Bradycardia SymptomsAPPROACH

CHEST AND CARDIOVASCULAR · 19 SECTIONS

⚲

523 items

☷ Legend

⚲

Resuscitation and Universal Approaches9▾

Chest and Cardiovascular12▾

Pacemaker And Icd Related Presentations Acute Limb Ischemia And Leg Pain Suspected Deep Vein Thrombosis Symptoms Hypertension Chest Pain Palpitations And Tachyarrhythmia Symptoms Bradycardia Symptoms Syncope And Presyncope Syncope With Neurologic Concern Unilateral Leg Swelling Bilateral Leg Swelling Calf Pain And Swelling

Respiratory11▾

Abdominal and Gastrointestinal24▾

Renal and Urinary7▾

Neurologic11▾

Back and Neck8▾

Women's Health, Pregnancy, and GU11▾

Infectious Disease and Fever Syndromes11▾

Allergy and Dermatology7▾

Musculoskeletal and Extremities14▾

Trauma and Wounds14▾

ENT, Eye, Dental10▾

Endocrine, Metabolic, and Abnormal Labs9▾

Toxicology and Behavioral14▾

Pediatrics16▾

Environmental and Exposure4▾

01History/hx77

Presenting pattern

›Symptom context

›Bradycardia awareness

›Incidental low heart rate on device or triage vitals

›Symptom onset relative to rest

›Symptom onset relative to exertion

›Symptom onset relative to sleep

›Symptom pattern

›Constant

›Episodic

›Postural

›Situational

›Baseline heart rate if known

›Prior episodes

›Response to prior interventions

OPQRST

›OPQRST for predominant symptom

›Onset

›Sudden

›Gradual

›First episode

›Recurrent

›Provocation and palliation

›Exertion related

›Postural trigger

›Valsalva trigger

›Cough trigger

›Micturition trigger

›Pain trigger

›Relief with lying flat

›Relief with stopping activity

›Quality

›Lightheadedness

›Presyncope

›Syncope

›Fatigue

›Weakness

›Dyspnea

›Chest discomfort

›Confusion

›Region and radiation

›Chest discomfort location

›Radiation pattern if present

›Severity

›Functional limitation

›Near fall

›Injury

›Unable to ambulate

›Timing

›Duration of episodes

›Frequency

›Time of day pattern

›Relation to meals

Associated symptoms

›Symptom cluster

›Chest pain features

›Dyspnea features

›Palpitations

›Diaphoresis

›Nausea

›Vomiting

›Altered mental status

›Seizure like activity

›Focal neurologic symptoms

›Fever

›Rash

›Recent infection symptoms

Reversible cause clues

›Trigger and exposure history

›Recent medication change

›Missed doses

›Extra doses

›Recent procedure

›Recent ablation

›Recent cardiac surgery

›Recent catheterization

›Recent tick exposure

›Cold exposure

›Heat illness

›Vomiting and diarrhea

›Poor oral intake

02Alarm Features/alarm29

Immediate escalation triggers

›Unstable bradycardia features

›Hypotension with end organ signs

›Altered mental status

›Ischemic chest pain

›Acute heart failure

›Shock

›Recurrent syncope

›Ventricular arrhythmia

Vital sign danger thresholds

›High risk vitals pattern

›Heart rate less than 40 with symptoms

›Heart rate less than 50 with ischemia

›Systolic blood pressure less than 90

›Respiratory distress

›Oxygen saturation less than 90 despite oxygen

High risk ECG patterns

›ECG red flags

›High grade AV block

›Complete heart block

›Mobitz type II

›Ventricular escape rhythm

›Wide QRS escape rhythm

›Pauses 3 seconds or longer with symptoms

High risk contexts

›High risk history

›Recent myocardial infarction

›Post cardiac surgery

›Known conduction disease

›Pacemaker dependence concern

›Suspected toxic ingestion

›Hyperkalemia risk

›Hypothermia

03Medications/meds19

Bradycardia provoking agents

›Medication classes associated with bradycardia

›Beta blocker exposure

›Non dihydropyridine calcium channel blocker exposure

›Digoxin exposure

›Amiodarone exposure

›Sotalol exposure

›Clonidine exposure

›Opioid exposure

›Sedative exposure

