Impact of left ventricular hypertrophy on ventricular arrhythmias in the absence of coronary artery disease

Stromal Cell-SLIT3/Cardiomyocyte-ROBO1 Axis Regulates Pressure Overload-Induced Cardiac Hypertrophy

BACKGROUND

Recently shown to regulate cardiac development, the secreted axon guidance molecule SLIT3 maintains its expression in the postnatal heart. Despite its known expression in the cardiovascular system after birth, SLIT3's relevance to cardiovascular function in the postnatal state remains unknown. As such, the objectives of this study were to determine the postnatal myocardial sources of SLIT3 and to evaluate its functional role in regulating the cardiac response to pressure overload stress.

METHODS

We performed in vitro studies on cardiomyocytes and myocardial tissue samples from patients and performed in vivo investigation with SLIT3 and ROBO1 (roundabout homolog 1) mutant mice undergoing transverse aortic constriction to establish the role of SLIT3-ROBO1 in adverse cardiac remodeling.

RESULTS

We first found that SLIT3 transcription was increased in myocardial tissue obtained from patients with congenital heart defects that caused ventricular pressure overload. Immunostaining of hearts from WT (wild-type) and reporter mice revealed that SLIT3 is secreted by cardiac stromal cells, namely fibroblasts and vascular mural cells, within the heart. Conditioned media from cardiac fibroblasts and vascular mural cells both stimulated cardiomyocyte hypertrophy in vitro, an effect that was partially inhibited by an anti-SLIT3 antibody. Also, the N-terminal, but not the C-terminal, fragment of SLIT3 and the forced overexpression of SLIT3 stimulated cardiomyocyte hypertrophy and the transcription of hypertrophy-related genes. We next determined that ROBO1 was the most highly expressed roundabout receptor in cardiomyocytes and that ROBO1 mediated SLIT3's hypertrophic effects in vitro. In vivo, Tcf21+ fibroblast and Tbx18+ vascular mural cell-specific knockout of SLIT3 in mice resulted in decreased left ventricular hypertrophy and cardiac fibrosis after transverse aortic constriction. Furthermore, α-MHC+ cardiomyocyte-specific deletion of ROBO1 also preserved left ventricular function and abrogated hypertrophy, but not fibrosis, after transverse aortic constriction.

CONCLUSIONS

Collectively, these results indicate a novel role for the SLIT3-ROBO1-signaling axis in regulating postnatal cardiomyocyte hypertrophy induced by pressure overload.

Beta-blockers in Hypertensive Left Ventricular Hypertrophy and Atrial Fibrillation Prevention

BACKGROUND

Hypertensive left ventricular hypertrophy (HTN LVH) is a key risk factor for atrial fibrillation (AF).

OBJECTIVE

To evaluate the possible role of beta-blockers (BBs) in addition to a renin-angiotensinaldosterone system (RAAS) blocker in AF prevention in patients with HTN LVH.

METHODS

We performed a PubMed, Elsevier, SAGE, Oxford, and Google Scholar search with the search items 'beta blocker hypertension left ventricular hypertrophy patient' from 2013-2023. In the end, a 'snowball search', based on the references of relevant papers as well as from papers that cited them was performed.

RESULTS

HTN LVH is a risk factor for AF. In turn, AF substantially complicates HTN LVH and contributes to the genesis of heart failure (HF) with preserved ejection fraction (HFpEF). The prognosis of HFpEF is comparable with that of HF with reduced EF (HFrEF), and, regardless of the type, HF is associated with five-year mortality of 50-75%. The antiarrhythmic properties of BBs are wellrecognized, and BBs as a class of drugs are - in general - recommended to decrease the incidence of AF in HTN.

CONCLUSION

BBs are recommended (as a class) for AF prevention in several contemporary guidelines for HTN. LVH regression in HTN - used as a single criterion for the choice of antihypertensive medication - does not capture this protective effect. Consequently, it is worth studying how meaningful this antiarrhythmic action (to prevent AF) of BBs is in patients with HTN LVH in addition to a RAAS blocker.

Genome-wide association analysis of left ventricular imaging-derived phenotypes identifies 72 risk loci and yields genetic insights into hypertrophic cardiomyopathy

Left ventricular regional wall thickness (LVRWT) is an independent predictor of morbidity and mortality in cardiovascular diseases (CVDs). To identify specific genetic influences on individual LVRWT, we established a novel deep learning algorithm to calculate 12 LVRWTs accurately in 42,194 individuals from the UK Biobank with cardiac magnetic resonance (CMR) imaging. Genome-wide association studies of CMR-derived 12 LVRWTs identified 72 significant genetic loci associated with at least one LVRWT phenotype (P < 5 × 10-8), which were revealed to actively participate in heart development and contraction pathways. Significant causal relationships were observed between the LVRWT traits and hypertrophic cardiomyopathy (HCM) using genetic correlation and Mendelian randomization analyses (P < 0.01). The polygenic risk score of inferoseptal LVRWT at end systole exhibited a notable association with incident HCM, facilitating the identification of high-risk individuals. The findings yield insights into the genetic determinants of LVRWT phenotypes and shed light on the biological basis for HCM etiology.

Gut microbiota and cardiac arrhythmia

One of the most prevalent cardiac diseases is cardiac arrhythmia, however the underlying causes are not entirely understood. There is a lot of proof that gut microbiota (GM) and its metabolites have a significant impact on cardiovascular health. In recent decades, intricate impacts of GM on cardiac arrythmia have been identified as prospective approaches for its prevention, development, treatment, and prognosis. In this review, we discuss about how GM and its metabolites might impact cardiac arrhythmia through a variety of mechanisms. We proposed to explore the relationship between the metabolites produced by GM dysbiosis including short-chain fatty acids(SCFA), Indoxyl sulfate(IS), trimethylamine N-oxide(TMAO), lipopolysaccharides(LPS), phenylacetylglutamine(PAGln), bile acids(BA), and the currently recognized mechanisms of cardiac arrhythmias including structural remodeling, electrophysiological remodeling, abnormal nervous system regulation and other disease associated with cardiac arrythmia, detailing the processes involving immune regulation, inflammation, and different types of programmed cell death etc., which presents a key aspect of the microbial-host cross-talk. In addition, how GM and its metabolites differ and change in atrial arrhythmias and ventricular arrhythmias populations compared with healthy people are also summarized. Then we introduced potential therapeutic strategies including probiotics and prebiotics, fecal microbiota transplantation (FMT) and immunomodulator etc. In conclusion, the GM has a significant impact on cardiac arrhythmia through a variety of mechanisms, offering a wide range of possible treatment options. The discovery of therapeutic interventions that reduce the risk of cardiac arrhythmia by altering GM and metabolites is a real challenge that lies ahead.

Physiotherapy Screening for Referral of a Patient with Patent Foramen Ovale Presenting with Neck Pain as Primary Complaint: A Case Report

Neck pain is a common musculoskeletal disorder encountered by physiotherapists. However, it may be the early manifestation of more alarming conditions, such as cardiovascular diseases mimicking musculoskeletal pain. Patent foramen ovale (PFO) is a congenital heart defect consisting of a small opening between the right and the left atrium. A 56-year-old male presented with neck pain and head heaviness as primary complaints. The cardiovascular profile and the behavioral symptoms led the physiotherapist to find an exaggerated blood pressure response during exercise; in addition to subtle neurological signs, this prompted the physiotherapist to make an urgent referral. At the emergency department a PFO was diagnosed. To the best of the authors' knowledge, this is the first case to describe a rare clinical presentation of a PFO presenting neck pain as primary complaint. This case report emphasizes the importance for physiotherapists to be able to triage patients for conditions outside their scope suggestive of further medical investigation.

