atrial fibrillation Flashcards
A mid-aged patient comes in to the emergency department complaining about heart palpitations that started early in the day. He states that he feels his heart fluttering in his chest. He tried to walk around and take deep breaths, but nothing has worked. He has previously felt his heart skip a beat. He has no lightheadedness, blurry vision, muscle weakness, chest pain, or shortness of breath. The patient has hypertension that is well controlled with valsartan and amlodipine. He does not use tobacco, alcohol, or recreational drugs. He has no medication allergies. The patient appears anxious and in mild discomfort due to palpitations. Blood pressure is 140/80 mm Hg and respirations are 19/min. Cardiac auscultation reveals no murmurs. Lungs are clear to auscultation. The abdomen is soft, non-tender, and non-distended. Neurologic examination is normal. An ECG is performed and the patient is placed on a telemetry monitor. What is the most appropriate next step in management of this patient?
This patient’s ECG shows a narrow QRS-complex tachycardia, absence of organized P waves, and an irregularly irregular rhythm with varying R-R intervals is consistent with atrial fibrillation (AF) with rapid ventricular response. The ventricular rate is estimated at 138/min (23 beats in 10 seconds); because rapid heart rate can lead to poor ventricular filling and low cardiac output, the best next step in management is to control the ventricular response rate (goal rate in the acute setting <110/min). AF rate control is usually achieved with the use of atrioventricular (AV) nodal blocking agents such as beta blockers (eg, metoprolol, atenolol) or nondihydropyridine calcium channel blockers (eg, diltiazem, verapamil). These drugs also have negative inotropic effects and so are contraindicated or must be used with caution in patients with hypotension or decompensated heart failure.
What is atrial fibrillation (AF)?
Atrial fibrillation is a common cardiac arrhythmia characterized by disorganized electrical activity in the atria, leading to irregular and often rapid heartbeats.
What is the typical age group for the onset of atrial fibrillation?
Older adults, typically above 65 years.
What is one of the most common symptom of atrial fibrillation that patients tend to vocalize at presentation?
The most common symptom of atrial fibrillation that patients often report are palpitations. Palpitations are typically described by the patient as a sensation of a racing heart, fluttering, or of a beat skipping. This sensation is due to the rapid and irregular beating of the atria.
What are the other clinical symptoms of atrial fibrillation aside from “skipping a beat?”
Aside from palpitations, the clinical features include angina, fatigue, exertional dyspnea, dizziness, or syncope. Patients will have an irregularly irregular pulse.
Fill in the blank: Atrial fibrillation is classified as __________ if it lasts less than 7 days.
Paroxysmal. This is a condition where atrial fibrillation often comes and goes, however atrial fibrillation can persist days to weeks or become permanent.
What does ‘AF with RVR’ stand for?
Atrial fibrillation with rapid ventricular response
What type of rhythm is typically seen on an ECG in atrial fibrillation?
Irregularly irregular rhythm with an absence of P-waves.
What tends to be the heart rate range in a patient with atrial fibrillation?
Multiple foci in the atria fire continuously in a chaotic pattern, leading to a totally irregular rapid ventricular rate. The atria quiver instead of contracting, with an atrial rate over 400 bpm, but most impulses are blocked at the AV node, resulting in a ventricular rate of 75-175 bpm.
True or False: Atrial fibrillation is always symptomatic.
False
What is one lifestyle modification recommended for patients with atrial fibrillation?
Avoiding excessive alcohol intake, which causes a condition known as holiday heart syndrome.
True or False: Atrial fibrillation can be a result of heart valve disease.
True
What extremes in lifestyle lead to atrial fibrillation?
Extremes of activity such as a sedentary lifestyle or excess exercise such as marathon running.
True or False: Atrial fibrillation can be associated with hyperthyroidism.
True. Check the serum TSH, if the TSH is low while the T3 / T4 is high, give propanolol. Accompanying symptoms include diarrhea, heat intolerance, weight loss, or warm skin.
What are the common hyperandrogenic states that lead to atrial fibrillation?
stress, pheochromocytoma, and elevation of sex hormones.
What heart condition involving inflammation leads to atrial fibrillation?
pericarditis.
What drugs of abuse can promote atrial fibrillation?
cocaine or methamphetamines.
What is the relationship between atrial fibrillation and sleep apnea?
Atrial fibrillation is commonly associated with obstructive sleep apnea.
What underlying heart conditions increase the risk for developing atrial fibrillation?
Heart disease, coronary artery disease, myocardial infarction, hypertension, mitral valve disease, or a history of cardiac surgery (scar can predispose to ectopic foci of activity).
Why do heart conditions amplify the risk of patients with atrial fibrillation?
Patients with AFib in the presence of underlying heart disease have an especially high risk of embolization and hemodynamic compromise.
What are the two most common reasons for increased sympathetic tone that lead to atrial fibrillation?
