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August 1, 2011
Kenley Jansen, LAN (Cardiac Arrhythmia) [AGL: TBD, ATD: TBD] (Explanation)
The causes of arrhythmias are numerous and include everything from scarring of the heart caused by heart attacks to hyperthyroidism. Structural changes in the heart and blocked arteries can cause changes in the heart’s rhythm. Even the less scary sounding culprits, like stress, too little sleep, or supplements can have the same affect.
Tests to evaluate the heart include electrocardiogram (ECG or EKG), Holter monitor, and echocardiogram, along with CTs and MRIs. The most common test is the ECG, which can easily be performed in any office or medical area with the proper equipment. This is the common test seen on TV in which electrodes are placed on the chest and limbs to measure the timing and duration of the electrical phases during each heartbeat. The short test measures the peaks, valleys, and frequencies of the sinus rhythm and is evaluated by a cardiologist after completion. The Holter monitor is a portable EKG with a device smaller than a deck of cards that is worn for 24 hours to evaluate the heart’s rhythm during normal daily activities like working, sleeping, etc.
There has been a lot of discussion over the last several years about using ECGs as a screening tool for pre-participation physicals at the adolescent and collegiate levels. Studies such as this oneand this one, have shown that ECGs increase the sensitivity but not the specificity of pre-participation cardiac screenings in athletes. The number of false positives increases significantly, leading to further testing and many sleepless nights for the athletes and their families. The high incidence of mistakes and a lack of cost-effectiveness explains why this measure isn’t implemented more often. With each tragic case of sudden death, it becomes more likely that routine pre-participation screenings will be mandated at the collegiate level.
When the ECG shows an abnormality or there is concern about a structural issue with the heart, an echocardiogram can be performed. An echocardiogram allows for evaluation of the heart in real time and has the added benefit of simultaneously providing an ECG. Gel is applied to the chest to allow the ultrasonic waves to pass from the transducer through the skin with as little disruption as possible. As the ultrasonic waves bounce back to the transducer and pop up on the screen, accurate measurements of the thickness of each heart chamber can be recorded. The heart is evaluated at several different angles to ensure all the proper measurements are taken.
Jansen said he felt fluttering in his chest that worsened during Tuesday's game, and an EKG at the stadium showed an irregular heartbeat. He was taken to the hospital for further evaluation, likely including an echocardiogram, but his rhythm remained abnormal after medication. His heart had to be shocked back into rhythm, according to this report. He was placed on the disabled list, in part per Jansen's choice, and will remain on it for at least three weeks because of the blood-thinning medication.
Nate McLouth, ATL (Lower abdominal strain) [AGL: 21, ATD: -.066]
Nick Punto, STL (Left oblique strain) [AGL: 23, ATD: .010]
There is also surely a conditioning component to this. The obliques act as a stabilizer and power generator and are a key part of the kinetic chain. Larger muscles of the legs, hips, upper back and shoulders receive a lot of strengthening attention because gains in these areas can improve performance. These may be overpowering the obliques, resulting in a strain. This trend may continue over the next few years before a conditioning program can be proven to help prevent oblique strains.
Clayton Richard, SDN (Left shoulder surgery) [AGL: 113, ATD: -.023]
Nelson Cruz, TEX (Right quadriceps tightness) [AGL: 1 (13DL), ATD: -.027 (+.063DL)]
Flesh Wounds: Chris Leroux injured his left calf and was moved to the disabled list retroactive to July 28th… Derek Jeter left Sunday's game with a bruised right finger after being hit by a pitch and is day-to-day... Chris Denorfia left his game with a right hamstring strain and is also day-to-day... Clay Buchholz will meet with Dr. Robert Watkins today about his balky back. As we alluded to on Friday, it doesn't look good, and we think there might be a herniated disc involved.
Corey Dawkins is an author of Baseball Prospectus. Follow @CoreyDawkinsBP