Mohammed A. Mashali

Global longitudinal strain (GLS), assessed via speckle tracking echocardiography (STE), is increasingly recognized as a sensitive and early indicator of left ventricular (LV) dysfunction in pediatric patients with bicuspid aortic valve (BAV)

Congenital heart disease (CHD), the most common congenital anomaly, remains a significant lifelong burden despite advancements in medical and surgical interventions. Induced pluripotent stem cells (iPSCs) have emerged as a groundbreaking platform in CHD research, offering patient-specific models to investigate the genetic, epigenetic, and molecular mechanisms driving the disease. Utilizing technologies such as CRISPR/Cas9 gene editing, cardiac organoids, and high-throughput screening, iPSCs enable innovative strategies in disease modeling, precision drug discovery, and regenerative therapies. However, clinical translation faces challenges related to immaturity, differentiation variability, large-scale feasibility, and tumorigenicity. Addressing these barriers will require standardized protocols, bioengineering solutions, and interdisciplinary collaboration. This review examines the critical role of iPSCs in advancing CHD research and care, demonstrating their potential to revolutionize treatment through patient-specific, regenerative approaches. By addressing current limitations and advancing iPSC technology, the field is positioned to pave the way for precision-based CHD therapies for this lifelong condition.

Heart failure (HF) presents a significant clinical challenge, with current treatments mainly easing symptoms without stopping disease progression. The targeting of calcium (Ca²⁺) regulation is emerging as a key area for innovative HF treatments that could significantly alter disease outcomes and enhance cardiac function. In this review, we aim to explore the implications of altered Ca²⁺ sensitivity, a key determinant of cardiac muscle force, in HF, including its roles during systole and diastole and its association with different HF types—HF with preserved and reduced ejection fraction (HFpEF and HFrEF, respectively). We further highlight the role of the two rate constants k_on (Ca²⁺ binding to Troponin C) and k_off (its dissociation) to fully comprehend how changes in Ca²⁺ sensitivity impact heart function. Additionally, we examine how increased Ca²⁺ sensitivity, while boosting systolic function, also presents diastolic risks, potentially leading to arrhythmias and sudden cardiac death. This suggests that strategies aimed at moderating myofilament Ca²⁺ sensitivity could revolutionize anti-arrhythmic approaches, reshaping the HF treatment landscape. In conclusion, we emphasize the need for precision in therapeutic approaches targeting Ca²⁺ sensitivity and call for comprehensive research into the complex interactions between Ca²⁺ regulation, myofilament sensitivity, and their clinical manifestations in HF.

BACKGROUND: The left and right ventricles of the human heart differ in embryology, shape, thickness, and function. Ventricular dyssynchrony often occurs in cases of heart failure. Our objectives were to assess whether differences in contractile properties exist between the left and right ventricles and to evaluate signs of left/right ventricular mechanical synchrony in isolated healthy and diseased human myocardium. METHODS: Myocardial left and right ventricular trabeculae were dissected from nonfailing and end-stage failing human hearts. Baseline contractile force and contraction/relaxation kinetics of the left ventricle were compared to those of the right ventricle in the nonfailing group (n=41) and in the failing group (n=29). Correlation analysis was performed to assess the mechanical synchrony between left and right ventricular myocardium isolated from the same heart, in nonfailing (n=41) and failing hearts (n=29). RESULTS: The failing right ventricular myocardium showed significantly higher developed force (Fdev; P=0.001; d=0.98), prolonged time to peak (P<0.001; d=1.14), and higher rate of force development (P=0.002; d=0.89) and force decline (P=0.003; d=0.82) compared to corresponding left ventricular myocardium. In healthy myocardium, a strong positive relationship was present between the left and right ventricles in time to peak (r=0.58, P<0.001) and maximal kinetic rate of contraction (r=0.63, P<0.001). These coefficients were much weaker, often nearly absent, in failing myocardium. CONCLUSIONS: At the level of isolated cardiac trabeculae, contractile performance, specifically of contractile kinetics, is correlated in the nonfailing myocardium between the left and right ventricles‚ but this correlation is significantly weaker, or even absent, in end-stage heart failure, suggesting an interventricular mechanical dyssynchrony.

Background: Because body mass index (BMI) is generally used clinically to define obesity and to estimate body adiposity, BMI likely is positively correlated with epicardial adipose tissue (EAT) level. Based on echocardiography, previous outcomes on this matter have varied from almost absent to rather strong correlations between BMI and EAT. The purpose of our study was to unambiguously examine EAT content and determine if correlations exist between EAT content and BMI, cause of heart failure, or contractile force. Methods and Results: We qualitatively scored 150 human hearts ex vivo on EAT distribution. From each heart, multiple photographs of the heart were taken, and both atrial and ventricular adipose tissue levels were semiquantitatively scored. Main findings include a generally higher EAT content on nonfailing hearts compared with end‐stage failing hearts (atrial adipose tissue level 5.70±0.13 vs. 5.00±0.12, P P =0.0048). The results also suggest that EAT quantity is not strongly correlated with BMI in nonfailing (atrial adipose tissue level r =0.069, ventricular adipose tissue level r =0.14) or failing (atrial adipose tissue level r =−0.022, ventricular adipose tissue level r =0.051) hearts. Atrial EAT is closely correlated with ventricular EAT in both nonfailing ( r =0.92, P r =0.87, P <0.001) hearts. Conclusions: EAT volume appears to be inversely proportional to severity of or length of time with heart failure based on our findings. Based on a lack of correlation with BMI, it is incorrect to assume high EAT volume given high body fat percentage.

The relationship between hypothyroidism and the occurrence and progression of heart failure (HF) has had increased interest over the past years. The low T3 syndrome, a reduced T3 in the presence of normal thyroid stimulating hormone (TSH), and free T4 concentration, is a strong predictor of all-cause mortality in HF patients. Still, the impact of hypothyroidism on the contractile properties of failing human myocardium is unknown. Our study aimed to investigate that impact usingex-vivoassessment of force and kinetics of contraction/relaxation in left ventricular intact human myocardial muscle preparations. Trabeculae were dissected from non-failing (NF;n= 9), failing with no hypothyroidism (FNH;n= 9), and failing with hypothyroidism (FH;n= 9) hearts. Isolated muscle preparations were transferred into a custom-made setup where baseline conditions as well as the three main physiological modulators that regulate the contractile strength, length-dependent and frequency-dependent activation, as well as β-adrenergic stimulation, were assessed under near-physiological conditions. Hypothyroidism did not show any additional significant impact on the contractile properties different from the recognized alterations usually detected in such parameters in any end-stage failing heart without thyroid dysfunction. Clinical information for FH patients in our study revealed they were all receiving levothyroxine. Absence of any difference between failing hearts with or without hypothyroidism, may possibly be due to the profound effects of the advanced stage of heart failure that concealed any changes between the groups. Still, we cannot exclude the possibility of differences that may have been present at earlier stages. The effects of THs supplementation such as levothyroxine on contractile force and kinetic parameters of failing human myocardium require further investigation to explore its full potential in improving cardiovascular performance and cardiovascular outcomes of HF associated with hypothyroidism.