Perioperative Arrhythmias

Abstract

Background

Perioperative arrhythmias are common depending on the type of the operation and can increase morbidity and mortality.

Methods

This review is based on pertinent publications retrieved by a selective search in PubMed, as well as the relevant European guidelines.

Results

Arrhythmias are seen in more than 90% of cardiac operations; they are usually transient and often asymptomatic. The risk factors for arrhythmia include ion channel diseases, old age, structural heart disease, cardiac surgery, noncardiac surgery with major fluid shifts, and pulmonary resection. The full spectrum of supraventricular and ventricular arrhythmias can arise perioperatively. Correct ECG interpretation, consideration of the arrhythmia in the overall clinical context, and an understanding of its causes, pathophysiology, and options for effective treatment are critically important. According to a meta-analysis, beta-blockers lower the risk of perioperative atrial fibrillation (OR = 0.56; 95% confidence interval: [0.35; 0.91]). If anticoagulant treatment is not interrupted for surgery, there is less bleeding with direct oral anticoagulants than with vitamin K antagonists (relative risk: 0.62 [0.47; 0.82]). Moreover, clinical follow-up is important, especially for patients with new-onset atrial fibrillation or heart failure.

Conclusion

The identification of high-risk patients and the provision of individualized perioperative monitoring are essential aspects of patient safety. Outpatient cardiological follow-up can improve outcomes.

Perioperative arrhythmias can prolong hospital stays and cause morbidity and mortality (1, 2). Their frequency can exceed 90%, depending on the type of surgery and type of arrhythmia. They are particularly common in cardiac surgery, noncardiac surgery with major fluid shifts, and pulmonary resection (3–12).

The diagnosis, prevention, and treatment of perioperative arrhythmias thus helps preserve the stability of cardiac function and lessen perioperative complications. Cardiac arrhythmias arising either under general anesthesia or in its aftermath are sometimes harmless, but they can also be severe and dangerous; they must, therefore, be detected, evaluated, and (if necessary) treated at an early stage.

Now that increasing numbers of elderly patients with multiple comorbidities are undergoing surgery, the preoperative evaluation and, where indicated, prevention of perioperative risks have become an important component of patient safety management (13).

One important part of this is the recognition and management of pre-existing heart disease. Often, a newly arising cardiac arrhythmia may or may not pose a danger for the patient depending on his or her existing cardiovascular comorbidities.

Frequency.

Perioperative arrhythmias can prolong hospital stays and cause morbidity and mortality. Their frequency can exceed 90%, depending on the type of surgery and type of arrhythmia.

Preoperative risk assessment.

Now that increasing numbers of elderly patients with multiple comorbidities are undergoing surgery, the preoperative evaluation and, where indicated, prevention of perioperative risks have become an important component of patient safety management.

Learning objectives

This article should enable readers to:

• know the types of perioperative arrhythmia and their causes,

• reliably identify patients at risk for potentially harmful arrhythmias,

• and initiate appropriate diagnostic assessment and treatment whenever perioperative arrhythmias occur.

Aside from the preoperative state of the cardiovascular system, the type of surgery and the nature and depth of sedating anesthesia play a key role in the occurrence of arrhythmias. These factors affect intraoperative fluid shifts and fluid loss and the severity of perioperative inflammation, possibly constituting systemic inflammatory response syndrome (SIRS). They are major causes of perioperative arrhythmias (1, 2). For example, the use of a heart-lung machine produces large volume shifts and markedly activates the cascades of coagulation and inflammation. Furthermore, activation of the vagal and sympathetic portions of the autonomic nervous system by surgical manipulation and/or analgesia can promote arrhythmias, especially transient bradycardias. Depending on the patient‘s preoperative risk profile, an individualized preoperative diagnostic evaluation should be performed in order to assess the risk of intra- and postoperative arrhythmias (13, 14).

The necessary perioperative monitoring techniques should be determined in the light of the risks of the planned intervention, and the interventions that might be required should be decided upon in advance. The purpose is to ensure intra- and early postoperative circulatory stability through the availability of appropriate treatments that can be used in a prompt and targeted manner whenever needed. Postoperative arrhythmias, which may be temporary, e.g., postoperative atrial fibrillation after cardiac surgery, must also be monitored and treated as required (15, 16).

In this article, we provide an overview of perioperative arrhythmias and describe possible algorithms for their diagnostic evaluation and treatment.

