///2016 Abstract Details
2016 Abstract Details2019-07-15T10:10:51-05:00

Intrapartum Management of a Patient with HOCM Complicated by Chordal SAM

Abstract Number: T-77
Abstract Type: Case Report/Case Series

Andrew T Koogler MD1 ; Goran Ristev MD2; Kasey Fiorini MD3

Introduction: Patients with hypertrophic cardiomyopathy (HOCM) are at increased risk for dynamic LVOT obstruction due to systolic anterior motion (SAM) of the anterior mitral valve leaflet and subvalvular apparatus. Patients with preexisting SAM warrant close hemodynamic monitoring intrapartum as hemodynamic changes common in labor can provoke LVOT obstruction. We present the management of a recent case, which was also complicated by ICD lead malfunction during pregnancy.

Case: A 34 year old G1 with a history of HOCM confirmed by genetic testing was referred to a multidisciplinary team consisting of congenital cardiologists, maternal fetal medicine specialists, cardiac and obstetric anesthesiologists for delivery planning. History was significant for septal thickness of 2.3cm, mid-LV pressure gradient of 21mmHg with chordal SAM, syncope, and ICD for primary prevention of sudden cardiac death. Unfortunately, at 19 weeks gestation she was discovered to have a fractured RV lead and was instructed to wear a LifeVest for the remainder of her pregnancy. She was admitted for induction of labor at 39w5d with telemetry monitoring intrapartum and for 12 hours postpartum with an external defibrillator immediately available in case of ventricular arrhythmia. Prior to epidural placement, one liter of normal saline was administered to support preload, and a right radial arterial line was inserted for close hemodynamic monitoring. Labor epidural was placed at L3-4. 5ml of bupivacaine 0.125% with fentanyl 2mcg/ml was bolused, followed by an infusion of bupivacaine 0.0625% with fentanyl 2mcg/ml at 12ml/h. Six hours after epidural placement the patient delivered utilizing vacuum-assisted second stage. APGAR scores were 6 and 9 at 1 and 5 minutes, respectively. She was transferred to the postpartum unit wearing her LifeVest without additional monitoring. She wore the LifeVest until 6 weeks postpartum when the fractured RV lead was extracted and subcutaneous ICD placed.

Discussion: Patients with significant LVOT gradients on echocardiography at rest are at increased risk for LVOT obstruction with hemodynamic alterations known to provoke SAM. During delivery, LVOT obstruction may be exacerbated by tachycardia associated with sympathetic stimulation and hypovolemia secondary to blood loss. Preload is intermittently decreased during Valsalva, which can be minimized by assisting the second stage of labor. Neuraxial anesthesia attenuates pain associated with labor that may lead to tachycardia; however, avoiding sudden decreases in systemic vascular resistance is imperative. Physiologic changes of pregnancy such as increased intravascular volume may decrease LVOT obstruction, so serial echocardiography is helpful for delivery planning. Maintaining adequate preload, avoiding tachycardia, and assisting the second stage of labor may avoid complications and improve patient safety.

References:

1. Heart 2003;89:752-756

2. ProgCD 2012;54:503-511

3. IJOA 2015;24:344-355

SOAP 2016