Diabetes and the Risk of Sudden Cardiac Death

Effects of canagliflozin preconditioning on post-resuscitation myocardial function in a diabetic rat model of cardiac arrest and cardiopulmonary resuscitation

BACKGROUND

Canagliflozin can reduce the risk of cardiovascular disease in patients except for its targeted antidiabetic effects. However, it remains unknown whether canagliflozin alleviates the post-resuscitation myocardial dysfunction (PRMD) in type 2 diabetes mellitus.

OBJECTIVE

To explore the effects and potential mechanisms of canagliflozin on myocardial function after cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) in a type 2 diabetic rat model.

METHODS

Twenty-four type 2 diabetic rats were randomized into four groups: (1) sham + canagliflozin, (2) sham + placebo, (3) CPR + placebo, and (4) CPR + canagliflozin. Except for the sham + canagliflozin and placebo groups, both the CPR + placebo and canagliflozin groups underwent 8 min of CPR after the induction of ventricular fibrillation for 6 min. Myocardial function and hemodynamics were assessed at baseline and within 6 h after autonomous circulation (ROSC) return. Left ventricular tissues were sampled to determine the expressions of relevant proteins in the NLRP3 inflammasome pathway.

RESULTS

The results demonstrated that the mean arterial pressure (MAP) was significantly improved in the CPR + canagliflozin group after ROSC compared with the CPR + placebo group (p < 0.05). Meanwhile, both ejection fraction (EF) and fraction shortening (FS) were dramatically increased in the CPR + canagliflozin group when compared with the CPR + placebo group at 2h, 4h, and 6h after ROSC (p < 0.05). In addition, the levels of NT-proBNP, cTn-I, and NLRP3 inflammatory inflammasome-associated proteins were significantly decreased in the CPR + canagliflozin group compared with the CPR + placebo group.

CONCLUSIONS

In type 2 diabetic rats, pretreatment of canagliflozin alleviates PRMD. The potential mechanisms may include inhibition of the NLRP3/caspase-1 signaling pathway.

Metabolic dysfunction-associated steatotic liver disease correlates with higher lower graft survival in liver transplant recipients with hepatocellular carcinoma

BACKGROUND

Direct-acting antivirals (DAAs) have revolutionized hepatitis C virus (HCV) treatment. The changing landscape of hepatocellular carcinoma (HCC) in liver transplant (LT) recipients lacks a thorough description of the outcomes of HCC based on etiology.

OBJECTIVE

To assess the waitlist (WL) dropout and graft survival in HCC LT candidates based on the etiology of HCC in the post-DAA era.

METHODS

This retrospective cohort study analyzed United Network Organ Sharing/Organ Procurement Transplant Network data from 2015 to 2022. Graft survival was analyzed using Kaplan-Meier curves, and predictors of WL dropout and graft failure were assessed using multivariate analysis.

RESULTS

Among LT recipients, etiologies were HCV (53.6%), alcohol-associated liver disease (ALD) (12.0%), metabolic dysfunction-associated steatotic liver disease (MASLD) (16.6%), hepatitis B virus (HBV) (5.6%), and other (12.1%). MASLD and ALD had the highest dropout rates (1-year: 20.4%, 21.7%; 3-year: 58.2%, 51.1%; P < 0.001). Dropout was linked to diabetes, low albumin, high Model of End-Stage Liver Disease, high alpha-fetoprotein, tumor number, and size. MASLD had the worst 1-, 3-, and 5-year graft survival (89.8%, 81.8%, and 74.1%) and higher failure risk than HCV (hazard ratio: 1.143, 95% CI: 1.021-1.281). Diabetes negated MASLD's impact on graft failure but worsened survival for MASLD-HCC compared with HBV and ALD, matching HCV.

CONCLUSION

MASLD has the highest WL dropout and post-LT graft failure among HCC LT candidates, surpassing HCV in the post-DAA era. The worst graft survival in MASLD-HCC is associated with pre-LT diabetes.