Etiology

Most perioperative arrhythmias are supraventricular tachycardias, with an incidence of up to 40%; ventricular tachycardia also occurs in 15% of cases (Table 1) (3–12). Perioperative arrhythmias have multiple causes. The recurrence of a pre-existing arrhythmia has a different significance than the initial manifestation of a new one, and there is an important distinction between patients with and without pre-existing structural heart disease. Persons who are apparently in good cardiac health but actually have ion channel diseases are few, but perhaps especially endangered. These conditions include Brugada syndrome, which causes 4% of sudden cardiac deaths overall and 20% of such deaths in patients without structural heart disease, and long-QT syndrome, which causes up to 2% of sudden cardiac deaths; affected persons may develop malignant arrhythmias or even sudden cardiac death in the perioperative period (17). Long-QT syndrome increases the risk of torsade de pointes tachycardia (polymorphic ventricular tachycardia with QRS complex peak reversal around the ECG baseline). Whatever operation is performed, and whatever the patient’s comorbidities may be, perioperative arrhythmias can be induced by anesthetic drugs, electrolyte and blood gas abnormalities, inflammation, and effects on the autonomic nervous system (Box 1).

Table 1. Types and frequencies of perioperative cardiac arrhythmia, according to Refs. 3–12.

Perioperiative arrhythmia	Frequency (%)
Supraventricular arrhythmias  – atrial tachycardia  – AVNRT/AVRT  – supraventricular extrasystoles  – atrial fibrillation	≤ 16   ≤ 6   ≤ 100   ≤ 40
Ventricular arrhythmias  – ventricular fibrillation  – ventricular extrasystoles  – ventricular tachycardia	≤ 3   ≤ 100   ≤ 15
Bradycardias  – high-grade AV block  – sinus arrest	≤ 16   ≤ 2

AVNRT, AV node reentry tachycardia; AVRT, AV reentry tachycardia

Box 1. Causes of perioperative arrhythmias.

Patient-related factors

• ion channel diseases

• advanced age

• structural heart disease

Type of surgery

• cardiac surgery

• non-cardiac surgery with increased arrhythmia risk:

  • surgery with major fluid shifts (e.g., major visceral surgery, polytrauma with hypovolemic shock)

  • lung resection

Causes relating to anesthesia and other factors

• high catecholamine requirement

• electrolyte disturbances

• thromboembolism, air embolism

• hypoglycemia

• hypothermia

• hypoxia

• mechanical manipulation (e.g., central venous catheter placement)

• drugs

• metabolic disorders

• myocardial ischemia

• inflammation

• ion channel diseases

• structural heart diseases

• vagal reaction (intubation/extubation, pain, etc.)

• cerebral ischemia

Procedure-related causes

The occurrence of arrhythmias.

Aside from the preoperative state of the cardiovascular system, the type of surgery and the nature and depth of sedating anesthesia play a key role in the occurrence of arrhythmias.

Procedure-related causes.

More than 90% of patients develop arrhythmias after cardiac surgery, but most of these are self-limiting and of little or no clinical importance. There is no immediate reason to treat most of the detected arrhythmias.

More than 90% of patients develop arrhythmias after cardiac surgery (1), but most of these are self-limiting and of little or no clinical importance. There is no immediate reason to treat most of the detected arrhythmias.

In non-cardiac surgery with only intermittent rhythm monitoring, a 16–62% frequency of perioperative arrhythmias has been reported (4). This frequency rises to 89% with continuous monitoring, similar to the figures for cardiac surgery (5); but, as already stated, most arrhythmias are transient, and many are asymptomatic. The most common cause is stimulation of the vagus nerve, which can lead to bradycardia, AV block, and asystole (e.g., in visceral surgery or vascular surgery of the carotid arteries). In a meta-analysis including more than 2.6 million patients, postoperative AF was most commonly encountered after lung surgery (especially transplantation) and esophageal surgery. In contrast, its frequency after minor surgical procedures (e.g., minor orthopedic surgery) was only 0.8% (4). Fluid shifts, inflammatory responses, and the resulting cardiovascular stress appear to be important triggers of perioperative arrhythmias. Dental surgery is another common trigger of mostly benign arrhythmias (2). These seem not to depend on the specific dental procedure but rather to arise through the activation of the sympathetic and parasympathetic nervous systems and the depth of sedation. Anxiety and stress may also be relevant triggers of the autonomic nervous system; thus, preoperative anxiolytic medication is advisable. Older studies showed that mechanical ventilation combined with administration of a muscle relaxant caused fewer arrhythmias than superficial sedation with continued spontaneous breathing (18, 19).

