Impact of Metoprolol on Postoperative Atrial Fibrillation

Lessening the Incidence of Postoperative Atrial Fibrillation
The issue of reducing or preventing atrial fibrillation (AF) after cardiac surgery has been the subject of numerous studies. Existing studies sought to establish which agents are effective in this process since multiple agents are used to prevent AF. Reduction of incidence of postoperative atrial fibrillation is critical in order to promote the outcomes of patients undergoing cardiac surgery. In addition to flutter, atrial fibrillation is usually observed in the immediate aftermath of cardiac surgery. While clinical studies have shown that medications have positive impacts in preventing atrial fibrillation, they can be cause of these kinds of arrhythmias. Therefore, clinicians are faced with the need to identify suitable interventions for lessening the incidence of postoperative atrial fibrillation in the aftermath of cardiac surgery, which is the subject of this research.
Clinical Question and Importance to Nursing
The incidence rates of postoperative arrhythmias such as flutter and atrial fibrillation in the first days after cardiac surgery is estimated to be between 17% and 33% and differs based on the method used for its identification and the criteria for definition (Lucio et al., 2004). Given these statistics, atrial fibrillation is regarded as one of the most common types of postoperative arrhythmias among patients undergoing cardiac surgery. This condition can also coexist with other forms of arrhythmias like atrial flutter. While the incidence rates of atrial fibrillation continues to increase among these patients, its etiology remains relatively unknown. As a result, current clinical practice relies on stimuli like pericarditis, intraoperative atrial ischemia, and extreme adrenergic stimulation for detection. In this regard, the stimuli play a critical role in the appearance of atrial fibrillation among vulnerable patients undergoing cardiac surgery.
Despite the recognition of the high incidence rates of atrial fibrillation among cardiac surgery patients, the modern healthcare environment struggles to identify a suitable intervention for lessening these incidence rates. As a result, multiple agents including amiodarone and metoprolol have been used to help prevent AF after cardiac surgery. While these agents have shown promising results, clinicians face the need to establish their effectiveness in lessening postoperative AF incidence rates. To this extent, this study seeks to establish the effectiveness of one of these agents i.e. metoprolol in achieving this. The research will be guided by the following PICO question…
Does taking Metoprolol before cardiac surgery reduce the incidence of postoperative atrial fibrillation?
Examining this issue is critical to nursing because the increasing incidence rates of postoperative AF among patients undergoing cardiac surgery continues to pose significant threats to enhanced patient outcomes and safety in cardiac care settings. Valtola et al. (2007) states that the rates of postoperative atrial fibrillation remains significantly high while the effectiveness of beta-blockers like metoprolol in reducing these rates efficiently remains unknown. Therefore, this study will help address existing gaps in literature regarding the role and significance of beta-blockers such as metoprolol in lessening the incidence of postoperative atrial fibrillation in an efficient manner. Through addressing the existing gap in literature, the study will contribute toward enhanced clinical practice with regards to provide evidence-based care to patients undergoing cardiac surgery while enhancing their outcomes and safety.
Literature Search
To achieve the purpose of the study, a search of existing literature on the topic was carried out. The literature search helped to identify studies on this issue and their key findings that could be utilized to promote changes in clinical practice with regards to providing care to patients undergoing cardiac surgery. The researcher conducted the search on electronic databases, which provide credible information on the research topic. Electronic databases like Cochrane, EBSCOHost, CINAHL, and ProQuest were utilized to help enhance the validity and reliability of this study’s findings. The search involved using key terms and phrases relating to the PICO question. Some of these terms and phrases include metoprolol, use of beta-lockers in preventing postoperative atrial fibrillation, incidence rates of postoperative atrial fibrillation, cardiac surgery, arrhythmias, and effectiveness of metoprolol in lessening postoperative atrial fibrillation (AF).
