Left Atrial Myopathy is Associated With Exercise Incapacity and Ventilatory Inefficiency in Hypertrophic Cardiomyopathy.

BACKGROUND: Left atrial (LA) myopathy is an established component of hypertrophic cardiomyopathy (HCM); however, the data about its association with exercise incapacity or ventilatory inefficiency that may be seen in HCM patients are limited. This study aimed to explore the association between LA myopathy, evaluated by echocardiography LA strain, and exercise capacity and ventilatory efficiency, evaluated by cardiopulmonary exercise testing (CPET), in HCM patients. METHODS: This study included 241 consecutive HCM patients (aged 51.2±15.7 years 67.2% male) in sinus rhythm who underwent CPET and transthoracic echocardiography at the same visit. Exercise incapacity (maximal/predicted oxygen consumption [%peakVO2] <80%) and ventilatory inefficiency (ventilation/carbon dioxide output [VE/VCO2] slope >34) were assessed by CPET. Left atrial myopathy was examined by speckle-tracking myocardial deformation parameters: LA reservoir, conduit and booster strain. RESULTS: All three LA strain values were univariate predictors of exercise capacity and ventilatory efficiency. Among them, LA reservoir strain had the higher r correlation coefficient for predicting both %peakVO2 and VE/VCO2 slope. Left atrial reservoir strain, presence of angina and family history of HCM were independent predictors of exercise capacity. Left atrial reservoir strain, male gender and non-sustained ventricular tachycardia were independent predictors of ventilatory efficiency. Left atrial reservoir strain was a significant predictor of %peakVO2<80% with an optimal cut-off value of 27% (sensitivity 87% and specificity 31%) and VE/VCO2>34 with an optimal cut-off value of 18% (sensitivity 71% and specificity 83%). CONCLUSION: Left atrial myopathy, as reflected by the LA strain values, was associated with exercise incapacity and ventilatory inefficiency in HCM individuals. Left atrial reservoir strain was the only common independent predictor of %peakVO2 and VE/VCO2 slope.

ST elevation myocardial infarction following a cannabis smoking binge.

Cannabis smoking is considered the most popular illicit drug used worldwide. We present the case of a 26-year-old male with ST elevation myocardial infarction and heart failure subsequent to cannabis smoking abuse. We searched the literature regarding acute myocardial infarction following cannabis smoking and the possible pathophysiologic mechanisms.

The TRACE registry (Trans-Radial Approach in Central and northErn Greece).

OBJECTIVE: We examined trans-radial approach (TRA) use in coronary angiographies (CAs) as well as in percutaneous coronary interventions (PCIs) in specific regions of Greece, its distribution in public and private catheterization laboratories (CLs) and its preference by operators. Reliable data regarding the use of TRA are not available in Greece. METHODS: The study was performed in northern and central Greece, which constitutes 35.32% of the national population. This study focused on the years 2004, 2009 and 2013. RESULTS: There are 12 CLs. CAs performed using TRA were 0.43% in 2004, 12.28% in 2009 and 39.81% in 2013, whereas PCIs performed using TRA were 0.38%, 9.20% and 39.48%, respectively. Operators familiar with TRA, but who performed TRA electively, were 13.33% in 2004, 60.38% in 2009 and 42.37% in 2013. However, operators performing TRA routinely were 2.2%, 5.66%, and 49.15%, respectively. In 2013, there was a 3.76% decrease in CAs and 4.51% decrease in PCIs compared to 2009; in private CLs, there was a 29.63% decrease in CAs and 34.72% decrease in PCIs performed, which was contradictory to the 27.27% increase observed in CAs and 29.83% increase in PCIs in public CLs. CONCLUSIONS: This is the first study to reveal the volumes and trends in interventions performed via TRA across central and northern Greece. TRA has gained a reputation among operators in both public and private CLs. Due to the financial crisis in Greece, catheterizations have been diminished, whereas private CLs have lost a great amount of their turnover.

Initial Experience with Renal Denervation for the Treatment of Resistant Hypertension - The Utility of Novel Anesthetics and Metaiodobenzylguanidine Scintigraphy (MIBG).

BACKGROUND: The Symplicity-HTN 3 trial failed to show significant difference in blood pressure (BP) lowering between patients undergoing catheter-based renal denervation (RDN) and the sham-procedure arm of the study. However, there is still optimism about the role of RDN in the treatment of resistant hypertension, because identification of patients with increased sympathetic activity thus being good RDN responders, improvements in the RDN procedure and new technology RDN catheters are all expected to lead to better RDN results. We present our initial experience with RDN for the treatment of resistant hypertension, and the utility of novel anesthetics and cardiac (123)I-metaiodobenzylguanidine scintigraphy ((123)I-MIBG). METHODS AND RESULTS: Seven patients with resistant hypertension underwent RDN and were followed up for 6 months. MIBG was performed before RDN, in order to estimate sympathetic activity and predict the response to RDN. All patients were sedated with dexmedetomidine and remifentanil during RDN. All patients tolerated the procedure well, were hemodynamically stable and their peri-procedural pain was effectively controlled. A median of 7.6 ± 2.1 and 6 ± 1.4 ablations were delivered in the right and left renal artery respectively, making an average of 6.8 burns per artery. No peri-procedural or late complications - adverse events (local or systematic) occurred. At 6 months, mean reduction in office BP was -26.0/-16.3 mmHg (p=0.004/p=0.02), while mean reduction in ambulatory BP was -12.3/-9.2 mmHg (p=0.118/p=0.045). One patient (14.3%) was a non-responder. None of the cardiac (123)I-MIBG imaging indexes(early and late heart-to-mediastinum (H/M) count density ratio, washout rate (WR) of the tracer from the myocardium) were different between responders and non-responders. CONCLUSION: Patients with resistant hypertension who underwent RDN in our department had a significant reduction in BP 6 months after the intervention. (123)I-MIBG was not useful in predicting RDN response. Dexmedetomidine and remifentanil provided sufficient patient comfort during the procedure, allowing an adequate number of ablations per renal artery to be performed, and this could probably lead to improved RDN results.

