B P4 C32 Exercise and Sports Cardiology Flashcards
The normal CV adaptations to exercise training include:
Resting bradycardia
Global cardiac enlargement
Functional pulmonic and aortic valve flow murmurs
Physical activity acutely increases systemic oxygen (O2) demand, which prompts the CV system to increase _____ and the _____.The increase in Q is coupled to the energy required such that there is a ____ liter increase in Q for each 1-liter increase in oxygen consumption (V” O2). Q is increased by augmentation of both the heart rate (HR) and stroke volume (SV).
Cardiac output (Q)
Arterial-venous (A-V) O2 difference
5-6 L increase for each 1L increase in O2 consumption
Several mechanisms increase the A-V O2 difference, including:
Shunting of blood from non-exercising tissue to working muscle
Increased O2 extraction by exercising muscle
Hemoconcentration
This increase in MO2 can produce ischemia in individuals with flow-limiting coronary artery lesions.
In addition, the coronary arteries _____ in response to the myocardial metabolic demands of exertion, but _____ develops with exercise in some individuals with coronary atherosclerosis because of endothelial dysfunction.
Dilate
CAD: Inadequate vasodilation or vasoconstriction
The _____ work rate is the VO” 2 required by the exercise task and, as mentioned, is a direct determinant of Q. V”O2 can also be crudely estimated from treadmill speed and grade or from a stationary bicycle watt requirement
External work rate
The _____ work rate refers to the myocardial oxygen consumption (MO2) required for the exercise task and relates directly to increases in HR.
Internal
Individuals with higher exercise capacity and a greater VO2max have a larger ____ at any given external work rate, such that any exercise task, and VO2 demand, requires a ____ HR to generate the same externally determined Q.
Larger SV
Slower HR
Repetitive aerobic exercise sessions and aerobic exercise training increase maximal exercise capacity, measured physiologically by an increase in VO2max. This increase in healthy individuals results from increases in both _________ and _________
Maximal Q and the maximal A-V O2 difference.
The reduction in ____ and thereby MO2 contributes to the increase in exercise capacity in patients with angina pectoris after exercise training.
Reduction in HR and MO2
In addition to the increase in maximal exercise capacity, exercise training also increases _____, the ability to perform submaximal effort for a prolonged period.This effect contributes critically to the exercise training response because few work or recreational tasks require maximal CV effort.
Endurance capacity
Intense and prolonged aerobic exercise training produces an array of CV adaptations, commonly referred to as “athlete’s heart”. Such changes include an _____.
Increase in resting SV
Decrease in resting HR
Characteristic adaptations during endurance training:
Mild to moderate eccentric LVH and RV dilation
Biatrial enlargement
Normal to slightly reduced resting LVEF
Normal or enhanced early LV diastolic function
Normal or enhanced LV twisting/untwisting
Characteristic adaptations during strength training:
Mild concentric LVH but no RV remodeling
Normal to mildly enlarged left atrial size
Normal to hyperdynamic resting LVEF
Normal or slightly reduced early LV diastolic function
Increase in late LV diastolic function
The physiologic mediators of training-induced reductions in resting HR are related in part to increased resting _____ and reduced resting sympathetic tone
Increased: Resting vagal tone
Reduced: Resting sympathetic tone
Highly trained endurance athletes often develop resting bradycardia, which may be associated with _____.
Marked sinus arrhythmia
First-degree heart block
Mobitz I second-degree AV block
Third-degree AV block during sleep
The _____ AV conduction velocity may make accessory conduction pathways, such as those of Wolff-Parkinson-White syndrome, more apparent
Reduced AV conduction
Athletes also have an increased prevalence of an ____ and ____, ECG findings also historically attributed to increased vagal tone
Early-repolarization ST-segment pattern
ST-T wave abnormalities
Cessation of exercise training, or “detraining,” may help in clinically differentiating adaptations to exercise training from _____.
Hypertrophic cardiomyopathy (HCM).
Regression of eccentric LVH can occur in highly trained athletes after _____ weeks of abstinence from exercise.
