The Contractile Machines of the Heart.

This chapter will describe basic structural and functional features of the contractile apparatus of muscle cells of the heart, namely, cardiomyocytes and smooth muscle cells. Cardiomyocytes form the contractile myocardium of the heart, while smooth muscle cells form the contractile coronary vessels. Both muscle types have distinct properties and will be considered with respect to their cellular appearance (brick-like cross-striated versus spindle-like smooth), arrangement of contractile proteins (sarcomeric versus non-sarcomeric organization), calcium activation mechanisms (thin-filament versus thick-filament regulation), contractile features (fast and phasic versus slow and tonic), energy metabolism (high oxygen versus low oxygen demand), molecular motors (type II myosin isoenzymes with high adenosine diphosphate [ADP]-release rate versus myosin isoenzymes with low ADP-release rates), chemomechanical energy conversion (high adenosine triphosphate [ATP] consumption and short duty ratio versus low ATP consumption and high duty ratio of myosin II cross-bridges [XBs]), and excitation-contraction coupling (calcium-induced calcium release versus pharmacomechanical coupling). Part of the work has been published (Neuroscience - From Molecules to Behavior", Chap. 22, Galizia and Lledo eds 2013, Springer-Verlag; with kind permission from Springer Science + Business Media).

The influence of the cardiac cycle on the halo sign and its impact on the ultrasound diagnosis of giant cell arteritis.

OBJECTIVES: To investigate whether hypoechoic wall thickness is influenced by the systole or diastole moment in the cardiac cycle and if this can influence ultrasound (US) assessments of giant cell arteritis (GCA). METHODS: US videos of 100 consecutive patients (50 with GCA, 50 without) performed between January 2021 and June 2023 were reviewed. Intima-media thickness (IMT) of temporal (including common trunk, frontal and parietal branches), axillary and subclavian arteries were measured at two different time points, at systolic peak (SP) and at the end-diastole (ED). Differences between SP IMT and ED IMT, as well as in the halo count (HC) and in the OMERACT GCA Ultrasonography Score (OGUS) between these two times, were analyzed. RESULTS: IMT was significantly higher (4.8-5%) at ED in all arteries, in both GCA and non-GCA groups. HC and OGUS were also higher in ED in both groups. In 4 non-GCA patients (8%), the HC was positive in ED and negative in SP; in all of them the HC in ED was 1. In the GCA group, the timing of the cardiac cycle did not influence the final US diagnosis; however, it did modify the HC in 14 patients (28%). CONCLUSION: IMT can fluctuate during the cardiac cycle, with higher measurements occurring at ED. This variability could potentially impact the accuracy of US diagnoses and assessments of GCA. If further research corroborates these findings, it may be imperative to revise the guidelines for employing US in diagnosing GCA in order to incorporate these nuanced aspects.

The mediating role of the left ventricular mass index on the relationship between the fluid balance and left ventricular diastolic function in patients with chronic kidney disease.

BACKGROUND: The pathophysiological mechanism of cardiovascular disease in patients with chronic kidney disease (CKD) is complicated. Mediation analysis is an important statistical tool for gaining insight into the complex mechanisms of exposure-outcome effects. We investigated the potential mediating role of the left ventricular mass index (LVMI) on the association between fluid balance (overhydration/extracellular water, OH/ECW) and left ventricular diastolic function (E/e´ ratio) in patients with CKD not yet on dialysis. METHODS: Bioimpedance spectroscopy, echocardiography, and laboratory evaluations were performed on 425 consecutive patients on the same day. The patients were classified into two groups according to the estimated glomerular filtration rate corresponding to CKD stages 3 and 5. Mediation analysis was performed using the PROCESS macro and bootstrapping methods. RESULTS: OH/ECW and LVMI were positively correlated with the E/e´ ratio in both the CKD stages 3 and five groups. In CKD stage 5, there was a statistically significant association between OH/ECW and LVMI, whereas no correlation was observed in CKD stage 3. In the mediation analysis, LVMI positively mediated the relationship between OH/ECW and E/e´ ratio when controlling for confounders in patients with CKD stage 5 (B = 2.602; Boot 95% confidence interval, 1.313-4.076). CONCLUSION: In our analysis, the indirect effect of mediators was significant in patients with advanced CKD. Therefore, our study suggests that further research on several other risk factors may be needed to determine the underlying mechanisms of association between the associated factors in all CKD stages.

