Author + information
- Received October 21, 2015
- Revision received December 30, 2015
- Accepted January 28, 2016
- Published online June 1, 2016.
- Stuart A. Ostby, BSa,
- J. Martijn Bos, MD, PhDb,c,
- Heidi J. Owen, RNb,
- Philip L. Wackel, MDb,
- Bryan C. Cannon, MDb and
- Michael J. Ackerman, MD, PhDa,b,c,d,∗ ()
- aMayo Medical School, Mayo Clinic, Rochester, Minnesota
- bDepartment of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, Minnesota
- cDepartment of Molecular Pharmacology & Experimental Therapeutics; Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
- dDepartment of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
- ↵∗Reprint requests and correspondence:
Dr. Michael J. Ackerman, Windland Smith Rice Sudden Death Genomics Laboratory Guggenheim 501, Mayo Clinic, 200 First Street Southwest, Rochester, Minnesota 55905.
Objectives The study sought to determine the outcomes of continued sports participation in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT).
Background Patients with CPVT are at increased risk of sudden death with exertion. Currently, CPVT patients are advised disqualification from nearly all sports in accordance with expert opinion guidelines. However, we have approached this complex issue with a shared decision making model respecting a patient’s and their family’s right to be a competitive athlete following institution of comprehensive CPVT-directed treatment program.
Methods A retrospective record review was performed on patients with CPVT who were >6 years of age at the time of initial evaluation to determine their athlete status and frequency/scope of subsequent CPVT-triggered events.
Results Among 63 eligible patients with CPVT (34 females, mean age at diagnosis 16.6 ± 12.9 years), 31 (49%) were athletes at some point in their life. Compared to the nonathletes, these athletes were significantly younger at diagnosis (11.8 ± 6.6 years vs. 21.3 ± 15.6 years; p = 0.003) and more symptomatic (21 [68%] vs. 13 [41%]; p = 0.04). Following diagnosis, 21 of 24 athletes (88%) continued competition. For these 21 athletes, 16 (76%) had experienced 32 CPVT-triggered events prior to diagnosis versus 57 events in 18 nonathletes (43%; p = 0.02). During follow-up, 3 events occurred in 3 of 21 athletes (14%) compared to 7 events in 6 of 42 nonathletes (14%, p = 1.00). No event resulted in death, and all received an adjustment in their CPVT therapy.
Conclusions Although sports participation is a risk taking behavior in undiagnosed and untreated CPVT, the risk may be acceptable for a well-treated and well-informed athlete following the diagnosis of CPVT.
- catecholeminergic polymorphic ventricular tachycardia
- left cardiac sympathetic denervation
- sudden death
Sudden cardiac death (SCD) in athletes is tragic and occurs in approximately 1 of every 43,000 to 200,000 athletes (1,2). It is more common in males, more commonly occurs at higher levels of competition, and is often due to hypertrophic cardiomyopathy or coronary artery anomalies (3). Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an uncommon genetic channelopathy recognized as a cause of death in those with structurally normal hearts during the modern era of postmortem genetic testing (4).
In CPVT, increased catecholamines induce ventricular arrhythmias leading to syncope, seizure, and SCD. Five genes have now been associated in the pathogenesis of CPVT, the 2 most common being the RYR2-encoded cardiac ryanodine type 2 receptor (5), and less common being the CASQ2-encoded calsequestrin 2 (6,7). CPVT is genetically and clinically diverse with variable penetrance, and is associated classically with polymorphic ventricular tachycardia during exercise stress testing although this is not always present (8).
Suspicion for the disease may also be generated with onset of premature ventricular contractions (PVCs) in isolation at heart rates above 120 beats per minute with progression to PVCs in bigeminy, and sometimes bidirectional ventricular couplets (9). Use of beta-blockers (BBs) significantly reduces the risk of cardiac events (8,10), and is coupled with the sodium channel blocker flecainide when standalone BB therapy is not sufficient (11,12). Furthermore, additional treatment via left cardiac sympathetic denervation (LCSD) can be considered (13–15). In fact, in CPVT, this might be preferred to placement of an implantable cardioverter defibrillator (ICD), as shocks can be self-promoting when the arrhythmia is triggered by adrenaline release leading to an electrical storm (16).