Differences in Stress Forces and Geometry between Left and Right Coronary Artery: A Pathophysiological Aspect of Atherosclerosis Heterogeneity.

INTRODUCTION: We sought to assess noninvasively the differences in hemorrheologic and geometric parameters between the left and right coronary artery (RCA). Low endothelial shear stress (ESS), high molecular viscosity (MV), and high wall stress (WS) induce atherosclerosis, while curvature and torsion have lately been implicated in the atherosclerotic process. METHODS: We studied 28 coronary arteries from 22 subjects undergoing coronary computed tomography angiography. We performed 3D reconstruction of the left anterior descending (LAD, n=14), left circumflex (LCx, n=5), and RCA (n=9) arteries. ESS, MV, and WS were calculated for 2-mm segments using computational fluid dynamics. Curvature and torsion were calculated for each segment using morphometric algorithms. RESULTS: A total length of 187 cm of coronary arteries was studied. ESS was higher in the LAD compared to the LCx and RCA (13.76 Pa vs. 3.49 Pa vs. 3.76 Pa, p<0.001); MV was higher in the LCx compared to the LAD and RCA (0.00542 Pa·s vs. 0.00173 Pa·s vs. 0.00240 Pa·s, p<0.001); and WS had higher values in the RCA compared to the LAD and LCx (289.98 mmHg vs. 255.93 mmHg vs. 235.18 mmHg, p<0.001). Curvature was greater in the LCx compared to the LAD and RCA (0.1447 mm-1 vs. 0.1229 mm-1 vs. 0.1234 mm-1, p<0.05), while torsion was found not to differ among the coronary arteries. CONCLUSIONS: Hemorrheologic and geometric parameters differ between the left and right coronary arteries. These factors, either alone or in association with local flow patterns and geometry, may affect the topography of atherosclerosis in the coronary arterial tree.

Insights on atherosclerosis by non-invasive assessment of wall stress and arterial morphology along the length of human coronary plaques.

Wall stress (WS) is associated with high arterial pressure and affects the localization of atherosclerotic lesions. We sought to non-invasively investigate the distribution of WS along the length of human coronary arteries and investigate its potential effect on atherosclerosis in association with vascular stiffness, local arterial curvature and plaque volume. We reconstructed three-dimensionally 28 coronary arteries from 22 subjects who had undergone coronary computed tomography angiography. Coronary arteries were divided in 2 mm-long segments. WS, vascular stiffness, plaque volume and curvature were calculated in each segment using computational fluid dynamics and morphology measurements. Plaque segments exhibited lower WS compared to their adjacent normal segments. Within plaques, WS was lower in the mid plaque portion compared to the upstream portion. Plaque volume was higher in the mid plaque portion compared to upstream and downstream portions. Low WS was associated with high curvature and both low WS and high curvature were associated with increased plaque volume. The current study demonstrates that WS and plaque volume are not uniform in the longitudinal axis of human coronary plaque. Calculation of WS could serve as a surrogate for the localization of plaque development and the identification of plaques at a more advanced stage of progression.

Association of remodeling with endothelial shear stress, plaque elasticity, and volume in coronary arteries: a pilot coronary computed tomography angiography study.

We sought to noninvasively assess the relationship between arterial remodeling, endothelial shear stress (ESS), and wall stiffness in coronary arteries. We studied 28 coronary arteries from 22 patients undergoing coronary computed tomography angiography (CCTA). The ESS was calculated in 2-mm long segments using computational fluid dynamics. Local remodeling, plaque dimensions, and local wall stiffness were assessed in each segment. The ESS was lower in the regions of excessive expansive remodeling versus compensatory expansive versus inadequate expansive versus constrictive remodeling. Areas of decreased wall stiffness more frequently exhibited excessive expansive remodeling. Plaque volume was higher in segments showing excessive expansive and inadequate remodeling than segments with constrictive remodeling. In conclusion, CCTA enables the noninvasive assessment of coronary hemodynamics and arterial/plaque morphology. Excessive expansive remodeling is associated with high-risk plaque features, such as low ESS, decreased plaque stiffness, and increased plaque volume. This methodology may be useful in the risk assessment of individual coronary lesions.