Reply to: E. Kasikcioglu. A Crucial Point: The Early Diagnosis of Increased Risk Subjects Before Sudden Cardiac Death

Dear Editors,

We greatly appreciate the letter from colleague Kasikcioglu with further detailed results on identifying high risk athletes with hypertrophic cardiomyopathy (HCM).

Indeed, screening of all athletes on HCM presents an overwhelming challenge. Due to limited financial support, organization, implementation, and especially athlete compliance, screening on HCM can be realized only to a limited degree in any kind of social system.

QT-dispersion has been proposed to evaluate high risk groups with HCM. However, there was no convincing correlation found to symptomatic or Holter-based arrhythmias in HCM. Only in patients with QT-dispersion > 140 ms waiting for heart transplantation, a 4-fold risk of sudden cardiac death could be shown [[5]]. Now, Kasikcioglu et al. report interesting results concerning QT-dispersion during exercise in soccer players, which are reported to be lower than in sedentary controls [[3]]. Though results on QT-dispersion during exercise in patients with myocardial ischemia or congenital long QT-syndrome have been presented, convincing data during exercise in the case of HCM athletes are lacking [[1], [2]]. Being non-invasive, not expensive, and relatively easy to detect, QT-dispersion during or after exercise could reveal additional information for risk stratification. Sufficient evidence of higher QT-dispersion in affected HCM athletes is needed, compared to unaffected athletes as controls, to yield valid data as a basis for such important decisions as sports eligibility. We agree that it could be rewarding to clarify this question despite a very limited data base due to low prevalence of affected athletes.

Tissue Doppler echocardiography is used to detect myocardial abnormalities in patients with hypertrophic cardiomyopathy as a means for an early diagnosis, even before and independently of hypertrophy [[4]]. Kasikcioglu proposes that myocardial performance index measured by tissue Doppler imaging has the best sensitivity and specifity in differentiating left ventricular hypertrophy with regard to hypertensive and athletic hypertrophy. Again, HCM-specific design is required, but results will probably be obtained without considerable difficulties. We think that the main issue is not “HCM or athlete's heart”, but rather “HCM or not HCM”. Left ventricular wall thickening can be detected neither in case of endurance nor strength training athletes who have no hypertension and do not use anabolic steroids [[6], [7]].

References

• 1 Arab D, Valeti V, Schünemann H J, Lopez-Candales A. Usefulness of the QTc interval in predicting myocardial ischemia in patients undergoing exercise stress testing.  Am J Cardiol. 2000;  85 764-766
• 2 Dillenburg R F, Hamilton R M. Is exercise testing useful in identifying congenital long QT syndrome?.  Am J Cardiol. 2002;  89 233-236
• 3 Kasikcioglu E, Kayserilioglu A, Yildiz S, Akhan H, Cuhadaroglu C. QT-dispersion in soccer players during exercise testing.  Int J Sports Med. 2004;  25 177-181
• 4 Nagueh S, Bachinski L, Meyer D, Hill R, Zoghbi W A, Tam J W, Quinones M A, Roberts R, Marian A J. Tissue Doppler imaging consistently detects myocardial abnormalities in patients with hypertrophic cardiomyopathy and provides a novel means for an early diagnosis before and independently of hypertrophy.  Circulation. 2001;  104 128-130
• 5 Pinsky D J, Sciacca R R, Steinberg J S. QT-dispersion as a marker of risk in patients awaiting heart transplantation.  J Am Coll Cardiol. 1997;  29 1576-1584
• 6 Urhausen A, Kindermann W. Sports-specific adaptations and differentiation of the athlete's heart.  Sports Med. 1999;  28 237-244
• 7 Wernstedt P, Sjöstedt C, Ekman I, Du H, Thuomas K A, Areskog N H, Nylander E. Adaptation of cardiac morphology and function to endurance and strength training.  Scand J Med Sci Sports. 2002;  12 17-25