Associations of Clinical Characteristics With Sudden Cardiac Arrest in People With Type 2 Diabetes With and Without Cardiovascular Disease: A Longitudinal Case-Control Study Using Routine Primary Care Data

OBJECTIVE

To assess longitudinal associations with sudden cardiac arrest (SCA) of clinical characteristics recorded in primary care in people with type 2 diabetes (T2D), both with and without cardiovascular disease (CVD).

RESEARCH DESIGN AND METHODS

We performed a case-control study, with SCA case subjects with T2D from the Amsterdam Resuscitation Studies (ARREST) registry of out-of-hospital resuscitation attempts in the Dutch Noord-Holland region (2010-2020) and up to five matched (age, sex, T2D, general practitioner [GP] practice) non-SCA control subjects. We collected relevant clinical measurements, medication use, and medical history from GPs' electronic health care records. We analyzed the associations of clinical characteristics and medication use with SCA in the total sample and in subgroups with or without CVD using multivariable time-dependent Cox regression (hazard ratios, 95% confidence intervals).

RESULTS

We included 689 SCA case subjects and 3,230 non-SCA control subjects. In multivariable models, low fasting glucose (<4.5 mmol/mol: 1.91 [1.00-3.64]), antihypertensive (1.80 [1.39-2.33]), glucose lowering (oral only: 1.32 [1.06-1.63]; insulin only: 2.31 [1.71-3.12]; oral and insulin: 1.64 [1.21-2.22]), heart failure (1.91 [1.55-2.35]), and QTc-prolonging prokinetic (1.78 [1.27-2.50]), antibiotic (1.35 [1.05-1.73]), and antipsychotic (2.10 [1.42-3.09]) medication were associated with SCA in the total sample. In subgroup effect modification analyses, QTc-prolonging antibiotic (1.82 [1.26-2.63]) and antipsychotic (3.10 [2.09-4.59]) medication use were associated with SCA only in those without CVD.

CONCLUSIONS

In people with T2D, low fasting glucose and QTc-prolonging prokinetic, antibiotic, or antipsychotic medication use and a history of heart failure are associated with SCA risk. Subgroup analyses indicate antibiotic and antipsychotic medication use increases SCA risk specifically in those without CVD.

Exploring electrocardiographic alterations and the prolongation of QT interval in patients with diabetes mellitus

Background

Diabetes mellitus (DM) affects a substantial proportion of the world's population and is associated with an increased risk of sudden cardiac death (SCD) due to cardiac arrhythmias, specifically prolonged QT intervals. This study investigates the correlation between glycemic control and cardiac health in 77 diabetic patients.

Methods

Patients with both type 1 and type 2 DM aged 14 to 82 years were included. Various clinical and metabolic parameters were evaluated, including glycated hemoglobin (HbA1C). QT intervals were measured using electrocardiograms (ECGs), and patients were categorized based on their QTc intervals. SPSS was used for statistical analysis, including one-way ANOVA tests.

Results

The study revealed diverse age and gender representation among diabetic patients. Most patients had type 2 diabetes (87%) with varying illness durations. Patients ranged in age from 14 to 82 years, with a mean of 48.14 16.58 years. The gender distribution was even (49% male and 51% female). Most participants had diabetes for less than five years (57%) and varied treatment histories (71% managed with oral hypoglycemic agents, 17% with insulin, and 12% with a combination). The ECG revealed ST-T alterations (4%) as well as sinus tachycardia (13%) and left ventricular hypertrophy (19%).

Conclusion

This study sheds light on the intricate relationship between diabetes, glycemic control, and cardiac health. QTc interval variations were observed even though the clinical and metabolic profiles of the patients varied. The influence of glycemic control on QT intervals and cardiovascular outcomes in diabetic patients requires additional study.

A real-world pharmacovigilance study of drug-induced QT interval prolongation: analysis of spontaneous reports submitted to FAERS

Purpose

To identify the most commonly reported drugs associated with QT interval prolongation in the FDA Adverse Event Reporting System (FAERS) and evaluate their risk for QT interval prolongation.

