Cardiac Arrhythmias: Atrial Fibrillation, SVT

By admin On Nov 25, 2023

Ovid: 5-Minute Sports Medicine Consult, The

Charles W. Webb

Nicole Y. Gesik

Basics

Any deviation from normal (sinus) heart rhythm broadly classified as bradyarrhythmias (slow) or tachyarrhythmias (fast) (1)

Epidemiology

Incidence

Bradyarrhythmias (2,3):

Common in aerobically trained athletes secondary to elevated resting vagal tone
Sinus bradycardia (50–65% of athletes vs 23% in general population)
Sinus arrhythmias (13.5–69% of athletes vs 2.4–20% in general population)
Sinus pause of >2 sec (37.1% of athletes vs 5.7% in general population)
1st-degree AV block (6–33% of athletes vs 0.65% in general population)
2nd-degree AV block, Mobitz I (2.4–10% of athletes vs 0.003% in general population)
3rd-degree AV block (0.017% in athletes vs 0.00002% in general population)
Junctional rhythms (0.031–7% of athletes vs 0.06% in general population)
These changes are readily reversed in athlete's heart as increased sympathetic drive overcomes resting vagal tone. If presents with symptoms (impaired consciousness or fatigue) or not readily reversed, often associated with underlying cardiac disease.

Tachyarrhythmias (2,3):

Atrial fibrillation more common in competitive athletes (0.063%) than general population (0.004%)
Other supraventricular atrial or AV nodal tachyarrhythmias are not more common in athletes in comparison to the general population.
Wolff-Parkinson-White syndrome (EKG showing short PR interval with wide QRS and slurred upstroke or delta wave) equal in athletes and general population (0.15%)
Premature ventricular contractions occur at similar rates in athletes vs general population.
Complex ventricular arrhythmias are always pathologic and should seek prompt cardiology examination.

Risk Factors

Structural heart disease (hypertrophic cardiomyopathy, anomalous coronary syndrome, arrhythmogenic right ventricular dysplasia, Marfan's syndrome, aortic stenosis, dilated cardiomyopathy) (1,3)
Myocarditis
Atherosclerotic coronary artery disease (especially if >35 yrs old)
Drugs (amphetamines, cocaine, ephedrine)
Long QT syndrome with QTc >0.46 sec (congenital vs iatrogenic, including medications such as class Ia antiarrhythmics, antifungals, nonsedating antihistamines, antibiotics, promotility agents).
Commotio cordis (direct nonpenetrating trauma to chest wall)
Metabolic abnormalities (electrolyte disturbances, hyperthyroidism)

Etiology

Special considerations (1,2):

Systematic training may cause physiologic adaptations, including a variety of abnormal EKG findings, in about 40% of elite athletes, termed the “athlete's heart”
Increased QRS voltage, incomplete right bundle branch block, early repolarization, and peaked T waves related to increase in overall cardiac mass.

Diagnosis

Wide range of clinical presentations, from occasional palpitations to sudden cardiac death (3)
Bradyarrhythmias can present with impaired consciousness or fatigue.
Tachyarrhythmias can cause palpitations, chest pain, and exertional dyspnea.
Unstable ventricular tachyarrhythmias may cause lightheadedness or syncope.
Supraventricular tachycardia (SVT):
- Evaluation:
  - Identify rate response of SVT during activity or exercise.
  - If unable to induce SVT with exercise, can induce with either atrial/esophageal pacing, then monitor with exercise stress test
Atrial fibrillation:
- May be present intermittently or chronically
- More common with diseases such as coronary artery disease or hypertension
- Evaluation:
  - Determination of ventricular response with athletic activity
  - 12-lead EKG
  - Long-term 24-hr EKG
  - Echocardiogram

History

Based on AHA Consensus Panel Recommendations for Preparticipation Athletic Screening (1,3):

Family history:
- Premature sudden cardiac death
- Heart disease in relatives <50 yrs old
Personal history:
- Heart murmur, fatigue, systemic hypertension, exertional chest pain, syncope/near syncope during or after exercise, unexplained or disproportionate exertional dyspnea
- Presence of palpitations, chest pain, lightheadedness, syncope, and relation of symptoms to activity or rest
- Note prescription and OTC medications, especially cold or diet remedies (especially those containing ephedra), nutritional supplements, recreational drugs (especially cocaine).

Physical Exam

Vital signs (pulse, temperature, BP, respiration rate)
Dynamic heart evaluation looking for heart murmur, documented in at least 2 positions (usually supine and standing) to discern murmurs with outflow obstruction
Hypertrophic cardiomyopathy murmur INCREASES with maneuvers that decrease venous return (such as Valsalva or moving from squat or stand)
Aortic stenosis murmur DECREASES with the same maneuvers.
Pathologic murmur identified as any systolic murmur graded 3/6 or greater, or any diastolic murmur or any holosystolic murmur.
Palpation of radial and femoral pulses to exclude coarctation of the aorta (3,4)

P.63

Diagnostic Tests & Interpretation

Workup for athletes with significant arrhythmia includes (3,4):

