Exercise and CVS Flashcards
Benefits of exercise
CNS - Reduces risk of stroke, dementia, depression
CVS - Reduces risk of CAD, obesity, BP, DM, LDL; 13% decrease in cardiac mortality per MET
Onco - Reduces risk of breast, prostate and bowel CA
MSK - Reduces risk of falls, osteoporosis, disability
MET definition
Metabolic unit used to quantify PA intensity; ratio of metabolic rate during exercises to metabolic rate at rest
0 MET = No regular exercise
4 MET = Walking 4mph
10 MET = Brisk jogging
Risks of exercises
Increased risk of sudden cardiac death
Triggers of SCD in athletes
Acid base and electrolyte imbalance
dehydration
adrenergic surges
Aetiology of SCD
- Channelopathies
Long QT syndrome
Brugada syndrome
Cathecholaminergic polymorphic VT - Cardiomyopathies
HOCM
Arrhythmogenic RV Cardiomyopathy
Dilated cardiomyopathy - Coronary Artery disease
Atherosclerosis
Anomalous coronary ostia
Causes for those with normal heart
- channelopathies
- WPW syndrome
- comotio cordis
- drugs
- electrolyte disturbances
What is the peak age (per 100,000)
Around 40-50
Mean age
23yo (40% of deaths at <18yo)
Epidemiology of SCD
1/ 4,000 to 1/50,000 per year M>F (9:1) black > white football and basketball 90% during or immediately after exertion 80% asymptomatic prior
Clinical Presentation
FHx
- known heritable disorder
- premature death (<50)
- SCD
- epilepsy
- unexplained drowning
- road traffic accident
Sx
- EXERTIONAL = chest pain, dyspnoea, dizziness, excessive breathlessness, palpitation, epilepsy, prior cardiac disease
O/E
Check weight, peripheral signs around eyes and roof of mouth, pulse and BP, CVS examination
Ix
- ECG diagnostic in accessory pathways, channelopathies, conduction tissue disorders; 95% HCM abnormal and 80% ARVC
- ECHO
- Stress ECG
- MRI
Hypertrophic Cardiomyopathy
Commonest cause of SCD in young athletes
LV outflow tract obstruction from asymmetric septal hypertrophy
Sx
- Chest pain, dyspnoea, palpitations, presyncope, syncope
- Aborted SCD
- Asymptomatic
FHx of HCM or SCD in 1st degree relative
Ix ECG positive in 95% - LVH voltage criteria - T wave inversion inferior lateral - ST depression - Q waves - LBBB ECHO
Individualised therapy
- lifestyle modifications
- medical therapy
- surgical therapy
- family screening
High risk pt –> ICD
Arrhythmogenic RV Cardiomyopathy
RV myocardium replaced by fibro-fatty tissue
Progression
1. Myocardial stretch => Asymptomatic
2. Myocyte detachment and myocarditis => VT/ Sudden death, electric storm
3. Fibro-fatty replacement of cardiomyocytes => HF, sudden cardiac death
Sx - palpitation, syncope during exercise
ECG
- Epsilon waves (positive deflection buried in QRS)
- T wave inversion
- Broad QRS in V1-V3
CVD Management of Athletes
General: exercise prescription
Specific WPW => ablation Marfan => surgery Anomalous coronary artery => surgery Comotio cordis => protective clothes/ softballs Myocarditis => no sports for 3-6months
Cardiovascular adaptations to exercise
Electrical
- sinus bradycardia
- voltage criteria for LVH
- repolarisation anomalies
Structural
- incr LVWT 10-20%
- incr LV mass 40-65%
- incr LVED/ RVED 15%
- incr LA size 20%
Functional
- incr diastolic filling
- incr SV
Collectively cause 5x increase in CO
Adaptation - Adult, male, large BSA, endurance, black
Black Athlete’s heart
Typically asymptomatic
No FHx
ECG
- voltage criteria for LVH
- T wave inversion in V1-4
- ST segment elevation
TTE
- Maximal LVWT <=16mm in M and <=13mm in F
- concentric hypertrophy
- enlarged LVEDD
- normal diastolic function
Common combination for false positive diagnosis
Mild HCM + Athlete’s heart
Voltage criteria LVH
LVH Present when:
- R in aVL + S in V3 = >28mm in M or >20mm in F
- R wave in aVL >12mm amplitude
- S wave in V1 + R wave in V5 or V6 = >35mm
or use Romhilt-Estes LVH Point Score System
Investigations for suspected CVD
Exercise stress testing - BP response
Cardiopulmonary exercise testing - peak consumption
24hr Holter monitoring - ventricular arrhythmia
Cardiac MRI with gadolinium enhancement - Miyocardial fibrosis
Physiological vs Pathological Changes
Physiological changes
- voltage criteria for LVH
- symmetrical dilatation of ventricles
- good RV/LV function
- regression of changes with 4-8wks of detraining
Pathological changes
- abnormal FHx
- ventricular tachycardia on holter
- poor functional capacity/ Low peak VO2
- Fibrosis = low gadolinium enhancement
- positive gene test
Pre-participation Screening
Young competitive athletes
- > family and personal history, physical examination, ECG
- >Negative findings => eligible for participation
- >Positive findings => further Ix
- ECHO, stress test, 24h Holter, cardiac MRI, angio
- >Positive findings => Dx and Mx accordingly
- >Negative findings => eligibility to play
Criteria for further evaluation: Sx, physical examination, ECG
Goal of screening
To identify silent CV abnormalities that lead to SCD
Impact of screening
Reduced incidence from 4:100,000 to 0.5:100,000
1 in 300 young athletes affected
Concerns regarding ECG screening
High cost Expertise and facilities needed Low incidence of SCD Diverse disorders/Effectiveness - false negatives - false positives high (23.5% for white and 34% for black [ESC 2010])
Role of AEDs in Sports
Most sudden cardiac arrests start with VF
Survival affected mostly by time between arrest and defibrillation ; <=50% survival if done within 2-3 mins and <10% if in >10mins
effectiveness of 16-64%
Secondary Prevention of SCD
Implementing an effective emergency response with high-quality CPR and prompt used of AED
- Emergency response planning; a regularly rehearsed comprehensive emergency plan to ensure best possible outcome
- FIFA 11 steps; designed to enhance the resus team’s performance
