Drug and Electrolyte Effects Flashcards

1
Q

Inflammation of the pericardium

A

Pericarditis

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2
Q

What ECG changes do you see in pericarditis?

A

Elevated ST segments (usually flat or concave) that are more diffuse, affecting many leads (unlike more localized changes seen in MIs)

Depressed PR interval commonly seen as well

No Q waves

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3
Q

Characteristics of benign early repolarization on ECG

A

J-point notching

T-wave asymmetry, concordance with QRS

Upsloping ST-segment

No reciprocal ischemic findings in other leads

Stable findings on ECG

Minimal ST-elevation (relative to T-wave, <1/4 height)

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4
Q

In pericarditis with _______, fluid collection around the heart dampens the electrical output

A

Effusion

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5
Q

Characteristics of Pericarditis with effusion on ECG

A

Low voltage** seen in all leads with large effusions

May still see T wave and ST segment changes consistent with pericarditis

If large —> electrical alternans** manifested by changing amplitude of the QRS complex

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6
Q

Low voltage and electrical alternans

A

Pericarditis with effusion

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7
Q

Acute occlusion of the pulmonary artery that can cause acute right heart failure

A

Pulmonary embolism

May see evidence of distension of the right atrium and right ventricle

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8
Q

ECG changes seen with pulmonary embolisms

A

Most common = sinus tachycardia (esp if PE is small)

In massive PE —> S1-Q3-T3 pattern

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9
Q

What does S1-Q3-T3 mean?

A

Large S wave in Lead I

Deep Q wave in Lead III

Inverted T wave in Lead III

Indicative of massive PE

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10
Q

Other less common ECG changes you might see with PEs

A

RAD

Signs of RAE (tall, peaked P waves)

New RBBB acutely

T waves may be inverted in precordial leads (V1-4)

Persistence of lateral S-waves (even without complete RBBB)

TACHYARRHYTHMIAS

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11
Q

What is Long QT Syndrome (LQTS)?

A

Rare congenital condition

Delayed repolarization following depolarization, which is associated with ventricular dysrhythmias including ventricular fibrillation and Torsade de Pointes (TdP)

Arrhythmias often associated with exercise

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12
Q

What is Short QT Syndrome?

A

Rare inherited condition (QTI < 0.35s)

Syncope, ventricular arrhythmias, risk of sudden cardiac death

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13
Q

What is QTc Interval?

A

The “Corrected QT Interval”

Represents depolarization and repolarization but is corrected for heart rate

Can be determined from tables, software, or calculations

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14
Q

Visual tip for determining if QT interval is normal

A

Normal QT is less than half the R-R interval

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15
Q

There is an increased risk of Torsade de Pointes if QTc is prolonged - _______ in Men and ______ in Women

A

> 0.44s in Men

> 0.46s in Women

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16
Q

Key ECG characteristics for Hyperkalemia

A

Tall, peaked T waves

Flattened P waves

1st-degree AV heart block

Widened QRS complexes

Merging of S and T waves forming a sine-wave pattern

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17
Q

What’s the deal with the sine-wave pattern seen in hyperkalemia?

A

Widened QRS complexes and peaked T waves become indistinguishable, forming a sine-wave like pattern

Seen when K > 7.0 mmol/L

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18
Q

When do you start to see peaked narrow T waves in all leads?

A

When K 5.5-6.5 mmol/L

19
Q

What are the key ECG characteristics for hypokalemia?

A

Flattening of the T waves

Appearance of prominent U waves

ST segment depression

20
Q

Tall, peaked T waves and widened QRS complexes —> sine-wave pattern

A

Hyperkalemia

21
Q

Flattening of the T wave and appearance of U waves

A

Hypokalemia

22
Q

What happens to a patient’s heart in hypercalcemia?