6 to 34 weeks (mean, 13 weeks)
Because the LV wall thickening and concentric LVH common in strength-trained athletes can regress partially after _____ months and completely after _____ months of detraining, such diagnostic trials should last 6 months.
3 months: Partial
6 months: Complete
Multiple epidemiologic, cross-sectional studies examining the frequency of CV events in healthy individuals demonstrate that the more active participants have lower CV risk than their more sedentary counterparts.
The reduction in risk in the most active versus the least active individuals is approximately ___%
40%
Even small amounts of physical activity reduce CV risk. CV risk falls progressively with increasing physical activity until approximately ____ hours per week of moderate-intensity activity, such as brisk walking.
After this level of exertion, there appears to be little additional benefit and, possibly diminution, of the beneficial effects.
9.1 hours
None of these studies was large enough to provide conclusive results alone, but a meta-analysis of 63 RCTs including 14,486 patients demonstrated a __% decrease in CV mortality in the patients assigned to the exercise-based programs.
26%
Epidemiologic data suggest that the largest reduction in CV risk with physical activity occurs at _____ levels of activity.
Consequently, current American guidelines recommend _____ weekly of moderate aerobic activity such as brisk walking or _____ weekly of vigorous activity such as jogging, plus some resistance exercise twice weekly.
Low
150 to 300 minutes/week
75 to 100 minutes/week
Despite the putative benefits of habitual physical activity, vigorous physical activity transiently increases the risk for _____. This conclusion is based on studies comparing the hourly cardiac event rate during vigorous exertion with rates during more sedentary activities
SCD and AMI
Exercise-related SCD in young individuals, defined as age less than 30 or 40 years, has historically been attributed to inherited and congenital conditions, including _____, although acquired conditions such as _____ can also cause exercise-related SCD in this group
HCM and anomalous origin of the coronary arteries (AOCA)
Myocarditis and cardiomyopathy
_____causes most exercise-related AMI and SCD in adults, although there are rare reports of spontaneous coronary artery dissection with vigorous exertion (more often in young, but occasionally in older individuals)
Atherosclerotic cardiovascular disease (ASCVD)
AMI in previously asymptomatic adults during exercise is usually associated with acute coronary arterial plaque _____.
Disruption
Several triggering mechanisms for plaque disruption may pertain, including increased _____ of atherosclerotic coronary arteries.
Flexing and bending
Approximately ___% of SCDs in adults caused by ASCVD are associated with clinicopathologic findings of an acute coronary syndrome (ACS), whereas the remainder show evidence of nonacute ASCVD.
33%
The risk of exercise-related SCD appears higher in athletes than in nonathletes as evidenced by the fact that SCDs or cardiac arrests were ____-fold greater in French competitive athletes aged 10 to 35 than among recreational athletes of similar age
4.5 fold
Vigorous exertion increases the risk of ____ in adults between 3 and 17 times that of more sedentary activities.
SCD
Athletes with decreased exercise capacity are frequently referred to CV specialists for evaluation.
_____ contributes critically to Q and therefore to exercise capacity, but VO2 max also requires maximal performance from its other CV components, HR and A-V O2 difference, as well as from the central nervous system, lungs, and skeletal muscle.
Decrements in any of these components can compromise exercise performance.
SV
Many adult athletes with reduced exercise capacity referred for expert evaluation have LV _____ dysfunction because prior encounters have eliminated the more obvious diagnoses.
This scenario often presents as a lifelong endurance athlete with “borderline hypertension” who avoided antihypertensive treatment. These patients frequently have _____ but exhibit an _____ response to exercise.
Diastolic
Mild resting hypertension
Exaggerated blood pressure
_____ and _____ are useful when the history suggests diastolic dysfunction.
Exercise echocardiography
CPET with specific attention to the oxygen pulse curve
The oxygen pulse can be calculated by dividing _____, and assuming no important change in the A-V O2 difference, reflects SV.
It can help determine when cardiac performance becomes a limiting factor during exercise.
OP = VO2 (in mL/min) / HR (bpm)
Overtraining is a complex interaction of psychological and physiologic fatigue in athletes that can occur after prolonged _____ training. The diagnosis of overtraining is made by careful history because there is no diagnostic test for this condition.
