Ward 9 Flashcards
What can be used for stroke risk predictions
CHA2DS2VASc tool for stroke risk prediction in patients with atrial fibrillation
CHA2DS2VASc interpretation
- Congestive heart failure (1 point), Hypertension (1), Age
65–74y (1), Age >74y (2), Diabetes (1), previous Stroke/TIA/thromboembolism (2), Vascular disease (1), Sex Category (1 if female). - A score of 2 or more is considered high risk and anticoagulation should be offered, unless there is a contraindication (guidelines)
- If the patient receives a 0 score, it is considered “low-risk,” and anticoagulation is not recommended in such cases. If the patient receives a score of 1, it falls in the “low-moderate” risk category; the providers should consider anticoagulant or antiplatelet therapy. If the patient receives a score of greater than 2, they are in the “moderate-high” risk category, and anticoagulation therapy is indicated
What is the most common type of arrhythmia?
Atrial fibrillation
What is atrial fibrillation due to?
It is due to abnormal electrical activity within the atria of the heart, causing them to fibrillate
What is atrial fibrillation classified as and into?
- It is characterized as a tachyarrhythmia, which means that the heart rate is often fast
- This arrhythmia may be paroxysmal (spontaneously resolves in less than seven days) or persistent (more than seven days)
- Long standing persistent AF occurs when AF has been present for at least a year, either due to failure of initiation of pharmacological intervention or failure of cardioversion
- Permanent AF: It is the type where a decision has been made to abort all therapies because the rhythm is unresponsive
Dangers of atrial fibrillation
Overall, atrial fibrillation leads to a turbulent and abnormal flow of blood through the heart chamber, decreasing the heart’s effectiveness in pumping blood while increasing the likelihood of thrombus formation within the atria, most commonly the left atrial appendage, which can ultimately dislodge and cause a stroke. Atrial fibrillation is the leading cardiac cause of stroke.
Causes of atrial fibrillation
There are many causes of atrial fibrillation (AF), but it shares a strong association with other cardiovascular diseases. The commonly encountered causes include:
Advanced age
Congenital heart disease
Hemodynamic stress
Underlying heart disease - valvular disease, coronary artery disease, structural heart disease, atrial ischemia
Increased alcohol consumption
Hypertension - systemic or pulmonary
Endocrine disorders - diabetes, pheochromocytoma, and hyperthyroidism
Genetic factors
Neurologic disorders - subarachnoid hemorrhage or stroke
Hemodynamic stress - mitral or tricuspid valve disease, left ventricular dysfunction, pulmonary embolism
Obstructive sleep apnea
Inflammation - myocarditis and pericarditis
Any condition that leads to inflammation, stress, damage, or ischemia affecting the anatomy of the heart can result in the development of atrial fibrillation. In some cases, the cause is iatrogenic
When is atrial fibrillation referred to as recurrent?
When a patient has two or more episodes
Paroxysmal AF in younger individuals
In younger patients, paroxysmal AF has been commonly found to be secondary to electrically active foci within the pulmonary veins. Elimination of these foci is found to be effective in treating this type of AF since it eliminates the trigger for such episodes
Consequences of persistent AF
if it is associated with a rapid and uncontrolled ventricular rate, it may lead to electrical remodeling in the cardiac myocytes causing dilated cardiomyopathy.
This type of AF may present as the first episode or as a result of recurrent episodes of paroxysmal AF
Most common age group for atrial fibrillation
Although the worldwide prevalence of atrial fibrillation is approximately 1%, it is found in approximately 9% of individuals over the age of 75. At the age of 80, the lifetime risk of developing atrial fibrillation jumps to 22%
Pathophysiology of AF
- Variety of mechanisms, however it is cardiac remodelling that accounts for most of them
- Cardiac remodeling, particularly of atria, results in structural and electrical changes that eventually become the cause of deranged rhythm in AF. Structural remodeling is caused by the changes in myocytes and the extracellular matrix, and fibrous tissue deposition also plays a major role in some etiologies. On the other hand, tachycardia and shortening of the refractory period lead to electrical remodeling
- Most commonly, hypertension, structural, valvular, and ischemic heart disease illicit the paroxysmal and persistent forms of atrial fibrillation
Is AF genetic?
Most cases of atrial fibrillation are non-genetic and relate to underlying cardiovascular disease. Typically, an initiating trigger excites an ectopic focus in the atria, most commonly around the area of the pulmonary veins, and allows for an unsynchronized firing of electrical impulses leading to fibrillation of the atria
Presentation of AF
- The presentation of AF can range from asymptomatic to devastating complications such as cardiogenic shock and ischemic stroke
- Symptoms include palpitations, chest pain, shortness of breath, increased lower extremity swelling, dyspnea on exertion, presyncope/syncope, hypotension, pulmonary edema, and dizziness.
Important patient history relating to AF and questions to ask
- Identifying risk factors such as hypertension, history of valvular, structural, or ischemic heart disease, obstructive sleep apnea, obesity hypoventilation syndrome, smoking, alcohol intake, illicit drug use, history of rheumatic fever/heart disease, history of pericarditis, and hyperlipidemia
- Assessment of patients with existing AF includes questions regarding:
Duration and frequency of symptoms
History of triggers
Previously successful modes of termination
The use of anti-arrhythmic drugs
Antecedent cardiac diseases