›Cholinesterase inhibitor exposure

Recent changes and interactions

›Medication timeline

›New prescriptions within 14 days

›Dose increase within 14 days

›Renal function change with renally cleared agents

›Drug interactions increasing levels

Relevant therapeutic contraindications

›Contraindication screen for common ED therapies

›Atropine caution in cardiac transplant

›Pacing caution in severe hypothermia until rewarming

›Catecholamine infusion caution in active ischemia

04Diet/diet13

Intake and hydration

›Intake status

›Decreased intake

›Vomiting

›Diarrhea

›Dehydration symptoms

Caffeine and stimulants

›Stimulant exposure pattern

›Caffeine reduction

›Energy drinks

›Pre workout supplements

Alcohol and substances

›Substance exposure pattern

›Alcohol binge

›Cannabis exposure

›Other substance exposure

05Review of Systems/ros30

Cardiovascular

›Cardiovascular symptoms

›Chest pain

›Dyspnea

›Orthopnea

›Paroxysmal nocturnal dyspnea

›Edema

›Palpitations

›Exercise intolerance

Neurologic

›Neurologic symptoms

›Syncope

›Presyncope

›Dizziness

›Confusion

›Focal weakness

›Speech change

›Headache

›Seizure like activity

Infectious and endocrine

›Systemic symptoms

›Fever

›Chills

›Weight gain

›Cold intolerance

›Fatigue

›Myalgias

Toxicologic

›Toxicologic symptoms

›Nausea

›Vomiting

›Visual changes

›Diarrhea

›Altered mental status

06Collateral History and Family History/chafh14

Collateral sources

›Collateral information

›EMS report

›Family witness account

›Caregiver account

›Device downloads

Family history

›Inherited and early cardiac disease

›Sudden cardiac death in first degree relative

›Early coronary disease in first degree relative

›Inherited channelopathy history

›Cardiomyopathy history

Social support reliability

›Supervision and follow up reliability

›Lives alone

›Reliable escort available

›Ability to return if worse

07Risk Factors/rf21

Structural and conduction disease risks

›Cardiac risk factors

›Coronary artery disease

›Prior myocardial infarction

›Cardiomyopathy

›Heart failure

›Prior valve disease

›Prior endocarditis

›Known bundle branch block

Metabolic and endocrine risks

›Metabolic risk factors

›Chronic kidney disease

›Diabetes mellitus

›Thyroid disease

Exposure risks

›Exposure risks

›Tick exposure risk for Lyme disease

›Toxic ingestion risk

›Medication access risk

Special populations

›Population specific risks

›Pregnancy

›Older adult frailty

›Immunocompromised state

›Cardiac transplant

08Differential Diagnosis/ddx59

Life threatening

›Life threatening etiologies

›High grade AV block

›Mobitz type II second degree AV block (I44.1)

›Complete AV block (I44.2)

›Acute coronary syndrome with conduction involvement

›Inferior myocardial infarction

›Anterior myocardial infarction with infranodal block

›Hyperkalemia induced conduction abnormality (E87.5)

›Bradycardia with wide QRS

›Sine wave progression

›Beta blocker toxicity (T44.7)

›Hypotension

›Hypoglycemia

›Calcium channel blocker toxicity (T46.1)

›Hypotension

›Hyperglycemia

›Digoxin toxicity (T46.0)

›GI symptoms

›Visual changes

›Severe hypothermia (T68)

›J waves

›Ventricular irritability

›Cardiac tamponade (I31.4)

›Hypotension

›Elevated jugular venous pressure

Common

›Common etiologies

›Sinus bradycardia (R00.1)

›High vagal tone

›Sleep related

›Athlete physiology

›Medication effect

›Beta blockers

›Calcium channel blockers

›Digoxin

›Sedatives

›Sick sinus syndrome (I49.5)

›Tachy brady syndrome

›Sinus pauses

›Hypothyroidism (E03.9)

›Weight gain

›Cold intolerance

Less common

›Less common etiologies

›Myocarditis

›Viral prodrome

›Troponin elevation

›Lyme carditis (A69.2)