Rate of deterioration of umbilical artery Doppler indices in fetuses with severe early-onset fetal growth restriction.

BACKGROUND: Incorporation of umbilical artery Doppler in the surveillance of fetal growth restriction has been shown to reduce the risk of perinatal deaths. Systole/Diastole ratio, Pulsatility Index and Resistance Index are obtained upon Doppler interrogation of the umbilical artery however it is unknown which index predicts more advanced stages of placental deterioration. OBJECTIVE: This study aimed to examine risk factors for the development of absent or reversed end-diastolic velocity and the time intervals of deterioration from normal umbilical artery end-diastolic velocity (indicated by systole/diastole ratio, pulsatility index, or resistance index) to decreased and absent or reversed end-diastolic velocity in fetuses with early-onset severe fetal growth restriction. STUDY DESIGN: This was a retrospective cohort study performed from 2005 to 2020. All singleton pregnancies with severe (estimated fetal weight or abdominal circumference below the third percentile) and early-onset (diagnosed between 20 0/7 and 31 6/7 weeks of gestation) fetal growth restriction were included. Patients with fetal genetic or structural anomalies, suspected congenital infections, absent or reversed end-diastolic velocity at diagnosis, poor pregnancy dating, and absence of follow-up ultrasounds were excluded. Estimated fetal weight, abdominal circumference, and Doppler indices were reviewed longitudinally from diagnosis to delivery. To examine risk factors for absent or reversed end-diastolic velocity, we performed backward stepwise logistic regression and calculated odds ratios with 95% confidence intervals. Kaplan-Meier curves were compared using log-rank tests. RESULTS: A total of 985 patients met the inclusion criteria, and 79 (8%) progressed to absent or reversed end-diastolic velocity. Factors associated with development of absent or reversed end-diastolic velocity included gestational age at diagnosis (adjusted odds ratio, 4.88 [95% confidence interval, 2.55-9.37] at 20 0/7 to 23 6/7 weeks; adjusted odds ratio, 1.56 [95% confidence interval, 0.86-2.82] at 24 0/7 to 27 6/7 weeks compared with 28 0/7 to 31 6/7 weeks) and presence of chronic hypertension (adjusted odds ratio, 2.37 [95% confidence interval, 1.33-4.23]). Rates of progression from diagnosis of fetal growth restriction with normal umbilical artery Doppler to absent or reversed end-diastolic velocity were significant after 4 weeks from diagnosis (5.84% [95% confidence interval, 4.50-7.57]). Regarding the Doppler indices, the progression from normal values to abnormal indices was similar at 1 and 2 weeks. However, the rate of progression from normal to abnormal systole/diastole ratio compared with the rates of progression from normal to abnormal pulsatility index or resistance index was higher at 4 and 6 weeks. Deterioration from abnormal indices to absent or reversed end-diastolic velocity was shorter with abnormal resistance index and pulsatility index when compared with the systole/diastole ratio at 2, 4, and 6 weeks after diagnosis and at 6 weeks, respectively. CONCLUSION: Earlier gestational age at diagnosis and chronic hypertension are considered as risk factors for Doppler deterioration and development of absent or reversed end-diastolic velocity in the umbilical artery. With normal Doppler indices, significant deterioration and progression to absent or reversed end-diastolic velocity is unlikely until 4 weeks after diagnosis. Abnormal systole/diastole ratio seems to appear first. However, abnormal pulsatility index or resistance index was associated with absent or reversed end-diastolic velocity.

Increased Blood Pressure Variability Over a 16-Year Period Is Associated With Left Ventricular Diastolic Dysfunction in a Population-Based Cohort.

