Atrial fibrillation after cardiac surgery: an evidence-based approach to prevention

[Effect of ultrasound-guided right stellate ganglion block on perioperative atrial fibrillation in patients undergoing lung lobectomy: a randomized controlled trial]

OBJECTIVE

To observe the effects of preoperative right stellate ganglion block on perioperative atrial fibrillation in patients undergoing lung lobectomy.

METHODS

Two hundred patients who underwent a scheduled lobectomy were randomly divided into the S and C groups. The S group was injected with 4mL of 0.2% ropivacaine under ultrasound guidance, and the C group did not receive stellate ganglion block. The patients underwent continuous ECG monitoring, and the incidences of atrial fibrillation and other types of arrhythmias were recorded from the start of surgery to 24hours after surgery.

RESULTS

The respective incidences of atrial fibrillation in the S group and the C group were 3% and 10% (p=0.045); other atrial arrhythmias were 20% and 38% (p=0.005); and ventricular arrhythmia were 28% and 39% (p=0.09).

CONCLUSIONS

The results of the study indicated that preoperative right stellate ganglion block can effectively reduce the incidence of intraoperative and postoperative atrial fibrillation.

Post-operative atrial fibrillation: a maze of mechanisms

Post-operative atrial fibrillation (POAF) is one of the most frequent complications of cardiac surgery and an important predictor of patient morbidity as well as of prolonged hospitalization. It significantly increases costs for hospitalization. Insights into the pathophysiological factors causing POAF have been provided by both experimental and clinical investigations and show that POAF is ‘multi-factorial’. Facilitating factors in the mechanism of the arrhythmia can be classified as acute factors caused by the surgical intervention and chronic factors related to structural heart disease and ageing of the heart. Furthermore, some proarrhythmic mechanisms specifically occur in the setting of POAF. For example, inflammation and beta-adrenergic activation have been shown to play a prominent role in POAF, while these mechanisms are less important in non-surgical AF. More recently, it has been shown that atrial fibrosis and the presence of an electrophysiological substrate capable of maintaining AF also promote the arrhythmia, indicating that POAF has some proarrhythmic mechanisms in common with other forms of AF. The clinical setting of POAF offers numerous opportunities to study its mechanisms. During cardiac surgery, biopsies can be taken and detailed electrophysiological measurements can be performed. Furthermore, the specific time course of POAF, with the delayed onset and the transient character of the arrhythmia, also provides important insight into its mechanisms.

This review discusses the mechanistic interaction between predisposing factors and the electrophysiological mechanisms resulting in POAF and their therapeutic implications.

Atrail Fibrillation after Carfiac Surgery: Benign or Deserving of Prophylaxis

New onset atrial fibrillation (AF) is the commonest complication after cardiac surgery affecting around 30% of coronary artery bypass graft (CABG) patients, up to 50% of valve surgery patients and as many as 60% of those undergoing combined valve and CABG operations. After cardiac transplantation where the native pulmonary veins are electrically separated from the donor heart atria the incidence is only 11%.

Pharmacologic management of the postoperative cardiac surgery patient

Maintaining adequate cardiac output in postoperative cardiac surgery patients is a complex and challenging feat for health care teams. Alterations in preload, afterload, contractility, heart rate, and rhythm can be devastating to these patients and lead to lethal consequences. An array of pharmacologic therapies is available in the critical care setting to help prevent and treat such complications and ensure satisfactory cardiac performance.

Prevention of atrial fibrillation after cardiac surgery

Atrial fibrillation is the most common arrhythmia occurring after heart surgery. Its prevalence after coronary artery bypass surgery is 17-33%. Atrial fibrillation requires additional treatment, lengthens hospitalization and increases the overall expenses of cardiac surgery. Atrial fibrillation can cause hemodynamic problems, predispose to congestive heart failure and increase the risk of stroke. Beta-blockers have been shown to effectively prevent atrial fibrillation, and beta-blockers should be a part of the medication of every patient undergoing cardiac surgery, if there are no contraindications. Amiodarone therapy can also be considered for especially high-risk patients.