1. Other Cardiac Conditions and the ECG21
Other Cardiac Conditions and the ECG
Fast & Easy ECGs, 2nd E – A Self-Paced Learning Program

2. Other Cardiac Conditions
Many conditions cause changes to the ECG
Electrolyte abnormality
Ischemia
Infarction
Inflammation
Medications

3. Pericarditis Inflammation of the pericardium
Produces sharp, substernal chest pain
Instructional points:
The heart lies in the mediastinum and is covered by a thick membrane called the pericardial sac. This sac contains a small amount of fluid which allows the heart to move during contractions with minimal friction. Infection or inflammation can cause irritation to the pericardial sac which because it lies against the surface of the heart may cause inflammation of the outer layer of the myocardium as it moves against the inflamed pericardial sac.
Pericarditis can produce sharp substernal chest pain that worsens with inspiration and movement, particularly when the person is lying down. I

4. Pericarditis
Pain has an abrupt onset that worsens on inspiration or by movement, particularly when the individual is lying down
The pain lessens when sitting up and leaning forward

5. Causes of Pericarditis
Most common causes are viral and bacterial infections
Other causes include uremia, renal failure, rheumatic fever, connective tissue disease, and cancer
Sometimes pericarditis can accompany an MI
Instructional Point:
When pericarditis occurs in conjunction with MI, it develops several days after the infarction I

6. Characteristics of Pericarditis

7. ECG Changes in Pericarditis
T wave initially upright and elevated but then during recovery phase it inverts
ST segment elevated and usually flat or concave
Instructional point:
Unlike ST segment elevation seen in myocardial ischemia which is localize the ST changes in pericarditis are everywhere.

8. Pericardial Effusion Can occur with pericarditis
Can cause low-voltage QRS complexes in all leads and electrical alternans

9. Electrical Alternans
QRS complexes change in height with each successive beat

10. Pulmonary Embolism Acute blockage of one of the pulmonary arteries
Leads to obstruction of blood flow to the lung segment supplied by the artery
Produces large S wave in lead I, deep Q wave in lead III, inverted T wave in lead III
Called the S1 Q3 T3 pattern

11. Characteristics of Pulmonary Embolism

12. Effects of Pulmonary Embolism
The larger the artery occluded, the more massive the pulmonary embolus and therefore the larger the effect the embolus has on the lungs and heart
Due to the increased pressure in the pulmonary artery caused by the embolus, the right atrium and ventricle become distended and unable to function properly, leading to right heart failure
This condition is referred to as acute cor pulmonale

13. Effects of Pulmonary Embolism
Massive pulmonary embolism impairs oxygenation of the blood, and death may result
The most common source of the clot is in one of the large pelvic or leg veins
The pain that accompanies a pulmonary embolus is pleuritic, and shortness of breath is often present

14. Pulmonary Embolism
A number of dysrhythmias may be seen with massive pulmonary embolism, most commonly sinus tachycardia and atrial fibrillation

15. Electrolyte Imbalances
Increases or decreases in potassium and calcium serum levels can have a profound effect on the ECG

16. Hyperkalemia Is an abnormally elevated level of potassium in the blood
Levels between 5.1 mEq/L and 6.0 mEq/L reflect mild hyperkalemia
Levels of 6.1 mEq/L to 7.0 mEq/L reflect moderate hyperkalemia
Levels above 7 mEq/L reflect severe hyperkalemia
Signs and symptoms of hyperkalemia include weakness, paralysis, and respiratory failure

17. Hyperkalemia Key characteristics include: T wave peaking
Flattened P waves
1st-degree AV heart block
Widened QRS complexes
Deepened S waves
Merging of S and T waves

18. Hypokalemia Is a lower-than-normal amount of potassium in the blood
Symptoms of hypokalemia include weakness, fatigue, paralysis, respiratory difficulty, constipation, and leg cramps
Severe hypokalemia can lead to dysrhythmias and pulseless electrical activity (PEA) or asystole

19. Hypokalemia Key ECG characteristics include: ST segment depression
Flattening of the T wave
Appearance of U waves
Instructional Point:
The normal potassium level in the blood is 3.5–5.0 milliequivalents per liter (mEq/L).

20. QT Interval Changes In hyperkalemia the QT interval is shortened
In hypokalemia the QT interval is prolonged

21. Digoxin
Slows influx of sodium while allowing a greater influx of calcium
Increases myocardial contractility and improves the heart’s pumping ability
Slows heart rate and AV conduction
Useful in the treatment of fast atrial dysrhythmias

22. ECG Changes Seen with Digoxin
At therapeutic levels:
Produces a characteristic gradual downward curve of the ST segment
R wave slurs into the ST segment

23. Digoxin Very narrow therapeutic margin Excreted from the body slowly
Excessive levels can cause slower heart rates, faster heart rates and PVCs

24. Practice Makes Perfect
Identify if pulmonary embolism, low-amplitude waveforms, electrical alternans, electrolyte imbalance or digitalis use are present
Answer: Electrical alternans I

25. Practice Makes Perfect
Identify if pulmonary embolism, low-amplitude waveforms, electrical alternans, electrolyte imbalance or digitalis use are present
Answer: Pacemaker I

26. Practice Makes Perfect
Identify if pulmonary embolism, low-amplitude waveforms, electrical alternans, electrolyte imbalance or digitalis use are present
Answer: Low amplitude I

27. Summary Pericarditis is an inflammation of the pericardium
In pericarditis the T wave is initially upright and elevated but then during the recovery phase it inverts. The ST segment is elevated and usually flat or concave
Substantial pericardial effusion can occur with pericarditis and produce ECG changes which include low voltage QRS complexes in all leads and electrical alternans

28. Summary
A pulmonary embolism is an acute blockage of one of the pulmonary arteries
Characteristic ECG changes seen with massive pulmonary embolus include a large S wave in lead I, a deep Q wave in lead III and an inverted T wave in lead III

29. Summary
Increases or decreases in the potassium and calcium serum levels can have a profound effect on the ECG
Key characteristics of hyperkalemia include T wave peaking, flattened P waves, 1st-degree AV heart block, widened QRS complexes, deepened S waves and merging of S and T waves

30. Summary
Key ECG characteristics of hypokalemia include ST segment depression, flattening of the T wave and appearance of U waves
In hypercalcemia the QT interval is shortened while in hypocalcemia the QT interval is prolonged
Digoxin slows the influx of sodium while allowing a greater influx of calcium
A characteristic gradual downward curve of the ST segment is seen with digoxin