Because CPVT is heritable, genetic testing is recommended in family members, and treatment is recommended for asymptomatic, genotype positive family members (17). CPVT is often discovered in the young athlete following a cardiac event during athletic participation and its diagnosis has far reaching consequences. Recommendations regarding competitive sports participation for those with cardiovascular diseases are guided by the 36th Bethesda Conference guidelines (2005) (18), the European Society of Cardiology guidelines (19), and the most recent 2015 sports participation guidelines from the American Heart Association and the American College of Cardiology (20), all of which severely limits athletic activity in patients diagnosed with CPVT. In addition, the CPVT-specific guidelines in 2013 recommends to limit or avoid competitive sports, limit or avoid strenuous exercise, and limit exposure to stressful environments (21).
The mandate to cease competitive athletics is often devastating and has great impact on the quality of life for patients, often more impactful than the CPVT diagnosis itself. Similar to our experience with patients affected by long QT syndrome (LQTS) (22,23), we adhere to a shared decision making approach discussing the risks of continuing in the sport at length along with instruction for the family on risk reduction. Ultimately, we respect patient/family autonomy and their right to make a well-informed decision regarding plans for future activity. Here, we sought to determine the early outcomes among nonathletes and athletes with CPVT managed with this approach.
Following institutional review board approval, we performed a retrospective analysis of patients seen at Mayo Clinic’s Genetic Heart Rhythm Clinic after 1995 with the diagnosis of CPVT who were ≥6 years of age at their initial Mayo Clinic evaluation. Records were reviewed to ensure diagnostic criteria for CPVT (ventricular ectopy on treadmill exercise test, genetic testing, and patient history). Asymptomatic patients (i.e., those who have not had a cardiac event prior to diagnosis) required a positive CPVT genetic test or ectopy on exercise testing consistent with CPVT to be included in the cohort. Additionally, information on treatment, cardiac events prior to diagnosis, sport(s) participated in before and after diagnosis, the highest documented level of competition, and any cardiac events following the initiation of treatment was collected. Cardiac breakthrough events were defined as syncope, seizure, documented ventricular arrhythmias, appropriate ventricular fibrillation/ventricular tachycardia terminating ICD shocks, and/or SCD.
The decision to continue athletics is complex and all relevant family members (athlete and both parents if athlete is a minor) must be in agreement. Risks and benefits associated with exercise and competitive sports, the CPVT diagnosis, as well as impact of side effects of CVPT-associated (BB) treatment were discussed to inform the patients and their families appropriately before a decision was made (see Online Appendix 1 for an outline of the shared decision-making process and Online Appendix 2 for more detail on this discussion). BB therapy (specifically nadolol), is initiated as first line in our Genetic Heart Rhythm Clinic with a targeted dose of 1 to 2 mg/kg/day (twice daily dosing [b.i.d.] at <10 years of age, once-a-day dosing at ≥10 years of age), and titrated by weight or until side effects become intolerable. Repeat exercise testing is utilized to determine if exercise-associated ectopy has been suppressed to just PVCs in isolation/bigeminy.