Methods

We employed the preferred term (PT) "electrocardiogram QT prolonged" from the Medical Dictionary for Regulatory Activities (MedDRA) 26.0 to identify adverse drug events (ADEs) of QT interval prolongation in the FAERS database from the period 2004-2022. Reporting odds ratio (ROR) was performed to quantify the signals of ADEs.

Results

We listed the top 40 drugs that caused QT interval prolongation. Among them, the 3 drugs with the highest number of cases were quetiapine (1,151 cases, ROR = 7.62), olanzapine (754 cases, ROR = 7.92), and citalopram (720 cases, ROR = 13.63). The two most frequently reported first-level Anatomical Therapeutic Chemical (ATC) groups were the drugs for the nervous system (n = 19, 47.50%) and antiinfectives for systemic use (n = 7, 17.50%). Patients with missing gender (n = 3,482, 23.68%) aside, there were more females (7,536, 51.24%) than males (5,158, 35.07%) were involved. 3,720 patients (25.29%) suffered serious clinical outcomes resulting in deaths or life-threatening conditions. Overall, most drugs that caused QT interval prolongation had early failure types according to the assessment of the Weibull's shape parameter (WSP) analysis.

Conclusions

Our study offered a list of drugs that frequently caused QT interval prolongation based on the FAERS system, along with a description of some risk profiles for QT interval prolongation brought on by these drugs. When prescribing these drugs in clinical practice, we should closely monitor the occurrence of ADE for QT interval prolongation.

Strong independent association between third-degree AV-block and diabetes mellitus using a large database

BACKGROUND

Recent data suggests an association between DM and third-degree AV- Block. The goal of this study was to evaluate the independent association between diabetes and third-degree AV-Block using a very large database.

METHOD

We used ICD-9 Codes for DM and third-degree AV-block from the Nationwide Inpatient Sample (NIS) database. We randomly selected the 1992 and 2002 databases which are 10 years apart as two independent samples. We used uni- and multi-variate analysis to evaluate this association.

RESULTS

1992 database contained a total of 6,195,744 patients. Diabetes occurred in (0.5 %) of patients with third-degree AV-block vs. (0.2 %) of the control (OR: 2.15, CI 2.06-2.25, p < 0.0001). 2002 database contained a total of 7,853,982 patients. Diabetes occurred in (0.4 %) of patients with third-degree AV-block vs. (0.2 %) of the control (OR: 1.86, CI: 1.80-1.93, p < 0.0001). Using Multivariate analysis adjusting for age, congestive heart failure, and coronary artery disease, DM remained independently associated with third-degree AV block in both databases. (for 1999: OR: 2.54, CI 2.51-2.57, p < 0.0001 and for 2002 OR: 1.56, CI 1.55-1.57, p < 0.0001).

CONCLUSION

DM is independently associated with third-degree AV-block with persistent association over a period of 10 years. The cause of this association warrants further investigation.

Advanced Glycation End Products Downregulate Connexin 43 and Connexin 40 in Diabetic Atrial Myocytes via the AMPK Pathway

Purpose

Diabetes mellitus is an independent risk factor for atrial fibrillation (AF), which may be related to accumulation of advanced glycation end products (AGEs). However, the mechanisms involved are not completely clear. Abnormality of gap junction proteins, especially connexin 43 (Cx43) and connexin 40 (Cx40) in atrial myocytes, is an important cause of increased susceptibility of AF. The aim of our work is to investigate the mechanism of dysregulated Cx43 and Cx40 in atrial myocytes of diabetic rats.

Methods

We established a type 1 diabetic rat model by intraperitoneal injection of streptozotocin. HL-1 cells and primary rat atrial myocytes were treated with AGEs in vitro. Using Western blotting, immunofluorescence staining, immunohistochemistry, and lucifer yellow diffusion measurements, we investigated dysregulation of Cx43 and Cx40 and its mechanism in atrial myocytes of diabetic rats.