A

Decreased automaticity with slowed conduction —> increased PR interval and QRS interval, possible BBBs and AV block

Shorter refractory period —> shorter ST segment and shorter QT interval

23
Q

QT interval is _______ with hypercalcemia and ________ with hypocalcemia

A

Shortened = hypercalcemia

Prolonged = hypocalcemia

24
Q

When might you see a prolonged QT interval?

A

Hypo K+
Hypo Ca2+
Hypo Mg2+

25
Q

What might happen if prolonged QT is not corrected?

A

May progress to ventricular tachycardia or Torsade de Pointes

26
Q

Digoxin affects the movement of _____ and _____ during depolarization and repolarization

A

Sodium and Calcium

Slows sodium movement into cell

Facilitates movement of calcium out of the cell

27
Q

What are the end results of digoxin use?

A

Increased myocardial contractility and improved heart pumping ability

Slows HR and AV conduction

28
Q

How is Digoxin used?

A

To treat fast atrial dysrhythmias (positive inotrope that slows HR and AV conduction)

29
Q

What are the two categories of ECG changes with digoxin?

A

At therapeutic drug levels (0.8-2.0 ng/ml)
• Parasympathetic effect —> slowed HR
• See “Digoxin effect” on ECG - do not indicate need to d/c drug

Toxic blood levels (>2.4 ng/ml)
• Will see conduction blocks or tachy-dysrhythmias or both
• Increased risk with renal disease, hypokalemia, aging

30
Q

There is an increased risk of toxicity with digoxin in patients with…

A

Renal disease

Hypokalemia

Aging

31
Q

Digoxin effect changes

A

(See at therapeutic levels - don’t need to d/c)

Shortened QT interval (shorter with dig toxicity)

Flattened T waves

Asymmetric ST depression and T wave inversion in leads with tall R waves (gradual downslope of ST segment)
• Different from ST depression seen in ischemia)

32
Q

Why are renal patients advised not to take digoxin?

A

Renally excreted and very narrow therapeutic margin —> extreme risk of toxicity

33
Q

What ECG changes do you see with toxic levels of digoxin?

A

Slows conduction —> 1st, 2nd, or 3rd degree AV block

Causes virtually any tachydysrhythmia (a tachy, VT, VF)

PAT with 2nd-degree AV block (2:1) most characteristic

Toxicity can be exacerbated with hypokalemia

34
Q

Drugs that can prolong QT interval, putting patients at risk for v tach and TdP

A

Anti-arrhythmias (quinidine, Procainamide, disopyramide, Amiodarone, Sotalol)

TCAs (Amitriptyline, doxepin, nortriptyline)

Phenothiazines (prochlorperazine)

Macrolides (Azithromycin, clarithromycin, erythromycin)

35
Q

How should you monitor drug effects when prescribing drugs that can prolong QT?

A

Monitor QTI and d/c drug if >25% prolongation develops (QTc exceeds 0.5s)

36
Q

What happens to the ECG in TCA overdose?

A

Prolongation of QT

Narrow QR portion with widened RS portion

Often with long PRI hidden beneath T

37
Q

What happens to the ECG in hypothermia?

A

All intervals prolonged (PRI, QRS, QTI)

Osborn waves

38
Q

What are Osborn waves?

A

Distinctive type of ST segment elevation w/ an abrupt ascent at the J-point then a plunge back to the baseline

39
Q

Why do you often see muscle artifact on ECG with hypothermia?

A

Shivering. Duh.

40
Q

Rare clinical syndrome due to an inherited autosomal dominant genetic defect —> ECG abnormalities which cause sudden death due to ventricular fibrillation or rapid v tach

A

Brugada Syndrome

41
Q

Hx and Sx with Brugada Syndrome

A

FH of sudden cardiac death

PMH of serious heart rhythm problems and severe fainting spells

More common in younger patients (30’s)

More prevalent in Asian populations

42
Q

Treatment for Brugada Syndrome

A

ICD (Implantable cardioverter-defibrillator)

43
Q

Brugada Syndrome is characterized by _______ on ECG

A

3 different patterns with variable ST segment elevation abnormalities