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Cardiac Risks and Benefits in Swimmers.

Cardiac Risks and Benefits in Swimmers. W. Stewart Hillis. Cardiovascular Risk; Exercise and Mortality. 1 in 22 studies showed significant improvement. Problems of small groups and short term follow up Recent meta analysis confirms 20% reduction in mortality

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Cardiac Risks and Benefits in Swimmers.

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  1. Cardiac Risks and Benefits in Swimmers. W. Stewart Hillis

  2. Cardiovascular Risk;Exercise and Mortality • 1 in 22 studies showed significant improvement. Problems of small groups and short term follow up • Recent meta analysis confirms 20% reduction in mortality • Undoubted improvement in exercise capacity and quality of life

  3. Cardiovascular Risks; Training Benefits • Weight reduction with improved glucose tolerance • Improved lipid profile changes in HDL and LDL and triglycerides • Beneficial effects of platelet function. • Benefits in muscle function enhances capillary density, enhanced oxygen extraction, altered oxidative enzyme content and enhanced mitochondrial function • Psychological benefits both in health and disease.

  4. Cardiovascular Risk; Exercise Prescription • Physical activity an independent risk factor for cardiovascular disease and all cause mortality. • Evident in both occupational and recreational activity. • Conflicting evidence concerning dose response or modest intervention only. • ‘No pain no gain’ or 30 minutes of moderate activity on most days of the week. • Major problems of compliance.

  5. Energy Expenditure in Swimming. • Energy expended to maintain buoyancy and generating horizontal movement. • Overcoming drag forces of fluid medium influenced by size, shape and velocity. • Thermal stress metabolic and cardiovascular adjustment. • Shivering may occur to maintain core temperature.

  6. Problems Associated with Swimming • Problems of emersion particularly in cold. • Increased sympathetic activity increased demands on myocardium in coronary artery disease and hypertension. • Vagal over activity associated with the diving reflex with bradycardia, reduced cardiac output and intense vasoconstriction which may induce diastolic dysfunction. Lactate accumulation in muscle • Immersion may be associated with atrial and ventricular arrhythmias.

  7. Swimming benefits. • Single bout of ultra endurance exercise Reduction in triglycerides 39%,total cholesterol 9% LDL decreased by 11% with reduced propensity to peroxidation Ginsberg et al JAMA;27:63:221-225 • Echocardiography studies show increased stroke volume and oxygen consumption in trained subjects. Morris et al Sports Med.16;(4):225-236

  8. Swimming In Heart Failure • Water immersion leads to increase in intra thoracic circulation • With emersion heart failure patients increased cardiac output by 16%, compared to 21% in CAD and 19% in controls. Cardiac index increased by 53%, 77% and 87% respectively. • Selection by exercise testing VO2 of 15ml/kg/min • Schmid et al Card Prev and Rehab 93(6):722-7;2007

  9. Swimming for Acute Myocardial Infarction Patients. • National Exercise and Heart Disease Project. • 19 year survival in 30 to 64 year olds • Randomised to structured exercise or control. • Each 1 met increase in exercise capacity from work capacity from baseline to end of trial showed a reduction in all cause and CVD mortality. • Benefits reduced with time raising question of short term effects and compliance. • Dorn et al Circulation100:(17);1764-9.

  10. Cardiovascular Risk; Exercise Testing • Review of 167 programmes of rehabilitation. • 1.3 fatal events per million hours of activity • 3.4 myocardial infarctions • 8.9 resuscitations

  11. Cardiovascular Risk Related to Exercise • Uncommon; 2 cases per 100,000 subject years • 5 in 100,000 have a predisposing cardiac condition • 10% (1 in 200,000) of those at risk die suddenly • Causes of death similar in different countries and different sports.

  12. Cardiovascular Risk; Screening Issues • Sports participants highly motivated; Implications for earnings • Classification of high and low intensity sports Concept of dynamic and static components • Contact and non contact sports. • Risks of prosthetic valve dehiscence. Anti-coagulants • Particular risks with syncope in water borne sports

  13. Cardiovascular Risk; Preparticipation Screening • Remains controversial over appropriateness cost and practicality. • Identification of those at risk. • Targeting of those; Family history of sudden death. Premature coronary artery disease. Known structural abnormality • Education of those with symptoms Syncope, presyncope, palpitation, chest pain and dyspnoea. • Guidelines for disqualification from sport.

  14. Questionnaire • Specific health related questionnaire regarding family history of sudden death or premature cardiovascular disease. • Symptomatic enquiry regarding warning symptoms.

  15. Abnormal ECGs In Trained Athletes. • Most athletes (60%) have normal electrocardiograms • Variety of abnormal tracings usually indicative of physiological cardiac remodelling. 30% in swimmers • A small proportion have striking abnormalities but normal cardiac morphology as assessed by echocardiography. 15% in swimmers • Such false positives suggest the limitation of the electrocardiogram if used in screening. Pelliccia et al Circulation 2000;102:278-284. • 88.2% normal in nontrained preparticipants Eur Heart J.28(16)2006-10.