Results

Accumulation of AGEs was found in diabetic rats. The expression of Cx43 and Cx40 was reduced in the atrium of diabetic rats, accompanied by the decrease of phosphorylated Adenosine 5'-monophosphate-activated protein kinase (p-AMPK). Similar results were found in cultured HL-1 cells and primary rat atrial myocytes, suggesting a role of AGEs on gap junction proteins. An AMPK agonist, 5-Aminoimidazole-4-carboxamide ribonucleoside (AICAR), reversed the down-regulated Cx43 expression induced by AGEs stimulation. More importantly, lucifer yellow diffusion assay showed that AGEs significantly affected gap junctional function, and these changes were reversed by AICAR.

Conclusion

Thus, we conclude that AGEs cause dysregulation of Cx43 and Cx40 in diabetic atria via the AMPK pathway, thereby leading to gap junction dysfunction, which may contribute to the increased AF susceptibility in diabetes.

Sudden cardiac death, arrhythmias and abnormal electrocardiography in systemic sclerosis: A systematic review and meta-analysis

OBJECTIVE

To calculate the frequency of sudden cardiac death(SCD), arrhythmia and conduction defects in SSc.

METHODS

MEDLINE/EMBASE were searched to January 2023. English-language studies reporting the incidence/frequency of SCD, arrhythmia and electrocardiography(ECG) abnormalities in SSc were included. Odds ratios(OR), estimations of annual incidence or pooled frequencies were calculated.

RESULTS

Seventy-nine studies(n = 13,609 participants with SSc) were included in the meta-analysis. Methodology and outcomes were heterogeneous. Ten studies included cohorts with known/suspected SSc-associated heart involvement(SHI), generally defined as clinically-manifest cardiac disease/abnormal cardiac investigations. The incidence of SCD in SHI was estimated to be 3.3% annually(n = 4 studies, 301PY follow-up). On ambulatory ECG, 18% of SHI cohorts had non-sustained ventricular tachycardia(NSVT; n = 4, 95%CI3.2-39.3%), 70% frequent premature ventricular complexes (PVCs; n = 1, 95%CI34.8-93.3%), and 8% atrial fibrillation (AF; n = 1, 95%CI4.2-13.6%). Nineteen studies included participants without SHI, defined as normal cardiac investigations/absence of cardiac disease. The estimated incidence of SCD was approximately 2.9% annually (n = 1, 67.5PY). Compared to healthy controls, individuals without SHI demonstrated NSVT 13.3-times more frequently (n = 2, 95%CI2-102), and paroxysmal supraventricular tachycardia 7-times more frequently (n = 4, 95%CI3-15). Other ambulatory ECG abnormalities included NSVT in 9% (n = 7, 95%CI6-14%), >1000 PVCs/24 h in 6% (n = 2, 95%CI1-13%), and AF in 7% (n = 5, 0-21%). Fifty studies included general SSc cohorts unselected for cardiac disease. The incidence of SCD was estimated to be 2.0% annually(n = 4 studies, 1646PY). Unselected SSc cohorts were 10.5-times more likely to demonstrate frequent PVCs (n = 2, 95%CI 2-59) and 2.5-times more likely to have an abnormal electrocardiography (n = 2, 95%CI1-4).

CONCLUSIONS

The incidence of SCD in SSc is estimated to be 1.0-3.3% annually, at least 10-fold higher than general population estimates. Arrhythmias including NSVT and frequent PVCs appear common, including amongst those without known/suspected SHI.

The influence of different glucose tolerance on QTc interval: a population-based study

BACKGROUND

Corrected QT (QTc) interval has been reported to be associated with type 2 diabetes. This study aimed to explore the relationship between different glucose tolerance and QTc intervals among middle-aged and older Chinese individuals.

METHODS

We conducted a cross-sectional analysis that included 9898 subjects (3194 men and 6704 women) in a Chinese population. Glucose tolerance was studied during the oral glucose tolerance test (OGTT). Insulin, blood pressure, hemoglobin A1c (HbA1c), serum lipids, hepatic transaminases and waist-to-hip ratio were assessed. The QTc interval was derived from ECG recordings, and the subjects were stratified based on different glucose tolerance.