If complex ventricular ectopy (couplets or worse) persists during either treadmill stress testing or 24-h ambulatory Holter monitoring, the patient’s nadolol dose is either increased, combination therapy with flecainide is initiated, or LCSD is performed (21). In general, excellent suppression of ectopy (i.e., to just residual PVCs in isolation or bigeminy) is achieved with flecainide trough levels around 0.4 to 0.6 μg/ml with the reference therapeutic range for the plasma flecainide trough assay ranging from 0.2 to 1 μg/ml. This is achieved typically with a target dose of around 2 to 4 mg/kg/day divided b.i.d. or 100 to 150 mg/m2/day divided b.i.d. Initiation of flecainide at a starting dose of 1 mg/kg/day given b.i.d was done in the beginning of our program exclusively in the inpatient setting. However, flecainide has been started in the outpatient setting as well. Because a significant minority of patients are either ultra-rapid metabolizers or poor metabolizers of 2D6 substrates such as flecainide (24,25), cytochrome P450 2D6 (CYP2D6) genotyping is performed routinely when flecainide is utilized. This helps to tailor the targeted dose and the pace of dose escalation. Before each dose adjustment, a trough level is obtained and the stress test is repeated again with the objective goal of eliminating all complex ventricular ectopy.
Additionally, should the family wish to pursue continuation in sports, an automatic external defibrillator is recommended to be readily available for all sport practices and competitions. A competitive athlete was defined as anyone participating in physical activity with greater physiologic demands than perceived of class 1A sports (e.g., billiards, bowling, cricket, curling, golf, and riflery), including hiking and aerobic exercise given the stringent limitations on CPVT patients. For 3 patients, follow-up >1 year was not available. Because it was not possible to determine their athletic status, they were considered nonathletes. These 3 patients experienced no cardiac events during follow-up. Follow-up was censored to July 1, 2015, and all cohort members with confirmed diagnoses of CPVT were confirmed living on this date. Phenotype, clinical risk profile, and treatments were compared between athletes and nonathletes. All patients who were active in a sport at some point in their life were considered “ever-athletes” whereas those never involved were termed “never athletes.” Those who remained active in sports following their CPVT diagnosis were termed “athletes” whereas those who discontinued or never participated were termed “nonathletes” (Figure 1). Subsequently, outcome was evaluated for both subsets, specifically follow-up of CPVT-triggered cardiac breakthrough events after diagnosis as well as events following their Mayo Clinic evaluation and their “return-to-play” clearance.
Descriptive statistics were used to aid in summarizing patient characteristics, athletic activity, and cardiac events. Fisher’s exact test was used to compare ordinal values whereas the 2-tailed Student t test was used to compare continuous variables between groups. Overall event-free survival was determined as time from age of diagnosis until cardiac event or the closing of the study window (July 1, 2015) at which time follow-up had been gained in person or by telephone follow-up in 2015 for all athletes, and evaluated using Kaplan-Meier analyses (JMP version 10.0, SAS Software, SAS Institute, Cary, North Carolina).
The CPVT cohort at Mayo Clinic is composed of 63 study-eligible (patients ≤6 years of age were excluded) patients (29 male [46%]; mean 25.7 ± 13.1 years of age), of which 53 had a positive genetic test for a CPVT-causative mutation (84%), with 52 involving RYR2 (98%) (Table 1).
Most patients (83%) had some treatment combination of BB (79%), flecainide (35%), LCSD (30%), and ICD (32%). All ICDs had been placed in advance of the patient’s first Mayo Clinic appointment in this cohort. See Table 1 for further detail and breakdown by groups.
Prior to diagnosis, 31 patients identified themselves as athletic (“ever-athletes”) with 7 having done so in the past and 24 competing in a sport at the time of their CPVT diagnosis (Figure 1). Compared to the never athletes, patients who were either former or current athletes were significantly younger at ultimate diagnosis (11.8 ± 6.6 years compared to 21.3 ± 15.6 years; p = 0.003), and had significantly more cardiac events 21 (68%) versus 13 (41%; p = 0.02) prior to diagnosis. Additional clinical comparisons between these 2 groups can be found in Table 1.
Among the 24 current athletes at the time of their initial Mayo Clinic evaluation, 3 (13%) patients chose self-disqualification following their comprehensive evaluation and consultation. Of those, 1 was a female high-school swimmer who had 2 syncopal events while swimming leading to CPVT diagnosis. The second athlete was a male basketball player who received his diagnosis at the time of entering high school, and the third was a male who discontinued football in high school.