High-intensity training
_____ all characterize overtraining.
(1) Diminished exercise tolerance (sometimes with an elevated resting HR)
(2) Sensation of nocturnal fevers
(3) Insomnia
Overtraining should be diagnosed only when other conditions are excluded and frequently requires a therapeutic trial of ______ to see whether the symptoms resolve and performance improves.
The optimal duration of prescribed detraining for overtrained athletes has yet to be defined but may be weeks to months depending on the duration and severity of the overtraining symptoms.
Markedly reduced training
The ESC recommends including a ______ as a mandatory and universal component of screening.
In contrast, the most recent AHA/ ACC recommendations endorse the use of ECG only in _____.
ESC: Resting 12-lead ECG
AHA/ACC: athlete cohorts surrounded by adequate expertise and resources to support this process
Well-trained endurance athletes have a slow HR and large SV, which can produce _____ murmurs in young athletes, especially if the athlete is examined in the supine position, which expands central blood volume
Nonpathologic pulmonic flow murmurs
_____ flow murmurs are soft systolic ejection murmurs heard best in the left second and third intercostal spaces in the supine position. Such murmurs typically diminish or disappear when the athlete assumes a sitting position.
Pulmonic
Older athletes with hemodynamically insignificant aortic sclerosis may have ____ flow murmurs
Aortic
Athletes can also have ECG evidence of _____. Most of these abnormalities occur in athletes undergoing intense endurance training
Biatrial hypertrophy
LVH
Incomplete or complete RBBB
ST-T wave abnormalities
Conduction abnormalities
There are improved ECG criteria to separate the ECG patterns expected from exercise training from truly abnormal ECG tracings, but even these “refined” criteria suggest a possible cardiac abnormality in ___% of black and 5% of white athletes.
11%: black
5%: white
Most CV abnormalities found on screening are variants of _____, and most can be dismissed by a simple clinical examination and review of the ECG, with cardiac imaging procedures used to remove any residual doubt
Normal
Some families and athletes have ongoing concern once a screening abnormality is identified, so having the athlete and family return in _____ months is sometimes useful, even when no abnormalities are found, to provide additional reassurance.
3-6 months
A common problem in athletes with a screening abnormality is what we have termed “_____” —the finding of a minor abnormality on screening such as early ECG repolarization, which prompts a second diagnostic test such as echocardiography, which reveals another borderline finding such as mild LVH, which may prompt another diagnostic test such as cardiac magnetic resonance imaging (MRI).
Diagnostic creep
Screening abnormalities, especially if _____, should be judged with less concern than definite abnormalities found in symptomatic athletes, because the screening abnormalities will most frequently represent normal variants.
Borderline abnormal
_____ is a common complaint in young and old athletes, possibly because the importance of chest pain in public perception, and because athletes have increasing concerns about the possible cardiac risks of exercise.
Chest pain
_____ may be the first sign of important cardiac diseases, including HCM, AOCA, or coronary artery atherosclerosis, but several issues pertain particularly to athletes.
Exertional chest pain
Chest pain that is reproducible with exercise and relieved by rest (i.e.,typical angina), particularly when it occurs at a clear workload threshold that the athlete can identify, should be considered indicative of underlying cardiac pathology until proven otherwise.
Fleeting chest pain with movement in athletes may also be related to _____ issues.
Muscle and joint issues
The relationship between chest pain and recent _____ involving the chest muscles, such as push-ups and bench presses, is also important because such training is a frequent cause of chest discomfort in athletes
Recent resistance exercise
Some athletes who have died with AOCA had _____ exercise stress test results, indicating the importance of pursuing workups that include coronary imaging in athletes if the symptoms are worrisome, even when exercise testing yields normal results
Normal
Well-trained athletes often have vasovagal syncope, now formally referred to as “neurally mediated syncope,” probably because of their _____, which permits sequestration of large amounts of blood when the athlete is upright and motionless.
Resting bradycardia
Large venous capacity
Athletes also often have _____ tilt-table tests as a result of the same physiologic changes thus limiting the diagnostic utility of this test in athletes.
Positive
Neurally mediated syncope most often occurs in athletes immediately following exercise, particularly with _____ of exercise.
