Blog → Noteworthy ECGs – What is the Culprit Lesion?

Noteworthy ECGs – What is the Culprit Lesion?

Written by Eriny Hanna

Read this ECG first, and see if you can spot the abnormality.

Figure 1A from cited article.

What is your diagnosis?

Got it? Now read on.

Spoon Feed
There are two distinct ECG patterns to know for isolated right ventricular myocardial infarctions (IRVMI).

Why does this matter?
Patients with RV infarcts require adequate preload. Missing RV infarct ECG patterns can lead to nitrate and diuretic administration with subsequent hypotension.

(Pre)Load It Up
This article presents a case of a healthy 40-year-old patient with sudden onset chest pain. The initial ECG taken in the ambulance (Figure 1A above) shows ST-segment elevation (STE) in leads V1 and aVR, more pronounced in V1 as well as diffuse ST-segment depression (STD) in leads I, aVL, and V3-V6.

Upon arrival to the emergency department, a right-sided ECG was performed (Figure 1B below), which showed STE in leads V3R-V5R. The patient was taken to the cath lab and found to have complete occlusion of the proximal non-dominant right coronary artery (RCA); a stent was placed.

Figure 1B from cited article. Black arrows point to PVCs.

IRVMI occurs in less than 3% of patients presenting with MI. Culprit lesions involve the vessels that supply the right ventricular free wall. Clinical presentation typically includes hypotension, jugular venous distension, and clear lung sounds. Fluid resuscitation should be considered and vasodilators avoided. There are 2 main EGC patterns to recognize for IRVMI.

The first IRVMI pattern (see Figure 1A above) includes:

  • STE in right sided leads
    • STE amplitude is greater in V1 than aVR
    • Slight STE in lead III is possible, but not other inferior leads
  • STD in some, but usually not all, other leads
  • The authors stress that this pattern is not to be confused with left main occlusion or triple vessel disease, which causes another ECG pattern1 – STE amplitude greater in aVR than V1 and STD of >1mm in 8 or more leads.

The second IRVMI pattern (Figure 2 below) includes:

  • STE in anterior leads, with progressive decrease in STE amplitude from V1 to V5
  • STD should not be present in the inferior leads.
  • This pattern can be confused with an anterior MI pattern.2 The key here is that IRVMI will have decreasing STE amplitude progressing from V1 to V5 and there will not be STD in the inferior leads.
Figure 2 3

Another Spoonful
Don’t miss Amal Mattu’s ECG Weekly covering this topic.

Source
Diagnostic Traps—Noteworthy Electrocardiogram Patterns. JAMA Intern Med. 2022 May. doi:10.1001/jamainternmed.2022.1925

Works Cited

  1. ST elevation in aVR. Life in the Fast Lane. 2021 Sep.
  2. Anterior Myocardial Infarction. Life in the Fast Lane. 2022 Apr.
  3. Proximal complete occlusion of right coronary artery presenting with precordial ST-segment elevation: a case report. Medicine. 2016 Oct;95(41):e5113. doi:10.1097/MD.0000000000005113.

Leave a Reply