Risk Identification in Arrhythmic Athletes with Fatal or Resuscitated Cardiac Arrest

Resuscitated Cardiac Arrest

F. F

, A. B

, C. F

, G. G

, P. M

, F. F

, F. T

, M. D

, L. G

, M. B

, A. B

, G. V

, G. I

, G. B

, C. E

, M. M

, G. T

, R. C

Although rare and uncommon, sudden cardiac death (SCD) in young com- petitive athletes is a devastating event [1–18]. The identification of potential mechanisms precipitating SCD may help to prevent future events in athletes with similar conditions [1, 3, 13, 16].

Methods

We report on 30 years of continuous monitoring (see Table 1) of a popula- tion of 2640 young competitive athletes identified with important arrhyth- mias (2286 males; mean age 21.5 years), 345 (13%) competing at the interna- tional elite level (298 males; mean age 24.4 years). The arrhythmic athletes were evaluated with a codified individualised study protocol [1, 3, 7, 16].

Study subjects

Two categories of athlete are considered:

1. Athletes in whom cardiac arrest (CA) may be considered predictable:

a) Those with exertional premonitory cardiac symptoms that may indi- cate significant cardiac abnormality: syncope, prolonged palpitations, dyspnoea, and chest pain;

1

Department of Clinical Arrhythmia and Electrophysiology, Policlinico San Donato,

Milan;

Department of Cardiology, S.Chiara Hospital, Trento;

ITC / Irst, Trento;

Sport

Medicine Centre, S.Andrea Hospital, Rome;

Villa Bianca Hospital, Trento;

Sports

Science Institute, Italian National Olympic Committee, Rome;

Division of Cardiology-

Ospedale S.Maria del Carmine, Rovereto;

Department of Cardiology, Maggiore

Hospital, Crema;

Department of Pathology, S.Chiara Hospital, Trento;

Sport Medicine

Centre University, Florence;

Institute of Pathology, University of Padua Medical

School, Padua;

University of Verona, Italy

b) Those with a cardiac risk, i.e. identified as having life-threatening arrhythmias by cardiological screening, according to the current rec- ommendations for athletic eligibility (26th Bethesda Conference 1996, NASPE Consensus Conference 2001 [15], Italian COCIS 2003). This population included athletes not compliant with treatment and/or banned athletic activity.

2. Athletes in whom CA occurred as a ‘first cardiac symptom’.

Diagnostic Screening

For each athlete, the risk assessment, if necessary, included: family and past history, clinical evaluation, routine blood tests (including thyroid tests), rest- ing and stress test ECG, Holter recording, also during intense physical activity, cardiac events recorder, implantable loop-recorder, 2D–Doppler echocardiog- raphy, stress echocardiography (baseline and during exercise), transoe- sophageal echocardiography, CT, MRI, 3D MR angiography, signal-averaged ECG, head-up tilt-test, specific blood test (i.e. for viral agents, vector-borne pathogens), pharmacological testing (flecainide administration, isoproterenol infusion), genetic studies, transoesophageal electrophysiological (EP) study (until 1996), endocavitary EP study also with new mapping methods, cardiac catheterisation and angiography, endomyocardial biopsy, (as of 2001) micro- volt T-Wave Alternans (mTWA) before EP study [16]. Necropsy was performed in all athletes who died and the pathological investigation of the heart was car- ried out in the majority of the cases at the Institute of Pathology, University of Padua, according to methods previously reported [16, 19–21].

Results

During 30 years of monitoring, 62 major events were reported in 58 athletes, 24 of which (0.9%) were SD (4 with prior CA on field), while 38 (1.4%) were CA. In the subset of elite athletes, the major events were 13 (22.4%), made up of 6 SD (1.7%) and 7 (2.0%) CA (Table 1).

Table 1. Competitive athletes with arrhythmias (summary of the population studied from 1974 to April 2004)

Athletes N Male Female Average Follow-up N with SD N with CA

age (years) (months, min.–max.)

All 2640 2286 354 21.5 3-190 24 (0.9%) 38 (1.4%)

athletes

Elite 345 298 47 24.4 3-180 6 (1.7%) 7 (2.0%)

athletes

Underlying Condition

Underlying conditions among victims of CA and SD were: arrhythmogenic right ventricular dysplasia (ARVD) 15 (9 CA, 6 SD), Wolff–Parkinson–White syndrome (WPW) 9 (7, 2), myocarditis 9 (3, 6), coronary artery disease 7 [3 (1 congenital), 4], dilated cardiomyopathy 7 (4, 3), mitral valve prolapse 3 (1, 2), Lev-Lenègre disease 4, hypertrophic cardiomyopathy 3, primary electrical heart disease 1, long QT syndrome 1, commotio cordis 2 (1, 1) non compact myocardium with catecholaminergic polymorphic VT (CPVT) [1] (Table 2).

CA/SD were observed in competitive arrhythmic athletes regardless of rank- ing; 13 of the 58 (22.4%) were elite professional athletes.

