Abstract
Background
Congenital left ventricular diverticulum (LVD) is a rare cardiac malformation that may cause catastrophic complications, such as ventricular tachycardia (VT). The surgical indication for LVD remains controversial.
Case Summary
A 31-year-old man was diagnosed with LVD through multimodality imaging that involved electrocardiogram, transesophageal echocardiography, cardiac computed tomography angiography, and magnetic resonance imaging. Intracardiac echocardiography and electrophysiological mapping confirmed the arrhythmia originating inside the diverticular cavity. With ineffective conservative treatment, surgery became the preferable option. The surgical approach was guided by preoperative three-dimensional printed reconstruction. The procedure involved diverticulum patch repair combined with radiofrequency ablation and, unexpectedly, mitral valve replacement. The patient recovered well.
Discussion
VT originating from an LVD is a rare and catastrophic complication, with multimodal imaging essential for diagnosis. Surgical repair and radiofrequency ablation are effective treatments for LVD complicated by arrhythmia.
Take-Home Message
Treatment with medication alone may be insufficient for LVD with VT, and surgery is recommended.
Key words: congenital heart defect, electrophysiology, 3-dimensional printing, ventricular tachycardia
Graphical Abstract
Congenital left ventricular diverticulum (LVD) is a rare cardiac malformation, first described in 1816, caused by the reduction or deletion of local myocardial tissue or the replacement of normal myocardial tissue by fibrous tissue, resulting in abnormal bulging of myocardial tissues under high left ventricular pressure1 and associated with other cardiac, vascular, or thoracoabdominal abnormalities.2 The majority of patients with LVD are asymptomatic and are diagnosed occasionally. However, in some patients, LVD can cause significant morbidity and mortality owing to heart failure, ventricular tachycardia (VT), rupture of the lesion, thromboembolism, and sudden cardiac death.
Take-Home Message
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•
Conservative treatment may be insufficient for LVD with VT; surgery is recommended.
Case Presentation
A 31-year-old man was transferred to the cardiology department given recurrent palpitations with dyspnea for 3 years, followed by a recurrence with worsening symptoms over 7 days. Recent symptoms included syncope once, accompanied by convulsions and cold sweats. A 24-hour Holter monitor at the referral hospital showed 9,161 ventricular premature beats, including 12 episodes of rapid VT. The patient had a history of hyperthyroidism (Graves ophthalmopathy) for more than 10 years.
Physical examination during admission was unremarkable. During hospitalization, medication (landiolol, amiodarone, nifedipine, and lidocaine) controlled the patient's ventricular rhythm, but VT still occurred repeatedly (Figure 1). When his condition stabilized at a ventricular rate of 45 beats/min, a temporary pacemaker (VVI mode, 80 beats/min) was implanted. Transesophageal echocardiography revealed localized bulging in the lower basal segment of the LVD (Figure 2). Coronary angiography was initially performed, and no coronary stenosis was detected. Cardiac computed tomography (CT) angiography (Figure 3) and magnetic resonance imaging (MRI) (Figure 4) (before pacemaker implant) revealed a localized bulge in the basal segment of the left ventricular lateral wall, which indicated a diverticulum. Considering the patient's symptoms, electrocardiogram (ECG) (Figure 1), and other diagnostic tests, the ventricular arrhythmia most likely originated from the left ventricular base.
Figure 1.
Preoperative and Postoperative 12-Lead ECGs
(A) Preoperative ECG showing ventricular tachycardia. (B) No ventricular arrhythmia occurred on postoperative ECG. ECG = electrocardiogram.
Figure 2.
Transesophageal Echocardiography
(A) Preoperative TEE indicating the LVD (arrow). (B) The LVD (arrow) on 3D echocardiography model. Its size was 31 × 28 mm. (C) Postoperative TEE indicating no LVD (arrow). 3D = three-dimensional; LVD = left ventricular diverticulum; TEE = transesophageal echocardiography.
Figure 3.
Cardiac CT Angiography
(A) Preoperative CT angiography indicating the LVD (arrow). (B) Postoperative CT angiography indicating no LVD (arrow). CT = computed tomography; LVD = left ventricular diverticulum.
Figure 4.
Cardiac MRI
(A) Preoperative MRI indicating the LVD (arrow). (B) Postoperative MRI indicating no LVD (arrow). LVD = left ventricular diverticulum; MRI = magnetic resonance imaging.
