Left ventricular hypertrophy and arrhythmogenesis

Advancing Cardiovascular Risk Assessment with Artificial Intelligence: Opportunities and Implications in North Carolina

Cardiovascular disease mortality is increasing in North Carolina with persistent inequality by race, income, and location. Artificial intelligence (AI) can repurpose the widely available electrocardiogram (ECG) for enhanced assessment of cardiac dysfunction. By identifying accelerated cardiac aging from the ECG, AI offers novel insights into risk assessment and prevention.

Computed tomography myocardial perfusion imaging of patients with left ventricular hypertrophy in hypertension: A retrospective study

OBJECTIVE

Left ventricular hypertrophy (LVH) is a strong predictor of adverse cardiovascular outcomes including heart failure. This study evaluated characteristics and the influencing factors of computed tomography myocardial perfusion imaging (CT-MPI) of patients with LVH in hypertension.

METHODS

A total of 65 patients with stable chest pain and confirmed coronary stenosis <50% by coronary computed tomography angiography (cCTA) from September 2019 to February 2021 were recruited. According to the results of echocardiography, patients were divided into the LVH group (n = 33) and control group (patients without LVH, n = 32). The general data of all study subjects were collected, and the body mass index (BMI) and body surface area (BSA) were calculated. Myocardial blood flow (MBF), myocardial blood volume (MBV), and echocardiographic parameters were recorded. Spearman correlation analyses were conducted to analyze the relationship between MBF, MBV, and echocardiographic parameters.

RESULTS

The LVH group had significantly higher left ventricular end diastolic distance (LVEDd), septal wall thickness diastole (SWTd), and post wall thickness diastole (PWTd) than the control group, resulting in higher left ventricular mass index (LVMI) (P < .05). The LVH group showed significantly lower MBF than the control group (P < .05), but there was no significant difference in MBV between two groups (P > .05). Spearman correlation analysis demonstrated that MBF was negatively correlated with SWTd and LVMI (P < .05).

CONCLUSIONS

CT-MPI, as a new noninvasive modality to evaluate myocardial perfusion in hypertensive patients, revealed that MBF is reduced in patients with LVH, while MBV remains unchanged. In hypertensive patients, decreased MBF is significantly correlated with increased LVMI.

Serum exosomes derived from spontaneously hypertensive rats induce cardiac hypertrophy in vitro and in vivo by increasing autocrine release of angiotensin II in cardiomyocytes

Identifying the key factors mediating the progression from hypertension to cardiac hypertrophy is critically important for developing a strategy to protect against heart failure. Serum exosomes have been revealed to be involved in the development of cardiovascular disease. In the current study, we found that either serum or serum exosomes derived from SHR induced hypertrophy in H9c2 cardiomyocytes. SHR Exo injection through the tail vein for 8 weeks induced left ventricular wall thickening and decreased cardiac function in C57BL/6 mice. SHR Exo carried the renin-angiotensin system (RAS) proteins AGT, renin, and ACE into cardiomyocytes, which increased the autocrine secretion of Ang II. Moreover, the AT1-type receptor antagonist telmisartan prevented hypertrophy of H9c2 cells induced by SHR Exo.These results identified a novel role of exosomes derived from SHR serum in cardiac hypertrophy and revealed that SHR Exo induced cardiac hypertrophy by carrying AGT, renin, and ACE proteins into cardiomyocytes to increase their autocrine secretion of Ang II. The emergence of this new mechanism will help us better understand how hypertension progresses to cardiac hypertrophy.

QT interval instability and variability in dogs with naturally-occurring hypercortisolism

