How to interpret right ventricular remodeling in athletes

Abstract

Long-lasting athletic training induces an overload on the heart that leads to structural, functional, and electrical adaptive changes known as the "athlete's heart." The amount of this heart remodeling has been traditionally considered balanced between the left and the right heart chambers. However, during intense exercise, the right heart is exposed to a disproportional afterload and wall stress which over a long period of time could lead to more pronounced exercise-induced changes. Highly trained athletes, especially those involved in endurance sport disciplines, can develop marked right ventricular (RV) remodeling that could raise the suspicion of an underlying RV pathology including arrhythmogenic cardiomyopathy (ACM). The distinction between physiological and pathological RV remodeling is essential as ACM is a common cause of sudden cardiac death in athletes, and high-intensity exercise training has demonstrated to accelerate its phenotypic expression and worsen its prognosis. The distinction between physiological and pathological RV remodeling is essential since ACM is a common cause of sudden cardiac death in athletes, and high-intensity exercise training has demonstrated to accelerate the phenotypic expression and worsen the prognosis. This article outlines the physiological adaptation of the RV to acute exercise, the subsequent physiological structural and functional changes induced by athletic training and provides useful tips of how to differentiate between physiological RV remodeling and a cardiomyopathy phenotype.

Keywords: arrhythmogenic cardiomyopathy; athlete; endurance training; right ventricle.

Figure 1

Marked right ventricular remodeling in a veteran endurance athlete. The figure shows an example of extreme right ventricular remodeling rising the suspicion of arrhythmogenic cardiomyopathy. This is a 61 years old male competitive cyclist with more than 40 years of uninterrupted high intensity endurance training. He was asymptomatic and with negative family history for cardiomyopathies or sudden cardiac death. On resting ECG, A, incomplete right bundle branch block together with negative T waves in V1‐V3 was observed. Exercise Testing, B, showed a non‐sustained ventricular tachycardia of three beats with LBBB and inferior axis (from the RVOT). Echocardiography, C, revealed a significantly dilated right ventricle with huge trabeculations. The RVOT in short axis measured 18 mm/m² and in long axis 22 mm/m². The RV basal diameter was 58 mm. The global systolic function of the RV was normal with a fractional area change of 44% and with no evidence of regional wall motion abnormalities. Cardiac Magnetic Resonance, D, confirmed marked dilatation without dysfunction of the RV. The RV/LV volume ratio was 1.2. No areas of LGE were identified on the left and right ventricles. Despite the presence of ECG changes, arrhythmias, and significant RV dilatation there were no sufficient criteria for a diagnosis of arrhythmogenic cardiomyopathy; specifically, the athlete was asymptomatic, had negative family history and imaging revealed absence of RV global or regional systolic dysfunction. A periodical follow‐up every 6 months was, however, advised

Figure 2

Normal and abnormal patterns of T‐wave inversion in athletes. A, T‐wave inversion in V1 to V3 preceded by J‐point elevation and convex ST‐segment elevation in a 24‐year‐old asymptomatic mixed race (Caucasian/American black) athlete without family history of sudden cardiac death. This should be considered a normal repolarization pattern in mixed black and Caucasian adult athletes. B, Anterior T‐wave inversion in V1 to V2 and biphasic T in V3 in a 15‐year‐old asymptomatic athlete. This a normal “juvenile” pattern. C, Abnormal T‐wave inversion in leads II, aVF, aVL, and V1 to V6, in a 30‐year‐old amateur endurance athlete with confirmed diagnosis of apical hypertrophic cardiomyopathy. D, Abnormal T‐wave inversion in V1 to V6, II and aVF preceded by isoelectric ST segments together with left axis deviation and small QRS complexes in a 28‐year‐old trail runner with confirmed diagnosis of arrhythmogenic cardiomyopathy with biventricular involvement

Figure 3

Proposed work‐flow in the differential diagnosis of physiological or pathological right ventricular remodeling. In each step, if parameters are within normal limits (green charts), no further exploration is required. If abnormal values are obtained (red charts), physiological remodeling is excluded and specific work‐up for underlying disease assessment should be prompted. FIRST STEP: electrocardiographic signs of abnormal RV remodeling include T‐wave inversion and repolarization patterns of abnormal RV adaptation to exercise (RED FLAGS) (for additional details, see the text). SECOND STEP: RV echo measurements. RV dimensions that exceed reference values for male/female athletes must be considered warning signs of abnormal RV remodeling (red flags); additional echo measurements (third step) should be assessed. THIRD STEP: additional echo measurements. Thresholds for abnormal RV remodeling are given based on several parameters (red flags).If any of these values is met, RV remodeling should not be considered physiologic (underlying disease). FOURTH STEP: Additional tests: Exercise ECG/exercise echo/cardiac magnetic resonance/ambulatory ECG monitoring are indicated if aforementioned resting examinations still inconclusive. The exercise ECG evaluates blood pressure response to exercise and can detect ischemia or arrhythmias induced by the exercise stimulus. Both exercise echocardiography and exercise CMR can assess the presence of exercise‐induced wall motion abnormalities and/or impaired contractile reserve. In addition, the presence of myocardial fibrosis can be unmasked by CMR late gadolinium enhancement. Arrhythmic burden can be assessed by an ambulatory ECG. The athlete's epidemiological characteristics and his/her athletic training history (surrounding gray frame) must be taken into account in every step, with special attention on those characteristics related with more marked RV remodeling (high training load and duration, dynamic exercise, older age group, male sex: RED FLAGS). Footprints represent how these features leave a mark that cannot be ignored. CMR, cardiac magnetic resonance; GLS, global longitudinal strain; LV, Left ventricle; NSVT, non‐sustained ventricular tachycardia; PVBs, premature ventricular beats; RV, right ventricle; RVFAC, RV fractional area change; TAPSE, tricuspid annulus systolic excursion; TDI, Tissue Doppler Imaging; TWI, T‐wave inversion