Hypersynchrony in sarcomeric hypertrophic cardiomyopathy: description and mechanistic approach using multimodal electro-mechanical non-invasive cartography (HSYNC study).

Background: Little is known about left ventricular (LV) sequences of contraction and electrical activation in hypertrophic cardiomyopathy (HCM). A better understanding of the underlying relation between mechanical and electrical activation may allow the identification of predictive response criteria to right ventricular DDD pacing in obstructive patients. Objective: To describe LV mechanical and electrical activation sequences in HCM patients compared to controls. Materials and methods: We prospectively studied, in 40 HCM patients (20 obstructive and 20 non-obstructive) and 20 healthy controls: (1) mechanical activation using echocardiography at rest and cardiac magnetic resonance imaging, (2) electrical activation using 3-dimensional electrocardiographic mapping (ECM). Results: In echocardiography, healthy controls had a physiological apex-to-base delay (ABD) during contraction (23.8 ± 16.2 ms). Among the 40 HCM patients, 18 HCM patients presented a loss of this ABD (<10 ms, defining hypersynchrony) more frequently than controls (45% vs. 5%, p = 0.017). These patients had a lower LV end-diastolic volume (71.4 ± 9.7 ml/m2 vs. 82.4 ± 14.8 ml/m2, p = 0.01), lower native T1 values (988 ± 32 ms vs. 1,028 ± 39 ms, p = 0.001) and tended to have lower LV mass (80.7 ± 23.7 g/m2 vs. 94.5 ± 25.3 g/m2, p = 0.08) compared with HCM patients that had a physiological contraction sequence. There was no significant relation between ABD and LV outflow tract obstruction. While HCM patients with a physiological contraction sequence presented an ECM close to those encountered in controls, patients with a loss of ABD presented a particular pattern of ECM with the first potential more frequently occurring in the postero-basal region. Conclusion: The LV contraction sequence can be modified in HCM patients, with a loss of the physiological ABD, and is associated with smaller LV dimensions and a particular pattern of ECM. Further research is needed to determine whether this pattern is related to an electrical substrate or is the consequence of the hypertrophied heart's specific geometry. Clinical trial registration: ClinicalTrial.gov: NCT02559726.

Exercise Capacity and Perceived Exertion on Treadmill Stress Test Performed While Wearing vs Without a Surgical Mask: A Randomized Clinical Trial in Healthy Adults.

Background: The graded exercise treadmill stress test (GXT) is among the most frequently performed tests in cardiology. The COVID-19 pandemic led many healthcare facilities to require patients to wear a mask during the test. This study evaluated the effect of wearing a surgical face mask on exercise capacity and perceived exertion. Methods: In this prospective, randomized crossover trial, 35 healthy adults performed a GXT using the Bruce protocol while wearing a surgical mask, and without a mask. The primary outcome was exercise capacity in metabolic equivalents (MET), and the secondary outcome was exercise perception on the modified Borg scale (from 0 to 10). Effort duration, heart rate, oxygen saturation, and blood pressure were also analyzed. Results: Exercise capacity was reduced by 0.4 MET (95% confidence interval [CI] -0.7 to -0.2) during the GXT with a mask (11.8 ± 2.7 vs 12.3 ± 2.5 MET, P = 0.001), and the final perceived effort increased by 0.5 points (95% CI 0.2 to 0.8; 8.4 ± 1.3 vs 7.9 ± 1.6, P = 0.004). Effort duration was cut down by 24 seconds (CI -0:39 to -0:09; 10:03 ± 2:30 vs 10:27 ± 2:16 [minutes:seconds], P = 0.003). Oxygen saturation was slightly lower at the end of the test when participants wore a mask. No significant differences occurred in heart rate or blood pressure during the test. Conclusion: Wearing a surgical mask causes a statistically significant decrease in exercise capacity and increase in perceived exertion. This small effect is not clinically significant for the interpretation of test results.

