Palpitations – A Paroxysmal Pearl
Medical Student Clinical Pearl
Scott Fenwick
Class of 2021
Reviewed and Edited by Dr. David Lewis
Case Presentation:
A 49-year-old female presented with palpitations for the past 2 hours. She had two similar episodes in the last 2 weeks, both of which resolved within 1-2 minutes. She had no other symptoms. She was otherwise healthy, with no past medical history. She was a non-smoke and non-drinker who leads an active lifestyle. She denied weight loss, diarrhea, and heat intolerance.
On physical exam, she was tachycardic at 130bpm with an irregularly irregular pulse. She did not display any tremor or diaphoresis. On auscultation, S1 and S2 were audible, with no murmurs or extra sounds. Respiratory and abdominal exams were unremarkable.
What to ask on History?
Common Symptoms: palpitations, tachycardia, fatigue, weakness, dizziness, light-headedness, reduced exercise capacity, mild dyspnea, and polyuria. It is essential to know when exactly the symptoms started. AF that presents before 48 hours can be safely rhythm controlled without anticoagulation.(1)
Severe/Secondary Symptoms: angina, dyspnea at rest, presyncope and, uncommonly, syncope. Embolic events and heart failure can be severe complications of AF.
Past Medical History: cardiovascular or cerebrovascular disease, diabetes, hypertension, COPD, obstructive sleep apnea, and hyperthyroidism.
What to look for On Examination?
ABCs and vitals: particularly pulse rate and rhythm.
General Assessment: look for signs of thyroid disease, PE, pulmonary disease, alcohol withdrawal, and signs of liver disease from excessive alcohol ingestion.
CVS: precordial scars from prior cardiac surgery, JVP, peripheral edema, and auscultation for murmurs or additional sounds that might suggest valvular AF. There is often an apical-radial pulse deficit where not every apical beat has an associated radial beat due to lack of left ventricular stroke volume.(2)
Case Continued – Testing:
The patient was put on a cardiac monitor and an ECG was performed, demonstrating atrial fibrillation. There was also a right bundle branch block that was consistent with a previous ECG performed in 2017. Laboratory testing was unremarkable.
Depending on clinical suspicion, initial testing may include CBC, electrolytes, blood glucose, PT/INR, creatinine, BUN, TSH, cardiac enzymes, LFTs, and chest x-ray.2
See Basic ECG interpretation Pearl for a great guide to ECGs
Classifying Atrial Fibrillation:
AF is classically described as an irregularly irregular heartbeat, as can be observed from the variable RR intervals in the ECG above. In AF, there are no distinct P-waves due to the uncoordinated atrial activity. Broadly, AF can be divided into valvular and non-valvular subtypes. Non-valvular AF can be classified into the following categories:(1)
- Paroxysmal – AF terminates spontaneously or with intervention within 7 days of onset.
- Persistent – AF fails to terminate within 7 days of onset; often a progressive disease.
- Long-Standing Persistent – AF has persisted for greater than 12 months.
- Permanent – Joint decision between patient and provider to no longer pursue rhythm control.
AF commonly progresses from paroxysmal to persistent states. The above classification only refers to primary atrial fibrillation, not AF that is secondary to cardiac surgery, pericarditis, myocardial infarction, valvulopathy, hyperthyroidism, pulmonary embolism, pulmonary disease, or other reversible causes.
For persistent and permanent AF, the CHADS2 score can be used to estimate a patient’s 1-year risk of ischemic stroke without anticoagulation (0 = low risk, 1-2 = moderate risk, 3+ = high risk).(1)
CAEP and CCS now recommend using the CHAD-65 Score to determine anticoagulation requirement.
Treatment
DC and chemical (e.g. procainamide) cardioversion are two well-described methods of treating uncomplicated AF. The goal of treatment is to return patients to NSR. Some important points about the two methods include:
- DC cardioversion can be administered at an initial energy dose of 100J and increased up to 360J as needed.(2)
- Procainamide is often given in doses of 15-18mg/kg, or more simply, 1g over 60 minutes. Average time to cardioversion is about 1 hour.(1)
- DC cardioversion requires procedural sedation; whereas, chemical cardioversion does not.
- In a recent RCT, combination therapy achieved NSR in 99% of patients; Attempting DC cardioversion first decreased length of hospital stay by 1.2 hours.(3)
- Both therapies are generally well-tolerated by patients.
Case Continued – Treatment:
The patient was diagnosed with paroxysmal atrial fibrillation. The arrhythmia did not spontaneously resolve in the ED. DC and chemical cardioversion methods were considered and discussed with the patient. Direct Current (DC) cardioversion was performed under procedural sedation with propofol and fentanyl. Shocks of 100J and 200J were unsuccessful in converting the patient into normal sinus rhythm (NSR). A third shock at 300J was ultimately successful. The following ECG was obtained demonstrating NSR. As in the initial ECG, there is a RBBB present.
CHADS2 score was 0. Therefore anticoagulation or antithrombotic therapy not indicated.
Case Conclusion:
The patient was discharged home within 4 hours of arriving to hospital, anticoagulation was not prescribed. It is likely that she will experience AF again and require anticoagulation later in life.
References:
- January, C. T., Wann, L. S., Alpert, J. S., Calkins, H., Cigarroa, J. E., Cleveland, J. C., et al. (2014). 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: Executive summary. Journal of the American College of Cardiology, 64(21), 2246. doi:10.1016/j.jacc.2014.03.021
- Wakai, A., & Neill, J.O. (2003). Emergency management of atrial fibrillation. Postgrad Med J, 79(932), 313. doi:10.1136/pmj.79.932.313
- Scheuermeyer, F. X., Andolfatto, G., Christenson, J., Villa-Roel, C., & Rowe, B. (2019). A multicenter randomized trial to evaluate a chemical-first or electrical-first cardioversion strategy for patients with uncomplicated acute atrial fibrillation. Academic Emergency Medicine, 26(9), 969-981. doi:10.1111/acem.13669