BACKGROUND: Left ventricular diastolic dysfunction (LVDD) is often associated with elevated blood pressure (BP). It is prevalent among hypertensive patients. Additionally, increased BP variability has been linked to LVDD. However, the precise connection between LVDD and BP variability within the general population remains unclear. Thus, this study aimed to evaluate this association in a general population. METHODS: A total of 2,578 participants(1,311 females) with a mean age of 47.8 ±â€…6.7 years who had echocardiographic data from the Korean Genome and Epidemiology study with 16 years of follow-up were analyzed. LVDD was identified through the last echocardiography during the follow-up period. BP variability was assessed using mean, standard deviation (SD), and coefficient of variance (CV). RESULTS: LVDD was detected in 249 individuals. The cohort was divided into an LVDD group and a normal LV diastolic function group. The LVDD group had a higher percentage of females, more advanced age, higher body mass index (BMI), higher BP and BUN levels, lower heart rate, lower hemoglobin, and lower serum creatinine than the normal LV diastolic function group. Remarkably, LVDD was associated with higher BP variability. In the multivariate analysis, LVDD was associated with increased age, female sex, increased BMI, hypertension, and increased BUN. Elevated mean systolic and diastolic BPs, SD of systolic BP, mean pulse pressure (PP), SD of PP, and CV of PP were significantly linked to LVDD even after adjusting for other significant variables in the multivariate analysis. CONCLUSIONS: LVDD was identified in 249 (9.7%) participants. Increased long-term BP variability was significantly associated with LVDD in this population-based cohort.

Effects of the cardiac cycle on auditory processing: A preregistered study on mismatch negativity.

The systolic and diastolic phases of the cardiac cycle are known to affect perception and cognition differently. Higher order processing tends to be facilitated at systole, whereas sensory processing of external stimuli tends to be impaired at systole compared to diastole. The current study aims to examine whether the cardiac cycle affects auditory deviance detection, as reflected in the mismatch negativity (MMN) of the event-related brain potential (ERP). We recorded the intensity deviance response to deviant tones (70 dB) presented among standard tones (60 or 80 dB, depending on blocks) and calculated the MMN by subtracting standard ERP waveforms from deviant ERP waveforms. We also assessed intensity-dependent N1 and P2 amplitude changes by subtracting ERPs elicited by soft standard tones (60 dB) from ERPs elicited by loud standard tones (80 dB). These subtraction methods were used to eliminate phase-locked cardiac-related electric artifacts that overlap auditory ERPs. The endogenous MMN was expected to be larger at systole, reflecting the facilitation of memory-based auditory deviance detection, whereas the exogenous N1 and P2 would be smaller at systole, reflecting impaired exteroceptive sensory processing. However, after the elimination of cardiac-related artifacts, there were no significant differences between systole and diastole in any ERP components. The intensity-dependent N1 and P2 amplitude changes were not obvious in either cardiac phase, probably because of the short interstimulus intervals. The lack of a cardiac phase effect on MMN amplitude suggests that preattentive auditory processing may not be affected by bodily signals from the heart.

Echocardiographic characterization of cardiac chambers and vasculatures in buffaloes (Bubalus bubalis) during diastolic and systolic phases.

Background: Ultrasonography had diagnostic importance in the evaluation of different diseases in buffaloes, including cardiovascular diseases. Aim: The current work describes the normal echocardiographic findings in healthy buffaloes, along with establishing reference values for echocardiographic dimensions for both sides of the heart, i.e., left and right ones. Methods: About 30 healthy adult buffaloes that belonged to private farms in Assiut, Egypt, were included in this study. Each animal underwent a complete clinical evaluation as well as hematological analyses, lipid profile indices, liver functions, cardio-thoracic radiography, and echocardiography to confirm no diseased conditions were detected. The study was conducted on healthy buffaloes (n = 30) in Assiut Governorate, Egypt. Results: The obtained results reported healthy buffaloes with normal clinical findings as well as indices of blood pictures and serum biochemicals that were within the reference intervals. Radiography revealed a free reticulum and a well-defined diaphragm. The heart was seen as a typical radio-opaque organ. Ultrasonographically, using grayscale B-mode and M-mode, the heart was commonly imaged from the left fourth intercostal space. Different echocardiographic views were described, including the four chamber view, i.e., right atrium (RA), right ventricle (RV), tricuspid valve (TCV), left atrium, left ventricle, mitral valve, and interventricular septum (IVS), and the right ventricular outflow tract, i.e., RA, TCV, RV, pulmonary artery (PA), and pulmonary valve. Cross sections in each of the apex and base of the heart were described. Echocardiographic dimensions during cardiac diastole and systole, including diameters and wall thickness of each of the atria and ventricles, were demonstrated. Interventricular septal thickness wall thickness as well as diameters of the aorta and PA, were stated. Conclusion: The work tried to put reference values on the normal echocardiographic dimensions using 2-D B-mode gray scale ultrasonography in healthy adult buffaloes. These echocardiographic reference dimensions with normal echocardiographic imaging will be very helpful in enhancing the diagnostic efficacy of ultrasounds for recognizing abnormal findings related to cardiac disorders.

