Mathias Claeys

Exercise cardiac magnetic resonance to differentiate athlete’s heart from structural heart disease

Aims The distinction between left ventricular (LV) dilation with mildly reduced LV ejection fraction (EF) in response to regular endurance exercise training and an early cardiomyopathy is a frequently encountered and difficult clinical conundrum. We hypothesized that exercise rather than resting measures would provide better discrimination between physiological and pathological LV remodelling and that preserved exercise capacity does not exclude significant LV damage. Methods and results We prospectively included 19 subjects with LVEF between 40 and 52%, comprising 10 ostensibly healthy endurance athletes (EA-healthy) and nine patients with dilated cardiomyopathy (DCM). In addition, we recruited five EAs with a region of subepicardial LV. Receiver operating characteristic fibrosis (EA-fibrosis). Cardiac magnetic resonance (CMR) imaging was performed at rest and during supine bicycle exercise. Invasive afterload measures were obtained to enable calculations of biventricular function relative to load (an estimate of contractility). In DCM and EA-fibrosis subjects there was diminished augmentation of LVEF (5 ± 6% vs. 4 ± 3% vs. 14 ± 3%; P = 0.001) and contractility [LV end-systolic pressure-volume ratio, LVESPVR; 1.4 (1.3-1.6) vs. 1.5 (1.3-1.6) vs. 1.8 (1.7-2.7); P < 0.001] during exercise relative to EA-healthy. Receiver-operator characteristic curves demonstrated that a cut-off value of 11.2% for ΔLVEF differentiated DCM and EA-fibrosis patients from EA-healthy [area under the curve (AUC) = 0.92, P < 0.001], whereas resting LVEF and VO2max were not predictive. The AUC value for LVESPVR ratio was similar to that of ΔLVEF. Conclusions Functional cardiac evaluation during exercise is a promising tool in differentiating healthy athletes with borderline LVEF from those with an underlying cardiomyopathy. Excellent exercise capacity does not exclude significant LV damage.

Right ventricular systolic dysfunction at rest is not related to decreased exercise capacity in patients with a systemic right ventricle

BACKGROUND To evaluate the relationship between right ventricular (RV) systolic dysfunction at rest and reduced exercise capacity in patients with a systemic RV (sRV). METHODS All patients with congenitally corrected transposition of the great arteries (ccTGA) or complete TGA after atrial switch (TGA-Mustard/Senning) followed in our institution between July 2011 and September 2017 who underwent cardiac imaging within a six-month time period of cardiopulmonary exercise testing (CPET) were analyzed. We assessed sRV systolic function with TAPSE and fractional area change on echocardiogram and, if possible, with ejection fraction, global longitudinal and circumferential strain on cardiac magnetic resonance (CMR) imaging. RESULTS We studied 105 patients with an sRV (median age 34 [IQR 28-42] years, 29% ccTGA and 71% TGA-Mustard/Senning) of which 39% had either a pacemaker (n = 17), Eisenmenger physiology (n = 6), severe systemic atrioventricular valve regurgitation (n = 14), or peak exercise arterial oxygen saturation < 92% (n = 17). Most patients were asymptomatic or mildly symptomatic (NYHA class I/II/III in 71/23/6%). Sixty-four percent had evidence of moderate or severe sRV dysfunction on cardiac imaging. Mean peak oxygen uptake (pVO2) was 24.1 ± 7.4 mL/kg/min, corresponding to a percentage of predicted pVO2 (%ppVO2) of 69 ± 17%. No parameter of sRV systolic function as evaluated on echocardiography (n = 105) or CMR (n = 46) was correlated with the %ppVO2, even after adjusting for associated cardiac defects or pacemakers. CONCLUSIONS In adults with an sRV, there is no relation between echocardiographic or CMR-derived sRV systolic function parameters at rest and peak oxygen uptake. Exercise imaging may be superior to evaluate whether sRV contractility limits exercise capacity.

Inter- and intra-observer variability of visual fragmented QRS scoring in ischemic and non-ischemic cardiomyopathy

BACKGROUND Fragmented QRS (fQRS) on a 12-lead ECG has been linked with adverse outcome. However, the visual scoring of ECGs is prone to inter- and intra-observer variability. METHODS Five observers, two experienced and three novel, assessed fQRS in 712 digital ECGs, 100 were re-evaluated to assess intra-observer variability. Fleiss and Cohens Kappa were calculated and compared between subgroups. RESULTS The inter-observer variability for assessing fQRS in all leads combined was substantial with a Kappa of 0.651. Experienced observers only had a better agreement with a Kappa of 0.823. Intra-observer variability ranged from 0.736 to 0.880. In the subgroup with ventricular pacing the inter-observer variability was even significantly larger when compared to ECGs with normal QRS duration (Kappa 0.493 vs 0.664, p<0.001). CONCLUSION The visual assessment of QRS fragmentation is prone to inter- and intra-observer variability, mainly influenced by the experience of the observers, the underlying rhythm and QRS morphology.

Prognostic significance of improvement in right ventricular systolic function during cardiac resynchronization therapy

Objectives There is conflicting evidence concerning the role of right ventricular (RV) systolic dysfunction in the long-term clinical outcome after cardiac resynchronization therapy (CRT). Therefore we aimed to assess evolution of RV systolic function during CRT, covariates associated with its improvement, and its impact on outcome. Methods and results All CRT device implantations (Jan 2009-Dec 2011) in our institution were reviewed. Records of 69 patients (25% female, mean age 62.8 ± 9.2 years, mean left ventricular (LV) ejection fraction 27 ± 8%) were analyzed. Baseline RV fractional area change (FAC) < 35% was present in 37 patients (54%). At one year, 24 of them (65%) improved in RV FAC. LV remodeling and mitral regurgitation were significantly associated with the likelihood of RV FAC improvement (OR 4.80, 95% CI 1.13-20.46, P = 0.034 and OR 0.32, 95% CI 0.12-0.89, P = 0.029, respectively). The composite endpoint of death or heart transplantation occurred in 23 patients (33%) over a mean follow-up of 2.8 ± 1.4 years. RV FAC at one year (HR 0.90, 95% CI 0.86-0.94, P < .001) was, independently of NYHA class and LV remodeling, associated with clinical outcome. Conclusions RV systolic function might improve during CRT. This seems mainly due to changed left-sided hemodynamics and LV remodeling. Good RV systolic function is independently related with better outcome.