RESULTS

QTc interval levels were increased significantly in the subjects with abnormal glucose metabolism compared with the normal glucose regulation group. Multiple regression analyses showed that the QTc interval was significantly associated with fasting plasma glucose, 2-h OGTT plasma glucose and HbA1c. The odds ratio of prolonged QTc was 1.396 for impaired glucose regulation (IFG)/impaired fasting glucose (IGT) (95% CI 0.126-1.730), and 1.342 for type 2 diabetes (95% CI 0.142-1.577) after all potential confounders were adjusted.

CONCLUSIONS

Impaired glucose tolerance (IGR) and diabetes are associated with prolonged QTc intervals among middle-aged and older Chinese individuals. Abnormal glucose regulation can be used to monitor the QTc interval in the population.

Sudden Cardiac Death in Patients With Type 1 Versus Type 2 Diabetes

OBJECTIVE

To investigate the association between type 1 diabetes mellitus (T1D) and type 2 diabetes mellitus (T2D) with risk of sudden cardiac arrest (SCA).

METHODS

In a prospective community-based study of SCA from February 1, 2002, through November 30, 2019, we ascertained 2771 cases age 18 years of age or older and matched them to 8313 controls based on geography, age, sex, and race/ethnicity. We used logistic regression to evaluate the independent association between diabetes, T1D, T2D, and SCA.

RESULTS

Patients had a mean age of 64.5±15.9 years, were 33.3% female and 23.9% non-White race. Overall, 36.7% (n=1016) of cases and 23.8% (n=1981) of controls had diabetes. Among individuals with diabetes, the proportion of T1D was 6.5% (n=66) among cases and 2.0% among controls (n=40). Diabetes was associated with 1.5-times higher odds of SCA. Compared with those without diabetes, the odds ratio and 95% CI for SCA was 4.36 (95% CI, 2.81 to 6.75; P<.001) in T1D and 1.45 (95% CI, 1.30 to 1.63; P<.001) in T2D after multivariable adjustment. Among those with diabetes, the odds of having SCA were 2.41 times higher in T1D than in T2D (95% CI, 1.53 to 3.80; P<.001). Cases of SCA with T1D were more likely to have an unwitnessed arrest, less likely to receive resuscitation, and less likely to survive compared with those with T2D.

CONCLUSION

Type 1 diabetes was more strongly associated with SCA compared with T2D and had less favorable outcomes following resuscitation. Diabetes type could influence the approach to risk stratification and prevention of SCA.

Metformin Reduces Potassium Currents and Prolongs Repolarization in Non-Diabetic Heart

Metformin is the first choice drug for the treatment of type 2 diabetes due to positive results in reducing hyperglycaemia and insulin resistance. However, diabetic patients have higher risk of ventricular arrhythmia and sudden cardiac death, and metformin failed to reduce ventricular arrhythmia in clinical trials. In order to explore the mechanisms responsible for the lack of protective effect, we investigated in vivo the effect of metformin on cardiac electrical activity in non-diabetic rats; and in vitro in isolated ventricular myocytes, HEK293 cells expressing the hERG channel and human induced pluripotent stem cells derived cardiomyocytes (hIPS-CMs). Surface electrocardiograms showed that long-term metformin treatment (7 weeks) at therapeutic doses prolonged cardiac repolarization, reflected as QT and QTc interval duration, and increased ventricular arrhythmia during the caffeine/dobutamine challenge. Patch-clamp recordings in ventricular myocytes isolated from treated animals showed that the cellular mechanism is a reduction in the cardiac transient outward potassium current (Ito). In vitro, incubation with metformin for 24 h also reduced Ito, prolonged action potential duration, and increased spontaneous contractions in ventricular myocytes isolated from control rats. Metformin incubation also reduced IhERG in HEK293 cells. Finally, metformin incubation prolonged action potential duration at 30% and 90% of repolarization in hIPS-CMs, which is compatible with the reduction of Ito and IhERG. Our results show that metformin directly modifies the electrical behavior of the normal heart. The mechanism consists in the inhibition of repolarizing currents and the subsequent decrease in repolarization capacity, which prolongs AP and QTc duration.