Following their diagnosis of CPVT, 21 patients chose to remain an athlete and comprise the “current athlete” cohort for outcome analysis (Figure 1). Of those who were athletic before and after diagnosis, 2 patients changed sports, and 1 participated in class IA sports briefly, while being initiated on treatment, prior to returning to football and baseball. Overall, 20 unique sports are represented by these 21 athletes with several being multisport participants (Figure 2). Athletes had a high level of activity as a group with the majority, 19 of 21 (90%), involved in either high static (Class III) or high dynamic component (Class C) sports (Figure 2) (26). Seven athletes were competing in primary school (33%), 6 were in secondary school (29%), 4 were in college (19%), including 1 National Collegiate Athletic Association (the governing body of all U.S. collegiate athletes) athlete, and 4 athletes were adults (19%), with 1 competing professionally.
Compared to the never athletes and the former athletes (combined now as the nonathletes), these current and continuing athletes were significantly younger (20.3 ± 9.8 years of age vs. 28.4 ± 13.8 years of age, respectively; p = 0.02) at Mayo Clinic evaluation, and significantly younger at diagnosis (10.2 ± 5.3 years vs. 19.8 ± 14.3 years; p = 0.004). Further, 76% of athletes had prior cardiac events before diagnosis as compared to only 43% in the nonathlete group (p = 0.01). Additional comparisons between these patients can be found in Table 1.
Of the 63 patients in the overall cohort since their CPVT diagnosis, 9 patients (14%) have experienced a CPVT-associated cardiac event during follow-up despite medical therapy. However, there was no difference in events or event rates between the athletes and nonathletes. In fact, 3 patients were athletes (14%), and 6 were nonathletes (14%) at the time of their events, and there was no significant difference in event rate between groups (p = 0.70). Overall, the 3 athletes experienced 1 event each (average follow-up 108 ± 90 months), or an event-rate of 1.41 per 100 patient-years, which was not significantly different from the total of 7 events in the 6 nonathletes (event rate of 1.75 per 100 patient-years; 66 ± 41 months follow-up; p = 1.0) (Figure 3A). Compared to our event rate noted previously among athletes with LQTS (23,24), the event rate among these CPVT athletes was higher (1.41 in CPVT vs. 0.2 events per 100 athlete-years in LQTS) (Figure 3A).
Kaplan-Meier analyses showed that there was no time-dependent difference in outcome between athletes and nonathletes (log-rank p = 0.43) (Figure 3B). The average time to a cardiac event following diagnosis was 80 ± 58 months, and whether athletic or not, there was 86% event-free survival in 583 combined years of follow-up, see Figure 3B. There were no deaths, CPVT related or otherwise, in either subgroup.
Since their initial Mayo Clinic evaluation, only 5 of 63 patients (8%) have experienced CPVT-triggered breakthrough events. Of these 5, 2 were athletes who had made the decision of returning to play, and then had a single CPVT-triggered event each (Athletes 1 and 3; 10%) (Table 2). Meanwhile, 3 nonathletes had 4 CPVT-triggered events (Nonathletes 3, 4, and 5; 7%). Akin to our overall follow-up, there was no statistically significant difference in cardiac events between athletes and nonathletes after their initial evaluation in our Genetic Heart Rhythm Clinic and, for the athletes, after their “return-to-play” clearance (p = 1.0).
Among the 3 athletes that had a CPVT-triggered event while on therapy, all 3 had been symptomatic prior to diagnosis, and 2 had a previous family history of SCD and/or CPVT. Two had their event when not participating in their primary sport and 1 individual admitted to BB noncompliance. See Table 2 for details on each patient who experienced an event during the follow-up period.
Among the 6 nonathletes with subsequent CPVT-triggered events after their CPVT diagnosis, all 6 had been symptomatic prior to diagnosis, 2 had a family history of CPVT and/or SCD, and 1 event occurred during light exercise. Notably, 2 patients were BB noncompliant or had missed a BB dose. Case vignettes for each breakthrough event are available in Online Appendix 2.