›Fluctuating AV block

›Outdoor exposure

›Infiltrative disease

›Sarcoidosis

›Amyloidosis

›Elevated intracranial pressure

›Cushing reflex

›Head trauma history

Mimics and pitfalls

›Mimics and pitfalls

›Pulse oximeter artifact

›Frequent ectopy with pulse deficit

›Junctional rhythm misread as sinus bradycardia

›Asymptomatic physiologic bradycardia

09Past Medical History/pmh17

Cardiac history

›Prior cardiac conditions

›Coronary artery disease

›Prior myocardial infarction

›Heart failure history

›Valvular disease history

›Prior myocarditis

Conduction and device history

›Conduction system history

›Known AV block

›Prior syncope evaluation

›Prior electrophysiology study

›Prior ablation

›Pacemaker

›Implantable cardioverter defibrillator

Baseline function

›Baseline status

›Baseline exercise tolerance

›Baseline cognitive status

›Baseline heart rate range if known

10Physical Exam/exam31

General and hemodynamics

›Overall stability

›Mental status

›Work of breathing

›Perfusion

›Capillary refill

›Skin temperature

›Volume status

›Dry mucous membranes

›Jugular venous pressure

Cardiovascular exam

›Cardiovascular findings

›Heart rate regularity

›Murmur

›Gallop

›Signs of heart failure

›Pulmonary crackles

›Peripheral edema

Pulmonary exam

›Respiratory findings

›Crackles

›Wheeze

›Increased work of breathing

Neurologic exam

›Neurologic findings

›Focal deficit screen

›Gait stability if safe

›Speech

›Pupils

Toxicologic and endocrine clues

›Exam clues for reversible causes

›Hypothermia signs

›Pinpoint pupils

›Diaphoresis

›Skin rash

›Erythema migrans concern

11Lab Studies/labs29

Core labs and interpretation

›Essential laboratory evaluation

›Glucose

›Hypoglycemia as contributor

›Hyperglycemia suggesting calcium channel blocker toxicity

›Electrolytes

›Potassium

›Calcium

›Magnesium

›Creatinine

›Renal impairment increasing drug levels

›Complete blood count

›Anemia contributing to symptoms

›Leukocytosis suggesting infection

Targeted labs

›Etiology directed tests

›High sensitivity troponin

›Ischemia concern

›Myocarditis concern

›Thyroid stimulating hormone

›Hypothyroidism concern

›Myxedema features

›Digoxin level

›Digoxin exposure

›Drug interaction concern

›Toxicology screen

›Suspected ingestion

›Unknown pill exposure

Pitfalls and limitations

›Laboratory limitations

›Serum drug levels may not correlate with severity early

›Troponin may be normal early in acute coronary syndrome

12Imaging/img17

Scoring Systems

›Risk tools for syncope context

›Canadian Syncope Risk Score

›Use when syncope or near syncope in ED evaluation

›Avoid when persistent instability requiring resuscitation pathway

›San Francisco Syncope Rule

›Use when syncope with uncertain disposition

›Limited performance variability by setting

MRI

›MRI considerations

›Cardiac MRI for myocarditis concern

›Device conditional safety check for implanted devices

›CT considerations

›CT head for head injury after syncope when indicated

›CT pulmonary angiography only if pulmonary embolism concern based on risk assessment

Ultrasound

›Ultrasound and POCUS

›Cardiac POCUS for tamponade physiology

›Cardiac POCUS for severe left ventricular dysfunction

›Inferior vena cava assessment as adjunct for volume status

13Special Tests/spec7

Bedside diagnostics

›Bedside evaluation adjuncts

›Orthostatic vitals when safe

›Point of care glucose confirmation

›Core temperature measurement

Response based tests

›Therapeutic diagnostic responses

›Atropine response suggesting nodal level block

›Pacing capture response confirming bradycardia mechanism contribution

14ECG/ecg28

Acquisition and monitoring

›ECG strategy

›12 lead ECG early in symptomatic bradycardia

›Continuous telemetry

›Repeat ECG after interventions

Rhythm and conduction patterns

›Bradycardia pattern recognition

›Sinus bradycardia

›Sinus pause

›Junctional rhythm

›Atrial fibrillation with slow ventricular response

AV block identification

›AV block patterns

›First degree AV block (I44.0)

›Prolonged PR with 1 to 1 conduction

›Often benign if asymptomatic

›Second degree AV block type I (Wenckebach) (I44.1)

›Progressive PR prolongation

›Dropped QRS

›Second degree AV block type II (I44.1)

›Fixed PR

›Dropped QRS

›Higher risk of progression

›Third degree AV block (I44.2)

