EKGs

Question 1

Basic EKG grid

Answer 1

Question 2

EKG axis

Answer 2

Question 3

EKG intervals

Answer 3

Question 4

Signs of LVH on EKG

Answer 4

Question 5

Where to place V7, V8, and V9

Answer 5

Question 6

WPW on EKG

Answer 6

Question 7

STEMI evolution

Answer 7

Question 8

Parkinsonian tremor artifact

Answer 8

The ECG shows classic Parkinsonian tremor artifact (about 5 cycles/sec) simulating atrial flutter or coarse atrial fibrillation. True sinus P waves (obscured in the limb leads) are most evident in leads V2-V4 upon careful inspection. Note also: the variable pseudo-flutter (F) to QRS intervals are not consistent with pure 6:1 conduction. Also, the biphasic (negative/positive) “atrial” waves in V1 are not compatible with typical, clockwise atrial flutter which is associated with upright F waves in that lead.

The prominence of the baseline artifact in lead II (left leg-right arm) and in lead aVR was consistent with the patient’s overt right hand tremor.

The patient’s palpitations were characterized by an intermittent “skipped beat” sensation and were attributed to isolated atrial and ventricular beats, which are not present here but were observed at other times. Compare this record with that in Case #84.

Question 9

Left bundle branch block

Answer 9

Common in elderly, usually asymptomatic

In patients with ACS, may represent acute anterior wall MI (LAD).

Question 10

Right bundle branch block

Answer 10

• Asymptomatic and may be the result of degenerative disease or right heart strain
• Characterized by RSR’ pattern (small initial upward deflection followed by a small downward deflection, then a large upward deflection) in lead V1

Question 11

RBBB vs LBBB

Answer 11

Question 12

Right heart strain pattern

Answer 12

Called “S1Q3T3”. Sometimes seen in PE, but sensitivity and specificity are both poor.

S present in 1, Q present in 3, and T inverted in 3

Question 13

Hyperkalemia on ECG

Answer 13

Early: Peaked T waves

Late: Progresses to “sine wave” pattern

Question 14

Hyper- and hypo-calcemia on ECG

Answer 14

They effect the length of the ST segment inversely

The more calcium, the shorter it gets

Question 15

Normal p wave axis should align almost perfectly with. . .

Answer 15

. . . Lead II

Question 16

Heart rate by intervals

Answer 16

small boxes / 1500

Question 17

Discordant T waves

Answer 17

“T wave inversion”

Diffusely they should be a red flag for NSTEMI or unstable angina

Question 18

Calcium concentration is inversely proportional to ___.

Answer 18

Calcium concentration is inversely proportional to ST length

Hypercalcemia causes loss of ST segment, while hypocalcemia causes long QT.

Question 19

J waves

Answer 19

aka Osborn waves

Seen in hypothermia

Question 20

Five mechanisms of bradycardia

Answer 20

Question 21

“Nodal” and “Infra-nodal” 2nd degree heart block

Answer 21

“Nodal” is Mobitz I

“Infra-nodal” is Mobitz II

Question 22

Origins of Afib

Answer 22

1. Most common: Left atrium near pulonary veins
2. Second most common: Right atrium near opening of IVC

Question 23

Acquired long QT etiologies

Answer 23

Question 24

Principles of torsades management

Answer 24

Question 25

Left ventricular aneurysm syndrome and ECG

Answer 25

• Often occurs months post-MI
• EKG shows persistent ST elevations, deep Q waves in associated leads
• Thin and dyskinetic wall on echo
• Presents w/ heart failure, angina, ventricular arrhythmia, arterial embolism