Hypercortisolism is one of the most common endocrine diseases in dogs. In humans, it is clearly associated with a higher risk of cardiovascular events, but studies in dogs are scarce. To investigate the arrhythmogenic risk of dogs with naturally-occurring hypercortisolism (NOHC), indices of variability and instability of the QT interval were retrospectively studied in 38 dogs with NOHC and prospectively studied in 12 healthy dogs: variance (QTv), total instability (TI), short-term (STI) and long-term (LTI), and mean (QTm). Except for QTm, all parameters studied were higher in the NOHC group than in the control group. In addition, STI and QTv showed moderate positive correlation with left ventricle wall thickness. The NOHC group was subdivided according to cortisol suppression pattern in the low-dose dexamethasone suppression test. All electrocardiographic indices of partial and absent suppression patterns were numerically higher than healthy dogs. QTv and TI were lower in the control group than in both NOHC subgroups. LTI and STI were lower in the CG than in the group with the partial suppression pattern. There was no statistical difference between sex groups in any of the electrocardiographic parameters studied. This result might indicate that the etiology of NOHC, and its consequent influence on hypothalamus-pituitary-adrenal axis could interfere on the heterogeneity of ventricular repolarization parameters in different ways, especially in the short-term and the long-term stability; however further studies are necessary to understand the role of cortisol on electrical instability in dogs.

Hypertension and cardiomyopathy associated with chronic kidney disease: epidemiology, pathogenesis and treatment considerations

Chronic kidney disease (CKD) is a complex condition with a prevalence of 10-15% worldwide. An inverse-graded relationship exists between cardiovascular events and mortality with kidney function which is independent of age, sex, and other risk factors. The proportion of deaths due to heart failure and sudden cardiac death increase with progression of chronic kidney disease with relatively fewer deaths from atheromatous, vasculo-occlusive processes. This phenomenon can largely be explained by the increased prevalence of CKD-associated cardiomyopathy with worsening kidney function. The key features of CKD-associated cardiomyopathy are increased left ventricular mass and left ventricular hypertrophy, diastolic and systolic left ventricular dysfunction, and profound cardiac fibrosis on histology. While these features have predominantly been described in patients with advanced kidney disease on dialysis treatment, patients with only mild to moderate renal impairment already exhibit structural and functional changes consistent with CKD-associated cardiomyopathy. In this review we discuss the key drivers of CKD-associated cardiomyopathy and the key role of hypertension in its pathogenesis. We also evaluate existing, as well as developing therapies in the treatment of CKD-associated cardiomyopathy.

Deep learning assessment of left ventricular hypertrophy based on electrocardiogram

Background

Current electrocardiogram (ECG) criteria of left ventricular hypertrophy (LVH) have low sensitivity. Deep learning (DL) techniques have been widely used to detect cardiac diseases due to its ability of automatic feature extraction of ECG. However, DL was rarely applied in LVH diagnosis. Our study aimed to construct a DL model for rapid and effective detection of LVH using 12-lead ECG.

Methods

We built a DL model based on convolutional neural network-long short-term memory (CNN-LSTM) to detect LVH using 12-lead ECG. The echocardiogram and ECG of 1,863 patients obtained within 1 week after hospital admission were analyzed. Patients were evenly allocated into 3 sets at 3:1:1 ratio: the training set (n = 1,120), the validation set (n = 371) and the test set 1 (n = 372). In addition, we recruited 453 hospitalized patients into the internal test set 2. Different DL model of each subgroup was developed according to gender and relative wall thickness (RWT).

Results

The LVH was predicted by the CNN-LSTM model with an area under the curve (AUC) of 0.62 (sensitivity 68%, specificity 57%) in the test set 1, which outperformed Cornell voltage criteria (AUC: 0.57, sensitivity 48%, specificity 72%) and Sokolow-Lyon voltage (AUC: 0.51, sensitivity 14%, specificity 96%). In the internal test set 2, the CNN-LSTM model had a stable performance in predicting LVH with an AUC of 0.59 (sensitivity 65%, specificity 57%). In the subgroup analysis, the CNN-LSTM model predicted LVH by 12-lead ECG with an AUC of 0.66 (sensitivity 72%, specificity 60%) for male patients, which performed better than that for female patients (AUC: 0.59, sensitivity 50%, specificity 71%).

Conclusion

Our study established a CNN-LSTM model to diagnose LVH by 12-lead ECG with higher sensitivity than current ECG diagnostic criteria. This CNN-LSTM model may be a simple and effective screening tool of LVH.

Electrocardiography is Useful to Predict Postoperative Ventricular Arrhythmia in Patients Undergoing Cardiac Surgery: A Retrospective Study

Background: Preoperative detection of high-/low-risk postoperative ventricular arrhythmia (POVA) patients using a noninvasive method is an important issue in the clinical setting. This study mainly aimed to determine the usefulness of several preoperative electrocardiographic (ECG) markers in the risk assessment of POVA with cardiac surgery.