Dental surgery.

Dental surgery is another common trigger of mostly benign arrhythmias. These seem not to depend on the specific dental procedure but rather to arise through the activation of the sympathetic and parasympathetic nervous systems and the depth of sedation.

Patient-related causes

The first major patient-related predictor of perioperative arrhythmias is known cardiovascular disease, and the second is age. Both structural heart disease and aging lead to degeneration and myocardial remodeling processes that promote the occurrence of arrhythmias.

Anesthesiologic causes

Anesthesiologic causes.

Both intubation and extubation can induce arrhythmias through an autonomic reflex (20). The placement of a central venous or Swan-Ganz catheter can mechanically induce atrial or ventricular extrasystoles that lead, in turn, to supraventricular or ventricular arrhythmias.

Both intubation and extubation can induce arrhythmias through an autonomic reflex (20). The placement of a central venous or Swan-Ganz catheter can mechanically induce atrial or ventricular extrasystoles that lead, in turn, to supraventricular or ventricular arrhythmias. Mechanically induced AV or right bundle branch block is usually benign and fully reversible in the short-term. The triggering of such disturbances by anesthetic drugs is less common, but can have dramatic consequences. Volatile anesthetics can cause bradycardia and potentiate the arrhythmogenic effects of endogenous and exogenous catecholamines (21–24). Muscle relaxants can also induce cardiac arrhythmias intraoperatively: for example, pancuronium can promote atrial and ventricular arrhythmias, and vecuronium combined with high opioid doses or vagal stimulation can cause asystole (25, 26). A further mechanism of arrhythmia induction by drugs is the prolongation of repolarization due to an interaction with cardiac ion channels. This can occur with many drugs and, in the worst case, causes torsade de pointes tachycardia; yet the wholesale avoidance of any drug that might have this effect is not recommended. Rather, patients taking drugs that prolong the QT time should be intensively monitored, both clinically (occurrence of syncope?) and with repeated 12-lead ECG for measurement of the QTc time, particularly if they also have other risk factors for torsade de pointes tachycardia. These include female sex, recurrent hypokalemia, concomitant use of multiple drugs that can prolong the QT time, and renal failure (27). If the QTc time exceeds 500 ms, reducing the dose or discontinuing the drug may be indicated. Patients with congenital long-QT syndrome should be evaluated preoperatively by a cardiologist. Drugs that prolong the QT time are listed in Box 2.

Box 2. Drugs that prolong the QT interval, according to (4).

• antiarrhythmic drugs (including ajmaline, amiodarone, quinidine, disopyramide, dofetilide, ibutilide, propafenone, sotalol)

• antibiotics (including macrolides, fluoroquinolones, ampicillin, trimethoprim-sulfamethoxazole)

• antidepressants (including amitriptyline, clomipramine, desipramine, doxepin, imipramine, maprotiline)

• antihistamines (including clemastine, diphenhydramine, hydroxyzine, terfenadine)

• anticonvulsants (valproic acid)

• antiparkinsonian drugs (amantadine)

• chemotherapeutic drugs (tamoxifen, pentamidine)

• diuretics (indapamide)

• immunosuppressants (tacrolimus)

• antimalarial drugs (quinidine, chloroquine, halofantrine, mefloquine)

• muscle relaxants (tizanidine)

• neuroleptic drugs (including amisulpride, clozapine, chlorpromazine, fluphenazine, haloperidol, melperone, olanzapine, pimozide, quetiapine, sulpiride, thioridazine, risperidone, tiapride, trazodone)

• peptides (octreotide)

• radiologic contrast media (ioxaglinic acid)

• selective serotonin reuptake inhibitors (SSRI) (including fluoxetine, paroxetine, sertraline)

• antiviral drugs (foscarnet)

• other psychotropic drugs (including chloral hydrate, levomethadone, lithium, naratriptan, sumatriptan, venlafaxine, zolmitriptan)

Patients with Brugada syndrome (prevalence 1 to 5 : 10 000) are at increased risk for malignant arrhythmias (28). A preoperative cardiological consultation is advisable in this case as well. To prevent malignant arrhythmias in such patients, it is mandatory to avoid local anesthetics such as bupivacaine, increased vagal tone, fever, inadequate analgesia, and electrolyte disturbances.

Drug-induced arrhythmias.

Pancuronium can promote atrial and ventricular arrhythmias, and vecuronium combined with high opioid doses or vagal stimulation can cause asystole.

