The study presents a patient with PAPVC, which was initially missed during evaluations conducted for her chest pain. An initial TTE was performed in the patient’s hometown; however, the anomaly was not diagnosed. After being referred by a cardiac imaging specialist for additional evaluations, supplementary tests such as TEE and PCTA revealed the diagnosis of PAPVC. Surgical management was performed due to symptomatic presentation and abnormal imaging findings. The patient’s recovery involved a minor and relatively common complication of cardiac function overload, which was managed smoothly with medications. Follow-up was uneventful and showed normal findings.

PAPVC has been diagnosed in approximately 0.4-0.7% of the normal population during autopsy evaluations. The prevalence of symptomatic patients is nearly equal to that of the lower range of this spectrum (0.41%) [9]. Therefore, it is considered a rare anomaly that cardiologists should keep in mind [10]. This case report underscores the fact that diagnosis was missed for almost two years after symptomatic diagnosis due to the limitations of TTE in diagnosing PAPVC. This structural anomaly is present in 0.5-1% of the population. This suggests that many patients live their entire lives with this anomaly without symptoms or a diagnosis [11]. Although there are various subtypes of this condition, nearly four-fifths of diagnosed cases involve anomalous pulmonary veins draining into the RA via a sinus venosus connection with an ASD. In contrast, the diagnosis of pure PAPVC without a septal defect is seen in approximately one-tenth of cases and is substantially rare [12]. The presented case demonstrated no septal defect.

The presentation of PAPVC is considerably nonspecific and depends on the magnitude of the intracardiac shunt and the anomalous drainage of the PV. Therefore, diagnosis is not straightforward and requires a thorough evaluation using multimodal imaging [13]. However, regardless of the type of PAPVC, it causes left-to-right shunts in pre-tricuspid level, which result in recirculation of the oxygenated blood into the pulmonary circulation, increased pulmonary blood flow, and increased volume load on the right heart. Consequently, right atrial enlargement (RAE) and right ventricular enlargement (RVE) inevitably result from these functional abnormalities [14]. In summary, it is important to note that aging and its associated effects, such as HTN and diastolic dysfunction, contribute to increased pressure in the LA compared to the RA. This, in turn, can lead to increased blood flow to the right heart and a greater left-to-right shunt. However, the amount of blood that enters the right heart is influenced by the number of abnormal connections present. For instance, it has been observed that a single anomalous pulmonary vein connection may not cause significant overload on the right side of the heart.

Additionally, an atrial septal defect can facilitate diagnosis, as imaging techniques make it more easily visualized. This condition may also be associated with greater blood shunting and an increased likelihood of developing symptoms [14]. Cyanosis is an uncommon manifestation of this condition, occurring when pressure on the right side of the heart exceeds that on the left. This pressure difference can reverse blood flow, resulting in the development of Eisenmenger’s syndrome. While PHTN is an indication for the surgical or interventional correction of PAPVC, surgery is contraindicated in cases of Eisenmenger’s syndrome, as it may worsen the patient’s condition. Standard medications are used to manage pulmonary hypertension (PHTN) [1516].

Diagnostic procedures when encountering CHD usually start with CXR and an echocardiogram. Although increased heart size, abnormally located pulmonary vessel structure, and interstitial changes in the lungs might suggest abnormalities in the cardiovascular system, the first choice for detecting anatomical heart defects is an echocardiogram. TTE and TEE are used, with TEE offering more sensitivity and specificity, especially for visualization of the entire atrial septum and PV connections [10]. A limitation of TEE is its requirement for sedation, which entails specific requirements and potential risks [14]. Overall, TEE and TTE are suboptimal for diagnosing PAPVC, and multidetector computed tomography (MDCT) or magnetic resonance imaging (MRI) angiography provides significantly higher accuracy. Newer-generation three-dimensional MDCT has proven to be an excellent diagnostic modality [14].

The management of PAPVC depends on clinical findings, hemodynamic characteristics, and anatomical features. Therapeutic options include (1) follow-up, (2) medical management, (3) surgical treatment, and (4) transcatheter interventional procedures [17]. Corrective intervention is indicated in the following situations: the presence of significant symptoms related to this anomaly, a significant left-to-right shunt indicated by a Qp/Qs ratio greater than 2, or imaging evidence showing right ventricular (RV) dilation or RV volume overload (evidenced by a D-shaped septum during diastole). Additionally, surgical repair may be necessary alongside the simultaneous correction of other serious heart lesions and in cases of frequent respiratory infections. Other indications for intervention include persistent pulmonary hypertension (PHTN) and recurrent paradoxical emboli [18]. Open surgical correction remains the gold standard treatment for these patients. However, selected patients undergoing percutaneous transcatheter modification have demonstrated excellent outcomes. The selection is based on age, anatomical features, available expertise or devices, and clinical conditions [19]. Similar cases from the literature are summarized in Table 3 for reference. A graphical abstract illustrating and summarizing different aspects of this pathology is included in this manuscript (Fig. 5).

Although rare, PAPVC can be a potentially debilitating anomaly if it is not diagnosed on time. The presentation is nonspecific, and accurate diagnosis primarily relies on multimodal imaging techniques, especially PCTA or PMRA. Many of these patients are misdiagnosed or experience delayed diagnosis, resulting in complications and long-term impairments in cardiac function, such as congestive heart failure. Therapeutic options are determined by clinical presentation, anatomical characteristics, and the severity of the shunt. Surgical management, if indicated, is the gold standard. However, new percutaneous intervention techniques have been applied successfully and are increasingly favored for selected patients.

Graphical abstract of Partial Anomalous Pulmonary Venous Connection (PAPVC)