The effect of allopurinol on cardiovascular outcomes in patients with type 2 diabetes: a systematic review

BACKGROUND

Cardiovascular disease (CVD) remains the main cause of death in patients with type 2 diabetes (T2D). Although hyperuricemia has been associated with multiple CV complications, it is not officially recognized as a target parameter for CVD risk reduction.

AIM

To systematically review the literature in order to determine whether treating hyperuricemia with allopurinol in patients with T2D reduces CVD risk.

METHODS

A thorough literature search in the PubMed, CENTRAL, and EMBASE databases from inception to August 2022 was performed. After application of selection criteria, 6 appropriate studies were identified.

RESULTS

Detailed analysis of the data derived indicated that there is an association between allopurinol treatment and CV benefits, resulting in a reduced risk of CVD events and mortality rates. This association can be attributed mainly to the reduction of inflammation and oxidative burden, as well as to the improvement of glycemic and lipid profiles.

CONCLUSIONS

This systematic review provides evidence that allopurinol may reduce CVD risk in patients with T2D. Randomized, placebo-controlled trials should be performed in order to confirm these findings and identify specific subgroups of patients who will benefit most.

Echocardiographic Predictors of Ventricular Tachyarrhythmias in Patients With Cardioverter-Defibrillator Implanted for Primary Prevention of Sudden Cardiac Death. Results From a two-Year Prospective Follow-up Study

Aim      To compare variables of transthoracic EchoCG for determining echocardiographic predictors and their prognostic role in the development of persistent paroxysmal ventricular tachyarrhythmias (VT) in patients with ischemic CHF who had been implanted with a cardioverter defibrillator (CD) for primary prevention of sudden cardiac death.

Material and methods  This single-site prospective study included 176 patients with CHF of ischemic origin aged 58.7±7.4 years with a left ventricular ejection fraction (LV EF) of 30 % [25; 34] % who had been implanted with CD. The follow-up duration was 24 months. The primary endpoint was a newly developed persistent paroxysm of VT (duration ≥30 sec) detected in the “monitored” VT area or a VT paroxysm that required electric treatment. The echocardiographic picture was evaluated by 28 variables. Statistical analysis was performed with the c2, Fisher’s, and Mann—Whitney tests, and the one-factor logistic regression (LR). Prognostic models were developed with a multifactorial LR. The model accuracy was evaluated by 4 metrics: area under the ROC (AUC), sensitivity, specificity, and diagnostic efficacy.

Results The primary endpoint was observed in 60 (34 %) patients. Mean time to a persistent VT episode was 19.2±0.8 months (95 % confident interval (CI): 17.5–20.8). Superior-inferior dimensions of the right and left atria (RA and LA, respectively) and the left atrial volume (LAv) were independent predictors for VT. The odds of VT development in patients of the study cohort increased with RAl ≥4.5 cm (odds ratio (OR), 1.6; 95 % CI: 1.4–1.9; р=0.03), LAl ≥5.5 cm (OR, 2.5; 95 % CI: 1.01–6.1; р=0.04), LAv ≥95 ml (OR, 3.2; 95 % CI: 1.3–17.5; р=0.01). A comprehensive analysis of echocardiographic variables proved the prognostic potential of LAv that was linearly associated with the development of VT. The metrics of the best prognostic model were AUC 0.7±0.07 with 95 % CI: 0.54–0.83; specificity, 20.9 %; sensitivity, 95.7 %; and diagnostic efficacy, 47 %.

Conclusion      This study allowed evaluation of capabilities of transthoracic EchoCG for predicting the probability of VT in patients with CHF of ischemic origin and reduced LV EF. It was shown that linear and volumetric atrial dimensions could be used for stratification of risk of VT and for determining the tactics for primary prevention of sudden cardiac death in this patient category.

Assessing cardiovascular parameters and risk factors in physical therapy practice: findings from a cross-sectional national survey and implication for clinical practice

Background

Cardiovascular diseases are the leading cause of death and comorbidity worldwide. High blood pressure and resting heart rate are risk factors (or vital signs) critical to cardiovascular health, patient safety, and medical management. Physiotherapists play a fundamental role in risk factor identification, early diagnosis, and subsequent management of cardiovascular disease. To date there is limited research in Europe investigating the level of knowledge and skills possessed by physiotherapists regarding cardiovascular disease screening. Three studies previously observed inadequate vital signs screening behaviors of physiotherapists practicing in the United States and Saudi Arabia. The primary aim of this study was to investigate cardiovascular knowledge and screening practices among Italian physiotherapists, according to the current practice recommendations.

Methods

A Cross-Sectional Survey was developed adapting two previous surveys. The survey was administered to members of the Italian Physiotherapy Association. Chi squared test, Mann-Whitney test or Kruskal-Wallis test were used to study differences among subgroups and question responses.

Results

The required sample size was met with total of 387 Italian physiotherapists completing the survey. 80% consider relevant cardiovascular assessment. However, 72.2% were not familiar to guidelines recommendations and only 50% screen vital signs routinely. Their knowledge of normative blood pressure (high-normal, 16%; hypertension, 12%) and heart rate values (bradycardia, 24%; tachycardia, 26%) were low. Although participants reported being skilled for blood pressure measurement (quite sure, 52%; sure, 27%), their adherence to guidelines is low (baseline measurement on both arm, 25%; 3 repeated measures, 46%). Only 27.8% reported to measure exercise related BP and 21.3% of them understood the concept of exaggerated BP. No significant differences between subgroups were found.

Conclusions

Our study revealed that a concerning proportion of Italian physiotherapists are not versed in fundamentals of properly performing cardiovascular screenings. This lack of knowledge is present across the profession and may impact on appropriate triage and management. The poorly executed screening has the potential to negatively impact the patient and the practitioner. Given the absence of Italian guidelines, we produced and implemented three infographics for public use, which have the dual objective of raising awareness about this subject and providing practical resources for everyday practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05696-w.

Perspectives on the Use of Transthoracic Echocardiography Results for the Prediction of Ventricular Tachyarrhythmias in Patients with Non-ischemic Cardiomyopathy

Aim. To perform a comparative analysis of indicators of transthoracic echocardiography (TE), to establish echocardiographic predictors and their predictive role in the occurrence of stable ventricular tachyarrhythmia (VT) paroxysms in patients with nonischemic chronic heart failure (HF) and cardioverter-defibrillator (ICD) implanted for primary prevention of sudden cardiac death.

Material and Methods. A prospective study was carried out, which included 166 patients with nonischemic HF at the age of 54 (49; 59) years with the left ventricle ejection fraction (LV EF) ≤35% and an ICD implanted. The observation time was 24 months. The primary endpoint was the first-ever stable paroxysm of VT (lasting for ≥30 seconds), detected in the «monitor» zone of VT, or paroxysm of VT, which required ICD therapy.  A total of 34 TE indicators were evaluated. Chi-square, Fischer, Manna-Whitney, single-factor logistic regression (LR), and multi-factor LR were used for data processing and analysis and for predictive modelling. Model accuracy was estimated using 4 metrics: ROC curve area (AUC), sensitivity, specificity and diagnostic efficiency.

Results. During the two-year observation, 32 patients (19.3%) had a primary endpoint. The average time of occurrence of a stable VT episode was 21.6±0.6 months (95% confidence interval [CI] 20.5-22.8 months). The value of LV end-systolic dimension was the only parameter independently associated with VT (odds ratio 2.8 per unit increase, 95% CI 1.04-7.5; p=0.042). The complex analysis of echocardiographic indicators made it possible to identify 5 factors with the greatest predictive potential, which are linearly and nonlinearly related to occurrence of VT. These included the LV end-diastolic and end-systolic volumes, LV mass, index of relative LV wall thickness, upper-lower size of the right atrium. The metrics of the best predictive model were: AUC – 0.71 0.069 with 95% CI 0.574-0.843; specificity 50%, sensitivity 90.9%; diagnostic efficiency 57.1%.