- Acute illness
- Cardiac surgery or post-operative pain
Why does postoperative atrial fibrillation occur?
Atrial fibrillation is a common postoperative complication of cardiac surgery. Cardiac surgery causes transient atrial fibrillation via surgery-related atrial myocardial inflammation and an increased rate of triggers resulting from a surgery-related increase in sympathetic tone.
Who are at increased risk for postoperative atrial fibrillation?
Patients at risk for developing postoperative atrial fibrillation:
- Advanced age
- Hypertension
- Left ventricular dysfunction
What are the short-term complications for postoperative atrial fibrillation?
There are 2 significant points to recognize:
1) Most patients with no history of atrial fibrillation who develop postoperative atrial fibrillation following cardiac surgery will likely spontaneously convert to sinus rhythm within a few days.
2) Conversion to sinus rhythm does not signify resolution of atrial fibrillation and freedom from its associated complications. The development of postoperative atrial fibrillation likely indicates substantial underlying condition, so many patients will have recurrent episodes of atrial fibrillation (paroxysmal disease).
What are the long-term complications for postoperative atrial fibrillation?
- During hospitalization and following discharge, patients are at risk for complications, including embolic stroke and heart failure.
- Postoperative atrial fibrillation is also associated with increased long-term mortality.
Does reperfusion following PCI or CABG tend to cause atrial fibrillation?
Reperfusion in of itself is not a precipitant of atrial fibrillation, however, in the setting of acute coronary syndrome, atrial fibrillation is a common arrhythmia that occurs. The other rhythms that occur are PVCs, VT, and VF.
Does MI or acute ischemia tend to cause atrial fibrillation?
Acute ischemia is not a common or direct trigger of atrial fibrillation. Myocardial infarction (Ml) can sometimes precipitate atrial fibrillation via increased sympathetic tone or abrupt onset left ventricular failure with atrial stretching.
What respiratory conditions are associated with the development of atrial fibrillation?
pulmonary diseases that can cause atrial fibrillation include malignancy, PEs, chronic obstructive pulmonary disease (COPD), and any cause of hypoxia.
A patient needs to go to surgery, but they have a history of atrial fibrillation (or are presenting with acute onset), as the patient is being worked up for the surgical procedure, what is the major concern or consideration?
Hemodynamic stability
What is the first-line treatment for rate control in atrial fibrillation?
Beta blockers (metoprolol) or nondihydropyridine calcium channel blockers (diltiazem or verapamil) are the preferred first-line agents for ventricular rate control in patients with rapid atrial fibriation. These drugs are contraindicated or should be used with caution in patients with decompensated heart failure or hypotension.
When is digoxin used to establish rate control in atrial fibrillation?
When the patient has heart failure (HFrEF), Digoxin is appropriate. However, this tends to be given after first adding a first-line medication (Beta blocker). The preferred beta-blocker is metoprolol.
When is amiodarone considered in the management of atrial fibrillation?
Amiodarone is sometimes used for rate control when first-line medications are ineffective. Use of amiodarone is often limited by the risk of adverse effects like lung toxicity or thyroid toxicity. Amiodarone should be avoided when the patient has COPD.
Patients with new-onset AF should undergo thromboembolic risk stratification to identify those who would benefit from anticoagulation therapy. What scoring system is used to assess stroke risk in patients with atrial fibrillation?
CHA2DS2-VASc score
What is the major consideration for a patient with atrial fibrillation who is scheduled to undergo a surgical procedure, in the pre-pharmicological management in terms of anticoagulation?
“Bleeding risk.”
When is it appropriate to bridge with heparin preoperatively for a patient with atrial fibrillation?
When a patient is:
1) On warfarin
2) There is any risk of bleeding
3) There is any risk of developing a thrombus.
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This is when you stop warfarin 3-5 days before the surgery because the risk of bleeding is present, the patient will need to be able to develop a clot to stop the bleeding. These patients will require a bridge with heparin in the interim because stopping warfarin causes a hypercoagulable state.
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- The risk of thrombosis is contingent on CHA2D2VASC score.
- The risk is low when the score is 4 or less and there is no history of stroke.
- If the score is 5-6, or a stroke has occurred 3 months or longer, this is a moderate risk.
- If the score is 7 or more, a stroke has developed within 3 months, or the patient has a mechanical valve, this is a high risk. Either way, in each of these cases, given the same set of conditions, these low/moderate/high risk patients require heparin bridge.
Even in the context of an elevated bleeding risk, and an elevated CHADVASC score, when do you both STOP warfarin (3 to 5 days before the surgery) and NOT bridge with heparin?
When the risk of bleeding is elevated (beyond minimal) and the risk of thrombus is low, a CHADVASC score of 4 or less, and no history of stroke.
Do patients on warfarin always need a heparin bridge?
No, some patients who are on warfarin, and have a minimal risk for bleeding, they will continue on warfarin.
