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Cardiomyopathy
Case Reports
233 CASE REPORTS
Heart, Lung and Circulation 2009;18:222–235
Exercise-Induced Right Ventricular Dysplasia/Cardiomyopathy—An Emerging Condition Distinct from Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy Richard W. Harper, FACC, FCSANZ a,b,∗ and Philip M. Mottram, PhD, FRACP, FCSANZ a,b a
Monash Heart, Monash Medical Centre, 246 Clayton Road, Clayton 3168, Melbourne, Australia b Monash Cardiovascular Research Centre, Monash University, Department of Medicine, Melbourne, Australia
We report a case of a 32-year-old female world champion triathlete who developed exercise induced recurrent ventricular tachycardia (VT). Investigations supported a diagnosis of the newly recognised condition “exercise induced right ventricular dysplasia/cardiomyopathy” (EIRVD/C). The VT could be easily terminated by burst pacing from the RV apex and the athlete has been successfully treated with an internal cardioverter defibrillator (ICD). (Heart, Lung and Circulation 2009;18:222–235) © 2008 Australasian Society of Cardiac and Thoracic Surgeons and the Cardiac Society of Australia and New Zealand. Published by Elsevier Inc. All rights reserved. Keywords. Cardiomyopathy; Arrhythmia; Exercise; Right ventricle
Introduction
R
ecurrent sustained exercise induced ventricular tachycardia (VT) in elite ultra-endurance athletes is a rare but serious problem. Recent studies indicate that most serious ventricular arrhythmias (VA) in elite endurance athletes arise from the right ventricle (RV).1 In some the diagnosis may be arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). In others it is postulated that repeated extreme exercise may damage the RV thus providing a substrate for arrhythmias.1–3 In such cases the term EIRVD/C is applicable.4 Distinction between these two entities (ARVD/C and EIRVD/C) is important. ARVD/C is an inherited disorder characterised by progressive fibrofatty replacement of RV myocardium eventually leading to ventricular arrhythmias and right heart failure.5 The underlying pathophysiology is a genetic abnormality of cell adhesion proteins such as plakoglobulin, desmoplakin, plakophillin-2, and desmoglein-2.5 In patients with ARVD/C exercise may precipitate ventricular arrhythmias and aggravate or accelerate the condition but it is not the fundamental cause of the disorder. On the other hand EIRVD/C is thought to be the cumulative result Received 24 December 2007; received in revised form 16 December 2007; accepted 25 January 2008; available online 8 April 2008 ∗ Corresponding author. Tel.: +61 3 9594 2242; fax: +61 3 9594 6239. E-mail address: [email protected] (R.W. Harper).
of repeated bouts of extreme endurance exercise each of which has caused a small amount of damage to the RV.4 We report a case of exercise-precipitated recurrent sustained monomorphic ventricular tachycardia (VT) occurring in a 32-year-old multiple world champion female triathlete without a family history to suggest ARVD/C and in whom investigations support a diagnosis of EIRVD/C rather than ARVD/C.
Case Report The subject is a former world champion tri-athlete. Over a career of 10 years during which time she averaged 10–15 events per year she won many world class events and for a 4-year-period was rated number one in the world. In 2004 during a swimming training session she became dizzy and aware of palpitations. An ECG showed sustained monomorphic VT with LBBB morphology (Fig. 1b). DC cardioversion was required. She subsequently suffered further similar episodes each related to exercise. A typical baseline ECG (Fig. 1a) showed sinus bradycardia with anterior T wave changes. Echocardiography (Fig. 2) showed dilated ventricles with normal left ventricular systolic function but moderately reduced RV systolic function. An MRI scan (Fig. 3) confirmed the above findings and showed no features to suggest ARVD/C. Coronary angiography was normal. An RV biopsy (Fig. 4) showed fibre hypertrophy with evidence of patchy fibrosis but no evidence of fatty infiltration.
© 2008 Australasian Society of Cardiac and Thoracic Surgeons and the Cardiac Society of Australia and New Zealand. Published by Elsevier Inc. All rights reserved.
1443-9506/04/$30.00 doi:10.1016/j.hlc.2008.01.005
234
Case Reports
CASE REPORTS
Heart, Lung and Circulation 2009;18:222–235
Figure 1. (a) Baseline 12-lead ECG demonstrating T wave inversion in leads V1–V3. (b) Ventricular tachycardia (VT) occurring immediately after ceasing high workload exercise (17 min of the BRUCE protocol). The VT was appropriately sensed by the patient’s cardioverter-defibrillator and overdrive-paced back to normal sinus rhythm (c).