Cardiac Magnetic Resonance Left Ventricular Filling Pressure Is Associated with NT-proBNP in Patients with New Onset Heart Failure.

Background and Objectives: Cardiovascular magnetic resonance (CMR) is emerging as an important imaging tool for sub-phenotyping and estimating left ventricular (LV) filling pressure (LVFP). The N-terminal prohormone of B-type natriuretic peptide (NT-proBNP) is released from cardiac myocytes in response to mechanical load and wall stress. This study sought to investigate if CMR-derived LVFP is associated with the serum levels of NT-proBNP and, in addition, if it provides any incremental prognostic value in heart failure (HF). Materials and Methods: This study recruited 380 patients diagnosed with HF who underwent same-day CMR and clinical assessment between February 2018 and January 2020. CMR-derived LVFP was calculated, as previously, from long- and short-axis cines. During CMR assessment, serum NT-proBNP was measured. The pathological cut-offs were defined as follows: NT-proBNP ≥ 125 pg/mL and CMR LVFP > 15 mmHg. The incidence of HF hospitalisation was treated as a clinical outcome. Results: In total, 305 patients had NT-proBNP ≥ 125 pg/mL. Patients with raised NT-proBNP were older (54 ± 14 vs. 64 ± 11 years, p < 0.0001). Patients with raised NT-proBNP had higher LV volumes and mass. In addition, CMR LVFP was higher in patients with raised NT-proBNP (13.2 ± 2.6 vs. 15.4 ± 3.2 mmHg, p < 0.0001). The serum levels of NT-proBNP were associated with CMR-derived LVFP (R = 0.42, p < 0.0001). In logistic regression analysis, this association between NT-proBNP and CMR LVFP was independent of all other CMR variables, including LV ejection fraction, LV mass, and left atrial volume (coefficient = 2.02, p = 0.002). CMR LVFP demonstrated an independent association with the incidence of HF hospitalisation above NT-proBNP (hazard ratio 2.7, 95% confidence interval 1.2 to 6, p = 0.01). Conclusions: A CMR-modelled LVFP is independently associated with serum NT-proBNP levels. Importantly, it provides an incremental prognostic value over and above serum NT-proBNP levels.

Cardiac function and posttraumatic stress disorder: a review of the literature and case report. / Fonction cardiaque et trouble de stress post-traumatique : revue de la littérature et étude de cas.

INTRODUCTION: Posttraumatic stress disorder (PTSD) can induce an elevation in sympathetic tone; however, research pertaining to the cardiac cycle in patients with PTSD is limited. METHODS: A literature review was conducted with PubMed, MEDLINE and Web of Science. Articles discussing changes and associations in echocardiography and PTSD or related symptoms were synthesized for the current review. We have also included data from a case report of a male participant aged 33 years experiencing potentially psychologically traumatic events, who wore a noninvasive cardiac sensor to assess the timing intervals and contractility parameters of the cardiac cycle using seismocardiography. The intervals included systolic time, isovolumic contraction time (IVCT) and isovolumic relaxation time (IVRT). Calculations of systolic (IVCT/systole), diastolic (IVRT/systole) and myocardial [(IVCT+IVRT)/systole] performance indices were completed. RESULTS: The review identified 55 articles, 14 of which assessed cardiac function using echocardiography in patients with PTSD symptoms. Cardiac dysfunction varied across studies, with diastolic and systolic impairments found in patients with PTSD. Our case study showed that occupational stress elevated cardiac performance indices, suggesting increased ventricular stress and supporting results in the existing literature. CONCLUSIONS: The literature review results suggest that a controlled approach to assessing cardiac function in patients with PTSD is required. The case study results further suggest that acute bouts of stress can alter cardiac function, with potential for sustained occupational stress to induce changes in cardiac function. Cardiac monitoring can be used prospectively to identify changes induced by potentially psychologically traumatic event exposures that can lead to the development of PTSD symptoms.