Conclusion. The study made it possible to evaluate the possibilities of the results of TE in predicting the probability of VT occurrence in patients with nonischemic HF and reduced LV EF. Predictive indicators have been identified that can be used to stratify the arrhythmic risk in the exposed cohort of patients.

Late Potential Abolition in Ventricular Tachycardia Ablation

Ventricular tachycardia (VT) substrate-based ablation has become the gold standard treatment for patients with structural heart disease-related VT. VT is linked to re-entry in relation to myocardial scarring, with areas of conduction block (core scar) and of slow conduction (border zone). Slow conduction areas can be detected in sinus rhythm as late potentials (LPs). LP abolition has been shown to be the best end point to avoid long-term recurrences. Our study aimed to analyze the challenges of LP abolition and the predictors of failure. We analyzed 169 consecutive patients with structural heart disease (61% ischemic cardiomyopathy, left ventricular ejection fraction: 37 ± 13%) who underwent VT ablation between 2013 and 2018. A preprocedural clinical evaluation, including cardiac magnetic resonance, was done in 66% of patients. Electroanatomical mapping with the identification of LPs was performed in all patients. Noninducibility was achieved in 71% (119), and complete LP abolition was achieved in 61% (103) of patients. Incomplete LP abolition was a powerful predictor of VT recurrence (67% vs 33%, hazard ratio 3.19 [2.1 to 4.7]; p <0.001). Lack of use of a high-density mapping catheter (odds ratio 6.2, 1.2 to 38.1; p = 0.028), the septal substrate (odds ratio 9.34, 2.27 to 38.4; p = 0.002), and larger left ventricular mass (190 ± 58 g vs 156 ± 46 g, p = 0.002) were predictors of incomplete LP abolition. The main reasons that contributed to unsuccessful LP abolition were anatomic obstacles (such as the conduction system) and large extension of the LP area. In conclusion, incomplete LP abolition is related to VT recurrence. Lack of use of a high-density mapping catheter, the septal substrate, and larger left ventricular mass are related to incomplete LP abolition.

Relations Between Cardiac Magnetic Resonance Imaging-Derived Left Ventricular Mass, Early Repolarization, and Cardiovascular Events (from the Dallas Heart Study)

Early repolarization pattern (ERP) is associated with increased mortality in case-control studies, but the mechanism and role of left ventricular mass (LVM) remain unclear. Our objectives were to understand (1) whether ERP associates with adverse outcomes in a multiethnic population and (2) to explore the role of LVM in these associations. Participants from the Dallas Heart Study with an electrocardiogram interpretable for ERP, defined as J point elevation ≥1 mm in 2 contiguous leads, were included. Combined all-cause mortality and nonfatal cardiovascular disease (CVD) events and individual components were assessed using Cox proportional hazards modeling after adjustment for demographics, traditional CVD risk factors, electrocardiogram intervals, and cardiac magnetic resonance imaging-derived factors. Cardiac magnetic resonance imaging-defined LVM was then added to the most fully adjusted model. Of the 2,686 participants, 240 (8.9%) demonstrated ERP. Participants with ERP were more likely to be male and Black, with lower body mass index, greater left ventricular end-diastolic volumes, and LVM. Over a median follow-up of 11 years, the combined end point occurred in 326 patients. Multivariable modeling demonstrated ERP was associated with the combined end point (HR [95% CI] 1.61 [1.14 to 2.26]), all-cause mortality (1.67 [1.00 to 2.80]). However, further adjusting for LVM attenuated the associations of ERP with the primary end point (HR [95% CI] 1.22 [0.85 to 1.77]) and secondary end points of mortality (1.39 [0.80 to 2.41]) and nonfatal CVD (1.05 [0.68 to 1.64]). ERP was associated with increased mortality and nonfatal CVD events, which was attenuated after adjusting for LVM, a previously under-recognized clinical phenotype. Previous associations of ERP with adverse cardiovascular outcomes may be partially explained by greater LVM in those with ERP.

Assessing Cranial Nerves in Physical Therapy Practice: Findings from a Cross-Sectional Survey and Implication for Clinical Practice

BACKGROUND AND OBJECTIVE

Serious pathologies of the neck can potentially result in cranial nerve palsy. Knowledge about cranial nerve examination (CNE) seems sparse, and its use is still unknown. We aim to investigate the knowledge, skills, and utilization of CNE of Italian physiotherapists.

MATERIALS AND METHODS

An online cross-sectional survey.

RESULTS

396 completed the survey, reaching the required sample size. Although Italian physiotherapists consider CNE relevant (mean ± SD = 7.6/10 ± 2.0), over half of all responders (n = 229 (57.8%)) were not trained in the fundamentals and around a third did not use it in their daily practice (n = 138 (34.8%)). Additionally, participants were unconfident and insecure in conducting (n = 152 (38.4%) and n = 147 (37.1%)), interpreting (n = 140 (35.4%) and n = 164 (41.4%)), and managing the CNE (n = 141 (35.6%) and n = 154 (38.9%)). Possessing a musculoskeletal specialization was associated with an increased value attributed to clinical practice guidelines and reduced the lack of confidence in conducting, interpreting, and managing the CNE (respectively, n = 35 (25.5%), p = 0.0001; n = 32 (23.4%) p = 0.0002; n = 32 (23.4%) p = 0.0002). Working in a direct access setting significantly increased the considered relevance of guidelines and the concerns about arterial (p = 0.004) and other serious pathologies (p = 0.021). Pain and visual disturbances were considered the main indicators to CNE, demonstrating limited knowledge of signs and symptoms' indicating CNE. Participants considered specific training in CNE as relevant (mean ± SD = 7.6/10 = 2.1).

CONCLUSIONS

a substantial proportion of Italian physiotherapists are not schooled in the fundamentals of cranial nerve examination. Given the number of physiotherapists who work in first contact roles, this is a professional concern.

Effect of a long-term high-energy diet on cardiovascular parameters in Shetland pony mares

BACKGROUND

Changes in cardiovascular parameters, including blood pressure (BP) and cardiac anatomical dimensions, are an inconsistent feature of the equine metabolic syndrome. The order in which these changes arise is unknown.

OBJECTIVES

Determine the order in which EMS-associated changes in cardiovascular parameters arise.

ANIMALS

Twenty Shetland pony mares.

METHODS

High-energy (HE) diet mares were fed 200% of net energy requirements for 1 (n = 3) or 2 (n = 7) consecutive diet-years, with 17 weeks of hay-only between years. Noninvasive BP measurements and echocardiograms were performed during both years. Resting 24-hour ECGs and measurements of autonomic tone (splenic volume and packed cell volume [PCV]) were performed at the end of diet-year 1. Results were compared to control mares receiving a maintenance diet for 1 (n = 7) or 2 (n = 3) consecutive years.

RESULTS

In year 1, HE mares had significantly higher values than control mares for mean relative left ventricular wall thickness (P = .001). After 2 diet-years, mean systolic (P = .003), diastolic (P < .001) and mean arterial BP (P = .001), heart rate (HR; P < .001), and mean left ventricular wall thickness (P = .001) also were significantly increased in HE compared to control mares. No pathological arrhythmias or differences in splenic volume or PCV were detected.

CONCLUSIONS AND CLINICAL IMPORTANCE

Ingesting a HE diet first induced minor changes in BP, and progressed to left-sided cardiac hypertrophy in Shetland pony mares. These findings are of interest given the increasing incidence of obesity in horses.