At electrophysiology study sustained VT with a morphology identical to clinical episodes was easily induced. The site of origin of the VT was mapped to the posterolateral aspect of the RV. The VT was easily terminated by burst overdrive RV pacing. Attempts at catheter electrode ablation of the VT were unsuccessful and an ICD was inserted. Subsequent interrogation of the device has shown multiple episodes of exercise induced VT reliably terminated by burst pacing (Fig. 1c). The athlete has continued to undertake endurance exercise although not to the extreme levels of previously. Serial echocardiograms have not shown any further deterioration of RV function.
Discussion The absence of a family history and lack of typical changes on the MRI scan and cardiac biopsy make a diagnosis of ARVD/C unlikely in this case. Furthermore it is improbable that someone with ARVD/C could achieve world status in triathlon over such a long period of time with this diagnosis. We believe it more likely that the athlete suffers from the newly described condition EIRVD/C. The evidence that extreme endurance athletic activity can cause RV damage and dysfunction eventually leading to serious ventricular arrhythmias is compelling. In
Case Reports
235 CASE REPORTS
Heart, Lung and Circulation 2009;18:222–235
Figure 4. Right ventricular endomyocardial biopsy demonstrating mild non-specific changes, including mild myofibre hypertrophy and some patchy interstitial fibrosis. No evidence of fatty infiltration. Figure 2. Transthoracic echocardiogram. The apical four-chamber view demonstrates marked right ventricular (RV) dilatation and moderate RV systolic dysfunction. The left ventricle (LV) was mildly dilated (3.3 cm/m2 ) and mildly hypertrophic (LV mass index 134 gm/m2 ), with normal systolic function (ejection fraction 58%).
Familial ARVD/C was evident in only one athlete. Nine of 46 died suddenly during a 4.7 year follow up.1 In a subsequent study these investigators showed that similar athletes with VA had reduced RV function as compared to control athletes.2 These investigators were the first to suggest that endurance exercise might contribute to structural and electrical abnormalities in the RV independent of ARVD/C.1,2 ARVD/C and EIRVD/C pose different challenges to sports medicine. In the former the challenge is to identify affected individuals prior to and advise against their participation in high-level athletic activity. In the latter the challenge is to develop guidelines that will protect elite endurance athletes from serious damage to their RV.
References
Figure 3. Short axis magnetic resonance image with T1 weighting confirming marked RV dilatation. Delayed contrast sequences revealed no evidence of infarction or fibrosis of either ventricle. Fat-suppression sequences did not demonstrate evidence of RV fatty infiltration.
a recent study La Gerche et al.3 found that more than 50% of athletes had elevations of serum troponin levels and all had at least transient RV dysfunction after competing in an ultra-endurance triathlon event. In a similar study 86% of athletes had detectable serum troponin levels after completing an ironman event.6 These studies indicate that myocardial damage, albeit small, is common after such events. Furthermore, the RV appears more susceptible than the LV.1–3 In a landmark study of 46 high-level endurance athletes with VA, RV arrhythmic involvement was proven in 59% and suggested in a further 30%.1
¨ 1. Heidbuchel H, Hoogsteen J, Fagard R, Vanhees L, Ector H, Willems R, Van Lierde J. High prevalence of right ventricular involvement in endurance athletes with ventricular arrhythmias. Role of an electrophysiologic study in risk stratification. Eur Heart J 2003;24(16):1473–80. 2. Ector J, Ganame J, van der Merwe N, Adriaenssens B, Pison L, ¨ Willems R, Gewillig M, Heidbuchel H. Reduced right ventricular ejection fraction in endurance athletes presenting with ventricular arrhythmias: a quantitative angiographic assessment. Eur Heart J 2007;28(3):345–53. 3. La Gerche A, Connelly KA, Mooney DJ, MacIsaac AI, Prior DL. Biochemical and functional abnormalities of left and right ventricular function following ultra-endurance exercise. Heart, Epub ahead of print May 4, 2007. 4. La Gerch A, Prior DL. Exercise – Is it possible to have too much of a good thing? Heart Lung Circ 2007;16(Suppl. 3):S102–4. 5. Corrado D, Thiene G. Arrhythmogenic right ventricular cardiomyopathy/dysplasia: clinical impact of molecular genetic studies. Circulation 2006;113(13):1634–7. 6. Tulloh L, Robinson D, Patel A, Ware A, Prendergast C, Sullivan D, Pressley L. Raised troponin T and echocardiographic abnormalities after prolonged strenuous exercise – the Australian Ironman Triathlon. Br J Sports Med 2006;7:605–9.