Brugada Syndrom.

Patients with Brugada syndrome (prevalence 1 to 5 : 10 000) are at increased risk for malignant arrhythmias.

Further possible causes of perioperative arrhythmias include hypothermia (ventricular arrhythmias can especially likely at body temperatures below 34°C), infection, metabolic disturbances, electrolyte imbalances (especially hyper- and hypokalemia), and gas exchange disturbances with either hypercapnia or hypoxemia (2, 4).

Diagnostic evaluation

Preoperative assessment

The preoperative assessment differs depending on whether cardiac or non-cardiac surgery is planned. The standard assessment before cardiac surgery involves rhythm analysis with a 12-lead ECG. This is indispensable for the detection of any arrhythmia that may already be present, e.g., atrial fibrillation, which can then be directly treated during surgery (29). If atrial fibrillation is suspected but is not revealed by the 12-lead ECG, a long-term ECG can also be obtained.

The preoperative assessment for non-cardiac surgery depends on the urgency of the procedure. A risk evaluation should be performed before any elective procedure, commensurate with the known risks of the procedure in question (13, 30, 31). There is generally no time for an extensive assessment before emergency surgery.

The estimated periprocedural risk of cardiovascular complications is classified as high (> 5%, e.g., in emergency major surgery, particularly in elderly patients), medium (1–5%, e.g., in head and neck surgery), or low (< 1%, e.g., in endoscopic surgery) (30).

History-taking and physical examination are the fundamental clinical methods of detecting potentially serious heart disease, such as coronary artery disease (e.g., in patients with anginal symptoms or a prior myocardial infarction), heart failure, symptomatic cardiac arrhythmias, or the presence of a pacemaker or implantable defibrillator (32). For further cardiac risk stratification, risk scores are recommended: for example, Lee‘s Revised Cardiac Risk index uses clinical parameters to stratify the risk for cardiac events during non-cardiac surgery (33, 34). Risk stratification is easily accomplished with an online calculator that is available at www.medscape.com (see Revised Cardiac Index, Lee criteria; Table 2). An ECG should be obtained in patients who have cardiac risk factors or are about to undergo moderate- or high-risk surgery, but is otherwise not recommended as a routine preoperative test (13).

Table 2. Revised Cardiac Risk Index (Lee criteria) risk factors (points) for severe cardiac events.

Risk factor			Points
Coronary heart disease			1
High-risk operation			1
Heart failure			1
Cerebrovascular disease			1
Insulin-dependent diabetes mellitus			1
Serum creatinine concentration > 2 mg/dL			1
Risk of severe cardiac events
Points	Class	Risk
0	I	0.4%
1	II	0.9%
2	III	6.6%
≥ 3	IV	11.0%

Cardiac arrhythmias, such as atrial fibrillation or ventricular arrhythmias, that are detected on a preoperative ECG may be due to structural heart disease and require further evaluation before elective surgery.

Further diagnostic studies may be needed depending on the past cardiac history, the current cardiovascular risk, and the specific risks of the planned procedure. When indicated, studies such as the measurement of left ventricular function at rest, dynamic or pharmacological ischemia testing, long-term ECG, and coronary angiography yield further information about the risk of a new arrhythmia or other cardiovascular complications (13, 35).

Preoperatively detected cardiac arrhythmias.

Any preoperatively detected arrhythmia should be evaluated further before the patient undergoes elective surgery.

Intraoperative management (anesthesia induction and surgery)

Continuous ECG monitoring is recommended for all patients undergoing general anesthesia (class I recommendation, level C evidence) (13) and should be started before anesthesia is induced. Persistent ST-segment changes are correlated with perioperative myocardial infarction. Multiple ECG leads should be used for the sensitive detection of myocardial ischemia (13, 36); high-risk patients and cardiac surgery, a 12-lead ECG is mandatory. ECG is of limited utility for the detection of cardiac ischemia in patients with intraventricular conduction delay, any type of conduction block, or a pacemaker. Continuous ECG monitoring enables the intraoperative detection and treatment of clinically significant arrhythmias such as AV block, pauses, ventricular tachycardia, asystole, and ventricular fibrillation (13).

The limitations of the ECG.

ECG is of limited utility for the detection of cardiac ischemia in patients with intraventricular conduction delay, any type of conduction block, or a pacemaker.

