ECG Test – Mixed Conditions — The Cardiovascular

This is the 3rd ECG test.

14 question(s) with answers and explanations.

Question 1

Male 58 years with chest pain. Which abnormalities are present? Click to enlarge ECG.

✓ Sinus rhythm
✓ Acute inferolateral myocardial infarction (STEMI)
✓ Posterior acute myocardial infarction
✓ ST-segment depressions in V1–V3 are reciprocal (mirror) posterior ST elevations.
✓ Persistent ST elevations strongly suggest there is myocardium that can be salvaged by means of revascularization.
○ Sinus tachycardia

Explanation. Inferolateral STEMI with posterior engagement, sinus rhythm. Patients with chest pain and ST elevations should be referred immediately for angiography.

Question 2

Male 58 years with chest pain. Identify all abnormalities on the ECG. Click to zoom.

✓ Sinus rhythm
✓ Acute inferolateral myocardial infarction (STEMI)
✓ Posterior acute myocardial infarction
✓ ST-segment depressions in V1–V3 are reciprocal (mirror) posterior ST elevations.
✓ Persistent ST elevations strongly suggest there is myocardium that can be salvaged by means of revascularization.
○ Sinus tachycardia

Explanation. Inferolateral STEMI with posterior engagement, sinus rhythm. Patients with chest pain and ST elevations should be referred immediately for angiography.

A 64 year old male patient with hypertension. ECG is recorded during his annual health screening. He is asymptomatic during the recording. Heart rate 67 beats per minute. Identify all abnormalities on the ECG. Click to zoom.

○ AV block 1
○ ST depressions in lateral leads (V5, V6, aVL, I), possibly due to left ventricular hypertrophy secondary to hypertension.
○ ST depressions in lateral leads (V5, V6, aVL, I), possibly due to ongoing myocardial ischemia.
○ Normal AV conduction
✓ Sinus rhythm

Explanation. This is sinus rhythm (67 beats per minute), with AV block I and ST-T changes (ST depressions in lateral leads V5, V6, aVL, I) that may be due to left ventricular hypertrophy. This is suggested by the presence of hypertension and large R-wave amplitudes in lateral precordial leads (V4, V5, V6). Such ST-segment depressions are common in hypertrophy and occasionally referred to as "left ventricular strain pattern". Discrete ST elevations in V1-V3 are common in left ventricular hypertrophy, as can be seen here. Acute ischemia is less likely in this clinical context.

Question 4

✓ AV block 1
✓ ST depressions in lateral leads (V5, V6, aVL, I), possibly due to left ventricular hypertrophy secondary to hypertension.
✓ ST depressions in lateral leads (V5, V6, aVL, I), possibly due to ongoing myocardial ischemia.
○ Normal AV conduction
✓ Sinus rhythm

Explanation. This is sinus rhythm (67 beats per minute), with AV block I and ST-T changes (ST depressions in lateral leads V5, V6, aVL, I) that may be due to left ventricular hypertrophy. This is suggested by the presence of hypertension and large R-wave amplitudes in lateral precordial leads (V4, V5, V6). Such ST-segment depressions are common in hypertrophy and occasionally referred to as "left ventricular strain pattern". Discrete ST elevations in V1-V3 are common in left ventricular hypertrophy, as can be seen here. Acute ischemia is less likely in this clinical context.

Question 5

A 42-year-old male with obesity. Reports increasing dyspnea over the past month. Identify all abnormalities on the ECG. Click to zoom.

○ Sinus rhythm
✓ Sinus tachycardia
✓ Low voltage in precordial (chest) leads
○ Low voltage in limb leads
○ Pathological Q waves in inferior leads (II, aVF, III)

Explanation. The rhythm is sinus tachycardia, which can be estimated by dividing the constant 300 by the number of large boxes between two R-waves (i.e the RR interval, which is roughly 3): 300 / 3 = 100 beats per minute. Low voltage exists in the limb leads if no lead reaches 5 mV (5 mm), and in the chest (precordial) leads if no lead reaches 10 mV (10 mm). Thus, this ECG displays low voltage in limb and precordial leads. Low voltage may be explained by obesity. The inferior leads (II, aVF, III) display large negative waves. However, most of them exhibit a small positive wave preceding the negative wave; the small wave is a small r-wave, which results in the negative wave being an S-wave. Thus, we cannot confirm any inferior Q-waves.

Question 6

A 68-year-old male with type 2 diabetes. Identify all abnormalities on the ECG. Click to zoom.

✓ Heart rate is roughly 75 beats per minute (300/4=75)
○ Heart rate is roughly 100 beats per minute (300/3=75)
✓ Low voltage in chest leads
○ Normal voltage in chest leads
○ Low voltage in limb leads
✓ Normal voltage in limb leads
✓ Fragmented QRS complexes in inferior limb leads (II, aVF, III)
✓ Inferior leads show small r-waves followed by large S-wave. These could be the normalization of old Q-waves (with the resurgence of a small r-wave)
○ Inferior Q-wave infarction (pathological Q-waves in II, aVF, III)

Explanation. The QRS complex is fragmented in the inferior leads, which is typical of manifest myocardial infarction. There are, however, no definitive signs of pathological Q-waves in the inferior leads, although the fragmented QRS, small r-waves, and large S-waves may suggest that there have been large Q-waves, now appearing normalized due to the resurgence of small r-waves (occurs in 20% of cases).