Usefulness of echocardiography for predicting ventricular tachycardia detected by implantable loop recorder in syncope patients

Ventricular tachycardia (VT) may lead to syncope and sudden cardiac death. Implantable loop recorders (ILR) are recommended in the clinical work-up of patients with unexplained syncope. Our aim was to evaluate if echocardiographic parameters assessed prior to ILR implantation in patients with unexplained syncope may aid in identifying individuals with an increased risk of VT. The present study included 288 ambulatory patients (mean age 58 ± 19 years, 51% women) with syncope (90%) and presyncope (10%) who had an ILR implanted in the diagnostic workup. All patients underwent an echocardiographic examination prior to device implantation (median 3 months [IQR 1 to 6 months]). We examined incident VT, defined as a first-time episode of VT (> 30 s) or non-sustained VT (< 30 s) detected by the ILR. During median follow-up of 2.9 years [IQR 1.3 to 3.5 years] of continuous rhythm monitoring, 36 patients (13%) were diagnosed with incident VT (n = 25 non-sustained VT, n = 11 sustained VT). In unadjusted Cox proportional hazards models, left ventricular (LV) mass index (HR: 1.04 per 1 g/m² increase [1.00 to 1.08], P = 0.047), mean LV wall thickness (HR: 1.36 per 1 mm increase [1.08 to 1.71], P = 0.009), and global longitudinal strain (HR: 1.15 per 1% decrease [1.05 to 1.25], P = 0.002) were significantly associated with VT. After adjusting for age, sex, implantable loop recorder indication and known heart failure, the above-mentioned parameters remained significantly associated with incident VT. LV mass index, LV wall thickness, and GLS may aid in identifying patients with increased risk of incident VT among patients with syncope. Echocardiography may potentially help select patients who can benefit from ILR.

Certain beta blockers (e.g., bisoprolol) may be reevaluated in hypertension guidelines for patients with left ventricular hypertrophy to diminish the ventricular arrhythmic risk

Hypertensive left ventricular hypertrophy (HTN LVH) is associated with almost threefold increased risk of ventricular tachycardia (VT)/ventricular fibrillation (VF). Furthermore, HTN LVH increases the risk of sudden cardiac death (SCD). The reverse LV remodeling due to efficient antihypertensive therapy lowers the incidence rates of cardiovascular events and SCD and the vast majority of available arterial hypertension (HTN) guidelines recommend renin angiotensin system (RAS) blockers and calcium channel blockers (CCBs) for HTN LVH aiming for LVH regression. On the other hand, beta blockers (BBs) as a class are not recommended in HTN LVH due to their insufficient capacity to reverse LVH remodeling even though they are recommended as the first-line drugs for prevention/treatment of VT/VF (in general, unrelated to HTN LVH). Moreover, BBs are the best antiarrhythmic (against VT/VF) among antihypertensive drugs. Despite that, BBs are currently not recommended for LVH treatment in HTN Guidelines. It is important to prevent VT/VF in patients at high risk, such as those with HTN LVH. Therefore, certain BBs (such as Bisoprolol) may be reevaluated in guidelines for HTN (in the section of HTN LVH).

Prognostic implications of left ventricular geometry in coronary artery bypass grafting patients

Background

The prognostic implications of left ventricular (LV) mass and geometry have been confirmed in populations with different cardiac diseases. However, the prognostic value of LV geometry in coronary artery bypass grafting (CABG) patients is unclear.

Methods

A total of 2,517 patients undergoing CABG between January 2012 and September 2016 in our cardiac surgery unit were included. Patients were divided into the following 4 groups according to left ventricular mass index (LVMi) and relative wall thickness (RWT): normal geometry, concentric remodeling, eccentric hypertrophy, and concentric hypertrophy.

Results

The median follow-up period was 47.0 months (interquartile range was 32.5-61.3 months). Compared to the normal geometry group, the concentric remodeling group [hazard ratio (HR): 3.023; 95% confidence interval (CI): 1.134-8.060], the eccentric hypertrophy group (HR: 3.422; 95% CI: 1.395-8.398), and the concentric hypertrophy group (HR: 5.399; 95% CI: 2.289-12.735) have higher main adverse cardiovascular and cerebrovascular event (MACCE) risk. Moreover, increased MACCE risk was associated with higher LVMi (HR: 1.015 per 1 g/m² increase in LVMi; 95% CI: 1.005-1.026) and RWT (HR: 1.991 per 0.1-U increase in RWT; 95% CI: 1.343-2.952). We observed similar results concerning mortality. Adding LV geometry to the European System for Cardiac Operative Risk Evaluation (EuroSCORE) II significantly improved the area under the curve (AUC) for MACCE (from 0.621 to 0.703; P=0.042). The addition of LV geometry showed significant integrated discrimination improvement (IDI) and net reclassification improvement (NRI) for MACCE (IDI: 0.043, P<0.001; NRI: 0.200, P<0.001) and death (IDI: 0.018, P=0.020; NRI: 0.308, P=0.002), as was the addition of LVMi and RWT.

Conclusions

LV geometry is an independent and incremental prognostic factor for MACCE and death in CABG patients.

Joint effect of blood pressure and C-reactive protein and the risk of sudden cardiac death: A prospective cohort study

BACKGROUND

Both blood pressure and C-reactive protein (CRP) are each independently related to mortality risk. However, the combined effect of systolic blood pressure (SBP) and CRP on sudden cardiac death (SCD) risk has not been studied.

PATIENTS AND METHODS

We studied the joint impact of SBP and CRP and the risk of SCD in the Kuopio Ischemic Heart Disease prospective cohort study of 1953 men aged 42-61 years with no history of ischemic heart disease. Baseline investigations were conducted between March 1984 and December 1989. SBP and CRP were measured. SBP was divided based on median values to low and high (median cutoffs 132 mmHg) and CRP as low and high (median cut-off 1.30 mg/L). Hazard ratios (HRs) with confidence intervals (CIs) were calculated after multivariate adjustment.

RESULTS

Subjects were followed-up for 23.2 years, and 137 SCDs occurred. In this study, elevated SBP (>132 mmHg) combined with elevated (CRP >1.30 mg/L) were associated with SCD risk. Adjustment for age, examination year, alcohol consumption, BMI, energy expenditure during exercise, total cholesterol, HDL-cholesterol, type 2 diabetes, smoking, antihypertension medication and aspirin use, the risk of SCD remained statistically significant (HR, 2,73, 95% CI, 1.62-4.60, p < .001). Further adjustment for socio-economic status, years of education and history of cardiovascular disease in a family the results were only slightly changed (HR, 2.65, 95% CI, 1.57-4.49, p < .001).

CONCLUSIONS

In our male cohort study, the joint effect of high SBP together with increased CRP levels is a risk predictor of SCD compared with low SBP and CRP.

Non-diagnostic autopsy findings in sudden unexplained death victims

BACKGROUND

Several inherited cardiac diseases may lead to sudden cardiac death (SCD) a devastating event in the families. It is crucial to establish a post mortem diagnosis to facilitate relevant work-up and treatment of family members. Sudden unexplained death (SUD) victims constitute roughly one third of all SCD cases in Denmark.

METHODS

This was a single center, retrospective study investigating SUD cases. Victims who died unexplained due to suspected or confirmed cardiac disease were consecutively referred to a third line referral center established in 2005. All autopsy reports were investigated. Victims were divided into two groups: non-diagnostic cardiac findings and normal cardiac findings. None of the included victims had findings consistent with a diagnosis based on existing criteria.