Cerebral arterial flow dynamics during systole and diastole phases in young and older healthy adults.

BACKGROUND: Since arterial flow is the leading actor in neuro-fluids flow dynamics, it might be interesting to assess whether it is meaningful to study the arterial flow waveform in more detail and whether this provides new important information. Few studies have focused on determining the influence of heart rate variation over time on the arterial flow curve. Therefore, this study aimed to evaluate cerebral arterial flow waveforms at extracranial and intracranial compartments in young and elderly healthy adults, also considering systole and diastole phases. METHODS: Cine phase-contrast magnetic resonance imaging (CINE-PC MRI) was performed on twenty-eight healthy young volunteers (HYV) and twenty healthy elderly volunteers (HEV) to measure arterial blood flows at the extracranial and intracranial planes. A semi-automated protocol using MATLAB scripts was implemented to identify the main representative points in the arterial flow waveforms. Representative arterial profiles were estimated for each group. Moreover, the effects of age and sex on flow times, amplitude-related parameters, and parameters related to systole and diastole phases were evaluated at the extracranial and intracranial compartments. Student's t-test or Wilcoxon's test (depending on the normality of the distribution) was used to detect significant differences. RESULTS: In HYVs, significant differences were observed between extracranial and intracranial levels in parameters related to the AP1 amplitude. Besides the detected differences in pulsatility index (extracranial: 0.92 ± 0.20 vs. 1.28 ± 0.33; intracranial: 0.79 ± 0.15 vs. 1.14 ± 0.18, p < .001) and average flow (715 ± 136 vs. 607 ± 125 ml/min, p = .008) between HYV and HEV, differences in the amplitude value of the arterial flow profile feature points were also noted. Contrary to systole duration (HYV: 360 ± 29 ms; HEV: 364 ± 47 ms), diastole duration presented higher inter-individual variability in both populations (HYV: 472 ± 145 ms; HEV: 456 ± 106 ms). Our results also showed that, with age, it is mainly the diastolic phase that changes. Although no significant differences in duration were observed between the two populations, the mean flow value in the diastolic phase was significantly lower in HEV (extracranial: 628 ± 128 vs. 457 ± 111 ml/min; intracranial: 599 ± 121 vs. 473 ± 100 ml/min, p < .001). No significant differences were observed in the arterial flow parameters evaluated between females and males in either HYV or HEV. CONCLUSION: Our study provides a novel contribution on the influence of the cardiac cycle phases on cerebral arterial flow. The main contribution in this study concerns the identification of age-related alterations in cerebral blood flow, which occur mainly during the diastolic phase. Specifically, we observed that mean flow significantly decreases with age during diastole, whereas mean flow during systole is consistent.

Isolated cardiac muscle contracting against a real-time model of systemic and pulmonary cardiovascular loads.

Isolated cardiac tissues allow a direct assessment of cardiac muscle function and enable precise control of experimental loading conditions. However, current experimental methods do not expose isolated tissues to the same contraction pattern and cardiovascular loads naturally experienced by the heart. In this study, we implement a computational model of systemic-pulmonary impedance that is solved in real time and imposed on contracting isolated rat muscle tissues. This systemic-pulmonary model represents the cardiovascular system as a lumped-parameter, closed-loop circuit. The tissues performed force-length work-loop contractions where the model output informed both the shortening and restretch phases of each work-loop. We compared the muscle mechanics and energetics associated with work-loops driven by the systemic-pulmonary model with that of a model-based loading method that only accounts for shortening. We obtained results that show simultaneous changes of afterload and preload or end-diastolic length of the muscle, as compared with the static, user-defined preload as in the conventional loading method. This feature allows assessment of muscle work output, heat output, and efficiency of contraction as functions of end-diastolic length. The results reveal the behavior of cardiac muscle as a pump source to achieve load-dependent work and efficiency outputs over a wider range of loads. This study offers potential applications of the model to investigate cardiac muscle response to hemodynamic coupling between systemic and pulmonary circulations in an in vitro setting.NEW & NOTEWORTHY We present the use of a "closed-loop" model of systemic and pulmonary circulations to apply, for the first time, real-time model-calculated preload and afterload to isolated cardiac muscle preparations. This method extends current experimental protocols where only afterload has been considered. The extension to include preload provides the opportunity to investigate ventricular muscle response to hemodynamic coupling and as a pump source across a wider range of cardiovascular loads.

