Anesthetic Management of Sick Sinus Syndrome
Direct Recommendation
Patients with sick sinus syndrome require temporary transvenous pacing capability immediately available before anesthetic induction, as atropine is frequently ineffective and severe bradycardia or asystole can occur unpredictably even in asymptomatic patients. 1, 2, 3, 4
Preoperative Assessment and Risk Stratification
Identify High-Risk Features
Eliminate or hold bradycardia-exacerbating medications before surgery, including beta-blockers, non-dihydropyridine calcium channel blockers (verapamil, diltiazem), cardiac glycosides, and Class IC antiarrhythmics (flecainide, propafenone), as these unmask underlying sinus node dysfunction. 5, 6
Recognize that preoperative ECG may be completely normal in patients with latent or concealed sick sinus syndrome who will still develop severe intraoperative bradycardia or asystole. 1, 2, 3, 4
Age is a critical risk factor, as degenerative fibrosis affecting the sinus node predominantly affects patients in their 70s-80s. 5
Pacing Strategy Decision
Temporary transvenous pacing is mandatory for any patient with known or suspected sick sinus syndrome undergoing general anesthesia, even if asymptomatic preoperatively. 4
Set pacing mode to fixed-rate asynchronous ventricular pacing (VOO) at 50-60 bpm after anesthetic induction to prevent competition with intrinsic rhythm while ensuring backup pacing. 4
Have transcutaneous pacing pads applied and equipment immediately available as a bridge if urgent pacing is needed before transvenous access can be established. 7
Intraoperative Management
Hemodynamic Goals
Maintain sinus rhythm with normal heart rate and avoid hypotension, as tachycardia and systemic hypotension decrease coronary perfusion pressure and can trigger arrhythmias, myocardial injury, or death. 5, 8
Target mean arterial pressure ≥60-65 mmHg and titrate vasopressors to maintain blood pressure within the patient's normal range. 8
Monitoring Requirements
Continuous ECG monitoring is mandatory throughout the perioperative period to quickly identify arrhythmias. 5
Invasive hemodynamic monitoring (arterial line and central venous pressure) should be used for intermediate to high-risk procedures. 5
Anesthetic Drug Selection
All standard anesthetic agents are acceptable, but recognize that propofol, remifentanil, and epidural anesthesia with local anesthetics all have vagomimetic effects that can precipitate severe bradycardia or asystole. 1, 2, 3
Avoid combining multiple vagomimetic techniques (e.g., remifentanil infusion plus thoracic epidural) unless temporary pacing is in place, as this combination has caused prolonged asystole. 2, 3
Vasopressor Selection
Use norepinephrine or phenylephrine to increase blood pressure in patients without significant coronary artery disease. 8
Phenylephrine provides pure vasoconstriction without cardiac stimulation, while norepinephrine adds beta-agonist cardiac support, making it preferable if bradycardia or reduced contractility coexist. 8
Never use topical phenylephrine, as it has caused severe hypertension, pulmonary edema, cardiac arrest, and death. 8
Management of Intraoperative Bradycardia
Atropine (0.5-1.5 mg IV) is frequently ineffective in restoring normal heart rate in sick sinus syndrome patients. 1, 2, 3, 4
Immediately initiate temporary pacing if atropine fails, rather than escalating atropine doses. 1, 4
If asystole occurs without pacing capability, begin chest compressions immediately and administer dopamine (5 mcg/kg/min) or isoproterenol infusion while establishing emergent pacing. 2, 6
Postoperative Management
Monitoring Duration
Continue monitoring for 24-48 hours postoperatively until hemodynamics are stable. 8
Maintain temporary pacing capability until the patient is fully recovered from anesthesia and hemodynamically stable. 4
Definitive Treatment
Arrange urgent permanent pacemaker implantation if sick sinus syndrome is diagnosed perioperatively, as this is the definitive treatment for symptomatic disease. 5, 6
Physiological pacing (atrial or dual-chamber DDDR) is superior to VVI pacing and minimizes exertion-related symptoms while lowering the risk of atrial fibrillation. 7, 5, 6
Recognize that approximately 20% of patients experience recurrent syncope despite adequate pacing due to associated vasodepressor reflex mechanisms, requiring close follow-up. 7, 5, 6
Critical Pitfalls to Avoid
Do not rely on preoperative ECG to exclude sick sinus syndrome, as concealed disease is common and only manifests under anesthetic stress. 1, 2, 3
Do not assume atropine will be effective for treating intraoperative bradycardia in these patients—have pacing ready. 1, 2, 3, 4
Do not use beta-blockers to treat hypertension from topical phenylephrine, as this can precipitate severe bradycardia. 8
Do not proceed with elective surgery without temporary pacing capability in patients with known sick sinus syndrome, even if asymptomatic. 4