Adolescent Athlete With PRKAG2 Hypertrophic Cardiomyopathy

Abstract

Background

Providers treating pediatric athletes with hypertrophic cardiomyopathy (HCM) face challenging decisions for competitive sports participation.

Case Summary

A 16-year-old with PRKAG2+ HCM with Wolff-Parkinson-White presented for a second opinion regarding baseball participation. Under previous care, he was allowed to play baseball in a limited capacity. He had no symptoms or arrhythmias, and cardiac magnetic resonance imaging demonstrated asymmetric septal wall thickening without fibrosis and was initially cleared for full baseball participation. Over time, new arrhythmias were noted, and ventricular scar was seen on cardiac magnetic resonance. Using shared decision-making (SDM), the patient now plays competitive golf and is considering an implantable cardioverter defibrillator.

Discussion

This case demonstrates the temporal evolution of HCM and the importance of SDM when considering sport participation. Sports can play an important role in quality of life, and this should be considered in SDM.

Take-Home Message

HCM can evolve through adolescence, and SDM can assist in sport-participation decisions.

Visual Summary

Visual Summary.

Timeline of Events for the Clinical Case, Eventually Leading to a Change in Primary Sport From Baseball to Golf, Using Shared Decision-Making

History of Presentation

The patient is a 16-year-old who presented to our sports cardiology clinic as a second opinion due to personal and family history of gene-positive hypertrophic cardiomyopathy (HCM). The patient's father was diagnosed with HCM in his teenage years and found to have pathogenic PRKAG2 and MYBC3 mutations. The patient's father developed end-stage heart failure resulting in heart transplant in his 30s.

Take-Home Messages

• •Hypertrophic cardiomyopathy is an evolving and heterogenous disease.
• •Exercise and sports can contribute significantly to a child's quality of life.
• •Shared decision-making models should be utilized when assessing return-to-play for a hypertrophic cardiomyopathy patient.

Our patient, a competitive baseball player, had previously undergone genetic testing and was found to be positive for PRKAG2. He had multiple episodes of syncope, which appeared to be vagally mediated, and was diagnosed with postural orthostatic tachycardia syndrome and prescribed midodrine. He had no history of arrhythmia but did have Wolff-Parkinson-White pattern on multiple ambulatory rhythm monitors. At his previous institution, he was allowed to continue to play baseball in a limited capacity; he was not permitted to play as a fielder and was required to use a pinch runner whenever he reached base.

Past Medical History

• 1.PRKAG2 HCM
• 2.Postural orthostatic tachycardia syndrome

Differential Diagnosis

The initial differential diagnosis for the genotype-positive familial variant of HCM with episodes of syncope includes vasovagal syncope, HCM with left ventricular (LV) outflow tract obstruction, and HCM with atrial or ventricular arrhythmia.

Investigations

Much of the investigation of this teenager was aimed at understanding the patient specific risk. His electrocardiogram demonstrated sinus rhythm with a Wolff-Parkinson-White pattern and strong left-sided forces with abnormal repolarization. An echocardiogram showed normal biventricular systolic function and mildly asymmetric septal wall thickening. A cardiopulmonary exercise test using a ramp cycle ergometer protocol demonstrated a mildly exaggerated blood pressure response to exercise (max BP 198/72), a mildly low physical working capacity (2.77 W/Kg, ∼80% of predicted peak work rate), mildly low peak oxygen consumption (35 mL/kg/min), and 1 premature ventricular contraction in recovery but otherwise no electrocardiographic changes suggestive of subendocardial ischemia. There was persistence of preexcitation throughout exercise. Cardiac magnetic resonance imaging (CMR) demonstrated global LV hypertrophy with an LV mass measuring 138 g/m2 with additional moderate asymmetric septal hypertrophy with a maximal septal wall thickness of 1.7 cm, no left ventricular outflow tract obstruction, no fibrosis, and no edema. Holter demonstrated no arrhythmias.

Management

Management of this young man was centered around the shared decision-making (SDM) process as demonstrated in the accompanying Figure 1. First, assess the room dynamics: Both the patient and his parents expressed a strong desire to return to full participation in baseball if there was a way to do so safely. They noted increased depressive symptoms and perceived social isolation attributed to athletic restriction. The patient, who was 16, asked to be present for all discussions involving his disease and perceived sport-specific risk. Second, acknowledge uncertainty: It was explained to the patient and his family that the medical team could offer recommendations and interpretation of the data, but knowledge of this patient's sport-specific risk was limited. Third, discuss current data: While PRKAG2 can be a malignant form of cardiomyopathy characterized by arrhythmia, the patient thus far had no history of arrythmia, no fibrosis on CMR, and a reassuring exercise stress test. Fourth, provide recommendations: Ultimately, the decision was made that the patient would return to full participation in baseball and would bring a working automated external debrillator (AED) to all practices and games. His father, trained in CPR and AED use, became an assistant coach and attended all athletic activities. An emergency action plan (EAP) was confirmed with the school. The dynamic nature of the patient's disease was emphasized, and a willingness to continually reassess the risk/benefit of continued participation in athletics was agreed upon.