Left atrial strain as a predictor of left ventricular filling pressures in coronary artery disease with preserved ejection fraction: a comprehensive study with left ventricular end-diastolic and pre-atrial contraction pressures.

Assessing left ventricular (LV) filling pressure (LVFP) is challenging in patients with coronary artery disease (CAD) and preserved LV ejection fraction (LVEF). We aimed to correlate left atrial strain (LAS) with two invasive complementary parameters of LVFP and compared its accuracy to other echocardiographic data to predict high LVFP. This cross-sectional, single-center study enrolled 81 outpatients with LVEF > 50% and significant CAD from a database. Near-simultaneous echocardiography and invasive measurements of both LV end-diastolic pressure (LVEDP) and LV pre-atrial contraction (pre-A) pressure were performed in each patient, based on the definition of LVEDP > 16 mmHg and LV pre-A > 12 mmHg as high LVFP. A moderate to strong correlation was observed between LAS reservoir (LASr), contractile strain, and LVEDP (r: 0.67 and 0.62, respectively; p < 0.001); the same was true for LV pre-A (r: 0.65 and 0.63, respectively; p < 0.001). LASr displayed good diagnostic performance to identify elevated LVFP, which was higher when compared to traditional parameters. Median value of LASr was higher for an isolated increase of LVEDP than for simultaneously high LV pre-A. The cutoff found to predict high LVFP was lower for LV pre-A than that one for LVEDP. In the current study, LASr did not provide an additional contribution to the 2016 diastolic function algorithm. LAS is a valuable tool for predicting LVFP in patients with CAD and preserved LVEF. The choice of LVEDP or LV pre-A as the representative marker of LVFP leads to different cutoffs to predict high pressures. The best strategy for adding this tool to a multiparametric algorithm requires further investigation.

A Pilot Study Evaluating LV Diastolic Function with M-Mode Measurement of Mitral Valve Movement in the Parasternal Long Axis View.

This pilot study aimed to develop a new, reliable, and easy-to-use method for the evaluation of diastolic function through the M-mode measurement of mitral valve (MV) movement in the parasternal long axis (PSLA), similar to E-point septal separation (EPSS) used for systolic function estimation. Thirty healthy volunteers from a tertiary emergency department (ED) underwent M-mode measurements of the MV anterior leaflet in the PSLA view. EPSS, A-point septal separation (APSS), A-point opening length (APOL), and E-point opening length (EPOL) were measured in the PSLA view, along with the E and A velocities and e' velocity in the apical four-chamber view. Correlation analyses were performed to assess the relationship between M-mode and Doppler measurements, and the measurement time was evaluated. No significant correlations were found between M-mode and Doppler measurements in the study. However, M-mode measurements exhibited high reproducibility and faster acquisition, and the EPOL value consistently exceeded the APOL value, resembling the E and A pattern. These findings suggest that visually assessing the M-mode pattern on the MV anterior leaflet in the PSLA view may be a practical approach to estimating diastolic function in the ED. Further investigations with a larger and more diverse patient population are needed to validate these findings.

Cardiac imaging for the prediction of sudden cardiac arrest in patients with heart failure.

The identification of heart failure (HF) patients at risk for arrhythmic sudden cardiac arrest (SCA) is a major challenge in the cardiovascular field. In addition to optimal medical treatment for HF, implantable cardioverter defibrillator (ICD) is currently recommended to prevent SCA in patients with reduced left ventricular ejection fraction (LVEF). The indication for an ICD implantation, in addition to HF etiology, New York Health Association (NYHA) class and life expectancy, mainly depends on LVEF value at echocardiography. However, the actual role of LVEF in the prediction of SCA has recently been debated, while newer multimodality imaging techniques with increased prognostic accuracy have been developed. Speckle tracking imaging allows the quantification of mechanical dispersion, a marker of electrophysiological heterogeneity predisposing to malignant arrhythmias, while advanced cardiac magnetic resonance techniques such as myocardial T1-mapping and extracellular volume fraction assessment allow the evaluation of interstitial diffuse fibrosis. Nuclear imaging is helpful for the appraisal of sympathetic nervous system dysfunction, while newer computed tomography techniques assessing myocardial delayed enhancement allow the identification of focal myocardial scar. This review will focus on the most modern advances in the field of cardiovascular imaging along with its applications for the prediction of SCA in patients with HF. Modern artificial intelligence applications in cardiovascular imaging will also be discussed.