Method: We enrolled 1024 consecutive patients undergoing cardiac surgery, and a total of 823 patients were included in the study. Logistic regression analysis determined preoperative ECG markers. A new risk predicting model were developed to predict occurrence of POVA, and the receiver operating characteristic curve (ROC) was used to validate this model.

Results: Of these, 337 patients experienced POVA, and 485 patients did not experience POVA in this retrospective study. Among 15 ECG markers, a univariate analysis found a strong association between POVA and preoperative VA, the R-wave in lead aVR, the QRS wave, index of cardiac electrophysiological balance (iCEB), QT interval corrected (QTc), Tpeak–Tend interval (Tpe) in lead V2, the J wave in the inferolateral leads, pathological Q wave, and SV1+RV5&gt;35 mm. Multivariate analysis showed that a preoperative J wave [adjusted odds ratio (AOR): 3.80; 95% CI: 1.88–7.66; p &lt; 0.001], Tpe &gt;112.5-ms (AOR: 2.80; 95% CI: 1.57–4.99; p &lt; 0.001), and SV1+RV5 &gt;35 mm (AOR: 2.92; 95% CI: 1.29–6.60; p = 0.01) were independently associated with POVA. A new risk predicting model were developed in predicting POVA.

Conclusion: The ECG biomarkers including J wave, Tpe &gt;112.5 ms, and SV1+RV5 &gt;35 mm were significantly predicted POVAs. A risk predicting model developed with electrocardiographic risk markers preoperatively predicted POVAs.

MCC950 ameliorates ventricular arrhythmia vulnerability induced by heart failure

MCC950, a specific NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inhibitor, has been reported to play a role in various cardiovascular diseases. However, its role in heart failure (HF)-induced ventricular arrhythmias (VAs) remains unclear. Hence, the present study aimed to clarify the role and underlying mechanisms of MCC950 in HF-induced VAs. Male C57BL/6 mice were induced with HF via transverse aortic constriction (TAC). Histological analysis, echocardiography, electrophysiological investigation, and western blot analysis were conducted to evaluate VA vulnerability induced by TAC and the potential mechanisms underlying the effects. MCC950 markedly improved cardiac function and decreased pulmonary edema induced by HF. Moreover, MCC950 also decreased VA vulnerability, as shown by the shortened QTc duration and action potential duration 90 (APD₉₀), reduced APD alternans threshold, and decreased VA induction rate. Furthermore, MCC950 treatment significantly reversed TAC-induced cardiac hypertrophy and fibrosis. In addition, MCC950 administration increased the protein levels of ion channels (Kv4.2, KChIP2, and Cav1.2). Mechanistically, the above changes induced by MCC950 were due to the inhibition of the NLRP3 inflammasome. As a specific NLRP3 inhibitor, MCC950 significantly decreased HF-induced VA vulnerability by reversing cardiac structural remodeling and electrical remodeling, and the mechanism through which MCC950 exhibited this effect was inhibition of NLRP3 inflammasome activation.

Enhancing Fatty Acids Oxidation via L-Carnitine Attenuates Obesity-Related Atrial Fibrillation and Structural Remodeling by Activating AMPK Signaling and Alleviating Cardiac Lipotoxicity