RESULTS

In total, 99 SUD cases were referred. The mean age of the victims was 37 years (range 0-62 years, 75% males). A total of 14 (14%) victims had a cardiovascular diagnosis pre-mortem. Thirty-seven cases had normal cardiac findings and non-diagnostic cardiac findings were found in 62 cases (63%). The five most common findings included ventricular hypertrophy and/or enlarged heart (n = 35, 35%), coronary atheromatosis (n = 31, 31%), myocardial fibrosis (n = 19, 19%), dilated chambers (n = 7, 7%) and myocardial inflammation (n = 5, 5%).

CONCLUSION

One third of SUD victims had normal cardiac findings and non-diagnostic cardiac findings were seen in almost two thirds of the SUD victims. These non-diagnostic findings may be precursors or early markers for underlying structural cardiac disorders or may be innocent bystanders in some cases. Further studies and improved post-mortem examination methods are needed for optimization of diagnostics in SUD.

Association of ADHD medications with the risk of cardiovascular diseases: a meta-analysis

This meta-analysis was conducted to evaluate the association between Attention deficit hyperactivity disorder (ADHD) medications and risk of sudden death/arrhythmia, stroke, myocardial infarction as well as all-cause death. We searched PubMed, Web of Science and China National Knowledge Infrastructure from 1950 to May 2018. All observational studies that the exposure of interest was ADHD medications, the outcome of interest was sudden death/arrhythmia, stroke, myocardial infarction as well as all-cause death, and the study reported relative risks (RRs) with 95% confidence intervals (95% CIs) were included. Pooled RRs were estimated by random-effects model. Subgroup analyses were conducted to examine the effects of study design, population, Country, follow-up duration, female proportion, covariates adjustment on the risk of sudden death/arrhythmia. Eight articles with ten studies (4,221,929 participants) were included in this meta-analysis about the association between ADHD medications and risk of sudden death/arrhythmia. The pooled RRs with 95% CIs of sudden death/arrhythmia for ADHD medications were 1.39 (1.06, 1.83). The result of the cohort study was 1.24 (0.84, 1.83). The pooled RRs between ADHD medications and stroke, myocardial infarction, all-cause death were 1.00 (0.74, 1.35), 0.91 (0.79, 1.05), 0.89 (0.54, 1.45), respectively. As for methylphenidate, the pooled RRs between methylphenidate and sudden death/arrhythmia, stroke, myocardial infarction, all-cause death were 1.46 (1.03, 2.07), 0.92 (0.70, 1.21), 0.97 (0.77, 1.23), 1.00 (0.49, 2.04), respectively. Based on the results of cohort studies, there was no correlation between ADHD medications and sudden death/arrhythmia, stroke, myocardial infarction and all-cause death. However, some of the confidence intervals do not exclude modest elevated risks, e.g., for sudden death/arrhythmia.

The Relation of Emergency Duties to Cardiac Death Among US Firefighters

Sudden cardiac death accounted for 42% of all firefighter duty-related fatalities over the last decade. This retrospective study analyzed available medical examiner records for duty-related firefighter fatalities among male firefighters 18 to 65 years of age that occurred between 1999 and 2014 and reported the pathoanatomic substrate for cardiac-related fatalities. Odds of duty-related cardiac death during specific duties compared with fire station duties were calculated by pathoanatomic substrate. There were 285 cardiac fatalities. Of fatalities, 80% had evidence at autopsy of coronary heart disease (CHD) and increased heart size (cardiomegaly and/or left ventricular hypertrophy). CHD alone, cardiomegaly or left ventricular hypertrophy, and causes other than CHD or increased heart size were identified in 7.7%, 6.0%, and 6.7% of fatalities, respectively. The largest proportion of deaths occurred during fire suppression (33%), although only 1% of annual occupational time was estimated to be spent performing this duty. For deaths attributed to CHD and increased heart size, fire suppression, alarm response, and physical training were associated with approximately a 112-fold, eightfold, and sevenfold increased risk of cardiac death, respectively, compared with station duties. In conclusion, the majority of firefighters who suffered a duty-related cardiac death had CHD and increased heart size, which was associated with a markedly increased risk of death during fire suppression compared with station duties. Targeted occupational medical screening for CHD and increased heart size may reduce duty-related cardiac deaths among firefighters.

Pathoanatomic Findings Associated With Duty-Related Cardiac Death in US Firefighters: A Case-Control Study

Background Sudden cardiac death accounts for the greatest proportion of duty-related deaths among US firefighters. Increased understanding of the pathoanatomic causes of sudden cardiac death and the risk associated with underlying cardiac pathologies is needed to develop evidence-based screening recommendations. Methods and Results Using autopsy data for duty-related firefighter fatalities occurring between 1999 and 2014, this retrospective case-control study compared cardiac findings of male firefighters aged 18 to 65 years who died on duty of cardiac-related causes with those who died of noncardiac trauma-related causes. Data from 276 cardiac cases and 351 noncardiac trauma controls were analyzed. Among cardiac cases, the most prevalent (82%) underlying pathoanatomic substrate was comorbid coronary heart disease and cardiomegaly/left ventricular hypertrophy. Cardiac cases had a higher prevalence of cardiomegaly (heart weight >450 g), left ventricular hypertrophy (left ventricular wall thickness ≥1.2 cm), and severe coronary artery stenosis (≥75%) than trauma controls (all P<0.001). In multivariate analyses, heart weight >450 g, coronary artery stenosis ≥75%, and evidence of a prior myocardial infarction were strong independent predictors of cardiac death, with odds ratios of 6.1 (95% confidence interval, 3.6-10.4), 9.3 (95% confidence interval, 5.3-16.1), and 6.2 (95% confidence interval, 3.4-11.3), respectively. Conclusions The majority of cardiac fatalities had evidence of both coronary heart disease and increased heart mass, and each condition was independently associated with a markedly elevated risk of cardiac death. Targeted screening for coronary heart disease, increased heart mass, and evidence of prior myocardial infarction should be considered to reduce duty-related cardiac deaths among firefighters.

Long-term outcomes of patients admitted with heart failure in a tertiary care center in India

There are limited studies on heart failure in Indian population OBJECTIVE: Present study aimed to assess the in-hospital 90-day and two year outcomes in patients with ischemic (IHD-HF) and non ischemic heart failure (NIHD-HF).

METHODS

Patients with NYHA Class III & IV, who were admitted to our intensive care unit with heart failure (HF), were evaluated and followed up for 2years.

RESULTS

In our cohort of 287 patients, there were 192 (66.9%) males and 95 (33.1%) females. Patients were divided into IHD-HF of 180 (62.7%) patients and NIHD-HF of 107 (37.3%) patients. Mean age of IHD-HF group was 66 (+/-10) and in the NIHD-HF group was 61 (+/-11). Prevalence of HF increased with age in the IHD-HF population and there was no relation with age in the NIHD-HF population .Patients readmitted within 90days in the IHD-HF were 56% (n-101) and in the NIHD-HF were 32.7% (n-35) [p- 0.001]. Two- year recurrent admissions were 69.4% (n-125) in the IHD-HF patients and 52.3% (n-56) in the NIHD-HF patients, respectively (p-0.004). Mortality at 90days in the IHD-HF patients was 26.6% (n-48) and in NIHD-HF patients were 14.9% (n-16) [p- 0.021]. Two-year mortality was 42.3% (n-76) in the IHD-HF patients and 29.9%(n-32) in the NIHD-HF patients, respectively (p-0.037).

CONCLUSIONS

HF in IHD-HF heralds a bad prognosis with recurrent hospitalizations and high mortality when compared to patients with NIHD-HF.