›AV dissociation

›Escape rhythm

High risk ECG features

›ECG danger features

›Wide QRS escape rhythm

›Ventricular pause 3 seconds or longer

›Ischemic changes

›Hyperkalemia pattern features

15Assessment/ax24

Problem representation

›Syndrome summary

›Symptomatic bradycardia with pulse

›Asymptomatic bradycardia

›Bradycardia with syncope

Severity and risk stratification

›Severity features

›Hemodynamic instability

›End organ hypoperfusion

›Requirement for pacing

›High risk conduction disease features

›Mobitz type II

›Complete heart block

›Wide QRS escape rhythm

Reversible causes framework

›Reversible causes

›Ischemia

›Hypoxia

›Electrolyte abnormality

›Hypothermia

›Drug toxicity

›Endocrine disorder

Working diagnoses

›Working diagnosis options

›Sinus bradycardia (R00.1)

›Sick sinus syndrome (I49.5)

›Second degree AV block (I44.1)

›Complete AV block (I44.2)

16Plan/plan57

First 5 minutes workflow

›Immediate stabilization sequence

›Airway patency and oxygen if hypoxemic

›Cardiac monitor

›Defibrillator pads for pacing readiness

›IV access

›At least one large bore peripheral line

›Two lines if unstable or toxin concern

›12 lead ECG early

›Point of care glucose

›Reversible causes targeted treatment initiation

Algorithm based treatment

›Symptomatic bradycardia treatment pathway

›Atropine IV

›Dose 1 mg bolus

›Repeat every 3 to 5 minutes

›Maximum total 3 mg

›If atropine ineffective

›Transcutaneous pacing

›Analgesia and sedation if awake and time allows

›Mechanical capture confirmation

›Epinephrine infusion

›Dose 2 to 10 mcg per minute

›Titrate to perfusion targets

›Dopamine infusion

›Dose 5 to 20 mcg per kg per minute

›Titrate to perfusion targets

›Expert consultation

›Cardiology

›Electrophysiology when available

›Transvenous pacing

›Persistent instability despite above

›High grade AV block

Reversible cause directed therapies

›Etiology specific interventions

›Hyperkalemia management when suspected

›Calcium salt for ECG changes

›Insulin with dextrose

›Beta agonist therapy

›Dialysis pathway when indicated

›Beta blocker toxicity pathway

›Glucagon per local protocol dependent

›High dose insulin euglycemia therapy per local protocol dependent

›Lipid emulsion per local protocol dependent

›Calcium channel blocker toxicity pathway

›Calcium salts

›High dose insulin euglycemia therapy per local protocol dependent

›Vasopressor support per response

›Digoxin toxicity pathway

›Digoxin immune Fab per local protocol dependent

›Avoid calcium in severe digoxin toxicity concern

›Hypothermia pathway

›Active rewarming

›Gentle handling

Monitoring and reassessment loop

›Reassessment cadence

›Vitals every 5 minutes in unstable patient

›Mental status trend

›Perfusion markers

›Repeat ECG after each major intervention

›Infusion titration every 5 to 10 minutes to effect

17Disposition/dispo21

ICU criteria

›ICU level of care indications

›Transvenous pacing required

›Ongoing vasopressor or chronotrope infusion

›Persistent hypotension

›High grade AV block with instability

Inpatient admission criteria

›Admission indications

›Symptomatic bradycardia requiring ED intervention

›New high grade AV block

›Suspected acute coronary syndrome

›Suspected myocarditis

›Suspected Lyme carditis

›Drug toxicity requiring monitoring

Observation pathway criteria

›Observation considerations

›Transient medication related bradycardia with resolved symptoms

›Normalizing vitals after correction of reversible cause

Discharge criteria

›Discharge requirements

›Asymptomatic at rest and with brief ambulation when appropriate

›No high risk ECG features

›Reversible cause corrected or clearly identified with safe plan

›Reliable follow up within 72 hours when indicated

›Return precautions understood and feasible

18Discharge Instructions/di14

Copy discharge instructions

›Patient facing instructions

›Low heart rate was found and may cause dizziness or fainting

›Avoid extra doses of heart rate lowering medications unless specifically instructed

›Hydration and regular meals if dehydration contributed

›Follow up timing

›Primary care within 3 to 7 days

›Cardiology within 7 to 14 days if ongoing low heart rate or abnormal ECG

›Return to emergency department immediately for

›Fainting

›Chest pain

›Shortness of breath

›Confusion

›Weakness worsening

›Heart rate very low with symptoms

19References/r16

Guidelines and algorithms

›Evidence based sources

›American Heart Association

›Adult bradycardia with a pulse algorithm

›2025

›American College of Cardiology

›ACC AHA HRS guideline on bradycardia and conduction delay

›2018

›Circulation

›Adult advanced life support guideline update

›2025

›Resuscitation Council UK

›Adult bradycardia algorithm

›2021

›European Resuscitation Council

›Guidelines on cardiopulmonary resuscitation

›2025

Evidence & Review

Reviewed by SymptomDx Medical Team · Last reviewed February 24, 2026

SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.