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in clinical setting. Its pathogenesis was associated with metabolic disorder, especially defective fatty acids oxidation (FAO). However, whether promoting FAO could prevent AF occurrence and development remains elusive. In this study, we established a mouse model of obesity-related AF through high-fat diet (HFD) feeding, and used l-carnitine (LCA, 150 mg/kg⋅BW/d), an endogenous cofactor of carnitine palmitoyl-transferase-1B (CPT1B; the rate-limiting enzyme of FAO) to investigate whether FAO promotion can attenuate the AF susceptibility in obesity. All mice underwent electrophysiological assessment for atrial vulnerability, and echocardiography, histology and molecular evaluation for AF substrates and underlying mechanisms, which were further validated by pharmacological experiments in vitro. HFD-induced obese mice increased AF vulnerability and exhibited apparent atrial structural remodeling, including left atrial dilation, cardiomyocyte hypertrophy, connexin-43 remodeling and fibrosis. Pathologically, HFD apparently leads to defective cardiac FAO and subsequent lipotoxicity, thereby evoking a set of pathological reactions including oxidative stress, DNA damage, inflammation, and insulin resistance. Enhancing FAO via LCA attenuated lipotoxicity and lipotoxicity-induced pathological changes in the atria of obese mice, resulting in restored structural remodeling and ameliorated AF susceptibility. Mechanistically, LCA activated AMPK/PGC1α signaling both in vivo and in vitro, and pharmacological inhibition of AMPK via Compound C attenuated LCA-induced cardio-protection in palmitate-treated primary atrial cardiomyocytes. Taken together, our results demonstrated that FAO promotion via LCA attenuated obesity-mediated AF and structural remodeling by activating AMPK signaling and alleviating atrial lipotoxicity. Thus, enhancing FAO may be a potential therapeutic target for AF.

Intersection Between Chronic Kidney Disease and Cardiovascular Disease

PURPOSE OF REVIEW

The incidence of chronic kidney disease is increasing worldwide, and the previously decreasing incidence of cardiovascular disease has now plateaued. Understanding the intersection of both heart and kidney disease is crucial.

RECENT FINDINGS

Chronic kidney disease and cardiovascular disease share common risk factors and specific pathogenic mechanisms and impact a significant segment of the population. Patients with chronic kidney disease are more likely to have cardiovascular disease than progress to end-stage kidney disease requiring renal replacement therapy. We discuss shared risk factors and mechanisms for cardiovascular and chronic kidney disease. The following also addresses contemporary cardiovascular treatment considerations in patients with chronic kidney disease with a focus on atherosclerotic cardiovascular disease and heart failure.

Modified Cornell electrocardiographic criteria in the assessment of left ventricular hypertrophy geometry of patients with essential hypertension

To evaluate the value of modified Cornell electrocardiographic criteria in the assessment of left ventricular hypertrophy (LVH) for patients with essential hypertension. A total of 381 patients with essential hypertension diagnosed in our hospital were selected. Using the left ventricle (LV) geometric patterns classified by the American Society of Echocardiography (ASE), we examined the distribution of the modified Cornell criteria of Ravl + S_D (the deepest S wave in 12‐lead ECG) in different geometric patterns and analyzed the correlation of modified Cornell criteria with changes in the LV geometric patterns using multiple linear regression analysis. The distribution of modified Cornell criteria, Sokolow‐Lyon criteria (RV5/V6 + SV1), and Cornell criteria (Ravl + SV3) in gender‐specific hypertensive geometric patterns were significantly different (P ≤ .01 for all). The voltage of Ravl + S_D in male patients showed an increase trend in the normal geometry (NG), concentric remodeling (CR), concentric hypertrophy (CH), and eccentric hypertrophy (EH) groups, and this increase trend was significantly in the unadjusted model and the adjusted model. The voltages of Ravl + SV3 and RV5/V6 + SV1 of male patients in CR, CH and RH groups showed a gradual increase trend, but the increase trend in CR group has no statistical significance compared to that in NG group (P ≥ .05). The voltages of Ravl + S_D, RV5/V6 + SV1, and Ravl + SV3 in female patients in CR, CH and EH groups showed a trend of increase after decrease in the adjusted model. In conclusion, the modified Cornell criteria could dynamically reflect left ventricular hypertensive geometry of male patients.

Patients with elevated blood pressure or stage 1 hypertension have structural heart disease

BACKGROUND

The 2017 American College of Cardiology (ACC) and the American Heart Association (AHA) recommendations lower the hypertension threshold to 130/80 mmHg and recommends treatment for high-risk patients. Our aim is to determine whether the new blood pressure categories are associated with left ventricular (LV) structural changes and whether echocardiograms can provide risk stratification and help treatment initiation.

METHODS

We conducted a cross-sectional study and performed screening echocardiograms to consecutive primary care patients. We calculated the Framingham score to identify patients with a low or intermediate score who had structural heart disease.We classified everyone as having normal, elevated blood pressure, stage 1 or stage 2 hypertension according to the 2017 ACC/AHA guidelines. We defined structural heart disease as having LV hypertrophy and an abnormal LV mass index.

