Decoding the right force

Central illustration.

Twelve-lead electrocardiogram (ECG).

Clinical vignette

A 43-year-old man, who underwent lobectomy during childhood due to post-infectious bronchiolitis secondary to measles, presented at an outpatient clinic with shortness of breath and chronic cough. On the physical examination, the patient had diminished vesicular breath sounds on the right hemithorax. Cardiac auscultation showed more audible S1 and S2 on the right sternal border and diminished on the left precordium. There was a regurgitative murmur on the right sternal border which increased in intensity with forced inspiration.

Questions

• 1) What is the most likely diagnosis according to the clinical findings and electrocardiographic abnormalities

  1. Dextrocardia

  2. Right ventricular hypertrophy

  3. Cardiac dextroposition

  4. Pulmonary stenosis

  5. Chronic obstructive pulmonary disease

Discussion and explanation

Cardiac dextroposition occurs when the heart is displaced to the right side of the thorax, instead of the left side. Its caused by extracardiac conditions such as right pneumonectomy, diaphragmatic hernia, or left pleural effusion.¹ Cardiac axis deviation is not expected in this condition. On the other hand, dextrocardia is an anomaly in which the heart is located on the right side of the chest with the apex pointing to the right, like a mirror image.² In this electrocardiogram (ECG), the absence of R-wave progression in precordial leads V1–V6 can be noted. In fact, we observe a decrease in the amplitude of R waves from right to left leads, without any S waves. A normal cardiac axis is seen on the ECG, +30° to +60°.

Option A is incorrect. While the ECG does not show R-wave progression, the cardiac axis is normal. In dextrocardia, the ECG findings in Lead I include a negative QRS complex and inverted P and T waves. The 12-lead ECG in this case does not have criteria for right ventricular hypertrophy (right axis deviation + 90°, deep S waves in left ventricular leads, increase in QRS duration, ST-T changes opposite to QRS direction, incomplete right bundle branch block pattern in V1), so Option B is incorrect. Option C is the correct answer. The ECG demonstrates R-wave regression in precordial leads due to the increased distance between the heart and the leads in the thorax. A posteroanterior chest radiograph was performed and confirmed the diagnosis (see Supplementary material online, Figure S1). Options D and E are also incorrect.

• 2) What is the most plausible cause for the heart murmur?

  1. Mitral regurgitation

  2. Hypertrophic cardiomyopathy

  3. Pulmonary stenosis

  4. Tricuspid regurgitation

  5. Atrial septal defect.

Discussion and explanation

Tricuspid regurgitation (TR) is the most common disorder of the tricuspid valve.³ The majority of the cases TR are functional and can be primary or secondary. The TR is associated with a holosystolic murmur that normally is best heard along the left sternal border, in this case it was dislocated due to dextroposition. The forced inspiration increases the intensity of the murmur, this manoeuvre is called Rivero-Carvallo and can differentiate TR from mitral regurgitation (Option A incorrect). During deep inspiration, the venous blood flow into the right heart increases, leading to an augmented volume of blood through the tricuspid valve; as a result, the intensity of the TR murmur increases. The patient of the case has a pulmonary artery systolic pressure of 54 mmHg in the echocardiogram (Option D is correct). The murmur of hypertrophic cardiomyopathy is a systolic ejection murmur which becomes much louder with valsalva manoeuvre (Option B incorrect).⁴ Pulmonary stenosis can have a systolic ejection murmur, but its usually associated with ejection click and a split S2 (Option C incorrect) and atrial septal defect have a systolic murmur that may extend into the early diastolic phase and can radiate to the left side of the chest or to the back (Option E incorrect).

• 3) Which other finding can be noted in this ECG?

  1. Right ventricular hypertrophy

  2. Right atrial hypertrophy

  3. Right-axis deviation

  4. Left atrial hypertrophy

  5. Ventricular pre-excitation

The ECG shows a P-wave amplitude in lead II > 0.25 mV, compatible with right atrial hypertrophy. The patient of the case has an enlarged right atrium in the echocardiography (Option B correct). Prolongation of the total atrial activation is not noted (Option D incorrect). The ECG did not show right ventricular hypertrophy, right axis deviation, or ventricular pre-excitation (Options A, C, and E are incorrect).

Supplementary material

Supplementary material is available at European Heart Journal – Case Reports.

Consent: The authors confirm that written consent for submission and publication of this case report including images and associated text has been obtained from the patient in line with COPE guidance.

The data underlying this article are available in Zenodo, at https://doi.org/10.5281/zenodo.8118407.

Funding: No funding was involved in the development of this manuscript.

Data availability

The data underlying this article are available in the article and in its online Supplementary material.