Bradycardia SymptomsAPPROACH

CHEST AND CARDIOVASCULAR · 19 SECTIONS

⚲

523 items

☷ Legend

⚲

Resuscitation and Universal Approaches9▾

Chest and Cardiovascular12▾

Respiratory11▾

Abdominal and Gastrointestinal24▾

Renal and Urinary7▾

Neurologic11▾

Back and Neck8▾

Women's Health, Pregnancy, and GU11▾

Infectious Disease and Fever Syndromes11▾

Allergy and Dermatology7▾

Musculoskeletal and Extremities14▾

Trauma and Wounds14▾

ENT, Eye, Dental10▾

Endocrine, Metabolic, and Abnormal Labs9▾

Toxicology and Behavioral14▾

Pediatrics16▾

Environmental and Exposure4▾

01History/hx77

Presenting pattern

›Symptom context

›Bradycardia awareness

›Incidental low heart rate on device or triage vitals

›Symptom onset relative to rest

›Symptom onset relative to exertion

›Symptom onset relative to sleep

›Symptom pattern

›Constant

›Episodic

›Postural

›Situational

›Baseline heart rate if known

›Prior episodes

›Response to prior interventions

OPQRST

›OPQRST for predominant symptom

›Onset

›Sudden

›Gradual

›First episode

›Recurrent

›Provocation and palliation

›Exertion related

›Postural trigger

›Valsalva trigger

›Cough trigger

›Micturition trigger

›Pain trigger

›Relief with lying flat

›Relief with stopping activity

›Quality

›Lightheadedness

›Presyncope

›Syncope

›Fatigue

›Weakness

›Dyspnea

›Chest discomfort

›Confusion

›Region and radiation

›Chest discomfort location

›Radiation pattern if present

›Severity

›Functional limitation

›Near fall

›Injury

›Unable to ambulate

›Timing

›Duration of episodes

›Frequency

›Time of day pattern

›Relation to meals

Associated symptoms

›Symptom cluster

›Chest pain features

›Dyspnea features

›Palpitations

›Diaphoresis

›Nausea

›Vomiting

›Altered mental status

›Seizure like activity

›Focal neurologic symptoms

›Fever

›Rash

›Recent infection symptoms

Reversible cause clues

›Trigger and exposure history

›Recent medication change

›Missed doses

›Extra doses

›Recent procedure

›Recent ablation

›Recent cardiac surgery

›Recent catheterization

›Recent tick exposure

›Cold exposure

›Heat illness

›Vomiting and diarrhea

›Poor oral intake

02Alarm Features/alarm29

Immediate escalation triggers

›Unstable bradycardia features

›Hypotension with end organ signs

›Altered mental status

›Ischemic chest pain

›Acute heart failure

›Shock

›Recurrent syncope

›Ventricular arrhythmia

Vital sign danger thresholds

›High risk vitals pattern

›Heart rate less than 40 with symptoms

›Heart rate less than 50 with ischemia

›Systolic blood pressure less than 90

›Respiratory distress

›Oxygen saturation less than 90 despite oxygen

High risk ECG patterns

›ECG red flags

›High grade AV block

›Complete heart block

›Mobitz type II

›Ventricular escape rhythm

›Wide QRS escape rhythm

›Pauses 3 seconds or longer with symptoms

High risk contexts

›High risk history

›Recent myocardial infarction

›Post cardiac surgery

›Known conduction disease

›Pacemaker dependence concern

›Suspected toxic ingestion

›Hyperkalemia risk

›Hypothermia

03Medications/meds19

Bradycardia provoking agents

›Medication classes associated with bradycardia

›Beta blocker exposure

›Non dihydropyridine calcium channel blocker exposure

›Digoxin exposure

›Amiodarone exposure

›Sotalol exposure

›Clonidine exposure

›Opioid exposure

›Sedative exposure

›Cholinesterase inhibitor exposure

Recent changes and interactions

›Medication timeline

›New prescriptions within 14 days

›Dose increase within 14 days

