| ‣ |
|---|
| Special Test | Condition | Indication | Population | Matrix |
|---|---|---|---|---|
| ‣ | ‣ | Screening | Intermediate (10-90% risk) | 65% accuracy |
| ECG | ‣ | Diagnostic → r/i when + | 65% sensitivity; 79% specificity |
aVF is often opposite to other
On an ECG, a small square = 40 ms, and a large square represents 0.20 seconds (200 milliseconds)
10 s
| Item | Look at | Normal | Best Observed in which Lead | Key Conditions | |
|---|---|---|---|---|---|
| R | ‣ | Origin of P, | |||
| ratio, | |||||
| rate (# of 200 ms in RR. 300/#), | |||||
| PR Interval | Origin: I, II, aVF + | ||||
| Ratio: 1:1 | |||||
| Rate: 60-100 bpm | |||||
| PR: 120 - 200 ms (3-5 small square) | II | ‣ | |||
| ‣ | |||||
| ‣ | |||||
| ‣ | |||||
| ‣ | |||||
| ‣ | |||||
| A | ‣ | Origin of QRS | Origin: I, II, aVF + | I, avF | |
| (II for tide-breakder if I and aVF are both small and opposite) | ‣: I+, aVF- | ||||
| ‣ : I-, aVF+ | |||||
| T | ‣ | Duration, amplitude, transition, | |||
| Q wave | Duration: < 3 mm | ||||
| @Amplitude: 10-25 mm | |||||
| Q~~RS Transition: V3, V4 iso-electric~~ | |||||
| Q wave: non-pathological (<1/3 of R) | QRS Direction: | ||||
| V1 - (Up = RBBB, Down = LBBB/ normal) |
Bunner ear: RSR’ (V1, V2, V3 = RBBB) (I, II, III = LBBB)
Q wave: > 1/3 of R | ‣ ‣ ‣ ‣ / ‣ | | S | ‣ | Elevation, Depression | ST (J point) = TP baseline (after the T wave) <1 in limb leads < 1.5 in precordial lead | Check by regions | STE: ‣ (DDx: diffused =‣)
STD:
‣
‣ |
| Q | ‣ | Duration | (t wave) should be less that 1/2 of RR | All leads | Electrolyte Imbalances
Short:↑Ca
Long: ↓K, ↓Ca, ↓Mg2+, Medication |
| T | ‣ | amplitude,
inversion | 1/3 - 2/3 of the R wave.
Positive in all leads with upright QRS (dominant R) | TWI: NOT right-sided leads (aVR, III, V1)
Diffused Tall T wave: ‣ (DDx: VT)
Diffused T wave inversion: ‣ |
P
QRS