Of the 63 patients, 20 previously received an ICD (32%); 6 of 21 athletes (29%) versus 14 by the 42 nonathletes (33%; p = 0.8). Among the 20 individuals with an ICD, 6 received appropriate shocks (30%), with 2 individuals experiencing an ICD storm. Only 1 patient received inappropriate shocks (total of 5) due to atrial tachycardia. Overall, ICD interrogations also showed instances of nonsustained ventricular tachycardia in 3 nonathletes (21%) and 1 athlete (17%). In athletes, ICD interrogations also served to monitor BB effectiveness, specifically to search for the presence or absence of atrial and nonsustained ventricular tachycardias. However, none of these were seen prior to appropriate shocks in athletes.
Following breakthrough events, all patients were re-evaluated. Of note, although nonathlete 3 had 2 events, the second event closely followed the first one and occurred prior to re-evaluation and subsequent LCSD. Aside from this repeated event, none of the patients in the cohort experienced multiple recurrences. All patients with breakthrough events received alterations to treatment regimens as summarized in Table 2. None of the patients have had events since adjustments to treatment and are all doing well.
For patients and their health care providers, the desire and subsequent decision to maintain a level of athletic activity after a diagnosis of CPVT on the one hand and the recommendation for sports disqualifications on the basis of expert opinion guidelines on the other hand create difficult dilemmas in daily practice. Although the contemporary guidelines remain relatively strict on athletic activity in patients diagnosed with a cardiac channelopathy (18–21), data is emerging that shows low risk for events in these patients after their diagnosis had been made and a comprehensive treatment program has been established. A recent study from our institution showed almost no cardiac events in treated patients with LQTS (22,23).
Our clinic embraces respect of athlete/family autonomy and a shared decision-making approach, in which the allowance to continue sport, if so desired, comes only after the well-informed patient and family agrees, is optimally and aggressively treated, and an AED is recommended. In our cohort, families did not always choose to continue sports with each discussion, and in 1 case the severe phenotype of a family member greatly influenced their decision. However, when given the choice, the vast majority of athletes chose to compete in high static or dynamic component sports with a third of those athletes being at a lower level of competition in primary school.
Similar to the LQTS study, we designed the current study to evaluate the early outcomes in patients with CPVT, and in fact, whereas cardiac events did occur in patients with CPVT, there was no increased rate in patients who chose to remain a competitive athlete. In fact, our data supports that indeed, CPVT-triggered cardiac events, prior to diagnosis and treatment, are precipitated by athletic activity as demonstrated by an earlier age at diagnosis and higher rates of events in patients who were active prior to diagnosis (“ever-athletes”). Notably however, this difference disappeared once all patients were treated optimally for their disease as shown by the outcome data. In fact, although cardiac events occurred after initiation of therapy, this happened at a relatively low and equal rate between athletes and nonathletes.
Rather than activity level, CPVT-triggered events were associated with the severity of the phenotype at evaluation as well as patient noncompliance with medical therapy. Among patients with events following diagnosis, most patients had shown concerning phenotypes in that many suffered cardiac events prior to diagnosis, including 30% of those with ICDs having breakthrough arrhythmias. Other investigations, such as adequacy of beta-blockade and the presence of atrial tachycardias or nonsustained ventricular tachycardia during ICD interrogations were evaluated, but did not obviously serve as an adequate screen, as the 2 events in athletes with ICDs had normal interrogations just before breakthrough events. All appropriate ICD shocks were primary terminations for ventricular fibrillation; 2 patients suffered ICD storms.
