ECG Case n° 2

A 57 year-old-patient is brought in Emergency Department by ambulance complaining of fever, swelling and erythema of the left leg .

Medical History: not relevant.

Vital Signs: BP 130/80 mmHg, HR 90 bpm, SpO2 96% room air, RR 22/min, GCS 15, T 38°C.

Arterial Blood Gas analysis:

ECG. 1

ECG ANSWER and INTERPRETATION

Rate:

• 85 min

Rhythm:

• Regular P waves

Axis:

• -75°

Intervals:

• PR – normal (<200ms) and regular
• QRS – Wide (>120ms); rSR’ morphology V1-V3: RBBB.
• QT – 360ms (QTc Bazett 430ms)

Waves and Segments:

• P waves: left atrial abnormality (negative component>positive component)
• Q waves DII-DIII-aVF: >0.04ms and Q>R
• S wave in DI
• ST depression V1-3 and DI-aVL
• T waves: negative V1-V3, DIII, aVR
• SIQIIITIII (McGinn-White): S wave in DI, Q waves DIII, negative T waves in DIII

DIFFERENTIAL DIAGNOSIS

The ECG changes described may be seen with any cause of acute or chronic disease that causes right ventricular strain:

Acute	Chronic
Severe pneumonia Exacerbation of COPD /asthma Pneumothorax Recent pneumonectomy Upper airway obstruction Pulmonary Embolism	Chronic obstructive pulmonary disease Recurrent small PEs Cystic fibrosis Interstitial lung disease Severe kyphoscoliosis Obstructive sleep apnoea Pulmonary Ipertension

OUTCOME

There were no focal changes in lung parenchyma on chest radiographs.

The patient was allergic to iodinated contrast media (anaphylactic shock): A pulmonary scintigraphy was then performed in the suspicion of pulmonary embolism.

IMG. 1-4: Pulmonary scintigraphy

Ventilation images document areas of impaired ventilation in the posterior basal area of the left lung; Perfusion images document perfusion deficit in the posterior basal segment.

Conclusion: compatible with pulmonary embolism.

The patient was treated with Apixaban and discharged after a few days.

TRICKS

ECG changes associated with acute pulmonary embolism are nonspecific and may be seen in other condition [1-5]. The ECG in Pulmonary Embolism (PE) lacks sensitivity and specificity: it is neither sensitive nor specific enough to diagnose or exclude PE.

ECG changes in PE are related to dilation of the right atrium and right ventricle, right ventricular ischaemia, heart rotation and position shift, increased sympathetic tone due to pain, anxiety and hypoxia.

The most common findings are sinus tachycardia (44%) and nonspecific ST-segment and T-wave changes (50 %). The most specific finding is simultaneous T wave inversions in the inferior (II, III, aVF) and right precordial leads (V1-4), representing high pulmonary artery pressures; T wave inversion in lead V1 plus lead III was only seen in 1% of ACS patients versus 88% of patients with PE. 

Other ECG changes in pulmonary embolism include:

• Complete or incomplete RBBB (18%)
• Right ventricular strain pattern –  T wave V1-4 ± II, III, aVF
• Right axis deviation – (16%)
• Dominant R wave in V1 – representing acute right ventricular dilatation.
• Right atrial enlargement  – P wave in lead II > 2.5 mm (9%)
• SIQIIITIII –neither sensitive nor specific. Abnormalities historically considered to be suggestive of PE (S1Q3T3 pattern, right ventricular strain, new incomplete right bundle branch block) are uncommon (less than 10 percent) [6-7].
• Clockwise rotation
• Atrial tachyarrhythmias – AF, flutter, atrial tachycardia (8%)

Normal ECG is present in 9-26% of cases.

ECG abnormalities that are associated with a poor prognosis [1,2,4]:

●Atrial arrhythmias

● Right heart strain + RBBB

●Bradycardia (<50 beats per minute) or tachycardia (>100 beats per minute)

●Complete right bundle branch block

●Inferior Q-waves (leads II, III, and aVF)

●Anterior ST-segment changes and T-wave inversion (V1-V3)

●SIQIIITIII

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AUTHORS

Dr. Lorenzo Pelagatti

Emergency Department – Nuovo Ospedale di Prato S. Stefano – Prato, Tuscany, Italy

High Dependency Unit – AOU Careggi – Florence, Tuscany, Italy

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Dr. Franco Lai

Emergency Department – Nuovo Ospedale di Prato S. Stefano – Prato, Tuscany, Italy

REFERENCES

1. Geibel A, Zehender M, Kasper W, Olschewski M, Klima C, Konstantinides SV. Prognostic value of the ECG on admission in patients with acute major pulmonary embolism. Eur Respir J. 2005 May;25(5):843-8. doi: 10.1183/09031936.05.00119704. PMID: 15863641.
2. Ferrari E, Imbert A, Chevalier T, Mihoubi A, Morand P, Baudouy M. The ECG in pulmonary embolism. Predictive value of negative T waves in precordial leads–80 case reports. Chest. 1997 Mar;111(3):537-43. doi: 10.1378/chest.111.3.537. PMID: 9118684.
3. Rodger M, Makropoulos D, Turek M, Quevillon J, Raymond F, Rasuli P, Wells PS. Diagnostic value of the electrocardiogram in suspected pulmonary embolism. Am J Cardiol. 2000 Oct 1;86(7):807-9, A10. doi: 10.1016/s0002-9149(00)01090-0. PMID: 11018210.
4. Shopp JD, Stewart LK, Emmett TW, Kline JA. Findings From 12-lead Electrocardiography That Predict Circulatory Shock From Pulmonary Embolism: Systematic Review and Meta-analysis. Acad Emerg Med. 2015 Oct;22(10):1127-37. doi: 10.1111/acem.12769. Epub 2015 Sep 22. PMID: 26394330; PMCID: PMC5306533.
5. Co I, Eilbert W, Chiganos T. New Electrocardiographic Changes in Patients Diagnosed with Pulmonary Embolism. J Emerg Med. 2017 Mar;52(3):280-285. doi: 10.1016/j.jemermed.2016.09.009. Epub 2016 Oct 11. PMID: 27742402.
6. Panos RJ, Barish RA, Whye DW Jr, Groleau G. The electrocardiographic manifestations of pulmonary embolism. J Emerg Med. 1988 Jul-Aug;6(4):301-7. doi: 10.1016/0736-4679(88)90367-8. PMID: 3225435.
7. Thames MD, Alpert JS, Dalen JE. Syncope in patients with pulmonary embolism. JAMA. 1977 Dec 5;238(23):2509-11. PMID: 578884

SITOGRAPHY

1. Dr Smith’s ECG Blog
2. https://litfl.com 

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