RESULTS

We included 16 650 patients who underwent a screening echocardiogram and had recorded blood pressure. Out of the 16 650 patients, 1465 patients had a normal blood pressure, 1382 had elevated blood pressure, 1333 had stage 1 hypertension, and the remainder had stage 2 hypertension. The adjusted odds ratios of having structural heart disease for elevated blood pressure and stage 1 hypertension were 1.30; 95% CI, 1.112-1.64; P < 0.01 and 1.69; 95% CI, 1.25-2.30; P < 0.01, respectively. We identified 542 patients with stage 1 hypertension who had a low or intermediate Framingham score and 19% (95% CI, 16-23%) had structural heart disease.

CONCLUSION

A quarter of patients identified as having elevated blood pressure or stage 1 hypertension have structural heart disease. Screening echocardiograms may help to risk stratify those patients deemed ineligible for treatment.

Antihypertensive therapy and sudden cardiac death, should we expect the unexpected?

Hypertension (HTN) and sudden cardiac death (SCD) constitute major public health problems accounting for millions of deaths each year worldwide. Both HTN and HTN-induced left ventricular hypertrophy (LVH) have been shown to be independent risk factors for SCD. However, the association between antihypertensive pharmacotherapy and risk of SCD has been under-investigated. Given that antihypertensive pharmacotherapy effectively reduces overall cardiovascular mortality, it would be expected to protect patients from SCD. Nevertheless, available data demonstrate that antihypertensive medications (primarily thiazide diuretics), while effective in reducing the incidence of myocardial infarction, do not confer protection from SCD. The purpose of this review was to present the relationship between HTN, LVH, and SCD and to describe the potential association between antihypertensive pharmacotherapy and risk of SCD.

Missing Link between Molecular Aspects of Ventricular Arrhythmias and QRS Complex Morphology in Left Ventricular Hypertrophy

The aim of this opinion paper is to point out the knowledge gap between evidence on the molecular level and clinical diagnostic possibilities in left ventricular hypertrophy (LVH) regarding the prediction of ventricular arrhythmias and monitoring the effect of therapy. LVH is defined as an increase in left ventricular size and is associated with increased occurrence of ventricular arrhythmia. Hypertrophic rebuilding of myocardium comprises interrelated processes on molecular, subcellular, cellular, tissue, and organ levels affecting electrogenesis, creating a substrate for triggering and maintaining arrhythmias. The knowledge of these processes serves as a basis for developing targeted therapy to prevent and treat arrhythmias. In the clinical practice, the method for recording electrical phenomena of the heart is electrocardiography. The recognized clinical electrocardiogram (ECG) predictors of ventricular arrhythmias are related to alterations in electrical impulse propagation, such as QRS complex duration, QT interval, early repolarization, late potentials, and fragmented QRS, and they are not specific for LVH. However, the simulation studies have shown that the QRS complex patterns documented in patients with LVH are also conditioned remarkably by the alterations in impulse propagation. These QRS complex patterns in LVH could be potentially recognized for predicting ventricular arrhythmia and for monitoring the effect of therapy.

Anti-Inflammatory and Anticancer Properties of Bioactive Compounds from Sesamum indicum L.-A Review

The use of foodstuff as natural medicines has already been established through studies demonstrating the pharmacological activities that they exhibit. Knowing the nutritional and pharmacological significance of foods enables the understanding of their role against several diseases. Among the foods that can potentially be considered as medicine, is sesame or Sesamum indicum L., which is part of the Pedaliaceae family and is composed of its lignans such as sesamin, sesamol, sesaminol and sesamolin. Its lignans have been widely studied and are known to possess antiaging, anticancer, antidiabetes, anti-inflammatory and antioxidant properties. Modern chronic diseases, which can transform into clinical diseases, are potential targets of these lignans. The prime example of chronic diseases is rheumatic inflammatory diseases, which affect the support structures and the organs of the body and can also develop into malignancies. In line with this, studies emphasizing the anti-inflammatory and anticancer activities of sesame have been discussed in this review.