Postoperative management (the recovery phase and postoperative arrhythmias)

Postoperative rhythm monitoring depends on the type of surgery and the modality of anesthesia (13). After cardiac surgery, continuous ECG monitoring is mandatory for several hours to days, depending on the particular procedure and the associated estimated risk of postoperative arrhythmias: for example, AV block after valve surgery, and ventricular arrhythmias after aortocoronary bypass grafting (37). Continuous rhythm monitoring can reveal common postoperative arrhythmias such as atrial fibrillation so that they can be appropriately treated. There is no need to treat atrial fibrillation if it is hemodynamically insignificant, short-lasting, and self-limiting; otherwise, conversion is recommended. If sinus rhythm is not restored and atrial fibrillation persists for more than 48 hours, anticoagulation may be indicated, depending on the CHA₂DS₂-VASc score (15).

In non-cardiac surgery, the type of postoperative rhythm monitoring depends on the surgical procedure, the modality of anesthesia, and the need (if any) for continued anesthesia after surgery. Patients who must be kept under anesthesia in an intensive care unit after surgery need continuous monitoring, including a continuous ECG (13).

In all other patients, specific risk scores such as the Surgical Apgar Score are valid stratification tools that indicate the possible need for postoperative monitoring (38). The troponin or BNP level can be used to predict postoperative complications in patients at cardiac risk (39, 40). The time course of troponin elevation is important; new high-sensitivity troponin analyses can be used for checks 3 hours after an event. The monitoring of cardiac parameters at close intervals with the aid of such tests enables the rapid detection and treatment of cardiac complications as they arise.

Patients with pacemakers or implanted defibrillators

Many patients have a pacemaker or an implanted cardiac defibrillator (ICD). Proper perioperative management requires knowledge of the indications for these systems, of their programming, and of their perioperative risks. Surgery must be performed without the use of the monopolar electrocautery, which can render these systems dysfunctional and damage them permanently. The collaboration of a cardiologist in the pre- and postoperative management is mandatory, and any necessary programming must be performed as individually required and depending on the device used. Defibrillators should be turned off immediately before surgery and turned on again immediately afterward (e1). No special anesthetic procedures or adjustments of perioperative medication are required.

Treatment

Perioperative arrhythmias that cause hemodynamic instability must be treated at once. Recurrent, transient arrhythmia may be a warning sign of acute cardiac damage, e.g., from myocardial infarction or from volume or pressure overload. Thus, even though harmless arrhythmias are common and often lead to false alarms, the rapid detection and treatment of dangerous ones such as ventricular tachycardia (perioperative frequency ≤ 15%) and ventricular fibrillation (perioperative frequency ≤ 3%) remains a very important matter (3–12). Accurate diagnosis, identification of the precipitating factors, and real-time assessment of the hemodynamic state are essential, with categorization of the various potential causes in case of hemodynamic compromise. Rapid stabilization is usually achievable with targeted treatment (Table 3).

Table 3. The acute treatment of newly arising perioperative cardiac arrhythmias.

Perioperative arrhythmia	Treatment
Supraventricular arrhythmias
– atrial tachycardia	– if hemodynamically relevant → electrical cardioversion, otherwise rate control – if spontaneous conversion does not occur, aim for arrhythmia control before discharge – further cardiological treatment
– AV node reentry tachycardia (AVNRT) / atrioventricular reentry tachycardia (AVRT)	vagal maneuvers – adenosine (caveat: adenosine should not be given to patients with antidromic AVRT) – if this fails and the arrhythmia is hemodynamically significant → electrical cardioversion.
– supraventricular extrasystoles	usually no immediate need for treatment
– atrial fibrillation	– anticoagulation in case of increased risk of thromboembolism (to be weighed against the risk of perioperative bleeding) – if hemodynamically significant → electrical cardioversion, otherwise rate control – if spontaneous conversion does not occur, rhythm control is generally advisable over the further course – further cardiological treatment
Ventricular arrythmias
– atrial fibrillation	– cardiopulmonary resuscitation with defibrillation (and additional administration of catecholamines and amiodarone, as needed) – evaluate possible indication for immediate cardiac catheterization
– ventricular extrasystoles	usually no immediate need for treatment
– ventricular tachycardias	– monomorphic ventricular tachycardia:  electrical cardioversion if hemodynamically significant; if not, amiodarone as initial treatment – polymorphic ventricular tachycardia: evaluate possible indication for immediate cardiac catheterization – torsade de pointes tachycardia:  magnesium sulfate, correction of any electrolyte disturbances or drug triggers – in case of bradycardia, temporary pacemaker to raise the heart rate to 100–120/min
Bradycardias
– high-grade AV block and sinus arrest	depending on the precipitating factors, duration and hemodynamic state: – watch and wait; anticholinergic agents (atropine) or sympathomimetic agents (orciprenaline) – temporary pacemaker for strict indications

The prophylactic administration of drugs to prevent perioperative arrhythmias is generally not recommended; it should be considered only with regard to the possible administration of amiodarone or β-blockers for cardiac surgery (13, e2-e5). Essential preventive measures include the strict avoidance of triggers (e.g., electrolyte disturbances) and the identification of patients at risk.