Outpatient physical therapy cardiovascular assessment: Physical therapist perspective and experience

Background: Physical therapists are recognized healthcare providers who play an important role in cardiovascular disease prevention. Heart rate (HR) and blood pressure (BP) are important parameters in cardiovascular risk assessment; however, physical therapists do not usually integrate them into clinical practice. Therefore, this study aimed to examine the current practice and opinion of outpatient physical therapists toward HR and BP measurements in clinics. Methods: A 12-item survey questionnaire was distributed to outpatient physical therapists. Five senior staff from different specialties, including orthopedic, neurology, pediatric, cardiopulmonary, and sport specialties, participated in a focus group interview to gather their opinions. Results: In total, 285 (56%: male) physical therapists participated. Only 68 (24%) measured HR and BP; of these, 27 (41%) used manual sphygmomanometers. Nearly one-fifth reported that cardiovascular adverse events, such as syncope and chest pain, occurred during therapeutic exercise of their patients and were the highest among the sport and orthopedic physical therapists. Most physical therapists felt that measuring cardiovascular indices is not their job and does not add value to their treatment plan. Conclusion: Majority of the physical therapists were not measuring HR and BP during clinical assessment, although some reported cardiovascular adverse events occurring in their patients.

Prevalence of arrhythmias in patients with type 2 diabetes and the role of structural changes in myocardium in their development

OBJECTIVE

The aim of the study was to evaluate the prevalence of arrhythmias in patients with type 2 diabetes and their relationships with the structural parameters of the heart.

METHODS

A retrospective case-control study was conducted using clinical and biochemical profiles of patients with diabetes at the Endocrinology Centre and City Clinical Hospital No. 40, Ekaterinburg, Russia.

RESULTS

The total study sample included 75 subjects. The average age (SD) was 48.2 (5.6) years, and the mean duration of diabetes (SD) was 6.2 (2.4) years. The most common type of extrasystoles were the single supraventricular extrasystoles, observed in 72.29% of cases (vs 38.89% in the control group) and paired supraventricular extrasystoles, which were identified in 30% of cases (vs 19.44% in the control group). Ventricular cardiac arrhythmias in the form of ventricular extrasystoles (VE) were identified in 25.71% of cases (13.89% in the control group).

CONCLUSIONS

This study revealed the signs of the morphological restructuring of the right chambers of the heart and a relatively high prevalence of supraventricular arrhythmias in the early stages of type 2 diabetes. Moreover, according to the results, the incidence of some types of supraventricular arrhythmias and the occurrence of tachycardia episodes in patients with type 2 diabetes mostly depends on the restructuring of the right chambers of the heart, which may be caused by the peculiarities of the cardiac innervation, with the higher density of choline and adrenergic plexuses in the right chambers.

Spatial Heterogeneity of Cx43 is an Arrhythmogenic Substrate of Polymorphic Ventricular Tachycardias during Compensated Cardiac Hypertrophy in Rats

BACKGROUND

Ventricular remodeling increases the propensity of ventricular tachyarrhythmias and sudden death in patients. We studied the mechanism underlying these fatal arrhythmias, electrical and structural cardiac remodeling, as well as arrhythmogeneity during early, compensated hypertrophy in a rat model of chronic pressure overload.

METHODS

Twenty-six Wistar rats were subjected to transverse aortic constriction (TAC) (n = 13) or sham operation (n = 13). Four weeks postoperative, echo- and electrocardiography was performed. Epicardial (208 or 455 sites) and transmural (30 sites) ventricular activation mapping was performed on Langendorff perfused hearts. Subsequently, hearts were processed for (immuno)histological and molecular analyses.

RESULTS

TAC rats showed significant hypertrophy with preserved left ventricular (LV) function. Epicardial conduction velocity (CV) was similar, but more dispersed in TAC. Transmural CV was slowed in TAC (37.6 ± 2.9 cm s(-1)) compared to sham (58.5 ± 3.9 cm s(-1); P < 0.01). Sustained polymorphic ventricular tachycardias were induced from LV in 8/13 TAC and in 0/13 sham rats. During VT, electrical activation patterns showed variable sites of earliest epicardial activation and altering sites of functional conduction block. Wandering epicardial reentrant activation was sporadically observed. Collagen deposition was significantly higher in TAC compared to sham, but not different between arrhythmogenic and non-arrhythmogenic TAC animals. Connexin43 (Cx43) expression was heterogeneous with a higher prevalence of non-phosphorylated Cx43 in arrhythmogenic TAC animals.

CONCLUSION

In TAC rats with compensated cardiac hypertrophy, dispersion of conduction correlated to arrhythmogenesis, an increased heterogeneity of Cx43, and a partial substitution with non-phosphorylated Cx43. These alterations may result in the increased vulnerability to polymorphic VTs.

Intramural Reentrant Ventricular Tachycardia in a Patient with Severe Hypertensive Left Ventricular Hypertrophy

We describe the case of a patient with severe hypertensive left ventricular hypertrophy and sustained hemodynamically unstable ventricular tachycardia (VT). Entrainment was demonstrated in the electrophysiological study. Activation mapping and pacemapping identified the location of the intramural reentrant VT with the exit site close to the epicardium. However, VT persisted after ablation at the epicardial exit site. Successful ablation was performed endocardially at the corresponding position.

Left ventricular mass and the risk of sudden cardiac death: a population-based study

BACKGROUND

Left ventricular (LV) mass ascertained using echocardiography may enhance risk stratification for sudden cardiac death. The objective of this study was to assess the association between left ventricular mass and the risk of sudden cardiac death in a population-based cohort and determine its incremental value beyond conventional risk predictors.

METHODS AND RESULTS

Assessment of LV mass was based on echocardiography in a sample of 905 middle-aged men representative of the general population (aged 42 to 61 years). During the follow-up period of 20 years, there were a total of 63 sudden cardiac deaths. In a comparison of the top versus the bottom quartile of LV mass adjusted by body surface area (>120 versus <89 g/m(2)), the multivariable adjusted hazard ratio was 2.57 (95% CI 1.24 to 5.31, P=0.010). Further adjustment for LV function only modestly attenuated the risk of sudden cardiac death among men with LV mass of >120 g/m(2) (hazard ratio 2.29, 95% CI 1.10 to 4.74, P=0.026). Addition of LV mass adjusted by body surface area to a conventional risk factor model for sudden cardiac death improved the integrated discrimination index by 0.033 (95% CI 0.009 to 0.057, P=0.007) and the category-free net reclassification index by 0.501 (95% CI 0.092 to 0.911, P=0.016).

CONCLUSIONS

Indexed LV mass by body surface area is an independent predictor of sudden cardiac death and may help improve the risk prediction of sudden cardiac death beyond conventional cardiovascular risk factors.

Left ventricular geometry and outcomes in patients with atrial fibrillation: the AFFIRM Trial

BACKGROUND

Echocardiographically determined left ventricular hypertrophy (LVH) is a marker of cardiovascular disease related to prognosis and clinical outcomes. We sought to determine if LVH is a measure of outcomes in atrial fibrillation (AF) patients.

METHODS

We performed a post-hoc analysis of patients with echocardiographic data enrolled in the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) Trial. Patients were stratified based on gender-adjusted echocardiography derived interventricular septal (IVS) thickness, relative wall thickness (RWT), gender-adjusted LV mass, and type of LV remodeling (normal LV geometry, concentric hypertrophy, eccentric hypertrophy, and concentric remodeling).

RESULTS

Of 4060 patients in AFFIRM, echocardiographic data were available in 2433 patients (60%). Multivariate analysis revealed that LVH defined as moderately or severely abnormal IVS thickness was an independent predictor of both all cause mortality (HR 1.46, 95%CI 1.14-1.86, p=0.003) and stroke (HR 1.89, 95%CI 1.17-3.08, p=0.01). This association was confirmed when IVS thickness was assessed as continuous or categorical variable. Concentric LV hypertrophy was associated with the highest rates of all cause mortality (HR 1.53; 95%CI 1.11-2.12; p=0.009).