  16. Conditions with Known Cardiovascular Risk < 35 yrs • Hypertrophic cardiomyopathy • Idiopathic concentric L.V. hypertrophy • Anomalies of coronary arteries • Aortic rupture • Right ventricular dysplasia • Myocarditis • Valvular disease • Arrhythmias and conduction defects

  17. Cardiovascular Risk; Hypertrophic Cardiomyopathy • Leading cause of sudden unexpected death in young athletes • Hypertrophied, non dilated left ventricle No predisposing cause for hypertrophy • Chamber size reduced, impaired diastolic filling • Outflow tract obstruction; Hypertrophy of sub aortic septum. Systolic anterior motion of mitral valve

  18. Cardiovascular Risk; Hypertrophic Cardiomyopathy • Autosomal dominant; high degree of penetrance • Predisposition to s.v. and ventricular arrhythmias • Symptoms of chest pain. palpitation, syncope and dyspnoea • Signs; Jerky pulse, double apex beat, 4th heart sound, systolic murmur • ECG useful, Echo diagnostic

  19. Cardiovascular Risk; Hypertrophic Cardiomyopathy Adverse prognostic factors include: 1. Family history of sudden death 2. Documented ventricular tachycardia 3. Young age of onset of symptoms

  20. Cardiovascular Risk; Athlete Heart or HCM • Septal thickness <15 or >15mm • Septal free wall ratio <1.3 or .1.3 mm • LV End diastolic dimension; increased or decreased • Ejection fraction normal or increased • Abnormal ECG in 25-50% of AH, 90% in HCM • Problems associated with the Gray zone

  21. Conditions with Known Cardiovascular Risk < 35 yrs • Hypertrophic cardiomyopathy • Idiopathic concentric L.V. hypertrophy • Anomalies of coronary arteries • Aortic rupture • Right ventricular dysplasia • Myocarditis • Valvular disease • Arrhythmias and conduction defects

  22. Cardiovascular Risks; Arrhythmias and Heart Block • Mechanism of sudden death arrhythmic, • Disorders of automaticity, conduction or repolarisation • Autonomic changes during sporting activity • Arrhythmias associated with structural abnormalities

  23. Cardiovascular Risk; Arrhythmias • Exercise induced ventricular arrhythmias • Pre-excitation in Wolff-Parkinson-White syndrome • Repolarisation abnormalities in the prolonged QT syndrome • Brugada syndrome and other channelopathies. • R.V. arrhythmias associated with previous right ventriculotomy

  24. Conditions with Known Cardiovascular Risk > 35 Yrs • Coronary artery disease • Special problems of congenital heart disease, operated or unoperated

  25. Cardiovascular Risk; C.A.D. • Major cause of death in > 35 years • Most deaths occur in vigorous sports • Previous symptoms suggestive of coronary atherosclerosis recognised • Risk factors often present • Victims perceived as very fit and type A personalities

  26. Cardiovascular Risk; C.A.D. • Pathology confirms obstructive coronary artery lesions • Myocardium may show previous healed infarct • Not prevented by extreme forms of conditioning • Education for warning symptoms of chest pain, palpitation or syncope

  27. Cardiovascular Risk; Classification of Sports High to moderate dynamic & static demands: Boxing, Cycling,Fencing, Football,Handball, Ice hockey, Rowing, Rugby, Running, Skiing (downhill), Speed skating, Water polo, Wrestling High to moderate dynamic & low static demands: Badminton, Basketball, Hockey, Squash,Soccer, Swimming, Tennis, Table Tennis

  28. Cardiovascular Deaths in the Young. • In Scotland 2002. Central registration of deaths. • 42 males and 23 females died of acute circulatory problems aged less than 25 years. • If screening 16 year olds 33,439 males and 31,916 females. • Impractical to apply screening to whole population. • Problem perceived of access to facilities for screening.

  29. Screening Programmes. • In United States pre participation screening advocated for high school and college aged students on ethical, legal and medical grounds. • History and physical examination targeted to conditions with known risk, but without the use of non-invasive assessments. • ‘Addition of non invasive testing would undoubtedly enhance detection of many responsible lesions but unrealistic on a national scale owing to prohibitive costs and other practical details.’ Maron.

  30. Screening Programmes. • Italian model. Pre participation screening required for all young adults participating in organised sports. • Follow up study in 33,735 in Veneto region of Italy • Screened using a questionnaire, physical examination and an ECG. If indicated echo performed. 8.2 years of follow up. • 3,016 echoes performed 561 subjects disqualified rhythm and conduction problems, hypertension, valvular disease and cardiomyopathy. Corrado et al NEJMed 339:364; 1998.

  31. Italian Experience. • 269 sudden deaths, 49 in competitive athletes • 22 cases of hypertrophic cardiomyopathy diagnosed. No deaths in athletic group. • 16 deaths in non athletic population from HCM none previously screened.

  32. Screening. • Regarded as not appropriate on a cost basis. • Recommended by FIFA and UEFA and European agencies. • A challenge to governing bodies with regard to duty of care.

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