Postoperative management (the recovery phase and postoperative arrhythmias).

Postoperative rhythm monitoring depends on the type of surgery and the modality of anesthesia (13). After cardiac surgery, continuous ECG monitoring is mandatory.

Non-cardiac surgery.

In non-cardiac surgery, the type of postoperative rhythm monitoring depends on the surgical procedure, the modality of anesthesia, and the need (if any) for continued anesthesia after surgery.

Supraventricular arrhythmias

Atrial fibrillation (AF) accounts for approximately 90% of all perioperative supraventricular arrhythmias (2). In patients with pre-existing atrial fibrillation under treatment for either rate or rhythm control, the drug being used should generally be continued perioperatively. If permanent oral anticoagulation is indicated because the patient has risk factors for thromboembolism, the decision whether to interrupt its administration should be made in consideration of the surgical bleeding risk. Perioperative atrial fibrillation of new onset should be treated initially by rate control with β-blockers or calcium antagonists. Cardiac glycosides usually do not control the heart rate effectively because of increased sympathoadrenergic activation (13). The high rate of spontaneous conversion often obviates the need for cardioversion by electrical or pharmacological means, but immediate electrical cardioversion is indicated in case of hemodynamically significant new-onset AF. Once cardioversion has been achieved, temporary pharmacological recurrence prophylaxis with amiodarone or a class IC antiarrhythmic drug may be useful. Patients with symptomatic AF that does not spontaneously convert to sinus rhythm should undergo cardioversion before discharge. Perioperative rhythm control has not yet been shown to improve the clinical outcome and therefore can now only be considered a means of symptom control (15). Patients who have perioperative AF are at a high risk for recurrent AF, and their rates of stroke, myocardial infarction, and death are higher than those of patients who do not have perioperative AF; they therefore need continued outpatient cardiologic follow-up (16, e6-e8).

Scores for postoperative monitoring.

In all other patients, specific risk scores such as the Surgical Apgar Score are valid stratification tools that indicate the possible need for postoperative monitoring

Patients with pacemakers or implanted defibrillators.

Many patients have a pacemaker or an implanted cardiac defibrillator (ICD). Proper perioperative management requires knowledge of the indications for these systems, of their programming, and of their perioperative risks.

The indications for permanent oral anticoagulation in patients with perioperative AF are less clear than in those with spontaneous AF. Randomized controlled trials on this matter are now in progress, and it is hoped that they will yield crucial new information. The currently available data from meta-analyses and observational studies imply a likely clinical benefit of permanent oral anticoagulation in patients who are at increased risk for thromboembolic events (e6, e9, e10). The probability of stroke is up to 62% higher in patients with postoperative AF than in patients without AF (e6), and those with postoperative AF benefit just as much from oral anticoagulation as patients with AF of non-perioperative onset (for perioperative AF: adjusted hazard ratio = 0.55, 95% confidence interval: [0.32; 0.95], p = 0.03; for non-perioperative AF: adjusted hazard ratio = 0.59, [0.51; 0.68], p < 0.001) (e10). On the other hand, the risk of thromboembolism was no higher in patients with new-onset AF after bypass surgery than in patients without new-onset AF (adjusted hazard ratio = 1.11; [0.94; 1.32]; p < 0.24) (e9). On the basis of these data, the current ESC guidelines contain level B recommendation (class IIa evidence) for permanent oral anticoagulation in patients at risk for stroke after noncardiac surgery, and a level B recommendation (class IIb evidence) after cardiac surgery (e5). A listing of meta-analyses concerning perioperative atrial fibrillation that have appeared in the last five years is provided in Table 4.

Table 4. Recent meta-analyses concerning perioperative atrial fibrillation (e6, e12– e15).