Conventional and new electrocardiographic criteria for hypertension-mediated cardiac organ damage: A narrative review

Hypertension-mediated organ damage (HMOD) is frequently observed in hypertensive patients at different cardiovascular (CV) risk profile. This may have both diagnostic and therapeutic implications for the choice of the most appropriate therapies. Among different markers of HMOD, the most frequent functional and structural adaptations can be observed at cardiac level, including left ventricular hypertrophy (LVH), diastolic dysfunction, aortic root dilatation, and left atrial enlargement. In particular, LVH was shown to be a strong and independent risk factor for major CV events, namely myocardial infarction, stroke, congestive heart failure, CV death. Thus, early identification of LVH is a key element for preventing CV events in hypertension. Although echocardiographic assessment of LVH represents the gold standard technique, this is not cost-effective and cannot be adopted in routine clinical practice of hypertension. On the other hand, electrocardiographic (ECG) assessment of HMOD relative to the heart is a simple, reproducible, widely available and cost-effective method to assess the presence of LVH, and could be preferred in large scale screening tests. Several new indicators have been proposed and tested in observational studies and clinical trials of hypertension, in order to improve the relatively low sensitivity of the conventional ECG criteria for LVH, despite high specificity. This article reviews the differences in the use of the main conventional and the new 12 lead ECG criteria of LVH for early assessment of asymptomatic, subclinical cardiac HMOD in a setting of clinical practice of hypertension.

Evaluation of cardiac hypertrophy in the setting of sudden cardiac death

Ventricular hypertrophy is a common pathological finding at autopsy that can act as a substrate for arrhythmogenesis. Pathologists grapple with the significance of ventricular hypertrophy when assessing the sudden and unexpected deaths of young people and what it could mean for surviving family members. The pathological spectrum of left ventricular hypertrophy (LVH) is reviewed herein. This article is oriented to the practicing autopsy pathologist to help make sense of various patterns of increased heart muscle, particularly those that are not clearly cardiomyopathic, yet present in the setting of sudden cardiac death. The article also reviews factors influencing arrhythmogenesis as well as genetic mutations most commonly associated with ventricular hypertrophy, especially those associated with hypertrophic cardiomyopathy (HCM).

Danqi soft capsule prevents infarct border zone remodelling and reduces susceptibility to ventricular arrhythmias in post-myocardial infarction rats

Danqi soft capsule (DQ) is a traditional Chinese medicine containing Salvia miltiorrhiza and Panax notoginseng; it is safe and efficient in treating ischaemic heart diseases. The purpose of the present study was to assess whether DQ could prevent infarct border zone (IBZ) remodelling and decrease ventricular arrhythmias occurrence in post‐myocardial infarction (MI) stage. MI was induced by a ligation of the left anterior descending coronary artery. DQ was administered to the post‐MI rats started from 1 week after MI surgery for 4 weeks. The results showed that DQ treatment significantly attenuated tachyarrhythmia induction rates and arrhythmia score in post‐MI rats. In echocardiography, DQ improved left ventricular (LV) systolic and diastolic function. Histological assessment revealed that DQ significantly reduced fibrotic areas and myocyte areas, and increased connexin (Cx) 43 positive areas in IBZ. Western blot revealed that DQ treatment significantly reduced the protein expression levels of type I and III collagens, α‐smooth muscle actin (α‐SMA), transforming growth factor‐β1 (TGF‐β1) and Smad3 phosphorylation, while increasing Cx43 amounts. Overall, these findings mainly indicated that DQ intervention regulates interstitial fibrosis, Cx43 expression and myocyte hypertrophy by TGF‐β1/Smad3 pathway in IBZ, inhibits LV remodelling and reduces vulnerability to tachyarrhythmias after MI. This study presents a proof of concept for novel antiarrhythmic strategies in preventing IBZ remodelling, modifying the healed arrhythmogenic substrate and thus reducing susceptibility to ventricular arrhythmias in the late post‐MI period.

