Unstable angina pectoris

  Unstable angina pectoris is a clinical diagnosis.

  There is
no diagnostic ECG finding.

  Various ECG signs of ischemia may be observed during unstable angina pectoris.

  ECG findings may show
dynamic changes. Yesterday's ECG abnormality may not be observed today and a different ECG abnormality may be seen next day.

  Clinically, unstable angina is between stable angina pectoris and acute myocardial infarction.

  Not all patients with acute myocardial infarction experience the phases of stable and unstable angina pectoris serially.

  Some patients with stable angina pectoris may have acute myocardial infarction before experiencing unstable angina pectoris.




ECG findings that may be observed during unstable angina pectoris

  ST segment depression

  ST segment elevation

  T wave negativity

  Prominent T waves (increased amplitude of T waves)

  Negative U waves

  Atrioventricular (AV) blocks

  Arrhythmias

  QT interval prolongation




Caution

  Slightly horizontal or downsloping ST segment depression may be observed as a normal variant, especially in women.

  Patients with left ventricular hypertrophy
may have secondary ST segment depression / elevation and / or T wave negativity (strain pattern).

  In patients with cardiac pacemakers, pacemaker-induced beats may mask typical signs of ischemia.





ECG 1. The ECG above belongs to a 72 years-old woman with unstable angina pectoris. It was recorded the Emergency Room
just before coronary angiography. She was complaining of attacks of widespread retrosternal chest pain which were lasting
up to 30 minutes. Her chest pain was not related to effort. The ECG shows
VPC and ST segment depression .

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Figure 1a. Urgent coronary angiography showed
significant stenosis in the right coronary artery (RCA).




Figure 1b. Above is her coronary angiogram after successful stenting of the RCA.





ECG 2. The ECG above belongs to a 78 years-old man. It shows prominent T waves in the right precordials (V1-V3), and ST
segment depression and negative T waves in inferior leads. The leads V5 and V6 show more prominent ST depression.
Clinically she was diagnosed as unstable angina pectoris. Her coronary angiography showed 80% stenosis of the left
anterior descending (LAD) coronary artery. The rhythm is atrial fibrillation.

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ECG 3. The ECG above belongs to a 68 years-old man who had previously undergone coronary artery bypass graft surgery.
He was complaining of typical widespread chest pain unrelated to effort. He is under beta blocker therapy. His ECG shows

ST segment flattening
in anterior leads and prominent T waves in leads V2 and V3. Lead III shows negative T waves.

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ECG 4. The ECG above belongs to a 41 years-old man who is complaining of typical widespread chest pain unrelated to effort.
Coronary arteriography was performed although he had no ECG signs of ischemia. The Left Anterior Descending (LAD)
coronary artery was totally occluded proximally and was retrogradely receiving blood from the Right Coronary Artery
(RCA). He had not experienced acute myoardial infarction due to very slow occlusion of the LAD. This case shows that
a normal ECG does not rule out the presence of coronary artery disease . The patient's complaints should not be ignored.

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ECG 5a. The ECG above belongs to a 66 years-old man who is complaining of epigastric pain. The ECG does not show typical signs of myocardial ischemia.

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ECG 5b. His ECG, 4 days later, showed widespread ST segment depression. After this ECG, he was transferred to our hospital for urgent coronary angiography.

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ECG 5c. The ECG above was recorded just before coronary angiography. Widespread ST depression has disappeared.

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Figure 5. Coronary angiography showed signicant stenoses of
the Circumflex and
the Left Anterior Descending (LAD)
coronary arteries.





ECG 6. The ECG above belongs to a 60 years-old woman with normal coronary arteries. Precordial leads show slight ST segment depression with negative T waves.

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ECG 7. The ECG above belongs to a 64 years-old woman with uncontrolled hypertension and left ventricular hypertrophy. She has normal coronary arteries. ST segment depression is seen in leads V4 to V6.

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ECG 8a. Some patients with unstable angina may show dynamic ECG changes in a very short time. The ECG above belongs to a 63 years-old woman, complaining of chest pain. ST segment is depressed in leads V3 to V6. T wave is upright in the anterior leads. Anti-ischemic medical therapy was started.

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ECG 8b. Twelve minutes later, her ECG showed no more upright T waves in the precordial leads. Now, the ST segment is also depressed in leads I and aVL.

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ECG 8c. Seventeen minutes later the ECG was recorded again. This time, ST segment depression in leads V5 and V6 is less prominent.

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ECG 8d. The ECG was recorded 2 hours later. Under medical therapy, the ST segment depression disappeared, but the T wave negativity persisted.

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ECG 8e. Ten minutes after the ECG was recorded again. The negative T waves in precordial leads became flattened in this ECG.

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ECG 8f. The ECG above was recorded just after stenting of her Circumflex artery.

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ECG 8g. Twelve hours later, her ECG showed negative T waves in inferior leads. ST segment is not depressed anymore. Serum level of cardiac Troponin I was only slightly elevated.

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ECG 9a. The ECG above belongs to a 63 years old-man who had previously undergone implantation of 3 coronary stents. He has applied to the emergency room with the complaint of typical widespread retrosternal chest pain. Leads II, III and aVF show negative T waves with downsloping ST depression. Leads V4 and V5 show ST depression.

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ECG 9b. The ECG above was recorded 2.5 hours after the ECG 9a. The ST segment depression and negative T waves (except III) are not seen anymore. He was diagnosed as unstable angina pectoris and was referred for urgent coronary angiography which showed restenosis of the stent in LAD coronary artery.

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ECG 10a. The ECG above belongs to a 78 years-old man with coronary artery disease. He was advised to undergo coronary artery bypass grafting surgery. Precordial and lateral leads show negative T waves.

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ECG 10b. The ECG above belongs to the same man. It was recorded 4 days after ECG 10a during an episode of chest pain. Now, the ST segment is elevated in leads V1 to V4. Additionally, leads II and V6 show ST segment depression, while lead V5 shows flattened T wave.

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ECG 10c. The ECG above belongs to the same man. It was recorded two hours after ECG 10b. Now, the ST segment depression is deeper and also involves leads III and aVF. Additionally, lead V5 shows ST depression. This case is a good example for dynamic ECG changes in unstable angina.

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ECG 11. Above is an ECG from a middle-aged man complaining of retrosternal chest pain, unrelated to exertion. No pathological Q waves are seen (no clue of previous myocardial infarction). The ST segment is normal. However, there are
biphasic and negative T waves in precordial leads, suggesting myocardial ischemia (coronary artery disease). Taking into account his chest pain, this is compatible with unstable angina pectoris. He underwent coronary angiography after recording the above ECG. Coronary bypass artery surgery was performed for LAD and Cx coronary artery stenoses.

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