ECG Interpretation and Physiology
This ECG interval represents atrial depolarization through AV nodal delay.
PR interval
This lead is best for monitoring arrhythmias due to optimal P wave visualization.
Lead 2
This AV block is characterized by prolonged PR interval > 0.20 seconds with no dropped beats.
1st degree AV block
This lung volume is the sum of ERV and RV and represents volume at end expiration.
FRC
This type of compliance is measured when air is NOT moving.
Static
This ECG finding suggests interventricular conduction delay.
QRS duration > 0.12 seconds
These two precordial leads are most sensitive for detecting perioperative ischemia.
V3 and V4
This type of second-degree AV block shows progressively lengthening PR intervals until a beat is dropped.
Mobitz I (Wenckebach)
This condition occurs when alveoli are perfused but not ventilated.
Shunt
This type of compliance is affected by airway resistance and bronchospasm.
dynamic compliance
This is considered the true isoelectric line on an ECG
J point
This modified lead placement allows monitoring of anterior and lateral wall ischemia using a 3-lead system.
MCL5 or CS5
This AV block has constant PR intervals with dropped QRS complexes and risk of progressing to complete heart block.
Mobitz II
This condition occurs when alveoli are ventilated but not perfused.
Dead space
This condition increases lung compliance due to loss of elastic recoil.
emphysema
This electrolyte abnormality is associated with the presence of U waves.
Hypokalemia (most often)
This physiologic imbalance is the underlying cause of perioperative myocardial ischemia.
mismatch between myocardial oxygen supply and demand
This conduction abnormality presents with wide QRS, absent Q waves in V1/V6, and makes ischemia difficult to detect.
Left Bundle Branch Block (LBBB)
This physiologic reflex diverts blood away from poorly ventilated alveoli.
HPV
This formula is used to calculate static compliance.
TV / (Plateau pressure – PEEP)
This ECG change is diagnostic for ischemia when ST depression exceeds -1 mm in most leads.
ST segment depression
This ECG change suggests transmural ischemia rather than subendocardial ischemia.
ST elevation
This rhythm is suggested when aVR is upright and indicates a ventricular origin.
ventricular tachyarrhythmia
This equation describes transpulmonary pressure.
alveolar pressure minus intrapleural pressure
This airflow pattern requires higher pressure and is associated with airway obstruction.
Turbulent Flow