Clinical vignette
A 34-year-old man with a history of dilated cardiomyopathy had undergone orthotopic heart transplantation with bicaval anastomosis 4 weeks ago. His postoperative course was uneventful, and he was asymptomatic. Physical examination revealed no obvious findings other than tachycardia. A routine electrocardiogram (ECG) was performed at follow-up. Figure demonstrates his ECG at rest this time.
Question 1
What is the diagnosis?
Atrial tachycardia
Atrial flutter
Complete atrioventricular block
Complete pseudo-atrioventricular block
Mobitz Type II atrioventricular block
The correct answer is D.
The patient’s post-transplant ECG showed sinus tachycardia with dissociated P-waves representing dual atrial depolarizations in lead II. The donor atrial rate was 116 beats per minute, while the recipient’s was 75 beats per minute, which was dissociated from the donor atrial and ventricular rates (see Supplementary material online, Figure S1). This phenomenon, also known as a complete pseudo-atrioventricular block, occasionally occurs due to residual recipient atrial tissue after undergoing transplantation.1
Question 2
What is the mechanism of tachycardia in this patient?
The effect of medications for heart transplantation
Sympathetic nerve activation
Vagolytic effect
Elevation of circulating catecholamines
Anaemia
The correct answer is C.
The heart is dually innervated by vagal and sympathetic fibres. However, heart transplantation results in complete surgical denervation of the donor heart.2 Therefore, post-heart transplantation, patients usually have resting tachycardia, as was seen in our case.
Question 3
What would you do next?
Follow-up
Ablation
Anticoagulation
Pacemaker implantation
Holter electrocardiography
The correct answer is A.
The incidence of atrial arrhythmias after orthotropic heart transplantation is reportedly 5–25% and that of bradyarrhythmias is up to 25%, with a majority being sinus node dysfunction.1,3 Tachyarrhythmia and bradycardia are more common after biatrial anastomosis than after the more widely used bicaval technique; the biatrial technique anastomoses the donor and recipient atria resulting in a dual P-wave phenomenon owing to the coexistent, electrically isolated donor and recipient sinus nodes. However, arrhythmic complications, including a complete pseudo-atrioventricular block, can occur even with the bicaval anastamosis technique. Treatment is usually not required for complete pseudo-atrioventricular block.
Supplementary Material
Contributor Information
Ryohei Ono, Department of Cardiovascular Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan.
Togo Iwahana, Department of Cardiovascular Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan.
Yoshio Kobayashi, Department of Cardiovascular Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan.
Supplementary material
Supplementary material is available at European Heart Journal – Case Reports.
Consent: The authors confirm that written informed consent for the publication of this case report was obtained from the patient.
Funding: None declared.
Data availability
On reasonable request, derived data supporting the findings of this study are available from the corresponding author.
References
- 1. Huang WA, Woo JP, Boyle NG. The rogue P-wave: atrial dissociation following bicaval heart transplantation. J Innov Card Rhythm Manag 2019;10:3472–3475. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2. Schumacher O, Trachsel LD, Herzig D, Mohacsi P, Sigurdardottir V, Wilhelm M, et al. Heart rate kinetics during standard cardiopulmonary exercise testing in heart transplant recipients: a longitudinal study. ESC Heart Fail 2021;8:1096–1105. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3. Zghaib T, Guandalini G, Schaller RD. Two hearts, believing in just one mind: what is the rhythm? Am J Med 2022;135:456–458. [DOI] [PubMed] [Google Scholar]
Associated Data
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Supplementary Materials
Data Availability Statement
On reasonable request, derived data supporting the findings of this study are available from the corresponding author.