Morphological Changes of Anomalous Coronary Arteries From the Aorta During the Cardiac Cycle Assessed by IVUS in Resting Conditions.

BACKGROUND: Anomalous aortic origin of coronary artery (AAOCA) with intramural segment is associated with risk of sudden cardiac death, probably related to a compressive mechanism exerted by the aorta. However, the intramural compression occurrence and magnitude during the cardiac cycle remain unknown. We hypothesized that (1) in end diastole, the intramural segment is narrower, more elliptic, and has greater resistance than extramural segment; (2) the intramural segment experiences a further compression in systole; and (3) morphometry and its systolic changes vary within different lumen cross-sections of the intramural segment. METHODS: Phasic changes of lumen cross-sectional coronary area, roundness (minimum/maximum lumen diameter), and hemodynamic resistance (Poiseuille law for noncircular sections) were derived from intravascular ultrasound pullbacks at rest for the ostial, distal intramural, and extramural segments. Data were obtained for 35 AAOCA (n=23 with intramural tract) after retrospective image-based gating and manual lumen segmentation. Differences between systolic and end-diastolic phases in each section, between sections of the same coronary, and between AAOCA with and without intramural tract were assessed by nonparametric statistical tests. RESULTS: In end diastole, both the ostial and distal intramural sections were more elliptical (P<0.001) than the reference extramural section and the correspondent sections in AAOCA without intramural segment. In systole, AAOCA with intramural segment showed a flattening at the ostium (-6.76% [10.82%]; P=0.024) and a flattening (-5.36% [16.56%]; P=0.011), a narrowing (-4.62% [11.38%]; P=0.020), and a resistance increase (15.61% [30.07%]; P=0.012) at the distal intramural section. No-intramural sections did not show morphological changes during the entire cardiac cycle. CONCLUSIONS: AAOCA with intramural segment has pathological segment-specific dynamic compression mainly in the systole under resting conditions. Studying AAOCA behavior with intravascular ultrasound during the cardiac cycle may help to evaluate and quantify the severity of the narrowing.

Usefulness of electrocardiography QT interval for prediction of left ventricular diastolic dysfunction: a cross-sectional study.

Heart failure (HF) is a leading cause of morbidity and mortality worldwide, with projections showing a further rise in incidence, impacting a decline in quality of life and the costs incurred in its diagnosis and treatment. The authors aim to establish the correlation between the prediction of left ventricular diastolic dysfunction based on a change in QT wave intervals. Methods: A cross-sectional at Holy-family Hospital, Rawalpindi Medical University, Pakistan. One thousand five hundred patients were referred for electrocardiography (ECG) for clinical suspicion of HF between May and July 2022. Ejection fraction (EF), lateral mitral annulus velocity (e'), mitral inflow early (E) and late (A) velocities, left ventricular filling pressure (E/e' ratio), and QT interval (QTc) was calculated. Odds ratios with a 95% CI (odds) were obtained by comparing QTc with all variables. Results: The patients were mostly middle-aged adults with a mean age of 30.27 (±7.64). Male to female ratio was nearly balanced, with 771 (51.4%) males included in the clinical survey. The ECG parameters were; QT interval-494.07 (±63.61), EF-57.11 (±11.96), early to atrial filling velocity ratio-0.71 (±0.20), and lateral mitral annulus velocity-8.29 (±1.64). Conclusion: The promising results for correlation between QT interval and ECG parameters, particularly EF and lateral mitral annulus velocity, should not be considered as the alternative in diagnosing left ventricular diastolic dysfunction thus far. Prolonged electrocardiographic QTc interval in patients with HF is useful in predicting diastolic dysfunction.