How should symptomatic bradycardia during hemodialysis be treated?

Management of Symptomatic Bradycardia During Hemodialysis

Stop dialysis immediately, correct electrolytes (especially potassium, magnesium, and calcium), administer atropine 0.5–1 mg IV if the patient is symptomatic, and prepare for transcutaneous pacing while arranging emergent cardiology consultation. 1

Immediate Actions (First 5 Minutes)

• Discontinue hemodialysis immediately to halt ongoing electrolyte shifts and volume changes that are triggering the dysrhythmogenic state. 1
• Assess hemodynamic stability by checking for altered mental status, hypotension (systolic BP <90 mmHg), signs of shock, syncope, or presyncope—all of which indicate the bradycardia is causing inadequate perfusion. 2, 1
• Obtain stat electrolytes (potassium, calcium, magnesium) before any other intervention, as dialysis-induced electrolyte fluctuations are the primary trigger for life-threatening dysrhythmias in this population. 1
• Attach continuous ECG monitoring and establish IV access if not already present. 2

Critical Electrolyte Management (Class I Priority)

• Correct magnesium first, as hypokalemia and hypocalcemia are refractory to replacement without adequate magnesium. 1
• Maintain potassium levels between 3.5–4.5 mmol/L, as both hyper- and hypokalemia can precipitate bradyarrhythmias during dialysis. 1
• Correct calcium abnormalities, as dialysis-induced hypocalcemia worsens conduction abnormalities. 1
• Monitor electrolytes during and for 4–5 hours post-dialysis in all subsequent sessions, as the dysrhythmogenic window extends well beyond the treatment period. 1

Pharmacologic Management

First-Line: Atropine

• Administer atropine 0.5–1 mg IV bolus for symptomatic bradycardia, repeatable every 3–5 minutes up to a total of 3 mg. 2, 1
• Avoid doses <0.5 mg, as they may paradoxically worsen bradycardia. 2
• Atropine is most effective for sinus bradycardia and AV nodal blocks but less effective for infranodal (wide QRS escape) blocks. 2, 1
• Do not rely on atropine for third-degree AV block with wide QRS escape rhythm, as the block is in non-nodal tissue and will not respond to vagolytic agents. 1

Second-Line: Catecholamine Infusions (Use with Caution)

• Consider catecholamine infusions only if atropine fails and the patient has low risk for coronary ischemia—a critical consideration given the high prevalence of coronary artery disease in dialysis patients. 2
• Dopamine 5–20 µg/kg/min IV is preferred when combined chronotropic and inotropic support is needed. 2
• Epinephrine 2–10 µg/min IV or 0.1–0.5 µg/kg/min IV can be titrated to achieve target heart rate. 2
• Avoid catecholamines in patients at high risk for coronary ischemia, as they increase myocardial oxygen demand. 2

Temporary Pacing (Bridge Therapy)

• Initiate transcutaneous pacing immediately in hemodynamically unstable patients while preparing for definitive transvenous pacing. 2, 1
• Transcutaneous pacing is only a bridge and requires sedation/analgesia due to pain; it is not superior to drug therapy but is necessary when drugs fail. 2, 1
• Transvenous pacing is indicated for persistent hemodynamic instability refractory to medical therapy, with a complication rate of 14–40% (venous thrombosis, pulmonary emboli, arrhythmias, perforation). 2

Dialysis-Specific Considerations

• Third-degree heart block during dialysis represents a convergence of multiple risk factors: left ventricular hypertrophy (present in ~80% of dialysis patients), underlying coronary artery disease, and electrolyte fluctuations. 1
• Adjust future dialysis prescriptions to minimize recurrence by using cooler dialysate temperature, slower ultrafiltration rates, and optimizing dialysate potassium (3.5 mEq/L) and calcium (3 mEq/L) concentrations. 1, 3
• Consider catheter malposition if bradycardia is recurrent and temporally related to dialysis initiation—the catheter tip may be irritating the sinoatrial node if positioned too low in the superior vena cava. 4

Reversible Causes to Evaluate (Class I)

Reversible Cause	Evaluation	Treatment
Medications (β-blockers, calcium-channel blockers, digoxin, amiodarone, sotalol, tizanidine, fomepizole)	Review drug list	Discontinue or reduce dose [2,5,6]
Electrolyte abnormalities (K⁺, Mg²⁺, Ca²⁺)	Stat serum levels	Correct imbalances before any other intervention [1]
Acute myocardial infarction (especially inferior)	Cardiac biomarkers, ECG	Treat ischemia; bradycardia often resolves [2]
Catheter malposition	Review chest X-ray for catheter tip location	Reposition catheter if tip is touching SVC wall [4]
Drug toxicity (fomepizole during dialysis)	History of recent infusion	Monitor vital signs closely during and after infusion [6]

Monitoring and Disposition

• Continuous ECG monitoring is mandatory until permanent pacemaker placement or resolution of reversible cause, as infranodal blocks can progress unpredictably to asystole. 1
• All dialysis units must have on-site automatic external defibrillators (AEDs), as 61% of cardiac deaths in dialysis patients are due to arrhythmic mechanisms, with a cardiac arrest rate of 7 events per 100,000 dialysis sessions. 2

Indications for Permanent Pacemaker

• Permanent pacing is indicated (Class I) when symptomatic bradycardia persists after reversible causes have been excluded or adequately treated. 2
• High-grade AV block (Mobitz II or third-degree) with symptoms is a Class I indication for permanent pacing. 2

Common Pitfalls to Avoid

• Do not continue dialysis once symptomatic bradycardia develops—ongoing electrolyte shifts will worsen the arrhythmia. 1
• Do not correct hypokalemia or hypocalcemia without checking and correcting magnesium first, as these will be refractory to replacement. 1
• Do not assume bradycardia is benign in dialysis patients—it likely reflects drug-induced or electrolyte-induced decompensation of an already compromised conduction system. 1
• Do not administer atropine to heart-transplant recipients, as it may precipitate high-grade AV block. 2