Abrupt termination
This common entity, “postexertional syncope,” is benign and can frequently be managed by teaching the athlete avoidance techniques
The most important avoidance technique for syncope is for the athlete to _____ so that the muscle pump in the calf continues to return blood to the systemic circulation.
Keep moving after effort
Other useful techniques:
Dietary sodium augmentation
Aggressive pre-exercise hydration
Compression socks
A key issue in evaluating syncope in athletes is to determine whether the syncope truly occurred during exertion.
Syncope at rest or immediately after exercise under conditions consistent with _____ syncope is usually caused by these conditions.
Vasovagal syncope or postural syncope
Paradoxically, the athlete who feels fine after a syncopal episode and wants to return to the game immediately is the athlete most likely to have a _____ condition
Cardiac
Consequently, syncope during exercise and syncope with- out post-syncope confusion should prompt a careful search for more serious problems, including _____.
Inherited cardiomyopathies
Aortic stenosis (AS)
Cardiac arrhythmia
AOCA
_____ exercise increases the risk for SCD and AMI in adults with occult ASCVD, and individuals with diagnosed disease have greater increased risk with exercise.
Vigorous
Plaque stability likely increases with decreasing lipid content of the plaque, and most plaque regression occurs within ____ years of aggressive lipid lowering
2 years
Consequently, in athletes strongly wanting to return to competition, we advise a minimum of _____ years of aggressive lipid treatment with the goal of achieving the greatest possible plaque regression before returning to competition
2 years
We encourage athletes to continue _____ under the assumption that they may help avoid an acute cardiac event if plaque disruption occurs.
Aspirin and other antiplatelet medications
We continue therapy with a _____ to avoid the increase in adrenergic activity that occurs when use of these drugs is stopped abruptly.
Beta blocker
We generally discontinue other antihypertensive medications on _____ depending on the severity of the athlete’s hypertension, because exercise acutely reduces BP, and we want to avoid postexertional hypotension.
The day of the athletic event or on days with unusually demanding training sessions
We routinely discontinue statins for _____ days before endurance athletic competition because statins magnify the increase in creatine kinase (CK) that occurs with exercise, and the combined effects of statins and exercise could lead to rhabdomyolysis.
5-7 days
Athletes with echocardiographic evidence of critical AS should undergo careful evaluation for symptoms and _____ testing that simulates as closely as possible the athlete’s typical exercise training and competition
Maximal exercise stress testing
Many adult athletes with critical AS ignore important dyspnea at the start of exercise because it dissipates within _____ minutes, but this “warm-up dyspnea” frequently indicates clinically important AS.
5-10 mins
Athletes generally tolerate aortic regurgitation (AR) well, probably because the _____.
Consequently, we rarely restrict athletic com- petition despite severe AR in the absence of evidence of _____. We also rarely restrict _____ in this group despite concern that this type of exercise increases AR, because we know of no data that indicate any benefit of such restriction.
Increased HR during exercise decreases diastole and regurgitant flow
Exercise is rarely restricted in AR in the absence of:
- Ventricular deterioration
- Marked aneurysmal disease of the ascending aorta
- Unexplained symptoms with exertion
- Resistance exercise
Given the prevalence of BAV in approximately 1% of the population and the rarity of aortic dissection in young athletes, we do not restrict activity unless the aortic diameter exceeds _____ mm.
45 mm
The AHA/ACC Aortic Diseases Task Force recommends aortic root measurements biannually for individuals with aortic diameter greater than 40 mm in men and 36 mm in women
Biannual aortic root measurement if:
M: > 40 mm
F: > 36 mm
Athletes found to have BAV should undergo imaging to determine _____ at diagnosis and then should be monitored by serial imaging during their years of competitive sport participation.
Proximal ascending aortic dimensions
Cardiac troponin (cTn) T and I are highly sensitive and specific biomarkers of myocardial necrosis. However ,athletes can have _____ cTn levels after prolonged exertion, such as a marathon run, or even after a brief intense treadmill run.
Increased
Clinicians need to be aware that endurance athletes may have elevated cTn levels after exertion, and that the diagnosis of an acute cardiac event in an athlete requires confirmatory evidence of myocardial injury by either _____.
