history 5.