233 CASE REPORTS
Heart, Lung and Circulation 2009;18:222–235
Exercise-Induced Right Ventricular Dysplasia/Cardiomyopathy—An Emerging Condition Distinct from Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy Richard W. Harper, FACC, FCSANZ a,b,∗ and Philip M. Mottram, PhD, FRACP, FCSANZ a,b a
Monash Heart, Monash Medical Centre, 246 Clayton Road, Clayton 3168, Melbourne, Australia b Monash Cardiovascular Research Centre, Monash University, Department of Medicine, Melbourne, Australia
We report a case of a 32-year-old female world champion triathlete who developed exercise induced recurrent ventricular tachycardia (VT). Investigations supported a diagnosis of the newly recognised condition “exercise induced right ventricular dysplasia/cardiomyopathy” (EIRVD/C). The VT could be easily terminated by burst pacing from the RV apex and the athlete has been successfully treated with an internal cardioverter defibrillator (ICD). (Heart, Lung and Circulation 2009;18:222–235) © 2008 Australasian Society of Cardiac and Thoracic Surgeons and the Cardiac Society of Australia and New Zealand. Published by Elsevier Inc. All rights reserved. Keywords. Cardiomyopathy; Arrhythmia; Exercise; Right ventricle
Introduction
R
ecurrent sustained exercise induced ventricular tachycardia (VT) in elite ultra-endurance athletes is a rare but serious problem. Recent studies indicate that most serious ventricular arrhythmias (VA) in elite endurance athletes arise from the right ventricle (RV).1 In some the diagnosis may be arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). In others it is postulated that repeated extreme exercise may damage the RV thus providing a substrate for arrhythmias.1–3 In such cases the term EIRVD/C is applicable.4 Distinction between these two entities (ARVD/C and EIRVD/C) is important. ARVD/C is an inherited disorder characterised by progressive fibrofatty replacement of RV myocardium eventually leading to ventricular arrhythmias and right heart failure.5 The underlying pathophysiology is a genetic abnormality of cell adhesion proteins such as plakoglobulin, desmoplakin, plakophillin-2, and desmoglein-2.5 In patients with ARVD/C exercise may precipitate ventricular arrhythmias and aggravate or accelerate the condition but it is not the fundamental cause of the disorder. On the other hand EIRVD/C is thought to be the cumulative result Received 24 December 2007; received in revised form 16 December 2007; accepted 25 January 2008; available online 8 April 2008 ∗ Corresponding author. Tel.: +61 3 9594 2242; fax: +61 3 9594 6239. E-mail address: [email protected] (R.W. Harper).
of repeated bouts of extreme endurance exercise each of which has caused a small amount of damage to the RV.4 We report a case of exercise-precipitated recurrent sustained monomorphic ventricular tachycardia (VT) occurring in a 32-year-old multiple world champion female triathlete without a family history to suggest ARVD/C and in whom investigations support a diagnosis of EIRVD/C rather than ARVD/C.
Case Report The subject is a former world champion tri-athlete. Over a career of 10 years during which time she averaged 10–15 events per year she won many world class events and for a 4-year-period was rated number one in the world. In 2004 during a swimming training session she became dizzy and aware of palpitations. An ECG showed sustained monomorphic VT with LBBB morphology (Fig. 1b). DC cardioversion was required. She subsequently suffered further similar episodes each related to exercise. A typical baseline ECG (Fig. 1a) showed sinus bradycardia with anterior T wave changes. Echocardiography (Fig. 2) showed dilated ventricles with normal left ventricular systolic function but moderately reduced RV systolic function. An MRI scan (Fig. 3) confirmed the above findings and showed no features to suggest ARVD/C. Coronary angiography was normal. An RV biopsy (Fig. 4) showed fibre hypertrophy with evidence of patchy fibrosis but no evidence of fatty infiltration.
© 2008 Australasian Society of Cardiac and Thoracic Surgeons and the Cardiac Society of Australia and New Zealand. Published by Elsevier Inc. All rights reserved.
1443-9506/04/$30.00 doi:10.1016/j.hlc.2008.01.005
234
Case Reports
CASE REPORTS
Heart, Lung and Circulation 2009;18:222–235
Figure 1. (a) Baseline 12-lead ECG demonstrating T wave inversion in leads V1–V3. (b) Ventricular tachycardia (VT) occurring immediately after ceasing high workload exercise (17 min of the BRUCE protocol). The VT was appropriately sensed by the patient’s cardioverter-defibrillator and overdrive-paced back to normal sinus rhythm (c).
