Cardiac tamponade (CT) is a critical condition characterized by increased pericardial pressure due to the accumulation of fluid, pus, blood, clots, or gas within the pericardium [1]. This leads to impaired diastolic filling and a subsequent reduction in cardiac output [2]. Common causes include pericarditis, tuberculosis, trauma, tumors, and complications from cardiac interventional procedures [3]. Although infrequent during cardiac intervention, CT is a serious and life-threatening complication with a mortality rate as high as 50% and an incidence rate between 0.089–4.8% [4]. Treatments for CT mainly include pericardiocentesis and pericardiotomy [5]. While guidelines suggest surgery in cases of hemodynamic instability [1, 3], the choice of treatment often relies on the individual clinician’s experience. Our center’s experience suggests immediate pericardiocentesis after CT diagnosis to alleviate pressure in the pericardial cavity.

In this analysis, we sought to assess the conditions under which minimally invasive CT treatments can be used in place of more invasive surgical procedures. We conducted a single-center retrospective study of patients who developed iatrogenic CT over the last ten years. Our results suggest that the mechanism behind myocardial injury and the volume of drainage may be indicators to assess whether or not a patient will need open heart surgery.

In this study we observed cases of CT with perforation occurred during many procedures, including PCI, RFA, LAAO and the implantation of pacemaker electrodes. The majority of these mild iatrogenic CTs were successfully resolved with pericardiocentesis. Notably, the use of blunt tip instrument did not result in myocardial laceration, preserving myocardial tissue integrity. In patients who only required pericardiocentesis, the mean immediate drainage volume was 208.2 $\pm$ 173.84 mL, with a first-hour mean drainage volume of 38.5 $\pm$ 60.5 mL. Individuals with myocardial tears and limited bleeding did not require open heart surgery. However, in the distinct cases of two patients with left atrial appendage tears, non-surgical treatment was insufficient to stop the bleeding. While pericardiocentesis provided temporary symptom relief, surgical intervention ultimately became necessary. Surgery may be indicated for individuals exhibiting high drainage volumes to prevent hemodynamic collapse and the potential onset of multi-organ failure.

Over the past decade, our center has performed 51,821 cardiac interventional procedures, with an iatrogenic CT incidence rate of approximately 0.10%. Our center’s experience aligns with the notion that pericardiocentesis suffices as the primary treatment for most iatrogenic CT cases, often precluding the need for open surgery. This is largely because injuries caused by blunt device usually do not disrupt myocardial tissue continuity. This is similar to the finding of Laborderie et al. [6], who found that most ventricular pace lead perforations can be resolved by simply withdrawing the catheter. Similarly, Schwerg et al. [7] found no significant difference in myocardial thickness between patients with or without perforations caused by leads, with 96% of such perforations being sealed through transvenous lead withdrawal. This was further substantiated by Bauer et al. [8] with data from the European heart survey (EHS) PCI Registry, which included over 42,000 patients. They found that among the 124 patients who experienced myocardial perforations, 11.3% developed CT, but only a small percentage (3.3%) required emergency surgery [8]. In a study by Hamaya et al. [9], highlighted that only 3.92% of individuals with pericardial tamponade following atrial fibrillation ablation required surgery. Additionally, the need for surgery was attributed to lacerations caused by the left atrial appendage closure device [9]. Furthermore, numerous studies indicate that CT following RFA is manageable with medical interventions alone, without the need for surgery [10, 11, 12].

Iatrogenic CT can occur through different mechanisms depending on the type of cardiac intervention. For PCI, arterial perforations may be caused by the guidewire and arterial tears can result from balloon expansion [13, 14]. Notably, performing RFA for arrhythmias has the potential to injure the atrial and ventricular walls [12]. During the implantation or reposition of pacemaker leads, the electrode may puncture the chamber wall [4, 15]. Specifically, the left atrial appendage is at high risk of injury during the deployment or retrieval of an occluder during LAAO procedures [16]. Given the left atrial appendage’s thin wall, it is particularly susceptible to injury from sharp devices. Moreover, the left atrial appendage’s contraction is less effective at halting the bleeding compared to the atrium and ventricles, increasing the risk of significant hemorrhage.

There are several mechanisms to explain how non-surgical measures could stop the bleeding in patients with iatrogenic CT. (1) Myocardial anatomy and contraction. The inherent anatomical structure of the myocardium, particularly its ability to contract, can naturally prevent further bleeding. However, the efficacy of this mechanism varies with the myocardial thickness and is less effective in the left atrial appendage compared to other cardiac chambers. Additionally, the varying pressure within the cardiac chambers also varies and may contribute to bleeding control. (2) Blunt tip myocardium penetration during pacemaker implantation. The myocardium’s complex three-dimensional myofibril network structure enables spontaneous hemostasis. Circumferentially oriented myofibrils on the epicardial surface that can control the bleeding by fibrillar contraction [17]. For example, right ventricular perforations generated by pacemaker leads usually can be treated with pericardiocentesis alone [18]. (3) PCI-related injury. Arterial elasticity and local thrombus can seal perforations caused during PCI. Temporary balloon inflation may suffice to control the bleeding, and in cases where it does not, a covered stent may be deployed successfully. In our study, one patient received a covered stent to successfully seal the perforation. Al Mawed et al. [19] reported a case of delayed CT following PCI, occurring four days post PCI with stent placement, likely due to guidewire perforation. The perforation had initially formed a thrombus, but the thrombus dissolved after resuming anticoagulation, leading to delayed tamponade [19]. (4) Acute CT dynamics. The physiological response to acute CT includes an increased heart rate and shortened diastolic phase, reducing the opportunity for blood ejection from tears. The severity of these tears may vary with the cardiac cycle, limiting the volume of bleeding [20]. For example, in dry pericardiocentesis, right ventricular (RV) myocardial punctures are frequent and most do not require open surgery [21]. This suggests that holes due to direct myocardial puncture may be capable of spontaneous closure.