Left ventricular hypertrophy as protective factor after bypass grafting

Left ventricular hypertrophy (LVH) is a well established cardiovascular risk factor, accounting for an increase in cardiovascular morbid-mortality, although how much the magnitude and the kind of LVH could affect cardiovascular outcomes is in large part unknown. We speculate that mild LVH in absence of left ventricular (LV) chamber dilation, could play a protective role towards functional capacity, clinical outcome, cardiovascular and total morbi-mortality in conditions in which LV systolic function is generally reduced. Accordingly to many epidemiological observations, the availability of extra-quote of systolic function could lead to a significative improvement in the final outcome of some kinds of heart patients, as those undergoing bypass-grafting, where the stress for heart and cardiovascular system is always high. We suppose that the functional reserve available for patients with LVH could make the difference with respect to other patients undergoing myocardial revascularization. Similarly, the availability of a contractile reserve warranted by LVH could ensure a little gain in the outcome for patients after other major cardiovascular events (such as myocardial infarction or other heart surgery as surgical valve replacement). However, our hypothesis only involves mild LVH without LV chamber dilation, that is the initial stage of "non-dilated concentric" LVH and "non-dilated eccentric" LVH according to the new four-tiered classification of LVH based on relative wall thickness and LV dilation. Support for our hypothesis derives from the well-known protective role of systolic function that is a major factor in almost all cardiovascular diseases, where LV ejection fraction (LVEF) has shown to significantly improve quality of life, as well as morbidity and mortality. The knowledge that mild LVH in absence of LV chamber dilation is not as harmful in such conditions as believed at present could make avoidable some drugs prescription in some stages of the disease. Furthermore, it may allow a better evaluation of the risk profile of patients with LVH undergoing some cardiovascular major events like bypass grafting, myocardial infarction or surgical heart valve replacement.

The Promise of Molecular Autopsy in Forensic Pathology Practice

Molecular autopsy is changing the practice of forensic pathology. Under some circumstances, one must contemplate the involvement of genetic factors to help explain why someone has died unexpectedly. Such considerations most commonly occur when a young person dies by natural means. However, there are deaths that occur by nonnatural means that the forensic pathologist will be asked to investigate, which could involve natural disease that has a significant genetic underpinning. Elucidation of genetic mutations may not only further an understanding of the pathophysiology at hand, but also speak to underlying susceptibilities in an individual who dies that may not have been recognized. In addition, one may occasionally identify pathological findings that are confused for trauma that may actually be better explained by an underlying disease process. Using molecular medicine as a tool to explore such possibilities can improve the quality of death investigations and provide a new lens to probe challenging and contentious forensic cases that have proved resistant to traditional methods.

Black-White Differences in Incident Fatal, Nonfatal, and Total Coronary Heart Disease

BACKGROUND

Blacks have higher coronary heart disease (CHD) mortality compared with whites. However, a previous study suggests that nonfatal CHD risk may be lower for black versus white men.

METHODS

We compared fatal and nonfatal CHD incidence and CHD case-fatality among blacks and whites in the Atherosclerosis Risk in Communities study (ARIC), the Cardiovascular Health Study (CHS), and the Reasons for Geographic and Racial Differences in Stroke study (REGARDS) by sex. Participants 45 to 64 years of age in ARIC (men=6479, women=8488) and REGARDS (men=5296, women=7822), and ≥65 years of age in CHS (men=1836, women=2790) and REGARDS (men=3381, women=4112), all without a history of CHD, were analyzed. Fatal and nonfatal CHD incidence was assessed from baseline (ARIC=1987-1989, CHS=1989-1990, REGARDS=2003-2007) through up to 11 years of follow-up.

RESULTS

Age-adjusted hazard ratios comparing black versus white men 45 to 64 years of age in ARIC and REGARDS were 2.09 (95% confidence interval, 1.42-3.06) and 2.11 (1.32-3.38), respectively, for fatal CHD, and 0.82 (0.64-1.05) and 0.94 (0.69-1.28), respectively, for nonfatal CHD. After adjustment for social determinants of health and cardiovascular risk factors, hazard ratios in ARIC and REGARDS were 1.19 (95% confidence interval, 0.74-1.92) and 1.09 (0.62-1.93), respectively, for fatal CHD, and 0.64 (0.47-0.86) and 0.67 (0.48-0.95), respectively, for nonfatal CHD. Similar patterns were present among men ≥65 years of age in CHS and REGARDS. Among women 45 to 64 years of age in ARIC and REGARDS, age-adjusted hazard ratios comparing blacks versus whites were 2.61 (95% confidence interval, 1.57-4.34) and 1.79 (1.06-3.03), respectively, for fatal CHD, and 1.47 (1.13-1.91) and 1.29 (0.91-1.83), respectively, for nonfatal CHD. After multivariable adjustment, hazard ratios in ARIC and REGARDS were 0.67 (95% confidence interval, 0.36-1.24) and 1.00 (0.54-1.85), respectively, for fatal CHD, and 0.70 (0.51-0.97) and 0.70 (0.46-1.06), respectively, for nonfatal CHD. Racial differences in CHD incidence were attenuated among older women. CHD case fatality was higher among black versus white men and women, and the difference remained similar after multivariable adjustment.