Figure 1.

A Proposed Framework for Physicians Using Shared Decision-Making to Approach a Visit for an Adolescent Athlete With Hypertrophic Cardiomyopathy

First, assess the room dynamics and encourage all stakeholders to share opinions and fears. Then, acknowledge the uncertainty of disease and discuss all available data. As a group, come to a consensus of an “athletic prescription” that everyone feels comfortable with. Re-evaluation of new data is important, as hypertrophic cardiomyopathy is an evolving disease and safety of certain activities may change.

Outcome and Follow-Up

Six months after the initial visit, the patient developed atrial fibrillation which converted to sinus rhythm spontaneously, for which he was started on nadolol. He subsequently underwent an electrophysiology study, where orthodromic atrioventricular (AV) reentrant tachycardia utilizing a concealed left posteroseptal AV bypass tract was inducible. A distinct, intermittently manifesting, left lateral AV bypass tract capable of antegrade-only conduction was also identified. Both left posteroseptal and left lateral AV bypass tracts were eliminated by radiofrequency catheter ablation. He was also noted to have an intermittently manifesting bystander fasciculoventricular bypass tract not known to be involved in tachyarrhythmias or at risk of sudden life-threatening events, so therefore was not targeted with catheter ablation. This residual bystander bypass tract manifests intermittently on his electrocardiogram with a ventricular preexcitation pattern. An implantable loop recorder was placed during the same setting for ongoing ambulatory heart rhythm monitoring.

Continued SDM discussions were performed, and the patient played golf and baseball without symptoms or arrythmias. He completed an exercise test 1 month after ablation which demonstrated low physical working and aerobic capacity with 2 isolated premature ventricular contractions during exercise without symptoms.

Repeat CMR was performed 2 years after the initial visit with stable septal hypertrophy (1.7 cm) and normal function. However, there was new delayed enhancement in the mid-inferolateral left ventricle and a decrease in extracellular volume, suggesting potential progression of his disease. An exercise test demonstrated ventricular bigeminy in early recovery but no symptoms during exercise and mildly reduced aerobic capacity and physical working capacity. The electrophysiology team continued to follow up with the patient, and the implanted loop recorder demonstrated nonsustained ventricular tachycardia, for which nadolol was reinitiated and an implantable cardioverter defibrillator was discussed. Given the new nonsustained ventricular tachycardia, gene positive status, and evidence of scar on CMR, his risk of a sudden cardiac event was estimated to have increased, and this was articulated to the patient and family. The patient has continued to play baseball for his high school team, with an AED and EAP in place, but has elected to not pursue collegiate-level baseball. He has become more involved in golf and intends to focus on making this his primary sport moving forward. Discussions are underway about a primary prevention implantable cardioverter defibrillator.

Discussion

The most recent American Heart Association/American College of Cardiology scientific statement for sports participation in patients with cardiovascular abnormalities highlights the need for SDM.¹ This case of a teenage patient with PRKAG2 HCM demonstrates the importance of using an SDM framework and the way in which cardiomyopathy can evolve over the course of adolescence. Baseball has played a critical role in the patient's relationship with his father, his friends, and his emotional well-being. His genetic change is rare among HCM patients, with high rates of conduction abnormalities, atrial fibrillation, and life-threatening arrhythmias.² Reassuringly, his initial evaluation was without high-risk features, and it was thought that returning to baseball, a sport without a high frequency of burst activity or anaerobic activity, would not substantially increase his risk of a cardiac event. Importantly, provisions were made to have a working AED, trained adults, and an updated EAP in place at all times; which are critical measures given that our current ability to fully quantify risk is incomplete.

Also notable is that this young man's disease, and the potential risk of a sudden cardiac event, progressed over the course of his adolescence, with the development of arrythmias and scarring.^3,4 Given that the discussion about disease evolution was performed early, the patient sought out athletic opportunities like golf that were potentially lower risk but could still offer him many of the things he valued about participation in athletics. This advanced planning has prepared him for a potential gradual transition in the coming years that aligns with the recognition of disease progression.

Conclusions

HCM is a heterogenous disease, which can have both sudden and gradual consequences. Due to this heterogeneity, every case should be treated differently, applying validated risk stratification in conjunction with clinical judgement and family involvement. The SDM process should include clarification of parents and patient desires and normalization of any differing opinions and partnering with family to prescribe a safe and meaningful return-to-activity.

Funding Support and Author Disclosures

The authors have reported that they have no relationships relevant to the contents of this paper to disclose.