Cardiac breakthrough events occurred in 3 athletes with CPVT, 1 of which was associated with noncompliant BB therapy, and 2 of which occurred with some degree of exertion. However, these 2 events did not happen during official competition, athletic training or participation of the athlete’s primary sport. Athlete 2 had a severe phenotype demonstrated by 5 syncopal events prior to the age of 11, representing a harbinger for a more troubled clinical course. The nonathlete group experienced 7 cardiac events. Two of the members of this subgroup had events following missed dose(s) of their BB. Another nonathlete sought to perform light exercise and experienced numerous ICD shocks. This same patient also experienced the ICD storm phenomenon underlining the challenge in programming ICDs for patients with CPVT (16), whereas 2 had appropriate ICD shocks while playing video games or washing their dog.
Herein, the importance of proper therapy and medication compliance to effectively prevent CPVT-triggered events whether athletic or nonathletic once again comes to light. Medication noncompliance occurred in both the athlete and nonathlete subgroups, and 2 of 3 individuals were concerned about side effects relating to physical performance: 2 nonathletes and 1 athlete improperly took their BB which may corroborate the thought that exercise, although a risk, aids in compliance with the treatment program (23). For those not tolerating BB, or with continued ectopy during exercise testing while fully up-titrated on a BB by weight or side effect limitation, flecainide was utilized frequently (35%) as an adjuvant therapy for patients in this cohort. Alternatively, LCSD was considered similarly as an alternative or addition to flecainide therapy in 30% of patients. And, although it is not wholly protective and breakthrough events do occur, LCSD significantly decreases the arrhythmia burden in both LQTS and CPVT (13–15,27–29).
In retrospect and based on present knowledge of BB dosing, Athlete 2, Nonathlete 3, and Nonathlete 4 were not receiving ideal BB doses based upon weights, prior to their events (Table 2). However, their dose represented their maximum tolerated dose because of BB-attributable side effects, particularly fatigue and flat affect. Unfortunately, there was no information gathered by ICD interrogations or Holter monitoring to prompt a change in management prior to the events. Subsequently, they all underwent LCSD and Nonathlete 4 also had flecainide added. Of note, none of the patients on flecainide experienced a breakthrough event in our cohort, which may be attributed to both flecainide’s effectiveness and the aggressive, often multimodal treatment approach in most patients on flecainide.
Moreover, to what extent triple combination therapy with BB, LCSD, and flecainide can be protective has not been elucidated fully (11,21). Notably, 1 patient stopped sports when starting high school and then suffered an event with emotional stress. For this patient, it is unclear whether athletic participation affected his survival in a meaningful way. Of interest, a study in mice models of CPVT2 that underwent regular exercise has shown a decreased arrhythmia burden rather than an increased association with ventricular tachycardia (30).
Clearly, patients with CPVT want to live healthy lives—they do not all follow the Bethesda, European Society of Cardiology, or the latest American Heart Association/American College of Cardiology guidelines that call patients with CPVT to a near-sedentary lifestyle (17–20). An unintended consequence of these guidelines is perhaps an increased susceptibility for developing obesity, diabetes, and depression (31). This is evidenced by both the seeking out of low-intensity exercise as well as with the despondence associated with being limited in activity expressed by patients and their families. Greater insight into the risk of high levels of exercise in managed CPVT patients is needed to help give patients their preferred lifestyle and is the central message of this study. In an effort to strike a balance with respect to these issues, the latest American Heart Association/American College of Cardiology statement on sports participation retained a disqualification recommendation but indicated that exceptions to this recommendation could be considered if the athlete/family sought consultation from a CPVT specialist (20).
Our observations are limited by the size of our CPVT patient population and the length of follow-up. Additionally, larger studies, from our and other institutions, will be needed to fully understand the impact and outcomes of continued exercise and competitive sports participation in patients with CPVT specifically. Given our low event rate, it is possible that a single event can have too much impact in raising the event rate, or that the size could be under-representative of the event rate. Other limitations include limited age matching between the athlete and nonathlete groups. Although almost all athletes (n = 21) participated in a high static or dynamic component sport, one-third (n = 7), did so at the primary school level. Because the level and amount of expected coaching varies between these levels, this might have created some heterogeneity in the “athlete” group. At this time, we cannot predict a patient’s precise personal risk for having a cardiac event once their treatment program has been optimized fully, but in our program, that event rate appears very low, at approximately a 1.4% chance of a nonlethal event each year in athletes.