›Renal function change with renally cleared agents

›Drug interactions increasing levels

Relevant therapeutic contraindications

›Contraindication screen for common ED therapies

›Atropine caution in cardiac transplant

›Pacing caution in severe hypothermia until rewarming

›Catecholamine infusion caution in active ischemia

04Diet/diet13

Intake and hydration

›Intake status

›Decreased intake

›Vomiting

›Diarrhea

›Dehydration symptoms

Caffeine and stimulants

›Stimulant exposure pattern

›Caffeine reduction

›Energy drinks

›Pre workout supplements

Alcohol and substances

›Substance exposure pattern

›Alcohol binge

›Cannabis exposure

›Other substance exposure

05Review of Systems/ros30

Cardiovascular

›Cardiovascular symptoms

›Chest pain

›Dyspnea

›Orthopnea

›Paroxysmal nocturnal dyspnea

›Edema

›Palpitations

›Exercise intolerance

Neurologic

›Neurologic symptoms

›Syncope

›Presyncope

›Dizziness

›Confusion

›Focal weakness

›Speech change

›Headache

›Seizure like activity

Infectious and endocrine

›Systemic symptoms

›Fever

›Chills

›Weight gain

›Cold intolerance

›Fatigue

›Myalgias

Toxicologic

›Toxicologic symptoms

›Nausea

›Vomiting

›Visual changes

›Diarrhea

›Altered mental status

06Collateral History and Family History/chafh14

Collateral sources

›Collateral information

›EMS report

›Family witness account

›Caregiver account

›Device downloads

Family history

›Inherited and early cardiac disease

›Sudden cardiac death in first degree relative

›Early coronary disease in first degree relative

›Inherited channelopathy history

›Cardiomyopathy history

Social support reliability

›Supervision and follow up reliability

›Lives alone

›Reliable escort available

›Ability to return if worse

07Risk Factors/rf21

Structural and conduction disease risks

›Cardiac risk factors

›Coronary artery disease

›Prior myocardial infarction

›Cardiomyopathy

›Heart failure

›Prior valve disease

›Prior endocarditis

›Known bundle branch block

Metabolic and endocrine risks

›Metabolic risk factors

›Chronic kidney disease

›Diabetes mellitus

›Thyroid disease

Exposure risks

›Exposure risks

›Tick exposure risk for Lyme disease

›Toxic ingestion risk

›Medication access risk

Special populations

›Population specific risks

›Pregnancy

›Older adult frailty

›Immunocompromised state

›Cardiac transplant

08Differential Diagnosis/ddx59

Life threatening

›Life threatening etiologies

›High grade AV block

›Mobitz type II second degree AV block (I44.1)

›Complete AV block (I44.2)

›Acute coronary syndrome with conduction involvement

›Inferior myocardial infarction

›Anterior myocardial infarction with infranodal block

›Hyperkalemia induced conduction abnormality (E87.5)

›Bradycardia with wide QRS

›Sine wave progression

›Beta blocker toxicity (T44.7)

›Hypotension

›Hypoglycemia

›Calcium channel blocker toxicity (T46.1)

›Hypotension

›Hyperglycemia

›Digoxin toxicity (T46.0)

›GI symptoms

›Visual changes

›Severe hypothermia (T68)

›J waves

›Ventricular irritability

›Cardiac tamponade (I31.4)

›Hypotension

›Elevated jugular venous pressure

Common

›Common etiologies

›Sinus bradycardia (R00.1)

›High vagal tone

›Sleep related

›Athlete physiology

›Medication effect

›Beta blockers

›Calcium channel blockers

›Digoxin

›Sedatives

›Sick sinus syndrome (I49.5)

›Tachy brady syndrome

›Sinus pauses

›Hypothyroidism (E03.9)

›Weight gain

›Cold intolerance

Less common

›Less common etiologies

›Myocarditis

›Viral prodrome

›Troponin elevation

›Lyme carditis (A69.2)