CONCLUSIONS

After accounting for social determinants of health and risk factors, black men and women have similar risk for fatal CHD compared with white men and women, respectively. However, the risk for nonfatal CHD is consistently lower for black versus white men and women.

Biology of the cardiac myocyte in heart disease

Cardiac hypertrophy is a major risk factor for heart failure, and it has been shown that this increase in size occurs at the level of the cardiac myocyte. Cardiac myocyte model systems have been developed to study this process. Here we focus on cell culture tools, including primary cells, immortalized cell lines, human stem cells, and their morphological and molecular responses to pathological stimuli. For each cell type, we discuss commonly used methods for inducing hypertrophy, markers of pathological hypertrophy, advantages for each model, and disadvantages to using a particular cell type over other in vitro model systems. Where applicable, we discuss how each system is used to model human disease and how these models may be applicable to current drug therapeutic strategies. Finally, we discuss the increasing use of biomaterials to mimic healthy and diseased hearts and how these matrices can contribute to in vitro model systems of cardiac cell biology.

Hypertension, left ventricular hypertrophy, and sudden cardiac death

Hypertension (HTN) is the most common cause of hypertensive heart disease, which comprises of left ventricular hypertrophy (LVH), left atrial enlargement, diastolic dysfunction, functional mitral regurgitation and neurohormonal changes. All of these lead to significant arrhythmias such as atrial fibrillation (AF) as well as ventricular arrhythmias, and are known risk factors for sudden cardiac death (SCD). The association between LVH and SCD is well established, especially in the presence of myocardial ischemia, fibrosis and scar tissue, and AF. Inflammation, fibrosis and oxidative stress, as well as ischemia play a significant role and are the leading pathways to remodeling, arrhythmias, and SCD. Aggressive HTN control may lead, at least in part, to regression of LVH and thus lower the risk of AF and SCD. Therefore, LVH is a powerful, independent predictor of AF, ventricular arrhythmias and SCD, and is significantly underrecognized. Further investigation of the relationship and management of diastolic dysfunction, LVH and genetic factors and their association with SCD is certainly warranted.

Development and validation of a risk calculator predicting exercise-induced ventricular arrhythmia in patients with cardiovascular disease

BACKGROUND

Mortality due to cardiovascular disease is often associated with ventricular arrhythmias. Nowadays, patients with cardiovascular disease are more encouraged to take part in physical training programs. Nevertheless, high-intensity exercise is associated to a higher risk for sudden death, even in apparently healthy people. During an exercise testing (ET), health care professionals provide patients, in a controlled scenario, an intense physiological stimulus that could precipitate cardiac arrhythmia in high risk individuals. There is still no clinical or statistical tool to predict this incidence. The aim of this study was to develop a statistical model to predict the incidence of exercise-induced potentially life-threatening ventricular arrhythmia (PLVA) during high intensity exercise.

METHODS AND RESULTS

6415 patients underwent a symptom-limited ET with a Balke ramp protocol. A multivariate logistic regression model where the primary outcome was PLVA was performed. Incidence of PLVA was 548 cases (8.5%). After a bivariate model, thirty one clinical or ergometric variables were statistically associated with PLVA and were included in the regression model. In the multivariate model, 13 of these variables were found to be statistically significant. A regression model (G) with a X(2) of 283.987 and a p<0.001, was constructed. Significant variables included: heart failure, antiarrhythmic drugs, myocardial lower-VD, age and use of digoxin, nitrates, among others.

CONCLUSION

This study allows clinicians to identify patients at risk of ventricular tachycardia or couplets during exercise, and to take preventive measures or appropriate supervision.