Effect of hyperglycaemia in combination with moxifloxacin on cardiac repolarization in male and female patients with type I diabetes

Background

Patients with Type 1 diabetes mellitus have been shown to be at a two to ten-fold higher risk of sudden cardiac death (SCD) (Svane et al., Curr Cardiol 2020; 22:112) than the general population, but the underlying mechanism is unclear. Hyperglycaemia is a recognised cause of QTc prolongation; a state patients with type 1 diabetes are more prone to, potentially increasing their risk of ventricular arrhythmia. Understanding the QTc prolongation effect of both hyperglycaemia and the concomitant additive risk of commonly prescribed QTc-prolonging drugs such as Moxifloxacin may help to elucidate the mechanism of sudden cardiac death in this cohort. This single-blinded, placebo-controlled study investigated the extent to which hyperglycaemia prolongs the QTc in controlled conditions, and the potential additive risk of QTc-prolonging medications.

Methods

21 patients with type 1 diabetes mellitus were enrolled to a placebo-controlled crossover study at a single clinical trials unit. Patients underwent thorough QTc assessment throughout the study. A ‘hyperglycaemic clamp’ of oral and intravenous glucose was administered with a target blood glucose of > 25 mM and maintained for 2 h on day 1 and day 3, alongside placebo on day 1 and moxifloxacin on day 3. Day 2 served as a control day between the two active treatment days.

Thorough QTc assessment was conducted at matched time points over 3 days, and regular blood sampling was undertaken at matched time intervals for glucose levels and moxifloxacin exposure.

Results

Concentration-effect modelling showed that acute hyperglycaemia prolonged the QTc interval in female and male volunteers with type 1 diabetes by a peak mean increase of 13 ms at 2 h. Peak mean QTc intervals after the administration of intravenous Moxifloxacin during the hyperglycaemic state were increased by a further 9 ms at 2 h, to 22 ms across the entire study population. Regression analysis suggested this additional increase was additive, not exponential.

Hyperglycaemia was associated with a significantly greater mean QTc-prolonging effect in females, but the mean peak increase with the addition of moxifloxacin was the same for males and females. This apparent sex difference was likely due to the exclusive use of basal insulin in the male patients, which provided a low level of exogenous insulin during the study assessments thereby mitigating the effects of hyperglycaemia on QTc. This effect was partially overcome by Moxifloxacin administration, suggesting both hyperglycaemia and moxifloxacin prolong QTc by different mechanisms, based on subinterval analysis.

Conclusions

Hyperglycaemia was found to be a significant cause of QTc prolongation and the additional effect of a QTc-prolonging positive control (moxifloxacin) was found to be additive. Given the high risk of sudden cardiac death in type 1 diabetes mellitus, extra caution should be exercised when prescribing any medication in this cohort for QTc effects, and further research needs to be undertaken to elucidate the exact mechanism underlying this finding and explore the potential prescribing risk in diabetes.

Trial Registration

NCT number: NCT01984827.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00392-022-02037-8.

Let It Beat: How Lifestyle and Psychosocial Factors Affect the Risk of Sudden Cardiac Death-A 10-Year Follow-Up Study

(1) Background: The aim of this study was to evaluate the lifestyle and occurrence of psychosocial factors in patients with a high risk of sudden cardiac death (SCD) and to explore their effect on the occurrence of the adequate therapy of an Implantable Cardioverter Defibrillator (ICD). (2) Methods: In this retro-prospective single-centre study, a group of patients aged 18-65 years old, who underwent the first ICD implantation for primary (PP) or secondary (SP) prevention between 2010-2014, was studied. The control group consisted of pair-matched (age ± 5 years, gender) respondents without a high risk of SCD. Information was obtained using a self-reported questionnaire and hospital electronic health records. The adequacy of ICD therapy was evaluated regularly until 31 January 2020. Multivariate logistic regression models were employed to assess the risk of SCD. (3) Results: A family history of SCD, coronary artery disease, diabetes mellitus and depression significantly aggravated the odds of being at a high risk of SCD. The occurrence of an appropriate ICD therapy was significantly associated with being in the SP group, BMI, education level and TV/PC screen time. (4) Conclusions: Lifestyle and psychosocial factors have been confirmed to affect the risk of SCD. Early identification and treatment of coronary artery disease and its risk factors remain the cornerstones of preventive effort. Further research is needed to evaluate the complex nature of psychosocial determinants of cardiac health.