In certain cases, such as left atrial appendage lacerations, bleeding control through non-operative methods has proven challenging. The primary issue stems not from the puncture wounds themselves but from myocardial lacerations induced by the motion of a sharp needle tip against the beating heart [22]. For example, a 0.3–0.5 mm diameter acupuncture needle may accidentally cause a 2–3 mm tear in the RV wall, which can result in a rapid and significant blood accumulation often beyond the manageability of non-surgical treatment [23, 24, 25]. The resulting lacerated myocardial injuries are frequently followed by hemodynamic instability. Since the injury is transmural, the myocardial contractions cannot seal the hole, and may even exacerbate it, causing the situation to become increasingly critical with each heartbeat. A particularly poignant case reported by Kodikara et al. [26] involved a patient who committed suicide using a syringe needle, culminating in CT. Autopsy findings revealed that a 3 cm long syringe needle was used to puncture the left chest, causing two anterior pericardial perforations and laceration of the left anterior descending artery septal branches, illustrating the severe consequences of sharp device-related myocardial injuries [26].

Although pericardiocentesis and surgical intervention have similar prognosis for CT, the potential for increased complications with open surgical drainage necessitates careful patient selection for surgery. Horr et al. [27] conducted a comparative analysis of 1281 patients with CT after cardiac interventions, comparing surgical procedures with pericardiocentesis. They concluded that both approaches have similar in-hospital mortality rates (5.3% vs. 4.4%, p = 0.49) [27]. Similarly, Saltzman et al. [28] found no significant differences in overall mortality and long-term survival rates between the two therapies, but noted that open surgical drainage could introduce additional complications. Wu et al. [29] reported CT resulting from atrial fibrillation ablation, and found that if hemodynamic deterioration continues under pericardiocentesis and bleeding persists, surgical repair should be considered.

There are several limitations with this study. First, is the nature of the analysis. Being a retrospective analysis conducted at a single center, the data could be influenced by measurements, operators and techniques, and selection bias. These factors might affect the generalizability of our results to other settings or populations. Second, is the limited sample size. Only 51 cases identified for inclusion, and merely two of them proceeded to open surgery. This limitation underscores the need for future studies with larger sample sizes and a broader array of patients undergoing various percutaneous interventions to confirm our findings. Third, is follow-up duration. Although most patients experienced symptom relief within 1–2 days, our study lacks long-term follow-up data. The absence of extended monitoring may overlook potential late-onset complications or outcomes following the initial treatment period. Finally is the diagnosis of CT etiologies. For the majority of patients, the causes of cardiac tamponade were deduced theoretically rather than verified through direct examination. This approach may introduce uncertainties regarding the precise etiologies of CT in our patient cohort. Future investigations with larger sample sizes, diverse patient groups, and comprehensive long-term follow-up are essential to confirm our observations and address these limitations.

In patients with cardiac tamponade who undergo immediate pericardiocentesis, the cause of the injury and the amount of drainage volume after tamponade may be used as indicators for the need for emergency surgery. Open surgery may be considered if the wound is lacerated due to a sharp device and when the drainage volume exceeds 300 mL per hour.

MACEs, major adverse cardiovascular events; PCI, percutaneous coronary intervention; RFA, radiofrequency ablation; LAAO, left atrial appendage occlusion; BMI, body mass index; LvEF, left ventricular ejection function; CT, cardiac tamponade; SD, standard deviation; RV, right ventricular.

The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.

HL and GW performed the research. CQ, XS and FJ designed the research study. HL and XS analyzed the data. HL, GW and XS wrote the manuscript. All authors contributed to editorial changes in the manuscript. All authors read and approved the final manuscript. All authors have participated sufficiently in the work and agreed to be accountable for all aspects of the work.

The study protocol was approved by the Ethics Committee of The First Affiliated Hospital of Chongqing Medical University (ethics number: K2023-592) and has been performed in accordance with the ethical standards laid down in the 1964. Declaration of Helsinki and its later amendments. Written informed consent was also waived because of the retrospective nature of the study. We have deidentified all patients details to ensure they cannot be identified.

The authors would like to thank Gao Hui for her technical help.

This work was supported by Chongqing Municipal Science and Technology Bureau (No. cstc2019jscx-msxmX0307 to C-CQ); Chongqing Municipal Health Commission (No. 2020msxm113 to C-CQ); and National Nature Science Foundation of China (No. 82070523 to C-CQ).

The authors declare no conflict of interest.