Table 2.Underlying condition among young competitive athletes with fatal and resusci- tated cardiac arrest (CA)

Fatal CA Resuscitated CA Total CA

Events % Events % Events %

ARVD 6 25 9 23.6 15 24.2

WPW 2 8.3 7 18.4 9 14.5

Myocarditis 6 25 3 7.9 9 14.5

Coronary artery disease 4 16.6 3a 7.97 7 11.3

Dilated cardiomyopathy 3 12.5 4 0.6 7 11.3

Lev-Lenègre disease - - 4 10.6 4 6.4

Hypertrophic - - 3 7.9 3 4.8

cardiomyopathy

Commotio cordis 1 4.16 1 2.6 2 3.2

Non-compact myocardium - - 1 2.6 1 1.6

with catecholaminergic polymorphic VT

Mitral valve prolapse 2 8.3 1 2.6 3 4.8

Long QT syndrome - - 1 2.6 1 1.6

Primary electrical

heart disease - - 1 2.6 1 1.6

Total 24

38 62

ARVD, arrhythmogenic right ventricular dysplasia; WPW, Wolff–Parkinson–White syndrome; VT, ventricular tachycardia

a

1 congenital

b

4 with prior CA

CA/SD were exercise-related in the majority of cases (90%), occurring either during practice (51.8%) or during competition (48.2%) (Table 3). The mechanisms responsible for SCD on the athletic field were mostly represent- ed by destabilisation of an arrhythmogenic substrate. Ventricular tachycar- dia/fibrillation was the most frequent final event (~90% of the cases), with asystole in the remaining patients (Table 4). The majority of athletes (> 60%) suffered CA/SD after warning symptoms during exertion and/or with an arrhythmic risk already identified. The remaining athletes had CA/SD as the first, unpredictable presentation.

Table 3. Relationship between CA/SD and exercise activity

Activity CA SD Total

At rest 2 4 6 (9.6%)

Exertion 36 20 56 (90.4%)

Practice 19 10 29 (51.8%)

Competition 17 10 27 (48.2%)

Table 4. Risk identification in athletes with CA/SD: documented or induced decisive arrhythmic events

VT/VF 44

Torsades de pointes 2

Pre-excited AF 11

Total VF 57 (91.9%)

Paroxysmal AV block 4

Asystolic commotio cordis 1

Total asystole 5 (8.1%)

VT, ventricular tachycardia; VF, ventricular fibrillation; AF, atrial fibrillation; AV, atri- oventricular

Clinical Outcome and Management

The follow-up ranged from 12 to 208 months. At the last clinical control, 24

subjects had deceased and 34 were alive. Among these, 7 are active in sports

after successful radiofrequency catheter ablation (WPW), 3 are alive with

complete recovery (1 commotio cordis, 2 myocarditis). In 5, a cardiac pace-

maker was implanted. In 15, an implantable cardioverter–defibrillator (ICD)

was implanted, with hybrid therapy in all. The ICD discharges happened in

all but two. The time from implantation to first discharge ranged from 2 to

40 months. In 5, radiofrequency catheter ablation for refractory VT was per- formed. Four subjects are on long-term anti-arrhythmic drug treatment. One young subject underwent surgical correction of congenital coronary artery anomaly.

Summary

An unpredictable fatal and/or resuscitated CA occurred as first symptom only in 37% of the competitive athletes, independently of ranking (30% were in elite athletes). The underlying diseases were mainly myocarditis, coronary artery disease, WPW, and commotio cordis. CA/SD were observed in compet- itive arrhythmic athletes regardless of their ranking and was exercise-related in the majority of cases, occurring during either practice or competition;

only in few cases occurred at rest (in subjects with WPW, coronary artery disease, myocarditis, or dilated cardiomyopathy).

Warning symptoms such as exertional syncope and severe palpitations and/or an already identified risk with arrhythmological work-up occurred in 63% of cases, independently of ranking (70% in elite athletes with CA/SD).

Twenty-five percent of the athletes were totally non-compliant with treat- ment and/or banned from athletic activity.

Conclusions

Competitive athletes, including those at elite level, identified as being at high risk of arrhythmias must be forbidden athletic activity until the risk is still present in the individual subject. Additional measures should include a peri- odical clinical check-up, an appropriate life-style, anti-arrhythmic drug administration, interventional and/or hybrid therapies with special regard to ICD implantation, and, when possible, RFCA (i.e. in subjects with WPW, ven- tricular tachycardia recurrences, storm of ICD interventions). Every effort must be made to continuously add in to the arrhythmological clinical approach to the competitive athlete the newest non-invasive (genetic studies, T wave alternans study [16], etc.) and invasive risk stratifiers (electrophysio- logical testing and mapping), together with the newest cardiac imaging investigation tools.

This long-term ongoing arrhythmological study of a large population of

young competitive athletes offers an opportunity of making known in the

sport world any information that can realise an early diagnosis as well as

strong clinical management of subjects at high risk of CA/SD, particularly in

those with exertional premonitory cardiac symptoms or with a cardiac risk

already identified.

Aknowledgements: The authors wish to thank the secretary Anna Stenghel for her helpful cooperation.

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