Introduction: L'épreuve d'effort gradué sur tapis roulant (GXT, de l'anglais graded exercise test) compte parmi les épreuves les plus fréquemment réalisées en cardiologie. La pandémie de COVID-19 a poussé de nombreux établissements de soins de santé à exiger aux patients le port du masque durant l'épreuve. La présente étude portait sur l'évaluation des effets du port du masque chirurgical sur la capacité à l'effort et l'effort perçu. Méthodes: Dans cet essai croisé prospectif, 35 adultes en bonne santé ont réalisé une GXT selon le protocole de Bruce, avec le port du masque chirurgical et sans le port du masque. Le principal critère d'évaluation était la capacité à l'effort exprimée en équivalents métaboliques (MET, de l'anglais Metabolic Equivalent of Task), et le critère secondaire était la perception de l'effort selon l'échelle de Borg modifiée (de 0 à 10). La durée de l'effort, la fréquence cardiaque, la saturation en oxygène et la pression artérielle ont également fait l'objet de l'analyse. Résultats: La capacité à l'effort était réduite de 0,4 MET (intervalle de confiance [IC] à 95 % de ­0,7 à ­0,2) durant la GXT réalisée avec le port du masque (11,8 ± 2,7 vs 12,3 ± 2,5 MET, P = 0,001), et l'effort perçu final avait augmenté de 0,5 point (IC à 95 % de 0,2 à 0,8 ; 8,4 ± 1,3 vs 7,9 ± 1,6, P = 0,004). La durée de l'effort était réduite de 24 secondes (IC à 95 % de ­0:39 à ­0:09 ; 10:03 ± 2:30 vs 10:27 ± 2:16 [minutes:secondes], P = 0,003). La saturation en oxygène était légèrement plus faible à la fin de l'épreuve lorsque les participants portaient le masque. Aucune différence significative de la fréquence cardiaque et de la pression artérielle n'est apparue durant l'épreuve. Conclusion: Le port du masque chirurgical entraîne une diminution statistiquement significative de la capacité à l'effort et une augmentation de l'effort perçu. Cet effet minime n'est pas cliniquement significatif pour l'interprétation des résultats de l'épreuve.

Risk Factors for Recurrent Diabetic Ketoacidosis in Adults With Type 1 Diabetes.

OBJECTIVES: Identification of risk factors for recurrent diabetic ketoacidosis (DKA) in patients with type 1 diabetes could help target those at high risk so as to implement preventive measures. The main objective of this study was to identify factors associated with recurrent DKA in adult Canadian patients with type 1 diabetes. METHODS: This is a retrospective cohort study of adult patients who had a diagnosis of type 1 diabetes for at least 1 year and who were hospitalized for an isolated or recurrent DKA episode between January 2007 and January 2017 in 5 Québec City tertiary care hospitals. Factors associated with recurrent DKA in bivariate logistic regression with a p value <0.1 were included in a multivariate analysis. Results are reported as odds ratios (OR) and 95% confidence intervals (CI). RESULTS: We included 212 patients who met the inclusion criteria. Of these, 141 and 71 had an isolated episode or recurrent DKA episodes, respectively. Problems of alcohol or illicit drug abuse (OR 2.81; 95% CI 1.55 to 5.07; p<0.01) and higher glycated hemoglobin levels (OR 1.26; 95% CI 1.08 to 1.47; p<0.01) were associated with recurrent DKA in bivariate analysis. However, only nonadherence to insulin therapy (OR 26.29; 95% CI 1.78 to 388.5; p=0.02) was significantly associated with recurrent DKA in the multivariate analysis, although a diagnosis of psychiatric illness was possibly another risk factor (OR 2.72; 95% CI 0.94 to 7.89; p=0.06). CONCLUSIONS: Interventions targeting adherence to insulin therapy, and possibly also psychiatric illness, could help reduce recurrent DKA in patients with type 1 diabetes.