›Fluctuating AV block

›Outdoor exposure

›Infiltrative disease

›Sarcoidosis

›Amyloidosis

›Elevated intracranial pressure

›Cushing reflex

›Head trauma history

Mimics and pitfalls

›Mimics and pitfalls

›Pulse oximeter artifact

›Frequent ectopy with pulse deficit

›Junctional rhythm misread as sinus bradycardia

›Asymptomatic physiologic bradycardia

09Past Medical History/pmh17

Cardiac history

›Prior cardiac conditions

›Coronary artery disease

›Prior myocardial infarction

›Heart failure history

›Valvular disease history

›Prior myocarditis

Conduction and device history

›Conduction system history

›Known AV block

›Prior syncope evaluation

›Prior electrophysiology study

›Prior ablation

›Pacemaker

›Implantable cardioverter defibrillator

Baseline function

›Baseline status

›Baseline exercise tolerance

›Baseline cognitive status

›Baseline heart rate range if known

10Physical Exam/exam31

General and hemodynamics

›Overall stability

›Mental status

›Work of breathing

›Perfusion

›Capillary refill

›Skin temperature

›Volume status

›Dry mucous membranes

›Jugular venous pressure

Cardiovascular exam

›Cardiovascular findings

›Heart rate regularity

›Murmur

›Gallop

›Signs of heart failure

›Pulmonary crackles

›Peripheral edema

Pulmonary exam

›Respiratory findings

›Crackles

›Wheeze

›Increased work of breathing

Neurologic exam

›Neurologic findings

›Focal deficit screen

›Gait stability if safe

›Speech

›Pupils

Toxicologic and endocrine clues

›Exam clues for reversible causes

›Hypothermia signs

›Pinpoint pupils

›Diaphoresis

›Skin rash

›Erythema migrans concern

11Lab Studies/labs29

Core labs and interpretation

›Essential laboratory evaluation

›Glucose

›Hypoglycemia as contributor

›Hyperglycemia suggesting calcium channel blocker toxicity

›Electrolytes

›Potassium

›Calcium

›Magnesium

›Creatinine

›Renal impairment increasing drug levels

›Complete blood count

›Anemia contributing to symptoms

›Leukocytosis suggesting infection

Targeted labs

›Etiology directed tests

›High sensitivity troponin

›Ischemia concern

›Myocarditis concern

›Thyroid stimulating hormone

›Hypothyroidism concern

›Myxedema features

›Digoxin level

›Digoxin exposure

›Drug interaction concern

›Toxicology screen

›Suspected ingestion

›Unknown pill exposure

Pitfalls and limitations

›Laboratory limitations

›Serum drug levels may not correlate with severity early

›Troponin may be normal early in acute coronary syndrome

12Imaging/img17

Scoring Systems

›Risk tools for syncope context

›Canadian Syncope Risk Score

›Use when syncope or near syncope in ED evaluation

›Avoid when persistent instability requiring resuscitation pathway

›San Francisco Syncope Rule

›Use when syncope with uncertain disposition

›Limited performance variability by setting

MRI

›MRI considerations

›Cardiac MRI for myocarditis concern

›Device conditional safety check for implanted devices

›CT considerations

›CT head for head injury after syncope when indicated

›CT pulmonary angiography only if pulmonary embolism concern based on risk assessment

Ultrasound

›Ultrasound and POCUS

›Cardiac POCUS for tamponade physiology

›Cardiac POCUS for severe left ventricular dysfunction

›Inferior vena cava assessment as adjunct for volume status

13Special Tests/spec7

Bedside diagnostics

›Bedside evaluation adjuncts

›Orthostatic vitals when safe

›Point of care glucose confirmation

›Core temperature measurement

Response based tests

›Therapeutic diagnostic responses

›Atropine response suggesting nodal level block

›Pacing capture response confirming bradycardia mechanism contribution

14ECG/ecg28

Acquisition and monitoring

›ECG strategy

›12 lead ECG early in symptomatic bradycardia

›Continuous telemetry

›Repeat ECG after interventions

Rhythm and conduction patterns

›Bradycardia pattern recognition

›Sinus bradycardia

›Sinus pause

›Junctional rhythm

›Atrial fibrillation with slow ventricular response

AV block identification

›AV block patterns

›First degree AV block (I44.0)

›Prolonged PR with 1 to 1 conduction

›Often benign if asymptomatic

›Second degree AV block type I (Wenckebach) (I44.1)

›Progressive PR prolongation

›Dropped QRS

›Second degree AV block type II (I44.1)

›Fixed PR

›Dropped QRS

›Higher risk of progression

›Third degree AV block (I44.2)

›AV dissociation

›Escape rhythm

High risk ECG features

›ECG danger features

›Wide QRS escape rhythm

›Ventricular pause 3 seconds or longer

›Ischemic changes

›Hyperkalemia pattern features

15Assessment/ax24

Problem representation

›Syndrome summary

›Symptomatic bradycardia with pulse

›Asymptomatic bradycardia

›Bradycardia with syncope

Severity and risk stratification

›Severity features

›Hemodynamic instability

›End organ hypoperfusion

›Requirement for pacing

›High risk conduction disease features

›Mobitz type II

›Complete heart block

›Wide QRS escape rhythm

Reversible causes framework

›Reversible causes

›Ischemia

›Hypoxia

›Electrolyte abnormality

›Hypothermia

›Drug toxicity

›Endocrine disorder

Working diagnoses

›Working diagnosis options

›Sinus bradycardia (R00.1)