An electrophysiological study was conducted under the guidance of a DecaNav mapping catheter (Biosense Webster) and intracardiac echocardiography (ICE) (Figure 5A), and detected early ventricular premature beats (Figure 5C) and short episodes of rapid VT (Figure 5B). This indicated that the earliest origin of the premature beats was located within the LVD. Pacing measurements at this site revealed a QRS pattern 96% similar to spontaneous premature ventricular contractions (Figure 5D), further confirming the intradiverticular origin of the premature beats.
Figure 5.
Electrophysiological Study With the DecaNav Mapping Catheter
(A) LVD anatomy via intracardiac echocardiography. (B) VT mapping. (C) Homologous ventricular premature beat mapping. (D) Pacemaker mapping. LVD = left ventricular diverticulum; VT = ventricular tachycardia.
After multidisciplinary team consultation, because of the diverticulum's wide communication, close to the posterior annulus of the mitral valve and the anterior papillary muscle, percutaneous closure was ruled out. The patient was deemed a candidate for surgical intervention. Considering the anatomical proximity between the diverticulum and the left circumflex artery, a three-dimensional (3D) printed model reconstruction was created preoperatively to confirm their anatomical relationship (Figure 6). To preserve the left circumflex artery, surgeons accessed the left ventricle through a classic right atrial and atrial septal incision. After incising the mitral posterior leaflet from the mitral posterior annulus, the diverticulum (Figure 7A) was exposed well (Figure 7B). Guided by electrophysiological mapping, AtriCure single-polar radiofrequency ablation was performed around the diverticulum orifice (Figure 7C). The diverticulum neck was repaired using a bovine pericardium patch and 2-0 nylon suture with mattress sutures. Unfortunately, after reattaching the posterior mitral leaflet to the annulus using a continuous suture, severe mitral regurgitation occurred. Because of limited experience with pericardial patch augmentation for repair mitral regurgitation, and concerned that the diverticulum neck patch caused the displacement of the anterior papillary muscle, surgeons had to perform mechanical mitral valve replacement. Transient pacing induction via a temporary cardiac pacemaker (180 beats/min) before chest closure predicted no recurrence of VT. The procedure was successful but imperfect, and the patient ultimately recovered and was discharged, with postoperative follow-up confirming effective diverticulum neck closure (Figure 2C) and no arrhythmia (Figure 1B). After 2 months, transthoracic echocardiography showed that the LVD had closed well, and Holter monitoring indicated that no VTs were observed, although occasional premature ventricular contractions (89 isolated episodes in 122,350 beats) were noted.
Figure 6.
The 3D-Printed Model of the Heart
(A) The view of heart with the LVD in pale green (arrow). (B) The LVD is shown in green (arrow). (C) The LVD (pale green; arrow) shown with the left circumflex artery (red). (D) The LVD (green) shown with the mitral annulus (gray; arrow). 3D = three-dimensional; LVD = left ventricular diverticulum.
Figure 7.
Intraoperative Images
(A) The LVD with methylene blue staining (arrow). (B) The LVD is exposed with posterior mitral valve incision (arrow). (C) AtriCure single-polar radiofrequency ablation (arrow). LVD = left ventricular diverticulum.
Discussion
LVD lesions are usually benign, although some complications have been recorded, including thromboembolic events (2.9%), ventricular arrhythmias (9.9%), syncope (5.7%), heart failure (6.8%), and free wall rupture (4.2%).2,3 Ventricular arrhythmias and syncope may be the first symptom. VT is often monomorphic with right bundle branch block morphology, often inducible during electrophysiological studies, and a cardioverter-defibrillator may be required.4 In our case, the patient presented with recurrent VT and even syncope. Analysis of ECG and Holter monitoring suggested a possible left ventricular origin. Ventriculography (95.5%), CT (88.9%), cardiac MRI (84.2%), and echocardiography (78.2%) are all sensitive tools for diagnosing LVD.5 In the current case, coronary angiography excluded coronary artery disease, and echocardiography, cardiac CT angiography, and MRI diagnosed the diverticulum. ECG and electrophysiological mapping confirmed that the VT originated in the diverticulum and was precisely located.
