Anesthesia 31

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What does an ECG measure

electrical activity of the heart

What causes electrical activity in the heart

movement of ions across cell membranes

Which ions are most important for cardiac electrical activity

sodium potassium and calcium

What is depolarization

movement of ions causing cardiac cells to become electrically active and contract

What is repolarization

return of cardiac cells to resting electrical state

What is the relationship between electrical and mechanical activity

electrical activity triggers muscle contraction

What is an ECG tracing

a graphical representation of cardiac electrical activity

What happens during the cardiac action potential

ion channels open and close to create electrical changes

What ion is high inside cells at rest

potassium

What ion is high outside cells at rest

sodium

What is the purpose of the ECG

to evaluate heart rhythm and electrical function

What are the main components of an ECG waveform

P wave QRS complex and T wave

What does the P wave represent

atrial depolarization

What does the QRS complex represent

ventricular depolarization

What does the T wave represent

ventricular repolarization

Why is atrial repolarization not seen on ECG

it is hidden by the QRS complex

What does the PR interval represent

time from atrial to ventricular depolarization

What does the QT interval represent

total time of ventricular depolarization and repolarization

What is heart rate determined from on ECG

distance between R waves

What is a normal rhythm

consistent pattern of P QRS T waves

What is an arrhythmia

abnormal heart rhythm

Why are arrhythmias important during anesthesia

can indicate instability or complications

What is a common arrhythmia in anesthetized patients

varies but includes conduction abnormalities

What is the main goal of ECG monitoring during anesthesia

detect arrhythmias and monitor heart function

What is the difference between electrical and mechanical activity

electrical signals control contraction but are not the same as pumping

What does a lack of ECG activity indicate

possible cardiac arrest

What does irregular spacing of QRS complexes indicate

arrhythmia

What does a missing P wave suggest

abnormal atrial activity

What does a wide QRS complex suggest

ventricular origin or conduction delay

What is the main takeaway of ECG interpretation

identify waves and recognize abnormal rhythms