A Fighter's Heart - Cardiovascular Issues in MMA
Several months ago, as a cardiologist, I was asked to review a young, lean fighter who was told by his primary care physician that he could no longer fight. His electrocardiogram (ECG) showed possible “left ventricular hypertrophy” that could be suggestive of abnormally thickened heart muscle. After a few tests including a cardiac ultrasound and a stress test, I felt that his ECG was in fact normal for his relatively young age and thin body size and could not identify anything wrong. He has subsequently won 2 further MMA fights.
In November, 2013, UFC heavyweight fighter Shane Del Rosario suddenly collapsed at home with 2 cardiac arrests. He was comatose for several weeks thereafter and ultimately died. Although his urine had tested positive for cocaine and opiates, the listed cause of death was “Long QT syndrome”, a diagnosable entity on most standard pre-fight ECG’s.
Sudden cardiac death (SCD) is a rare concern for highly conditioned athletes. Although the incidence is low, the consequences are grave, and there is considerable debate regarding its true incidence and need for screening. The above two examples demonstrate the problem facing MMA – as there is a fine balance between over caution that can jeopardize a fighter's livelihood, and missing the opportunity to identify an individual at risk.
The incidence of SCD has likely been underestimated over the years. A study from 2011 examined 273 deaths amongst almost 2 million NCAA athletes over 5 years and found the rate to be 1 in every 43,770 athletes. However the study also noted the risk was very sport specific – with NCAA division I male basketball players having a rate of death of 1:3100 with 87% of deaths being cardiac and the remainder being mostly accidental (Harmon et al, Circulation, 2011).
Heart issues in athletic competitions can be divided into several broad categories:
1. Coronary artery disease – coronary artery anomalies or atherosclerotic disease (“blockages”). Coronary artery disease is the most common cause of SCD in athletes older than 35 years of age.
2. Structural heart disease- this can involve issues that affect the pumping function of the heart, thickness of the heart, or the heart valves themselves. Many such conditions will be congenital, arising from birth and may go undetected until early adulthood. Hypertrophic cardiomyopathy is the most common cause of SCD found in 1 in 300 to 1 in 600 people, and was most famously the cause of death in Boston Celtic Reggie Lewis in 1993. Echocardiograms are ultrasounds of the heart that can detect structural abnormalities.
Hypertrophic cardiomyopathy as seen on the right image involves abnormal thickening of the left ventricle (usually the septum) and is the most common cause of SCD
3. Arrhythmias – this refers to electrical problems in the heart that results in rhythm disturbances that can be potentially fatal. These are often identified on the surface ECG and can include a long QT interval, Brugada's syndrome, or arrhythmogenic right ventricular dysplasia (ARVD). UFC fighter Dan Hardy was diagnosed with Wolff Parkinson White syndrome (WPW), which is easily detectable on an ECG. WPW is associated with accessory pathways and development of several arrhythmias, and has a weak association with SCD (risk 0.13% per year).
A prolonged QT interval can increase one's risk of a fatal arrythmia and is easily measured on a 12 lead ECG. Above 450 ms in a male and 470 ms in a female is considered abnormal prolongation.
The electrocardiogram (ECG) is a heart tracing that uses 12 leads to record the electrical activity of the heart. The test is relatively inexpensive and easy to do. The ECG can screen for major structural abnormalities as well as electrical abnormalities. The issue is that athletes will have abnormalities on their ECG’s that will in fact be “normal” for an athlete. Guidelines on ECG interpretation for athletes are continuing to evolve in terms of what constitutes a “normal” ECG (Drezner et al, "Seattle Criteria"). While most athletic commissions require an ECG for pro fights, not all do.
MMA specific cardiovascular issues
The rise and rampant use of performance enhancing drugs (PEDs) will almost certainly contribute to increased cardiovascular risk in many. Almost all PEDs from HGH to testosterone have cardiovascular risk associated with them. Anabolic steroids have long been linked to the development of high blood pressure (hypertension) and abnormal thickening (hypertrophy) of the heart muscle. Use of androgens such as testosterone replacement therapy have been linked to increases in LDL (“bad" cholesterol) and decreases in HDL (“good" cholesterol). Consider also, the common practice of weight cutting where the dehydrational state can lead to electrolyte abnormalities and sudden reductions in potassium or sodium can be fatal, or stress related hypothermia can result in potential life threatening cardiac arrhythmias, even in patients with “normal” hearts.
MMA itself is a high intensity sport that involves "burst" exertion - rapid acceleration and deceleration. It is comprised of a large static component, in which there is maximal voluntary contraction (MVC). There is also a large dynamic component with significant cardiovascular demands where the percentage of maximal oxygen uptake is high and cardiac output is increased. Because of this, anyone with a high-risk pre-existing condition (e.g.- hypertrophic cardiomyopathy, ARVD, Marfan syndrome, long QT) should abstain from training even at a recreational level.
My own thoughts..
As a cardiologist, I feel MMA is generally a safe sport from a heart standpoint and the occurrence of cardiovascular complications is rare. This being said, the death of Shane del Rosario highlights the need for careful pre-fight screening. An ECG should be done on most athletes, and further assessed by a specialist if there are any abnormalities. Consideration should be given to a cardiac ultrasound if there are ECG abnormalities, murmurs, a family history of SCD or Marfan syndrome, or alarm symptoms (unexplained fainting, chest pain with exertion, turning blue during training, etc) as it is a quick and easy to perform noninvasive test. An ECG and an echocardiogram will identify most high risk entities for SCD. Ensuring that competition occurs in arenas with readily available automated external defibrillators (AEDs) is another important consideration and should be the responsibility of promoters and regional athletic commissions. And finally, we must always subscribe to prevention – avoidance of PEDs, supplements, drastic weight cutting practices are key to ensure that our fighters continue safe practices.