It is divided into four classes by the Canadian Cardiovascular Society:
■ Class I: Angina with strenuous physical activity
■ Class II: Slight limitation of normal physical activity
■ Class III: Severe limitation of normal physical activity
■ Class IV: Inability to perform physical activity
Unstable Angina (UA)
UA is angina occurring with minimal exertion/rest, new-onset angina (within
last 2 months), or an increasing frequency or duration of previously stable
angina.
CARDIOVASCULAR EMERGENCIES
TABLE 2.1. Summary of ECG Essentials
AXIS QRS CHARACTERISTICECG FINDINGS
RBBB Right or vertical Wide rR’ or rSR’ in V 1 and
Large S wave in V 6
LBBB Left Wide QS or rS in V 1 and
Monophasic R in V 6
LAFB Left (> −30°) Normal Q in I, S in III (Q 1 S 3 )
LPFB Right Normal S in I, Q in III (S 1 Q 3 )
RVH Right Normal R wave > S wave in V 1 and
Deep S wave in V 6
LV H Left or horizontal Normal S in V 1 +R in V 5 (or V 6 )≥35 mm and
R in aVL ≥11 mm
Hyperkalemia Any Normal or wide Peaked T waves →
PR prolongation →
P waves flattening →
Widened QRS →sine wave
Hypokalemia Any Normal Flattened T waves
Prominent U waves
Hypercalcemia Any Normal Shortened QT intervals
Hypocalcemia Any Normal QT prolongation
Digitalis Effect Any Normal Depressed (scooped or sagging) ST
segments
Shortened QT intervals
Flattened T waves
Prominent U waves
Hypothermia Any Normal or wide Osborn J waves
UA =new-onset angina,
angina with frequency or
duration, angina with minimal
exertion/rest
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