Risk Factors
These are some of the typical cardiovascular co-morbidities that predispose one to atrial fibrillation. Name at least 3.
Hypertension, CAD, Valvular Heart Disease (mitral valve disease), CHF, Sick Sinus Syndrome, Pericarditis, Cardiomyopathies, Atrial Myxoma
Also acceptable bc listed as CV Risk factor on amboss: age, DM, smoking, obesity, sleep apnea
The P wave on ECG correlates to this event on the anatomical heart. (Under typical circumstances)
Atrial contraction (coordinated contraction of RA and LA)
These are common symptoms of stable atrial fibrillation. (name at least 3)
Irregularly irregular pulse w/ or w/o tachycardia, Palpitations, fatigue, dyspnea, lightheadedness, syncope
Describe 3 types of damage that can cause stress to the atria, predisposing someone to Afib. There are 4 potential proposed mechanisms, though not well understood.
volume overload (will lead to atrial hypertrophy &/or atrial stretch), atrial ischemia, inflammation of the myocardium in the atria, altered ion conduction
Describe the difference in onset/duration of paroxysmal vs. persistent vs. long-standing persistent vs. permanent Afib.
Paroxysmal --> resolves within 7days of onset (spontaneously or s/p tx)
Persistent Afib --> continuous Afib >7 days
Long-standing persistent Afib --> continuous Afib for >1 year
Permanent Afib --> persistent Afib in which therapeutic attempts are no longer made to convert to maintain sinus rhythm (as agreed by pt and physician)
These are some Non-cardiac risk factors. Name at least 3.
Pulmonary diseases (COPD, PE, PNA), hyperthyroidism, catecholamine release/increase sympathetic activity (stress: sepsis, hypovolemia, post-surgical state, hypothermia; pheochromocytoma; cocaine, amphetamines), electrolyte imbalances (hypomagnesemia, hypokalemia), drugs (adenosine, digoxin), holiday heart syndrome, CKD
The QRS complex correlates to this anatomical event in the heart.
Ventricular contraction
These are some clinical features of unstable atrial fibrillation. Name 3.
Irregularly irregular pulse (w/ or w/o tachycardia), altered mental status, cardiogenic shock &/or end organ damage (can p/w ALOC, hypotension, hypovolemia, hypoperfusion, tachypnea), acute heart failure, ischemic chest pain
Name two proposed causes of electrical activity in the atria to explain the trigger of an Afib episode (Not asking for what has damaged the atria, that's another question).
1) Foci that are near the pulmonary veins (which enter the left atrium -- the exact mechanism is not understood per amboss).
2) The damaged atrial myocardium has caused atrial heterogeneity --> leads to uneven/uncoordinated bursts of electrical activity which thus lead to uncoordinated atrial contraction.
3) aberrant electrical pathways (ex: WPW)
Justify the use of CBC and CMP to rule out risk factors.
CBC can rule out anemia or infection. CMP can rule out electrolyte abnormalities or CKD.
What is one modifiable risk factor that the patient did NOT have, but that could be a potential risk factor for Afib?
Drug use that increases sympathetic activity/catecholamine release (cocaine, amphetamines), smoking
This feature on a normal ECG is absent or indiscernible on ECG in a patient with atrial fibrillation.
Patient with Afib will have absent P waves (there may be many multiple tiny P waves to represent the multiple different contractions but will not add up in amplitude to something discernible.
These are the Chapman's points for the heart (name anterior, double points for posterior point).
Anterior Chapman's point for the heart: Right anterior 2nd intercostal space
Posterior Chapman's point for the heart: between T2-T3 transverse process
Draw a rough diagram (with words) to explain how stroke or embolism can develop.
ectopic electrical signals --> rapid atrial contraction and uncoordinated atrial contraction -> stasis of blood in the atria --> clot can form --> clot can travel to systemic circulation
Explain the use of troponin in a cardiac patient.
This pathophysiological consequence of a variety of disorders can cause damage to the atrial cells, predisposing someone to atrial fibrillation.
atrial stretch (fibrosis also accepted, atrial heterogeneity)
This feature of a normal ECG is irregular on an ECG in a patient with atrial fibrillation.
QRS complex is at irregularly spaced intervals, may also be narrow
(rare cases of widened QRS -> more likely with a bundle branch block or AV block)
Name the two peripheral pulses palpated that were irregular but equal bilaterally.
Radial and posterior tibial
(Talking point: Amboss also mentioned apex pulse deficit present in all patients with rapid afib: heart rate auscultated is faster than peripheral pulse palpated. -Is this different?)
This is how atrial fibrillation manifests as generalized fatigue from a pathophysiological standpoint.
Because the heart rate is not controlled by the SA node, and the atria contract at irregular intervals, blood is circulated ineffectively to the rest of the body.
Without looking at the case, what lab was ordered to rule out one possible risk factor/cause of Afib? (Hint: it was within normal limits).
TSH to rule out thyrotoxicosis or hyperthryoidism, etc