From the Guidelines
Starting beta blockers in a patient with new myocarditis is not recommended during the acute inflammatory phase, as it may worsen hemodynamic status by reducing cardiac contractility and heart rate, potentially compromising cardiac output in an already inflamed and weakened myocardium. According to the 2015 ESC guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death 1, the management of heart failure and potentially fatal arrhythmias is the main clinical challenge in acute myocarditis. The guidelines recommend supportive measures, including avoiding exercise and using pharmaceutical treatment with neurohormonal blockade with ACE inhibitors, but the use of beta-blockers is not explicitly recommended during the acute phase.
Some key points to consider when managing a patient with new myocarditis include:
- Avoiding exercise and using supportive measures to manage heart failure and arrhythmias
- Monitoring for complications, such as progressive wall motion abnormalities, deteriorating left ventricular function, and frequent non-sustained ventricular arrhythmias
- Considering the use of ACE inhibitors or ARBs if the patient develops heart failure symptoms
- Individualizing the decision to start beta blockers based on the patient's hemodynamic stability, ventricular function, and presence of arrhythmias, ideally under the guidance of a cardiologist 1.
It is essential to carefully monitor vital signs, particularly heart rate and blood pressure, if beta blockers are eventually initiated, as they can worsen hemodynamic status in acute myocarditis. The 2015 ESC guidelines emphasize the importance of prolonged ECG monitoring and hospital admission for patients with ventricular arrhythmias or heart block in the setting of acute myocarditis 1.
From the FDA Drug Label
WARNINGS Heart Failure Beta-blockers, like metoprolol, can cause depression of myocardial contractility and may precipitate heart failure and cardiogenic shock.
- Starting beta blockers in a patient with new myocarditis can be harmful as beta blockers can cause depression of myocardial contractility, which may worsen the condition of a patient with myocarditis.
- The FDA drug label warns against the use of beta blockers in patients with heart failure, and myocarditis can lead to heart failure.
- Caution is advised when considering the use of beta blockers in patients with new myocarditis, and the decision to start beta blockers should be made with careful consideration of the potential risks and benefits 2.
From the Research
Myocarditis and Beta Blockers
- The use of beta blockers in patients with myocarditis is a topic of discussion, with some studies suggesting their potential benefits 3.
- However, the level of proof for the use of beta blockers in acute myocarditis remains weak, and more research is needed to determine their effectiveness 3.
- One study suggests that heart rate-lowering treatments, including beta blockers, may help manage patients with myocarditis by preventing heart failure and limiting "mechanical inflammation" and controlling arrhythmias 3.
Potential Risks of Beta Blockers in Myocarditis
- There is limited evidence on the potential risks of starting beta blockers in patients with new myocarditis, and more research is needed to fully understand their effects 4, 5.
- However, beta blockers are typically prescribed following myocardial infarction, and their use in patients with myocarditis may be similar 6, 7.
- It is essential to consider the individual patient's condition and medical history before starting beta blockers, as they may have different effects on patients with varying levels of left ventricular ejection fraction 6.
Management of Myocarditis
- The management of myocarditis typically involves supportive care, including respiratory and hemodynamic support 5.
- Treatment may also include the use of vasopressors, inotropes, and mechanical circulatory devices, such as extracorporeal membrane oxygenation, in severe cases 4, 5.
- The use of beta blockers, such as metoprolol and carvedilol, may be considered in certain cases, but their effectiveness and potential risks must be carefully evaluated 3, 6, 7.