Abstract
Introduction
Primary cardiac tumors are exceedingly rare, with a reported autopsy incidence of 0.0001-0.030%, of which approximately 25% are malignant. Angiosarcoma is the most common primary malignant cardiac tumor, predominantly arising in the right atrium, with a five-year survival of approximately 14%. Its aggressive, infiltrative behavior often necessitates extensive surgical resection, which may significantly alter right atrial anatomy and disrupt the sinoatrial node. We present a case of delayed sinus node dysfunction following right atrial angiosarcoma resection in which postsurgical anatomic alteration precluded atrial leadless pacemaker implantation, necessitating rescue ventricular leadless pacing.
Case Info
A 65-year-old woman with a history of breast cancer treated with lumpectomy and radiation was diagnosed with a large infiltrative right atrial angiosarcoma measuring 4.9 × 4.6 × 5.7 cm, extending into the caval inflow region and right coronary artery territory. She underwent surgical resection with right atrial reconstruction.
Approximately five months later, she developed recurrent lightheadedness and near-syncope. Ambulatory monitoring demonstrated symptomatic sinus pauses up to seven seconds with junctional escape rhythm, and inpatient telemetry confirmed intermittent sinus node dysfunction with sinus exit block. Echocardiography showed preserved left ventricular systolic function (ejection fraction 58%). Her sinus node dysfunction was attributed to either surgical injury or residual infiltrative tumor near the sinoatrial node.
Given symptomatic sinus node dysfunction, permanent pacing was indicated. With an indwelling mediport, upcoming chemotherapy, and infection risk from additional transvenous hardware, a leadless strategy was favored; with intact atrioventricular conduction, atrial leadless pacing was initially pursued.
However, intraprocedural angiography and intracardiac imaging revealed no suitable right atrial appendage for stable device deployment, and atrial leadless implantation was aborted. The procedure was converted to successful femoral-vein implantation of a leadless ventricular pacemaker programmed for backup pacing at 40 beats per minute.
At 18-month follow-up, she remained predominantly in sinus rhythm with intact intrinsic atrioventricular conduction and a ventricular pacing burden of only 3%. She experienced no recurrent lightheadedness and had returned to an active lifestyle.
Disc Clinical
This case illustrates two consequences of extensive right atrial tumor resection: delayed sinus node dysfunction and loss of the anatomic substrate required for atrial leadless pacemaker implantation. Although atrial leadless pacing was attractive given her isolated sinus node dysfunction, preserved atrioventricular conduction, and infection risk, successful implantation ultimately depended on preserved right atrial anatomy.
In this patient, the surgery that likely caused her sinus node dysfunction also created the anatomic barrier that prevented the intended atrial pacing strategy. Intraprocedural imaging demonstrated that prior resection and reconstruction had eliminated a suitable implantation site, necessitating an alternative approach. Ventricular leadless pacing provided effective rescue therapy, and a low backup rate preserved intrinsic conduction and sustained symptom resolution.
Conclusion
As atrial leadless pacing becomes increasingly utilized, clinicians should recognize that prior right atrial surgery may fundamentally alter device feasibility. Careful review of operative anatomy, along with targeted preprocedural imaging, may help anticipate these limitations. When atrial implantation is anatomically precluded in a patient with preserved atrioventricular conduction, low-rate ventricular leadless backup pacing may offer a practical and effective alternative.