The first phase of the search which involved looking for articles on metoprolol, cardiac surgery, arrhythmias, and incidence rates of postoperative atrial fibrillation generated 17,356 hits. The second phase of the literature search focused on identifying studies on the effectiveness of metoprolol in reducing postoperative AF generated 6710 hits. However, the researcher selected eight articles for inclusion in this paper. The selection criteria for determining articles for inclusion in the study included studies with level 2, 3 or 4 evidence, those that focus on the PICO question, and those that address the effectiveness of metoprolol before or after cardiac surgery with regards to incidence of postoperative atrial fibrillation.
Key Findings
As previously indicated, numerous studies have been conducted to examine whether multiple agents help prevent or lessen incidence of postoperative atrial fibrillation. These studies provide significant insights regarding this issue, which can be utilized to inform clinical practice on the care of patients undergoing cardiac surgery. One of the key findings in existing studies is that taking metoprolol before cardiac surgery reduce the incidence of postoperative atrial fibrillation. According to Skiba et al. (2013), administering metoprolol before conducting cardiac surgery is linked with significant decrease in postoperative atrial fibrillation. This implies that pharmacological interventions help in prevention of incidence of postoperative atrial fibrillation. Therefore, one of the emerging concepts or themes in existing literature on this topic is that lessening incidence of postoperative atrial fibrillation requires pharmacologic interventions. The most suitable pharmacological intervention for lessening incidence of postoperative AF is administering beta-blockers like metoprolol prior to the cardiac surgery. Beta-blockers act as the first line of preventive treatment or measures for atrial fibrillation (Halonen et al., 2010; Onk & Erkut, 2015). Based on their randomized controlled trial, these researchers found pre-operative administration of these medications to be effective in lessening the incidence of postoperative atrial fibrillation.
This emerging theme or finding seeming suggests that postoperative side effects of a surgery can be prevented through preoperative pharmacological interventions. There is a strong link between preoperative interventions and postoperative side effects. In this case, the preoperative pharmacological intervention for lessening postoperative atrial fibrillation is administration of metoprolol. The positive impact of preoperative pharmacological interventions in preventing or reducing postoperative side effects is evident in the role these interventions play in reducing hospitalization and enhancing patient outcomes. Hjalmarson et al. (2000) supports this concept by contending that taking metoprolol before cardiac surgery not only lessens postoperative atrial fibrillation, but also lessens hospitalizations, enhances functional class, and improves patient outcomes and well-being in cardiac care settings.
The second key finding or theme emerging from existing literature on the topic is that intravenous administration of metoprolol is seemingly more effective in prevention of atrial fibrillation following a cardiac surgery than oral administration (Halonen et al., 2006). While metoprolol is one of the antiarrhythmic medications for postoperative atrial fibrillation, the effectiveness of this drug is dependent on the mode of administration. This introduces the idea that the effectiveness of antiarrhythmic drugs in preventing postoperative atrial fibrillation is dependent on the way these drugs are administered. Intravenous administration of metoprolol is more effective than oral administration since the drug is mostly absorbed over a huge part of the intestine. During the preoperative period of cardiac surgery, metoprolol that is administered orally is not absorbed from the gastrointestinal tract.
Existing literature demonstrates a strong link between how a drug is administered and its effectiveness in enhancing patient outcomes and safety. This link is attributable to the fact that the mode of drug administration influences its absorption, which in turn determines the effect of the drug on the body. Abbaszadeh et al. (2012) supports this view by arguing that reduction of incidence of atrial fibrillation after a cardiac surgery during perioperative period requires intravenous corticosteroids like metoprolol. This is primarily because this mode of drug administration is associated with no serious complications and promotes suitable absorption of the drug. Therefore, the effect of taking metoprolol before cardiac surgery to reduce postoperative atrial fibrillation is determined by the mode of drug administration.
