3. • A 75-year-old man presented to the emergency department (ED) with the complaint of dizziness for the
past week.
• He denied any chest pain, shortness of breath, tinnitus, hearing loss, or syncope.
• He has a medical history of hypertension, diabetes mellitus, and glaucoma.
• His medications included aspirin, statin, amlodipine, hydrochlorothiazide, carvedilol, and timolol eye
drops.
• His dose of carvedilol was increased from 6.25 to 12.5 mg last week by his primary physician.
• He denied any toxic habits.
• On physical examination in the ED, he was vitally stable with no significant findings.
• Initial ECG is shown in the next slide.
• All prior ECGs showed normal sinus rhythm.
• CT of the head showed no abnormality.
8. Case Review
• This case describes the importance of medication review in the elderly population. Elderly
patients taking excessive atrioventricular (AV) node-blocking agents can have symptoms of
dizziness and syncope with remarkable ECG changes.
• The temporal association of the medication dose increase and careful review of the medication
list are key to diagnose the etiology of dizziness and AV block. β-Blockers (oral or topical) and
calcium channel blockers can be offending agents for this presentation.
What is your next step?
• Discharge
• Stay under observation
• Implant a pacemaker ?
10. • A 23-year-old African American female with no known past medical history presented
to the emergency department with 3 days history of nonproductive cough and runny
nose. Review of systems was otherwise negative, she denies chest pain, dizziness,
palpitation, or syncope. The patient was not taking any medications. She had no
recent travel or positive family history.
• On physical examination, the patient appeared comfortable. She was afebrile with
blood pressure of 107/74 mm Hg, heart rate of 45/minute, and oxygen saturation of
99% on ambient air. The patient had mild pharyngeal edema but no jugular venous
distension. Auscultation of the heart revealed slow heart rate, but it was regular with
normal first and second heart sounds having no murmurs. Auscultation of bilateral
lungs revealed clear breath sounds. There were neither skin rash nor pedal edema.
• Chest X-ray was unremarkable. Complete blood count and chemistry panel were
within normal limits. Troponin, erythrocyte sedimentation rate, and thyroid panel
were also within normal limits. Urine toxicology was negative. Lyme IgM antibody,
antinuclear antibody, and rheumatoid factor were also negative.
11. Admission
ECG
CHB characterized by AV dissociation with narrow QRS escape rhythm,
atrial rate of 90/minute, and ventricular rate of 45/minute
12. • The patient was admitted to the cardiac care unit in the diagnosis of CHB with profound bradycardia at
rest. Throughout her hospital stay, the patient remained asymptomatic. She occasionally switched to
2:1 heart block on the monitor.
• Her average systolic blood pressure was around 100 mm Hg, and her average heart rate was 40 to 50
beats per minute. The patient’s heart rate fluctuated along with her physical activity, the lowest being
32/minute during sleep and the highest being 116/minute during exertion.
• Transthoracic echocardiogram revealed normal left ventricular systolic and diastolic function without
major valvular or structural abnormalities. Exercise stress test was performed to assess the patient’s
chronotropic competency to physical activity. She exercised for 10 minutes. The maximum heart rate
during exercise was 139/minute, and she remained in junctional escape rhythm with CHB throughout
the exercise and recovery.
15. • Her hospital course was uneventful, and the
patient was discharged with an outpatient
cardiology appointment. She was also
scheduled to receive a loop recorder
implantation.
16. Conclusion
Treatment of asymptomatic CCHB with narrow complex escape rhythm is challenging.
Those patients are often very young, and implanting a permanent PM is not always an
easy decision. The likelihood of renewing multiple generators, potential of developing
infections, and vascular complications sometimes outweigh the benefits of early
intervention, and the ideal time for implanting a PM in those patients still remains a
subject for further investigation.
Nevertheless, the select group will benefit from close follow-ups, annual
echocardiography, and rhythm monitoring by a loop recorder when they opt for a
conservative approach without PM therapy.
17.
18. Transcutaneous pacing should be started immediately if:
• there is no response to atropine
• atropine is unlikely to be effective or if IV access cannot be quickly
established
• the patient is severely symptomatic
• all of the above
Test Your Knowledge
19. If transcutaneous pacing is ineffective for symptomatic bradycardia, the
next step would be to prepare for:
• prepare for transvenous pacing
• give repeat doses of atropine
• prepare for pacemaker placement
• begin CPR
• begin an infusion of dopamine or epinephrine
• both 1 and 5
Test Your Knowledge
20. For bradycardia unresponsive to atropine, what other drug should be
considered?
• vasopressin
• epinephrine
• magnesium sulfate
• all of the above
Test Your Knowledge
21. If atropine fails, the treatment of choice for symptomatic bradycardia
with signs of poor perfusion is
• pacemaker placement
• transcutaneous or transvenous pacing
• CPR
• none of the above
Test Your Knowledge
22. The correct dose of atropine given in the bradycardia algorithm is:
• 1 mg atropine, may repeat up to a total dose of 3 mg
• 0.5 mg atropine, may repeat up to a total dose of 2 mg
• 0.5 mg atropine, may repeat up to a total dose of 3 mg
• 1 mg atropine, may repeat up to a total dose of 4 mg
Test Your Knowledge
23. Preparation for transcutaneous pacing (standby pacing) should be
made for which of the following?
• 1. unstable sinus bradycardia
• 2. third degree AV block
• 3. Mobitz type II second-degree AV block
• 4. all of the above
Test Your Knowledge