Study	Methods	Findings	Comments
Jing et al./2022 (e14) effects of dexmedetomidine on the occurrence of PAF and stroke after cardiac surgery	18 RCTs with a total of 2933 patients	– dexmedetomidine lowered the frequency of PAF (OR = 0.82; 95% CI: [0.69; 0.98]; p = 0.03) – no effect on the frequency of stroke, duration of hospitalization, need for mechanical ventilation and intensive care, or mortality	Dexmedetomidine lowers the frequency of PAF but has no further clinical benefit.
Kim et al./2021 (e12)effects of β-blockers after cardiac surgery	13 trials (5 randomized, 8 non-randomized) with a total of 25 496 patients	– PAF arose significantly less frequently in patients receiving β-blockers (analysis of randomized trials: OR = 0.56; 95% CI: [0.35; 0.91]) – analysis of nonrandomized trials: OR = 0.70; 95% CI: [0.55; 0.91] – no effect on hospitalization, stroke, or mortality	β-blockers lower the frequency of PAF but have no further clinical benefit.
Siddiqui et al./2020 (e13)perioperative bridging in pateints with PAF	3 studies (2 randomized trials, 1 observational study) with a total of 6305 patients	– perioperative bridging did not lessen the frequency of thomboembolic events (RR = 1.25; 95% CI: [0.55; 2.85]) but did significantly elevate the risk of severe hemorrhage (RR = 3.29; 95% CI: [2.25; 4.81])	The perioperative bridging of patients with PAF who take OAC does not seem to be beneficial.
Lin et al./2019 (e6)association of stroke and mortality with PAF	35 cohort studies with a total of 2 458 010 patients	– PAF was associated with elevated stroke risk and increased mortality (stroke 0–30 days post-op: OR = 1.62; 95% CI: [1.47; 1.80]; death 0–30 days post-op: OR = 1.44; 95% CI: [1.11; 1.88] – stroke >30 days post-op: HR = 1.37; 95% CI: [1.07; 1.77]; death >30 days post-op: HR = 1.37; 95% CI: [1.27; 1.49]	Observation without targeted intervention, such as postoperative screening for VHF recurrence/systemic OACs.
Nazha et al./2018 (e15)periprocedural comparison of the safety and efficacy of DOAC and VKA	4 RCTs (including subtrials) with a total of 19 353 patients	– significantly fewer hemorrages occurred with uninterrupted periprocedural administration of DOACs compared with VKA (2.0% versus 3.3%; RR = 0.62; 95% CI: [0.47; 0.82]) – there was no difference in the frequency of stroke or death	DOACs seem to be safter than VKA when given periprocedurally without interruption.

AF, atrial fibrillation; CI, confidence interval; DOAC, direct oral anticoagulant drug; HR, hazard ratio; OAC, oral anticoagulant drug; OR, odds ratio; PAF, perioperative atrial fibrillation; RR, relative risk; VKA, vitamin K antagonists

The recommendations for the treatment of supraventricular tachycardias of perioperative onset are the same as those for supraventricular tachycardias in general. For AV nodal re-entrant tachycardia, vagal maneuvers and (if these are unsuccessful) the administration of adenosine are effective treatments. Over these patients’ further course, electrophysiological treatment (catheter ablation) is recommended as definitive treatment. Patients with Wolff-Parkinson-White syndrome for whom elective surgery is planned may benefit from prior catheter ablation of the accessory pathway (13).

Ventricular tachycardias and ventricular fibrillation

Persistent monomorphic ventricular tachycardias arise mostly in patients with existing myocardial scarring. In contrast, polymorphic ventricular tachycardias often reflect acute myocardial ischemia. The initial treatment is the same in both cases. Hemodynamic compromise necessitates the correction of the arrhythmia at once, either with amiodarone initially or else with immediate electrical cardioversion, depending on the hemodynamic state. In cases of polymorphic ventricular tachycardia, a cardiologist should be consulted at once and the possible indication for diagnostic cardiac catheterization should be evaluated.

Torsade de pointes tachycardia should be treated initially with the same measures just mentioned for ventricular tachycardia, along with the discontinuation of all drugs that can prolong the QT time and the prompt correction of any existing electrolyte disturbance. Magnesium sulfate administration can also help patients with long QT syndrome (e11). If recurrent torsade de pointes tachycardia arises in a bradycardic patient, a temporary pacemaker to increase the heart rate can lead to stabilization (13). Collaboration with an electrophysiology center is recommended.