›Sick sinus syndrome (I49.5)

›Second degree AV block (I44.1)

›Complete AV block (I44.2)

16Plan/plan57

First 5 minutes workflow

›Immediate stabilization sequence

›Airway patency and oxygen if hypoxemic

›Cardiac monitor

›Defibrillator pads for pacing readiness

›IV access

›At least one large bore peripheral line

›Two lines if unstable or toxin concern

›12 lead ECG early

›Point of care glucose

›Reversible causes targeted treatment initiation

Algorithm based treatment

›Symptomatic bradycardia treatment pathway

›Atropine IV

›Dose 1 mg bolus

›Repeat every 3 to 5 minutes

›Maximum total 3 mg

›If atropine ineffective

›Transcutaneous pacing

›Analgesia and sedation if awake and time allows

›Mechanical capture confirmation

›Epinephrine infusion

›Dose 2 to 10 mcg per minute

›Titrate to perfusion targets

›Dopamine infusion

›Dose 5 to 20 mcg per kg per minute

›Titrate to perfusion targets

›Expert consultation

›Cardiology

›Electrophysiology when available

›Transvenous pacing

›Persistent instability despite above

›High grade AV block

Reversible cause directed therapies

›Etiology specific interventions

›Hyperkalemia management when suspected

›Calcium salt for ECG changes

›Insulin with dextrose

›Beta agonist therapy

›Dialysis pathway when indicated

›Beta blocker toxicity pathway

›Glucagon per local protocol dependent

›High dose insulin euglycemia therapy per local protocol dependent

›Lipid emulsion per local protocol dependent

›Calcium channel blocker toxicity pathway

›Calcium salts

›High dose insulin euglycemia therapy per local protocol dependent

›Vasopressor support per response

›Digoxin toxicity pathway

›Digoxin immune Fab per local protocol dependent

›Avoid calcium in severe digoxin toxicity concern

›Hypothermia pathway

›Active rewarming

›Gentle handling

Monitoring and reassessment loop

›Reassessment cadence

›Vitals every 5 minutes in unstable patient

›Mental status trend

›Perfusion markers

›Repeat ECG after each major intervention

›Infusion titration every 5 to 10 minutes to effect

17Disposition/dispo21

ICU criteria

›ICU level of care indications

›Transvenous pacing required

›Ongoing vasopressor or chronotrope infusion

›Persistent hypotension

›High grade AV block with instability

Inpatient admission criteria

›Admission indications

›Symptomatic bradycardia requiring ED intervention

›New high grade AV block

›Suspected acute coronary syndrome

›Suspected myocarditis

›Suspected Lyme carditis

›Drug toxicity requiring monitoring

Observation pathway criteria

›Observation considerations

›Transient medication related bradycardia with resolved symptoms

›Normalizing vitals after correction of reversible cause

Discharge criteria

›Discharge requirements

›Asymptomatic at rest and with brief ambulation when appropriate

›No high risk ECG features

›Reversible cause corrected or clearly identified with safe plan

›Reliable follow up within 72 hours when indicated

›Return precautions understood and feasible

18Discharge Instructions/di14

Copy discharge instructions

›Patient facing instructions

›Low heart rate was found and may cause dizziness or fainting

›Avoid extra doses of heart rate lowering medications unless specifically instructed

›Hydration and regular meals if dehydration contributed

›Follow up timing

›Primary care within 3 to 7 days

›Cardiology within 7 to 14 days if ongoing low heart rate or abnormal ECG

›Return to emergency department immediately for

›Fainting

›Chest pain

›Shortness of breath

›Confusion

›Weakness worsening

›Heart rate very low with symptoms

19References/r16

Guidelines and algorithms

›Evidence based sources

›American Heart Association

›Adult bradycardia with a pulse algorithm

›2025

›American College of Cardiology

›ACC AHA HRS guideline on bradycardia and conduction delay

›2018

›Circulation

›Adult advanced life support guideline update

›2025

›Resuscitation Council UK

›Adult bradycardia algorithm

›2021

›European Resuscitation Council

›Guidelines on cardiopulmonary resuscitation

›2025

Evidence & Review

Reviewed by SymptomDx Medical Team · Last reviewed February 24, 2026

SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.