In addition, these results may not be generalizable. In a multicenter registry of pediatric CPVT patients managed in a variety of different ways by many pediatric heart rhythm specialists, there was a much higher event rate among the registry patients than among the CPVT patients treated at Mayo Clinic (32). Also, the yield in genetic testing varied between cohorts considerably: in our Mayo Clinic cohort 84% had a positive genetic test for CPVT compared to 39% in the larger multicenter registry in which 81% underwent genetic testing. Genetic testing is part of the typical CPVT patient evaluation, which takes place over the course of a few days and may account for this difference. In addition, the tertiary referral nature of Mayo Clinic’s Genetic Heart Rhythm Clinic may account for this higher CPVT1 genotype positive rate. Compared to our study where only 8% have experienced a CPVT-triggered event since their initial Mayo Clinic evaluation, 25% of the registry subjects had a breakthrough event while on BBs and nearly 50% of the ICD recipients had received an appropriate shock. In addition, their study noted 6 (2.7%) deaths, of which 2 occurred during exercise, among the 226 patients compared to none in our cohort. When comparing outcomes in our cohort and the multicenter study’s cohort, symptomatic burdens as well as treatment failure rates were greater in the multicenter cohort. Notably, CPVT-tailored treatment programs utilizing nadolol, flecainide, and LCSD were higher in our cohort, which might underlie the marked difference in outcomes.
CPVT is a potentially lethal condition and breakthrough events can and will occur as evidenced by the 10 nonfatal events occurring in 1 of every 7 patients with CPVT cared for in our dedicated CPVT clinic. However, juxtaposed to the disease-related risks, there are also the known risks of a sedentary lifestyle as well as a decreased quality of life that may come with cessation of physical activity and/or athletics. Even though the breakthrough event rate was higher in patients with CPVT than observed among our athletes with LQTS, this does not mean that the implemented shared decision-making approach is acceptable for one condition but not the other. Instead, this pilot, observational data suggests that after correct diagnosis and implementation of a robust CPVT-directed treatment program, the likelihood of a nonlethal cardiac event was the same among our CPVT patients whether currently an athlete or not.
COMPETENCY IN MEDICAL KNOWLEDGE: Respect of patient and family autonomy with regard to healthcare decisions plays an important role in clinical decision making. On the basis of our previous experience in patients with LQTS, our current study showed there was no increased number of cardiac breakthrough events in patients with CPVT, who—after extensive discussion on potential risks—decided to continue competitive athletics against professional guidelines. Larger studies with longer follow-up are needed to establish whether guidelines should be amended further in the future.
TRANSLATIONAL OUTLOOK: Although the results of our study are on the basis of early observations in a small group of patients, this study should provide the impetus for continued re-evaluation of the current restrictive guidelines as well as to compel larger studies to investigate effects of continued exercise and competitive sports participation in patients with cardiac channelopathies.
For expanded Methods and Results sections, please see the online version of this article.
This work was supported by the Mayo Clinic Windland Smith Rice Comprehensive Sudden Cardiac Death Program. Dr. Cannon is a consultant for Medtronic. Dr. Ackerman is a consultant for Boston Scientific, Gilead Sciences, Medtronic, and St. Jude Medical. Dr. Ackerman and the Mayo Clinic also receive sales-based royalties from Transgenomic’s FAMILION-LQTS and FAMILION-CPVT genetic tests. However, none of these entities have provided funding for this study. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- twice daily dosing
- catecholaminergic polymorphic ventricular tachycardia
- implantable cardioverter defibrillator
- left cardiac sympathetic denervation
- long QT syndrome
- premature ventricular contraction
- sudden cardiac death
- Received October 21, 2015.
- Revision received December 30, 2015.
- Accepted January 28, 2016.
- American College of Cardiology Foundation
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