Anecdotal evidence suggests 12 young people die every week due to undiagnosed inherited cardiac disease.
81% of these occur following exercise and 6% in competitive athletes.
96% of sudden cardiac death associated with males and 75% between 18 and 35y.
European Society of Cardiology advocate screening health questionnaires and a 12-lead ECG for all competitive athletes. Any ECG abnormalities, symptoms or positive FHx prompt referral for TTE.
Need to perform full standard echo and:
- Identify coronary ostia
- PSAX mid to apical level – measure wall thickness as with HCM. Excess trabeculation is common and may be challenging to distinguish from LV non-compaction.
Consider fundamental factors prior to performing:
- Age
- Gender
- Ethnicity
- Training type and volume
- Body size
- Symptoms, ECG changes
- FHx of unexplained cardiac death under the age of 40.
Physiological cardiac adaptation to regular exercise:
Main adaptation is eccentric hypertrophy of all cardiac chambers – variable depending on type and volume of exercise training.
Type of Sport:
Normal values may be variable depending on type of activity. See chart.
Resistance activity – anaerobic isometric exercise at incremental workloads of 40-60% maximum heart rate. Includes sports such as martial arts, wind surfing, weight lifting.
Endurance activity defined as aerobic isotonic dynamic exercise at incremental workloads of 70-90% maximum heart rate. Includes sports such as long or middle distance running, swimming or cycling, football and basketball.
Remember many sporting activities will combine both endurance and resistance activities.
Highest degree of LV/RV and atrial remodelling occurs in sports including high dynamic and high static components.
Training Volume:
Magnitude of adaptation dependent on patient’s training volume – can be defined as Metabolic Equivalent (met-h/week) = METS x duration. Low intensity exercise – 1.8-2.9METS, moderate 3-6METS and high intensity exercise >6METS.
Age and Sex:
Post-pubescent junior athletes between 14 and 18 will demonstrate eccentric remodelling but to a lesser degree than senior counterparts.
Female cardiac chamber dimensions rarely fall outside normative range.
LV cavity rarely exceeds 6.5cm.
Ethnicity:
Black athletes have higher incidence of abnormal ECG findings (T wave inversions, early repolarisation) compared with white athletes and are therefore more likely to be referred for echo. Higher incidence of excess trabeculations.
Also significantly larger LV wall thickness and normative values are different. Likely accept wall thickness of up to 1.4cm.
Less adaptation in different ethnic groups – Middle Eastern & South & East Asian do not have different adaptation compared to white athletes.
Algorithms:
Generally the algorithms surround identification of abnormal measurements which are more likely to represent pathological rather than physiological adaptations.
Key challenges can be to differentiate:
- Hypertrabeculation vs isolated left ventricular non-compaction – hypertrabeculation common in athletes, particularly in black ethnicity and may have TWI on ECG. ILVNC normally have LV systolic or diastolic function whereas hypertrabeculation should be normal. Additional imaging may be required.
- Eccentric hypertrophy vs mild phenotype HCM – HCM may have normal LV size which is considered small for training volume. Also may have some impaired diastolic velocities.
- Physiological LV enlargement vs DCM – if any abnormal function results or diameter larger than 6.5-7cm may need to consider referral for stress (exercise) echo or cMRI.