Case 1: Cardiac MRI a, b showing the tumor compressing the RVOT (circle), and an intraoperative photograph showing the large fibroma on the anterior surface of the heart (c)
Case 1: 3D modeling demonstrating the cardiac tumor (gray) compressing the RV (blue). The tumor is shown opaque (a), transparent (b), and after removal from RV surface (c). The 3D reconstruction assisted with assessing the extent of RV compression, which ultimately required surgical reconstruction after tumor debulking
Case 1: 3D printed heart model demonstrating the fibroma in a clear, flexible rubber printed material on the anterior surface of the heart demonstrated in an opaque, hard plastic printed material. The 3D model assisted with determining the extent of RV compression, as well as defining the left coronary course within a portion of the tumor
Figure 15.1d shows the tumor, which completely covered the anterior surface of the heart. The tumor filled the mediastinum making it difficult to visualize its total extent or move the heart as needed. Therefore, intraoperatively, the patient was placed on cardiopulmonary bypass. The resection was continued to relieve RVOT obstruction, with immense care taken to avoid putting the LAD at risk. The tumor was separated from the right coronary artery, and further dissection clearly revealed it arose from the myocardium. The majority of muscle of the RV free wall and the RVOT was very thin or had been completely replaced by tumor. Most of the anterior free wall from the atrioventricular groove to the interventricular septum up to the annulus of the main pulmonary artery was removed. Further lateral resection of the mass was not possible due to its intimate involvement with the LAD. After debulking as much of the tumor as deemed to be safe, the RVOT was reconstructed using CorMatrix patch (CorMatrix Cardiovascular, Inc., Roswell, GA). An intraoperative transesophageal echocardiogram showed the RV systolic function to be mildly depressed with severe hypokinesis of the anterior free wall, and no RVOT obstruction, or tricuspid or pulmonary valve insufficiency. The final pathology demonstrated that the tumor was a fibroma with foci of myxoid changes, consistent with the preoperative CMR findings. The patient was discharged home on postoperative day 17 and will be followed by oncology and cardiology to ensure no regrowth of the tumor or recurrent RVOT obstruction.
Because the LAD was covered for much of its length by the tumor, identifying its course intraoperatively was not possible. However, the 3D model clarified the relationship of the tumor, main pulmonary artery, and the LAD, prior to and during surgery, allowing us to plan a safe surgical approach and extent of resection.
Large Residual Cardiac Rhabdomyoma Causing Refractory Ventricular Tachycardia
The second patient was an adolescent with tuberous sclerosis and multiple cardiac rhabdomyomas with associated accelerated ventricular rhythm. He had one large residual rhabdomyoma in the basal left ventricular free wall that was causing mild left ventricular outflow tract obstruction and thought to be the focus for his recurrent ventricular arrhythmias. A 3D model facilitated electrophysiology study planning and discussion related to potential surgical resection.
An adolescent with a history of tuberous sclerosis and multiple cardiac rhabdomyomas, most of which had resolved, except for one large residual tumor in the left ventricular outflow tract, presented with episodic palpitations. An electrocardiogram was performed, which demonstrated a wide QRS complex tachycardia with right bundle branch block morphology and leftward inferior QRS axis. Atrial activity was not definitively seen. Adenosine was administered without apparent affect. Intravenous diltiazem was given and the heart rate slowed. During the episode, the patient became anxious but maintained consciousness. An invasive cardiac electrophysiology study showed monomorphic ventricular tachycardia originating near the rhabdomyoma. Radiofrequency lesions placed at the site of earliest ventricular activation did not have any effect on the tachycardia. Tachycardia termination was not achieved, and the patient left the laboratory with continued tachycardia which was resulting in hemodynamically instability. On one occasion, a short burst of ventricular pacing converted the tachycardia to ventricular fibrillation. An implanted cardioverter-defibrillator (ICD) was placed approximately 1 month later.