New insights into the role of melatonin in diabetic cardiomyopathy

Diabetic cardiovascular complications and impaired cardiac function are considered to be the main causes of death in diabetic patients worldwide, especially patients with type 2 diabetes mellitus (T2DM). An increasing number of studies have shown that melatonin, as the main product secreted by the pineal gland, plays a vital role in the occurrence and development of diabetes. Melatonin improves myocardial cell metabolism, reduces vascular endothelial cell death, reverses microcirculation disorders, reduces myocardial fibrosis, reduces oxidative and endoplasmic reticulum stress, regulates cell autophagy and apoptosis, and improves mitochondrial function, all of which are the characteristics of diabetic cardiomyopathy (DCM). This review focuses on the role of melatonin in DCM. We also discuss new molecular findings that might facilitate a better understanding of the underlying mechanism. Finally, we propose potential new therapeutic strategies for patients with T2DM.

Sudden cardiac death in diabetes and obesity: mechanisms and therapeutic strategies

Ventricular arrhythmias and sudden cardiac death (SCD) occur most frequently in the setting of coronary artery disease, cardiomyopathy and heart failure, but are also increasingly observed in individuals suffering from diabetes mellitus and obesity. The incidence of these metabolic disorders is rising in Western countries, but adequate prevention and treatment of arrhythmias and SCD in affected patients is limited due to our incomplete knowledge of the underlying disease mechanisms. Here, an overview is presented of the prevalence of electrophysiological disturbances, ventricular arrhythmias and SCD in the clinical setting of diabetes and obesity. Experimental studies are reviewed, which have identified disease pathways and associated modulatory factors, in addition to pro-arrhythmic mechanisms. Key processes are discussed, including mitochondrial dysfunction, oxidative stress, cardiac structural derangements, abnormal cardiac conduction, ion channel dysfunction, prolonged repolarization and dysregulation of intracellular sodium and calcium homeostasis. In addition, the recently identified pro-arrhythmic effects of dysregulated branched chain amino acid metabolism, a common feature in patients with metabolic disorders, are addressed. Finally, current management options are discussed, in addition to the potential development of novel preventive and therapeutic strategies based on recent insight gained from translational studies.

Sudden Cardiac Death in Systemic Sclerosis: Diagnostics to Assess Risk and Inform Management

Cardiac disease is a leading cause of death in systemic sclerosis (SSc) and sudden cardiac death (SCD) is thought to occur more commonly in SSc than in the general population. Diffuse myocardial fibrosis, myocarditis and ischaemic heart disease are all prevalent in SSc and can be reasonably hypothesised to contribute to an increased risk of SCD. Despite this, SCD remains a relatively understudied area of SSc with little understood about SSc-specific risk factors and opportunities for primary prevention. In this review, we present an overview of the possible mechanisms of SCD in SSc and our current understanding of how each of these mechanisms may contribute to cardiac death. This review highlights the need for a future research agenda that addresses the underlying epidemiology of SCD in SSc and identifies opportunities for intervention to modify the disease course of heart disease in SSc.

Silent coronary artery disease in type 2 diabetes: a narrative review on epidemiology, risk factors, and clinical studies

Silent coronary artery disease (CAD) is one of the manifestations of heart disease that particularly affects subjects with type 2 diabetes mellitus (T2DM). From a clinical point of view, silent CAD represents a constant challenge for the diabetologist, who has to decide whether a patient could or could not be screened for this disease. In the present narrative review, several aspects of silent CAD are considered: the epidemiology of the disease, the associated risk factors, and main studies conducted, in the last 20 years, especially aimed to demonstrate the usefulness of the screening of silent CAD, to improve cardiovascular outcomes in type 2 diabetes.