Cardiac Rhythms Well Explained 100% Accuracy, 2024
Sinus bradycardia
Rate: <60 bpm, regularity: regular, P-wave: normal, QRS complex: narrow, PR interval:
0.12-0.20 sec. Common causes: Cardiomyopathy, inferior wall MI, SA node pathology,
vagal stimulation, hyperkalemia, hypothermia, increased ICP. Effects: Asymptomatic (if
patient able to compensate), hypotension and subsequent hypoperfusion (if patient
unable to compensate), pulmonary edema, acute kidney injury, altered mental status,
decreased level of consciousness, dizziness.
Sinus tachycardia
Rate: >100 bpm, regularity: regular, P-wave: normal, QRS complex: narrow, PR
interval: 0.12-0.20 sec. Common causes: Shock, heart failure, anemia, hypovolemia,
hyperthyroidism, respiratory failure, pulmonary embolism, infection and sepsis,
exercise, fever, stress, alcohol, stimulant recreational drugs (such as caffeine, cocaine,
methamphetamine). Effects: May be asymptomatic in early phases, hypertension (if
increased sympathetic input and ventricles have adequate filling time), hypotension with
associated tissue hypoperfusion (as heart rate increases, ventricle filling time
decreases), chest pain, blurred vision, syncope.
Junctional rhythm
Rate: 40-60 bpm, possibly faster, regularity: regular, P-wave: absent or inverted, QRS
complex: narrow, PR interval: <0.12 sec (if P wave present). Common causes:
Cardiomyopathy, beta-blockers, calcium channel blockers, electrolyte disturbances,
heart failure, hypoxia, vagal stimulation, SA node damage, ischemia, cardiac valve
disease. Effects: May be asymptomatic, possible slow pulse rate with associated
hypotension, hypoperfusion, blurred vision, pain, syncope.
Atrial fibrillation
Rate: atrial rate is indiscernible but may be >400 bpm. Ventricular rate is variable - may
be bradycardic or profoundly tachycardic, usually <150 bpm. Regularity: irregularly
irregular. P-wave: unclear, not discernible; may resemble multiple P-waves or no P-
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller MUTUKACOURSEHERO. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $4.69. You're not tied to anything after your purchase.