At electrophysiology study sustained VT with a morphology identical to clinical episodes was easily induced. The site of origin of the VT was mapped to the posterolateral aspect of the RV. The VT was easily terminated by burst overdrive RV pacing. Attempts at catheter electrode ablation of the VT were unsuccessful and an ICD was inserted. Subsequent interrogation of the device has shown multiple episodes of exercise induced VT reliably terminated by burst pacing (Fig. 1c). The athlete has continued to undertake endurance exercise although not to the extreme levels of previously. Serial echocardiograms have not shown any further deterioration of RV function.
Discussion The absence of a family history and lack of typical changes on the MRI scan and cardiac biopsy make a diagnosis of ARVD/C unlikely in this case. Furthermore it is improbable that someone with ARVD/C could achieve world status in triathlon over such a long period of time with this diagnosis. We believe it more likely that the athlete suffers from the newly described condition EIRVD/C. The evidence that extreme endurance athletic activity can cause RV damage and dysfunction eventually leading to serious ventricular arrhythmias is compelling. In
Case Reports
235 CASE REPORTS
Heart, Lung and Circulation 2009;18:222–235
Figure 4. Right ventricular endomyocardial biopsy demonstrating mild non-specific changes, including mild myofibre hypertrophy and some patchy interstitial fibrosis. No evidence of fatty infiltration. Figure 2. Transthoracic echocardiogram. The apical four-chamber view demonstrates marked right ventricular (RV) dilatation and moderate RV systolic dysfunction. The left ventricle (LV) was mildly dilated (3.3 cm/m2 ) and mildly hypertrophic (LV mass index 134 gm/m2 ), with normal systolic function (ejection fraction 58%).
Familial ARVD/C was evident in only one athlete. Nine of 46 died suddenly during a 4.7 year follow up.1 In a subsequent study these investigators showed that similar athletes with VA had reduced RV function as compared to control athletes.2 These investigators were the first to suggest that endurance exercise might contribute to structural and electrical abnormalities in the RV independent of ARVD/C.1,2 ARVD/C and EIRVD/C pose different challenges to sports medicine. In the former the challenge is to identify affected individuals prior to and advise against their participation in high-level athletic activity. In the latter the challenge is to develop guidelines that will protect elite endurance athletes from serious damage to their RV.
References
Figure 3. Short axis magnetic resonance image with T1 weighting confirming marked RV dilatation. Delayed contrast sequences revealed no evidence of infarction or fibrosis of either ventricle. Fat-suppression sequences did not demonstrate evidence of RV fatty infiltration.
a recent study La Gerche et al.3 found that more than 50% of athletes had elevations of serum troponin levels and all had at least transient RV dysfunction after competing in an ultra-endurance triathlon event. In a similar study 86% of athletes had detectable serum troponin levels after completing an ironman event.6 These studies indicate that myocardial damage, albeit small, is common after such events. Furthermore, the RV appears more susceptible than the LV.1–3 In a landmark study of 46 high-level endurance athletes with VA, RV arrhythmic involvement was proven in 59% and suggested in a further 30%.1
¨ 1. Heidbuchel H, Hoogsteen J, Fagard R, Vanhees L, Ector H, Willems R, Van Lierde J. High prevalence of right ventricular involvement in endurance athletes with ventricular arrhythmias. Role of an electrophysiologic study in risk stratification. Eur Heart J 2003;24(16):1473–80. 2. Ector J, Ganame J, van der Merwe N, Adriaenssens B, Pison L, ¨ Willems R, Gewillig M, Heidbuchel H. Reduced right ventricular ejection fraction in endurance athletes presenting with ventricular arrhythmias: a quantitative angiographic assessment. Eur Heart J 2007;28(3):345–53. 3. La Gerche A, Connelly KA, Mooney DJ, MacIsaac AI, Prior DL. Biochemical and functional abnormalities of left and right ventricular function following ultra-endurance exercise. Heart, Epub ahead of print May 4, 2007. 4. La Gerch A, Prior DL. Exercise – Is it possible to have too much of a good thing? Heart Lung Circ 2007;16(Suppl. 3):S102–4. 5. Corrado D, Thiene G. Arrhythmogenic right ventricular cardiomyopathy/dysplasia: clinical impact of molecular genetic studies. Circulation 2006;113(13):1634–7. 6. Tulloh L, Robinson D, Patel A, Ware A, Prendergast C, Sullivan D, Pressley L. Raised troponin T and echocardiographic abnormalities after prolonged strenuous exercise – the Australian Ironman Triathlon. Br J Sports Med 2006;7:605–9.