12-lead EKG
Echocardiogram (evaluate for hypertrophic cardiomyopathy and structural disease such as valvular problems)
Exercise stress test to identify exertional arrhythmias or induced ischemia; may need to be adapted specifically for athlete (ie, at peak energy for sprinter) as well as sport (maximal ergometer stress test for rower reproducing training conditions that produce symptoms):
- Nonpathologic bradycardias in athlete usually resolve with exercise testing.
- Nonpathologic premature ventricular complexes usually resolve with exercise testing.
Holter 24 or 48 cardiac monitoring if possible during specific type of participation exercise
Implanted loop recorder, cardiac MRI, electrophysiologic studies rarely required

Differential Diagnosis

Anxiety disorder, panic attacks
Angina
Costochondritis
Neurocardiogenic syncope
Heat stroke
Seizure
Thyroid dysfunction

Treatment

Acute treatment (1,2):
- Symptomatic athletes should initially have ABCs assessed and stabilized (airway, breathing, circulation).
- If athlete is unstable, may require advanced cardiac life support, immediate DC cardioversion, and emergent transport to a medical facility.
- Suspected supraventricular tachycardias may respond to efforts to increase parasympathetic tone, including Valsalva maneuver, carotid massage, and ice applied to face/neck.
Long-term treatment:
- Antiarrhythmic medications, electrophysiologic cardiac ablation, treatment of underlying cardiac disease
- Should be re-evaluated every 6–12 mos after trained to determine if conditioning affects arrhythmia
- Beta-adrenergic blocking agents banned in some competitive sports

Ongoing Care

Return to play guidelines (2,5):
- Important for thorough cardiac examination, as underlying structural heart disease may place athlete at increased risk for sudden cardiac death with exertion
- Athletes with syncope or near syncope should not participate in sports where the likelihood of loss of consciousness could be hazardous until the cause has been determined and treated.
- Athletes with symptoms such as impaired consciousness and fatigue attributed to arrhythmias should be treated and if asymptomatic for 2–3 mos during treatment, may participate in all sports.
- Athletes with symptomatic tachy/brady arryhythmias should be treated, if no structural heart disease, for 2–3 mos, then they can return to sports.
Atrial flutter:
- Athletes with atrial flutter without absence of structural heart disease if without flutter for 2–3 mos may participate in all sports.
- Athletes with structural heart disease who have atrial flutter can participate in sports such as billiards, bowling, cricket, curling, golf, and rifle (Bethesda Guidelines class 1A sports).
- Athletes without structural heart disease who have had ablation or surgery can participate in all sports after 2–4 wks without recurrence.
- Athletes who require anticoagulation cannot participate in competitive sports where the chance of collision is present.
Atrial fibrillation (a-fib):
- Athletes with asymptomatic atrial fibrillation without structural heart disease who maintain a ventricular rate that appropriately increases and slows, with or without treatment, can participate in all sports. (Use caution, as beta-blockers are banned in some sports.)
- Athletes with a-fib and structural heart disease who have rate control can participate to the limits and recommendations of the structural disease.
- Athletes who require anticoagulation cannot participate in competitive sports where the chance of collision is present.
- Athletes without structural heart disease who have had ablation or surgery can participate in all sports after 4–6 wks without recurrence.
SVT:
- Athletes without structural heart disease who have controlled SVT may participate in all sports.
- Athletes with syncope, near syncope, or significant symptoms due to arrhythmia, or who have structural heart disease may participate in class 1A sports once treated and have no recurrence for 2–4 wks.
- Athletes without structural heart disease who have had ablation or surgery can participate in all sports after 2–4 wks without recurrence.
- Asymptomatic athletes with SVT ranging 5–10 sec without increased duration with exercise can play in all sports.

References

1. Giada F, Barold SS, Biffi A, et al. Sport and arrhythmias: summary of an international symposium. Eur J Cardiovasc Prev Rehabil. 2007;14:707–714.

2. Pelliccia A, Zipes DP, Maron BJ. Bethesda Conference #36 and the European Society of Cardiology Consensus Recommendations revisited a comparison of U.S. and European criteria for eligibility and disqualification of competitive athletes with cardiovascular abnormalities. J Am Coll Cardiol. 2008;52:1990–1996.

3. Goldberger JJ, Cain ME, Hohnloser SH, et al. American Heart Association/American College of Cardiology Foundation/Heart Rhythm Society scientific statement on noninvasive risk stratification techniques for identifying patients at risk for sudden cardiac death: a scientific statement from the American Heart Association Council on Clinical Cardiology Committee on Electrocardiography and Arrhythmias and Council on Epidemiology and Prevention. Circulation. 2008;118:1497–1518.

4. Maron BJ, Haas TS, Doerer JJ, et al. Comparison of U.S. and Italian experiences with sudden cardiac deaths in young competitive athletes and implications for preparticipation screening strategies. Am J Cardiol. 2009;104:276–280.

5. Mitchell JH, Haskell W, Snell P, et al. Task Force 8: classification of sports. J Am Coll Cardiol. 2005;45:1364–1367.

Codes

ICD9

427.9 Cardiac dysrhythmia, unspecified
427.31 Atrial fibrillation
427.89 Other specified cardiac dysrhythmias