CONCLUSION

An easily obtained echocardiographic index of LVH (IVS thickness) may enhance risk stratification of patients with AF, and raise the possibility that LVH regression should be a therapeutic target in this population.

Valvular regurgitations may increase risk of arrhythmias in Nigerians with hypertensive heart failure

BACKGROUND

Hypertensive heart disease (HHD) is the commonest cause of sudden cardiac death among Nigerians. A high frequency and early onset of valvular regurgitations (VHD) in hypertensives, and greater concentric hypertrophy are also common in that population.

AIMS AND METHODS

To further investigate the relationship between VHD and cardiac arrhythmias and their correlates seen in the hypertensive spectrum and to test the hypothesis that VHD predisposes to cardiac arrhythmias in hypertensive heart failure (HHF). HHF patients (n = 14), HHD patients n = 23, and normotensive controls (n = 9) all underwent 24 h electrocardiogram Holter monitoring as well as two-dimensional and Doppler echocardiography. Participants in each patient category were classified according to the presence and severity of VHD or its absence (NVHD).

RESULTS

There were statistically significant differences in the mean supraventricular tachycardia (SVT) (P < 0.001 analysis of variance; ANOVA), the mean and median frequency of ventricular tachycardia episodes (P < 0.02 ANOVA), and couplets (P = 0.0002 ANOVA) between groups. HHF-VHD always had more SVT (81/24 versus 4.4/24 h; P = 0.016) and ventricular arrhythmias 69/24 versus 34/24 h (P < 0.02) than HHF-NVHD. Multivalvular regurgitations (three or more valves), higher left ventricular mass index (g/m2) [274 (24) versus 191(19); P < 0.001 ANOVA], and lower ejection fraction (EF; %) [29(3) versus 53(14)] in HHF-VHD were arrhythmogenic. Mean ventricular tachycardia/triplet frequency/24 h were HHF-VHD 69, HHF-NVHD 39, HHD-VHD 0.3, HHD-NVHD 6, and controls 0.2 (P < 0.02 ANOVA). Compared with 35% (10/27) of all VHD, 15.7% (3/19) of all NVHD participants had nonsustained ventricular tachycardia. The number of regurgitant valves was positively correlated with the frequency of the Lown class of the arrhythmias 0-IVB (r = 0.42, P = 0.003) and to ventricular tachycardia (r = 0.3, P = 0.04) (both n = 46).

CONCLUSION

Left ventricular hypertrophy (LVH) increased arrhythmias. But multivalvular regurgitations predisposes to greater SVT and complex ventricular arrhythmias, especially in HHF. Low EF and concentric LVH are correlates.

Disproportionate pregnancy-induced myocardial hypertrophy in women with essential hypertension

BACKGROUND

Pregnancy and arterial hypertension (AH) have a prohypertrophic effect on the heart. It is suspected that the 2 conditions combined cause disproportionate myocardial hypertrophy. We sought to evaluate myocardial hypertrophy (LVH) and left ventricular function in normotensive and hypertensive women in the presence or absence of pregnancy.

METHODS

This prospective cross-sectional study included 193 women divided into 4 groups: hypertensive pregnant (HTP; n = 57), normotensive pregnant (NTP; n = 47), hypertensive nonpregnant (HTNP; n = 41), and normotensive nonpregnant (NTNP; n = 48). After clinical and echocardiographic evaluation, the variables were analyzed using 2-way analysis of variance with pregnancy and hypertension as factors. Left ventricular mass (LVM) was compared using nonparametric analysis of variance and Dunn's test. Predictors of LVH and diastolic dysfunction were analyzed using logistic regression (significance level, P < 0.05).

RESULTS

Myocardial hypertrophy was independently associated with hypertension (odds ratio (OR) = 11.1, 95% confidence interval (CI) = 3.2-38.5; P < 0.001) and pregnancy (OR = 6.1, 95% CI = 2.6-14.3; P < 0.001) in a model adjusted for age and body mass index. Nonpregnant women were at greater risk of LVH in the presence of AH (OR = 25.3, 95% CI = 3.15-203.5; P = 0.002). The risk was additionally increased in hypertensive women during pregnancy (OR = 4.3, 95% CI = 1.7-10.9; P = 0.002) in the model adjusted for stroke volume and antihypertensive medication. Although none of the NTNP women presented with diastolic dysfunction, it was observed in 2% of the NTP women, 29% of the HTNP women, and 42% of the HTP women (P < 0.05).

CONCLUSIONS

Hypertension and pregnancy have a synergistic effect on ventricular remodeling, which elevates a woman's risk of myocardial hypertrophy.

Association of sodium and potassium intake with ventricular arrhythmic burden in patients with essential hypertension

BACKGROUND

Hypertensive populations suffer from an increased susceptibility to ventricular arrhythmias and sudden cardiac death. A high-salt diet appears to be a major factor involved in cardiovascular complications in hypertension. We examined the relationship between dietary salt and potassium, as indicated by urinary sodium (UNa), urinary potassium (UK), and urinary sodium/potassium ratio (UNa/K), and the arrhythmic burden in patients with essential hypertension.

METHODS

We included 255 consecutive adult patients with well-controlled hypertension who were being followed in the hypertension outpatient clinic of a university tertiary hospital and complained of episodes of atypical chest pain and/or palpitations. All underwent 24-hour ambulatory electrocardiograph monitoring and their UNa, UK, and UNa/K ratio from 24-hour urinary excretion specimens were evaluated.

RESULTS

No significant correlation was found between premature supraventricular contractions and the parameters that were examined. However, the percentage of premature ventricular contractions (PVC%) showed a weak positive association with UNa (r = 0.2; P = .001) and a moderate negative association with UK (r = -0.396; P < .001). The partial correlation coefficient of PVC% with the UNa/UK ratio remained significant even after controlling for left ventricular mass index (r = 0.437; P < .001).

CONCLUSIONS

A higher UNa/UK excretion ratio is significantly associated with PVCs, indicating an increased susceptibility to ventricular arrhythmias even among hypertensives with well-controlled blood pressure. Our findings reinforce recommendations for dietary interventions in those populations.

Relation of systemic blood pressure to sudden cardiac death

The role of systolic blood pressure (SBP) as an independent risk factor for sudden cardiac death (SCD) is not well defined in a general population. Thus, we assessed the association between BP at rest and risk of SCD. BP and other risk factors were measured in a representative population-based sample of 2,666 Finnish men (42 to 61 years of age). During an average follow-up period of 18.9 years (interquartile range 17.9 to 22.6), 213 SCDs occurred. Each increment 10-mm Hg of SBP at rest was associated with an increased risk of SCD (relative hazard 1.15, 95% confidence interval 1.07 to 1.25, p <0.001) after adjustment for age, alcohol consumption, cigarette smoking, serum low-density lipoprotein cholesterol, type 2 diabetes, body mass index, left ventricular hypertrophy, previous myocardial infarction, family history of coronary heart disease, and use of antihypertensive medications. Men with increased SBP of >145 mm Hg had a 2.04-fold (95% confidence interval 1.23 to 2.52, p = 0.003) adjusted risk for SCD compared to those with SBP <123 mm Hg. In conclusion, this study emphasizes the importance of the definition of SBP at rest because it provides a valuable prognostic measurement for SCD.