Limitations of the Current Research
Current research provides significant insights on the reduction of incidence of postoperative atrial fibrillation using metoprolol. As shown in current research, the two major themes in literature show that taking metoprolol before cardiac surgery significantly reduces the incidence of postoperative atrial fibrillation. However, the effectiveness of these drugs is largely influenced by the mode of drug administration. Despite providing these significant findings, there are some current gaps in literature on this issue. One of this weaknesses is the absence of the reasonable level or extent of implementing the use of metoprolol prior to cardiac surgery. Existing studies do not provide insights on the reasonable time period with which a patient should take metoprolol prior to undergoing cardiac surgery. Even though existing literature establishes the need to use metoprolol during preoperative and perioperative periods, there is dearth of information on the exact time periods for use of this drug prior to cardiac surgery. Secondly, existing literature does not examine the role individual factors play in determining the effectiveness of metoprolol in lessening the incidence of postoperative atrial fibrillation. This is a critical factor given the differences in body responses to different drugs, which implies that individual factors could play a role in the effectiveness of these drugs.
Therefore, future studies should be conducted to examine whether the length of time between taking metoprolol and undergoing cardiac surgery affects its ability to lessen incidence of postoperative AF. This would help ensure the drugs are administered at an appropriate time before surgery. Secondly, the role of individual factors in determining the effectiveness of metoprolol should be examined. This would help to establish suitable conditions that would enhance the drug’s effectiveness prior to administration.
Discussion
Literature findings demonstrate that clinical practice in cardiac care setting should entail the administration of metoprolol prior to cardiac surgery. Clinicians should increase their use of this drug in the clinical setting in comparison to other processes/measures targeting reduction of incidence of postoperative atrial fibrillation. During this process, clinicians should ensure that the drugs are administered intravenously rather than orally. These suggested changes or improvements in nursing practice would help enhance the reduction of postoperative atrial fibrillation rates among patients undergoing cardiac surgery.
References
Abbaszadeh, M., Khan, Z.H., Mehrani, F. & Jahanmehr, H. (2012, Jan/March). Perioperative Intravenous Corticosteroids Reduce Incidence of Atrial Fibrillation Following Cardiac Surgery: A Randomized Study. Brazilian Journal of Cardiovascular Surgery, 27(1), 18-23.
Halonen et al. (2010, December 7). Metoprolol Versus Amiodarone in the Prevention of Atrial Fibrillation After Cardiac Surgery: A Randomized Trial. Annals of Internal Medicine, 153(11), 703-709.
Halonen et al. (2006, July 4). Intravenous Administration of Metoprolol is More Effective than Oral Administration in the Prevention of Atrial Fibrillation After Cardiac Surgery. Circulation, 114(1), 1-4.
Hjalmarson et al. (2000, March 8). Effects of Controlled-release Metoprolol on Total Mortality, Hospitalizations, and Well-being in Patients with Heart Failure: the Metoprolol CR/XL Randomized Intervention Trial in Congestive Heart Failure (MERIT-HF). MERIT-HF Study Group. JAMA, 283(10), 1295-1302.
Lucio, E.A., Flores, A., Blacher, C., Leaes, P.E., Lucchese, F.A. & Ribeiro, J.P. (2004, January). Effectiveness of Metoprolol in Preventing Atrial Fibrillation and Flutter in the Postoperative Period of Coronary Artery Bypass Graft Surgery. Arquivos Brasileiros de Cardiologia, 82(1), 42-46.
Onk, O.A. & Erkut, B. (2015, October). Is the Preoperative Administration of Amiodarone or Metoprolol More Effective in Reducing Atrial Fibrillation. Medicine, 94(41). doi: 10.1097/MD.0000000000001576
Skiba et al. (2013, August). Prophylaxis Against Atrial Fibrillation after Cardiac Surgery: Beneficial Effect of Perioperative Metoprolol. Heart, Lung and Circulation, 22(8), 627-633.
Valtola, A., Kokki, H., Gergov, M., Ojanpera, I, Ranta, V.P. & Hakala, T. (2007, May). Does Coronary Artery Bypass Surgery Affect Metoprolol Bioavailability. European Journal of Clinical Pharmacology, 63(5), 471-478.