Ventricular fibrillation necessitates immediate cardiopulmonary resuscitation with defibrillation. Further diagnostic and therapeutic measures such as cardiac catheterization should be considered thereafter. If ventricular fibrillation cannot be terminated or repeated reinduction occurs, veno-arterial extracorporeal membrane oxygenation (VA-ECMO) can buy the time needed to identify the cause and initiate specific treatment.

Supraventricular arrhythmias.

Atrial fibrillation accounts for approximately 90% of all perioperative supraventricular arrhythmias.

Unclear state of the evidence.

The indications for permanent oral anticoagulation in patients with perioperative atrial fibrillation are less clear than in those with spontaneous atrial fibrillation.

Bradycardias

Perioperative bradycardias only rarely treatment. The cause is usually a vagal reaction. A hemodynamically relevant bradyarrhythmia can be treated with atropine. Persistent high-grade AV block (second-degree AV block of Mobitz type, third-degree AV block) should be treated in collaboration with a cardiologist.

The potential indication for a temporary pacemaker should be carefully considered; the criteria are no different than for bradycardias of non-perioperative onset.

Overview

Perioperative arrhythmias are common and associated with elevated morbidity and mortality. Especially in the context of operations that are frequently associated with new-onset arrhythmias, the identification of patients at risk is crucial.

Immediate treatment is needed in case of hemodynamic compromise; otherwise, one may wait, at least initially, for a spontaneous conversion, which is common. The evaluation and treatment of persistent ventricular arrhythmias are a complex matter that should be handled in collaboration with a cardiologist. In addition to acute treatment, patients with certain types of arrhythmia can benefit from continued outpatient cardiologic follow-up.

Torsade de pointes tachycardia.

Torsade de pointes tachycardia should be treated initially with the same measures just mentioned for ventricular tachycardia, along with the discontinuation of all drugs that can prolong the QT time and the prompt correction of any existing electrolyte disturbance.

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Only one answer is possible per question. Please select the answer that is most appropriate.

Question 1

What treatment should be considered in patients at increased risk of stroke who develop atrial fibrillation after non-cardiac surgery, as recommended in the 2020 ESC guidelines?

1. low-molecular-weight heparin until recovery of sinus rhythm

2. oral anticoagulation for four weeks

3. ASA 100 mg/day indefinitely

4. oral anticoagulation indefinitely

5. no oral anticoagulation in case of spontaneous termination of atrial fibrillation during hospitalization

Question 2

What immediate measure is the treatment of first choice for hemodynamically significant postoperative tachycardia?

1. catheter ablation

2. intravenous flecainide

3. Valsalva maneuver

4. electrical cardioversion

5. fluid administration

Question 3

What is the maximum reported frequency of perioperative arrhythmias after cardiac surgery?

1. 50–60%

2. 60–70%

3. 70–80%

4. 80–90%

5. > 90%

Question 4

What is among the standard preoperative diagnostic tests before cardiac surgery?

1. the vibration threshold test

2. the ankle-brachial index test

3. an exercise ECG

4. a 12-lead ECG

5. measurement of the urinary vitamin K concentration

Question 5

What cardiac arrhythmia is commonly associated with acute myocardial ischemia?

1. polymorphic ventricular tachycardia

2. AV nodal re-entrant tachycardia

3. monomorphic ventricular tachycardia

4. tachycardic new-onset atrial fibrillation

5. AV re-entrant tachycardia

Question 6

Torsade de pointes tachycardias are characteristic of what syndrome?

1. Brugada syndrome

2. long QT syndrome

3. WPW syndrome

4. carotid sinus syndrome

5. sick sinus syndrome

Question 7

What drug can be used to treat monomorphic ventricular tachycardia?

1. adenosine

2. acetylcholine

3. amiodarone

4. neostigmine

5. flumazenil

Question 8

What is a common cause of transient perioperative bradycardia?

1. activation of the autonomic nervous system

2. hypercapnia under mechanical ventilation

3. hypovolemia

4. an overdose of drugs that cause bradycardia

5. acute myocardial ischemia

Question 9

A patient develops AV nodal re-entrant tachycardia perioperatively, which is terminated with adenosine. What further treatment is indicated?

1. indefinite administration of amiodarone

2. bolus administration of acetylsalicylic acid

3. recommendation for catheter ablation

4. coronary angiography in the short term

5. exercise ECG before hospital discharge

Question 10

Which of the following is not included in the Revised Cardiac Risk Index as a risk factor for a major cardiac event?

1. coronary artery disease

2. high-risk surgery

3. heart failure

4. cerebrovascular disease

5. alanine aminotransferase level < 40 U/L