A potential role for integrin signaling in mechanoelectrical feedback

Certain forms of heart disease involve gross morphological changes to the myocardium that alter its hemodynamic loading conditions. These changes can ultimately lead to the increased deposition of extracellular matrix (ECM) proteins, such as collagen and fibronectin, which together work to pathologically alter the myocardium's bulk tissue mechanics. In addition to changing the mechanical properties of the heart, this maladaptive remodeling gives rise to changes in myocardium electrical conductivity and synchrony since the tissue's mechanical properties are intimately tied to its electrical characteristics. This phenomenon, called mechanoelectrical coupling (MEC), can render individuals affected by heart disease arrhythmogenic and susceptible to Sudden Cardiac Death (SCD). The underlying mechanisms of MEC have been attributed to various processes, including the action of stretch activated channels and changes in troponin C-Ca(2+) binding affinity. However, changes in the heart post infarction or due to congenital myopathies are also accompanied by shifts in the expression of various molecular components of cardiomyocytes, including the mechanosensitive family of integrin proteins. As transmembrane proteins, integrins mechanically couple the ECM with the intracellular cytoskeleton and have been implicated in mediating ion homeostasis in various cell types, including neurons and smooth muscle. Given evidence of altered integrin expression in the setting of heart disease coupled with the associated increased risk for arrhythmia, we argue in this review that integrin signaling contributes to MEC. In light of the significant mortality associated with arrhythmia and SCD, close examination of all culpable mechanisms, including integrin-mediated MEC, is necessary.

Vulnerable myocardial interstitium in patients with isolated left ventricular hypertrophy and sudden cardiac death: a postmortem histological evaluation

BACKGROUND

Concentric left ventricular hypertrophy (LVH) is independently associated with increased risk of sudden cardiac death (SCD). Some animal models of LVH display specific alterations of the myocardial interstitium that could increase myocardial vulnerability to ventricular arrhythmias, but these merit evaluation in humans with LVH and SCD.

METHODS AND RESULTS

Twelve consecutive patients with isolated LVH and SCD (LVH+SCD) in the absence of hypertrophic cardiomyopathy, coronary disease, or other cardiac structural abnormality were ascertained in the Oregon Sudden Unexpected Death Study. Detailed postmortem comparisons were conducted with 18 controls who had isolated LVH and unnatural deaths (Control Group A) and 6 controls who had structurally normal hearts and unnatural deaths (Control Group B). Postmortem left ventricular myocardial sections were obtained for measurement of collagen volume fraction, characterization of gap junctions, and quantification of collagen subtypes. Heart weight normalized to body weight was higher in LVH+SCD cases (6.9±1.2 g/kg) than in Control Group A (5.3±1.4 g/kg) and Control Group B (4.2±0.3 g/kg); P=0.001. Collagen volume fraction was also higher in LVH+SCD cases (3.1±0.4) than in Control Group A (2.3±0.4) and Control Group B (1.6±0.3); P=0.0002. The relative amount of collagen III was significantly higher in LVH+SCD cases (33.0±4.4%) than in Control Group A (20.9±4.3%) and Control Group B (13.4±3.5%); P=0.0001. There was an overall increase in the number of connexin 43-labeled gap junctions with increasing myocyte size. No subject was found to have high-risk hypertrophic cardiomyopathy mutations.

CONCLUSIONS

In addition to the expected increase in myocardial mass and overall collagen content, SCD with isolated LVH was associated with relative abundance of type III collagen, a novel finding that warrants further mechanistic evaluation. (J Am Heart Assoc. 2012;1:e001511 doi: 10.1161/JAHA.111.001511.).

Is the 'athlete's heart' arrhythmogenic? Implications for sudden cardiac death

Whether the ventricular hypertrophic response to athletic training can predispose to fatal ventricular dysrhythmias via mechanisms similar to that of pathological hypertrophy is controversial. This review examines current information regarding the metabolic and electrophysiological differences between the myocardial hypertrophy of heart disease and that associated with athletic training. In animal studies, the biochemical and metabolic profile of physiological hypertrophy from exercise training can largely be differentiated from that of pathological hypertrophy, but it is not clear if the former might represent an early stage in the spectrum of the latter. Information as to whether the electrical remodelling of the athlete's heart mimics that of patients with heart disease, and therefore serves as a substrate for ventricular dysrhythmias, is conflicting. If ventricular remodelling associated with athletic training can trigger fatal dysrhythmias, such cases are extraordinarily rare and thereby impossible to investigate by any standard experimental approach. Greater insight into this issue may come from a better understanding of the electrical responses to both acute bouts of exercise and chronic training in young athletes.

Functional consequences of abnormal Cx43 expression in the heart

The major gap junction protein expressed in the heart, connexin43 (Cx43), is highly remodeled in the diseased heart. Usually, Cx43 is down-regulated and heterogeneously redistributed to the lateral sides of cardiomyocytes. Reverse remodeling of the impaired Cx43 expression could restore normal cardiac function and normalize electrical stability. In this review, the reduced and heterogeneous Cx43 expression in the heart will be addressed in hypertrophic, dilated and ischemic cardiomyopathy together with its functional consequences of conduction velocity slowing, dispersed impulse conduction, its interaction with fibrosis and propensity to generate arrhythmias. Finally, different therapies are discussed. Treatments aimed to improve the Cx43 expression levels show new potentially anti-arrhythmic therapies during heart failure, but those in the context of acute ischemia can be anti-arrhythmogenic at the cost of larger infarct sizes. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics.

Beneficial effects of l-leucine and l-valine on arrhythmias, hemodynamics and myocardial morphology in rats

Branched chain amino acids (BCAA) have been shown to have a general protective effect on the heart in different animal models as well as in humans. However, so far no attempt has been made to specifically elucidate their influence on arrhythmias. Our study was performed to evaluate whether an infusion of either l-leucine or l-valine in a dose of 1mgkg(-1)h(-1) 10min before a 7-min period of left anterior descending artery occlusion followed by 15min of reperfusion, had an effect on arrhythmias measured during the reperfusion phase in the ischemia- and reperfusion-induced arrhythmias model in rats in vivo. The effect of the infusion of these substances on mean arterial blood pressure was monitored throughout the experiment. Both of the tested amino acids exhibited significant antiarrhythmic properties. l-Leucine reduced the duration of ventricular fibrillation (P<0.05) and l-valine decreased the duration of ventricular fibrillation (P<0.001) and ventricular tachycardia (P<0.05). The two amino acids were generally hypotensive. l-Valine lowered blood pressure in all phases of the experiment (P<0.05) while l-leucine lowered this parameter mainly towards the end of occlusion and reperfusion (P<0.05). In addition, 30min infusion of the amino acids in the used dose did not produce any apparent adverse histological changes that were remarkably different from control. In summary, the results of our study suggest that l-leucine and l-valine in the dose that was used attenuates arrhythmias and are hypotensive in their influence. Our findings lend support to the many ongoing investigations into the benefit of the application of l-leucine and l-valine in cardiology like their addition to cardioplegic solutions.

Evaluation of left ventricular hypertrophy in patients requiring permanent pacing

Objective: Hypertension may lead to left ventricular hypertrophy, fibrosis and degeneration of the conduction system. Our aim was to study the association of hypertrophy with certain arrhythmias such as complete atrioventricular block (AVB) and symptomatic sick sinus syndrome (SSS) that require implantation of permanent pacemaker.

Methods: We studied 130 patients that had been given a pacemaker because of complete AVB, 130 patients that had been given a pacemaker because of symptomatic SSS and 45 patients without cardiac conduction disturbances. In order to estimate left ventricular hypertrophy, indexes of relative wall thickness (RWT) and left ventricular mass (LVM) were evaluated by echocardiography.

Results: We observed significant association between complete AVB and abnormal values of echocardiographic indexes.

Conclusions: Our results lend further support to the hypothesis that complete AVB is associated with left ventricular hypertrophy. This hypothesis is enhanced by the observation that the majority of patients with complete AVB were hypertensive.