Question 7

A 68-year-old male with type 2 diabetes. Identify all abnormalities on the ECG. Click to zoom.

✓ Heart rate is roughly 75 beats per minute (300/4=75)
○ Heart rate is roughly 100 beats per minute (300/3=100)
✓ Low voltage in chest leads
○ Normal voltage in chest leads
○ Low voltage in limb leads
✓ Normal voltage in limb leads
✓ Fragmented QRS complexes in inferior limb leads (II, aVF, III)
✓ Inferior leads show small r-waves followed by large S-wave. These could be the normalization of old Q-waves (with the resurgence of a small r-wave)
○ Inferior Q-wave infarction (pathological Q-waves in II, aVF, III)

Explanation. The QRS complex is fragmented in the inferior leads, which is typical of manifest myocardial infarction. There are, however, no definitive signs of pathological Q-waves in the inferior leads, although the fragmented QRS, small r-waves, and large S-waves may suggest that there have been large Q-waves, now appearing normalized due to the resurgence of small r-waves (occurs in 20% of cases).

Question 8

A 79-year-old male. No other data. Identify all abnormalities on the ECG. Click to zoom.

✓ Left axis deviation
○ Right axis deviation
○ Normal heart axis
○ Generally low voltage
○ Acceptable voltage

Explanation. It may be speculated whether this patient has an old inferior (II, aVF, III) myocardial infarction, as suggested by low voltage and notched QRS complexes, although strict criteria for pathological Q-waves are not fulfilled. There is also poor R-wave progression in the chest leads (V1-V6).

Question 9

A 79-year-old male. No other data. Identify all abnormalities on the ECG. Click to zoom.

✓ Left axis deviation
○ Right axis deviation
○ Normal heart axis
✓ Generally low voltage
○ Acceptable voltage

Explanation. It may be speculated whether this patient has an old inferior (II, aVF, III) myocardial infarction, as suggested by low voltage and notched QRS complexes, although strict criteria for pathological Q-waves are not fulfilled. There is also poor R-wave progression in the chest leads (V1-V6).

Question 10

A 75-year-old male. No other data. Identify all abnormalities on the ECG. Click to zoom.

✓ Sinus rhythm
✓ Left axis deviation
○ Normal heart axis
✓ Poor R-wave progression in V1-V6
✓ AV block 1
✓ QRS duration >120 ms; non-specific intraventricular conduction delay (IVCD)
○ Normal QRS duration
○ Left bundle branch block
○ Right bundle branch block

Explanation. The QRS duration exceeds 120 ms, but without the typical pattern consistent with left or right bundle branch block; therefore, the diagnosis is non-specific intraventricular conduction delay. The R-wave progression in V1-V6 is abnormal (poor) and there is AV block 1.

Question 11

A 62-year-old male with chest discomfort. Are there signs of acute (ongoing) myocardial ischemia? Click to zoom.

○ There are no signs of ischemia.
○ There are definitive signs of ischemia.
○ There are changes suggestive of ischemia.

Explanation. The rhythm is sinus rhythm, with non-significant (<1 mm) ST-segment elevations in V5-V6, along with large T-waves in V1-V3. This could be the early phase of myocardial ischemia. Therefore, it is important to obtain a new ECG 5 to 10 minutes after the first recording or provide the patient with continuous ST-monitoring. Dynamic ST-T changes are suggestive of ischemia, and any increase in ST elevations is virtually diagnostic of ischemia.

Question 12

A 32-year-old male is in the ED. He had COVID-19 in December 2020, and has experienced pleuritic chest pain since the infection. Your colleague suggests his ECG shows acute perimyocarditis. Are there signs of acute perimyocarditis? Are the precordial T-waves within normal limits? Click to zoom.

✓ T-waves are within normal limits.
○ T-waves are not within normal limits.
○ There are signs of acute perimyocarditis.
✓ There are no signs of acute perimyocarditis.

Explanation. Acute pericarditis - The rhythm is sinus rhythm; acute pericarditis is typically accompanied by sinus tachycardia. - There are no significant ST-elevations. - Thus, this is not an acute pericarditis. T-waves - These T-waves are expected in a 30-year-old male with such R-waves. - T-wave amplitude is within normal limits.

Question 13

A 35-year-old female athlete with a history of syncope during exercise. Your initial assessment concludes that the ECG is normal, but your colleague warns you that lead V1 may reveal an ongoing atrial flutter. Is that correct?

✓ No, there are no signs of atrial flutter.
○ Yes, this ECH shows atrial flutter with normal ventricular rate.

Explanation. There are no signs of atrial flutter. There is one P-wave per TP-interval, and the other waveforms are artifacts.

Question 14

ECG recorded in a 60-year old male. The rhythm is sinus rhythm, but the morphology is clearly abnormal. Which conditions are consistent with this ECG? Click to zoom.

✓ Acute myocardial ischemia
✓ Left ventricular hypertrophy
✓ Apical hypertrophic (obstructive) cardiomyopathy

Explanation. The most likely diagnosis is left ventricular hypertrophy, which may be of apical HCM/HOCM type.

ECG Test – Mixed Conditions