Given its low overall prevalence (between 0.02% and 0.76%) and variability in presentation, a standardized treatment for LVD has yet to be delineated.6 Poor prognoses, including high mortality and morbidity, have been reported in infants and children with comorbid defects, and serious complications have been associated with LVD. In contrast, more favorable clinical outcomes have been demonstrated in adults, most notably in asymptomatic patients.7 Surgical removal should be considered based on the localization of the lesion and associated symptoms or with cardiac malformations. Unfavorable anatomy of the diverticulum and the patient's reluctance to undergo surgery adjudicate in favor of conservative management. In one study, the incidence of adverse events in symptomatic patients (arrhythmia-related symptoms, syncope, and embolic events) with isolated LVD and distinct abnormal ECG patterns increased during long-term follow-up (median follow-up: 50 months).8 However, there is still no consensus on surgical treatment for asymptomatic isolated LVD. Some clinicians believe that all LVD patients require surgical treatment in order to reduce potential risks such as left ventricular thrombosis, malignant arrhythmia, ventricular wall rupture, and massive hemorrhage. Others believe that radical surgical treatment of LVDs may cause damage to the left ventricular structure given the resection of normal left ventricular wall muscles, which can result in heart failure and even lead to death.3
The surgical technique depends on the location and size of the LVD. The first type of surgical repair is performed by direct suturing of the LVD orifice, usually when the connection to the left ventricle is small. The second type of repair is resection with a patch (pericardial, Dacron, or polytetrafluorethylene) closure, usually when the connection to the left ventricle is larger than 2 cm2. The third technique is undergoing transcatheter closure with an Amplatzer duct occluder for LVD localized in the left ventricular outflow tract; the diverticulum should have a narrow neck amenable to catheter intervention.9 In a case series by Yao et al1 describing LVD repair with a patch, the base of the diverticulum was directly incised, the neck of the diverticulum was closed with a Decorn patch (double-ended needle and spacer), and the diverticular cavity of the left ventricle was closed and repaired using the sandwich method.
Unlike most cases, our patient's cardiac CT angiography revealed that the LVD was close to the left circumflex artery. To clarify the anatomical relationship, our team adopted 3D printing technology preoperatively to reconstruct the diverticulum, cardiac coronary vessels, and mitral valve. The patient's diverticulum was adjacent to the left circumflex artery, with partial branches running through it. Considering potential damage to the artery, we ultimately performed diverticulum repair via an intracardiac approach. Unfortunately, despite suturing the posterior annulus and performing valvuloplasty, severe mitral regurgitation occurred, leading to mechanical mitral valve replacement. Our team concluded that the diverticulum was located at the base segment of the inferolateral wall of the left ventricle, adjacent to the mitral valve annulus and papillary muscles. A patch was used to isolate the diverticulum, resulting in papillary muscle displacement as well as valve leaflet tethering.
Very few cases of LVD have been treated with surgical radiofrequency ablation. Yamasaki et al10 reported a case of malignant arrhythmia associated with a diverticulum. The external protrusion was surgically addressed using an expanded polytetrafluorethylene patch to close the orifice, with subsequent cryoablation of the left ventricular wall surrounding the protrusion. However, their case differed in that subcutaneous implantable cardioverter-defibrillator placement was subsequently performed, and the preoperative evaluation failed to precisely identify the origin of the malignant arrhythmia.10 In our case, ICE-guided reconstruction and electrophysiological mapping confirmed that the recurrent VT originated within the LVD, providing critical guidance for localized radiofrequency ablation using an AtriCure single-polar ablation in the diverticular cavity. Postoperative Holter monitoring showed no recurrence of VT, with only occasional ventricular premature beats observed.
Conclusions
Congenital LVD is a rare cardiac malformation, and its management is unclear, even as most cases in adults are asymptomatic. In this article, we report a patient with LVD and frequent VT. Echocardiography, cardiac CT angiography, cardiac MRI, and coronary artery angiography were routinely examined. ICE-induced electrophysiological mapping is useful for confirming the original site of the arrhythmia. Regarding the anatomical complexity of the LVD, 3D printing technology may be needed to confirm the pathway to surgery. Surgical repair and radiofrequency ablation are effective treatments for LVD.
Funding Support and Author Disclosures
The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
Footnotes
The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the Author Center.
Contributor Information
Zhihong Wu, Email: wuzhihong915@csu.edu.cn.
Zhaoshun Yuan, Email: zsy7107@csu.edu.cn.
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