Symptoms
ECG
Echocardiography
The cause of the cTn increase with exercise is not clear, but could represent _____.
Mild myocardial injury
Increase in sarcolemmal permeability
Release of free Tn not bound to tropomyosin
The relationship between habitual exercise training and AF is complex and likely follows a _____ -shaped curve.
U-shaped curve
Few studies have examined how exercise training affects AF, but obese patients with AF participating in an exercise and weight loss intervention had the greatest reduction in AF if they lost ____% of their BW and increased their exercise capacity >/=_____ mL O2/kg/min.
Loss of 10% BW
Increase in EC >/=7 mL O2/kg/min
In contrast, large amounts of exercise appear to _____ the incidence of AF. A meta-analysis and review of studies of endurance athletes demonstrated an increase (up to fivefold) in AF
Increase
Possible mechanisms for AF in endurance athletes include ______.
Increased atrial size
Changes in autonomic tone with training
Acute increases in inflammation with exercise
Older athletes with AF should undergo the same evaluation as nonathletes to exclude _____.
Cardiac disease
Hyperthyroidism
Alcohol excess
Sleep apnea
AF in young athletes is unusual and should prompt clinicians to question and confirm the diagnosis and to exclude issues like _____.
Acute thyroiditis
Performance-enhancing drugs
Other illicit substances
Structural cardiac abnormalities
Several studies suggest that long-term endurance athletes have increased CAC scores compared to their sedentary counterparts. Coronary CT angiography (CCTA) demonstrates that the plaques in endurance athletes are primarily _____ and not the putatively more vulnerable mixed or non-calcified plaques.
Calcified
This suggests that these plaques in athletes are less likely to rupture and to produce an acute cardiac event.
Among athletes that come to us with elevated CAC scores, we evaluate for _____, treat _____, especially with lipid-lowering agents, and provide _____, rather than deleterious, because the plaque in athletes is predominantly calcified
Evaluate: Exercise-induced ischemia using maximal effort-limited exercise testing
Treat: ASCVD risk factors aggressively
Provide: Peassurance that the significance of this finding is unknown and may be protective
The LGE volume was small and often located where the ____, suggesting that it results from chronic right ventricular (RV) enlargement or RV dilatation during exercise
Right ventricle inserts into the interventricular septum
We do not routinely restrict athletes with incidentally detected myocardial fibrosis in the absence of _____.
Concomitant structural heart disease
Unexplained malignant arrhythmias
The left ventricle is highly trabeculated during _____ cardiac development to increase myocardial surface area and thus facilitate the delivery of oxygen and nutrients from intracavitary blood to the myocardium.
These trabeculae regress and the myocardium becomes compacted during normal embryonic development.
Embryonic
The degree of embryonic trabecular regression varies, and many healthy people have some trabecular tissue within the LV cavity. Noncompaction cardiomyopathy (NCCM) results from an arrest of this process characterized by a _____.
Hypertrabeculated left ventricle
+
Thin, subepicardial, compacted layer
NCCM can produce myocardial dysfunction, systemic emboli from the deep ventricular pits, and SCD. There are various diagnostic criteria, but a ratio of noncompacted (NC) to com- pacted (C) myocardium greater than _____ is frequently used.
NC:C > 2
Patients with true NCCM that require sport restriction have _____ that is often most profound in the noncompacted wall segments and a thin,compacted layer of myocardium.The com- pacted layer is normal and can even be slightly thickened in athletes
Decreased ventricular systolic function
Physiologic RV dilation in the vast majority of athletes is benign.
In contrast, genetically mediated arrhythmogenic RV cardiomyopathy/dysplasia results from defects in the genes that code for _____ proteins that facilitate connection of myocytes.
Desmosomal proteins
Athletes with defects in _____ protein genes are more likely to satisfy the diagnostic criteria of ARVC and to have a worse prognosis than similarly endowed nonathletes
Desmosomal
Individuals with confirmed genetic arrhythmogenic RV cardiomyopathy/dysplasia should be restricted from vigorous exercise training because it may increase the risk of _____.
Incident arrhythmias and progression to heart failure