Diabetes mellitus and risk of sudden cardiac death: A systematic review and meta-analysis

Diabetes and mortality risk in patients undergoing coronary angiography: The KARDIO study

BACKGROUND

Diabetes is an established risk factor for adverse cardiovascular outcomes including mortality, but the relationship between diabetes and mortality risk in the presence of the extensive or diffuse form of coronary artery disease (CAD) is controversial.

AIMS

We evaluated the association between diabetes and mortality risk in patients who underwent coronary angiography using a real-life clinical database.

METHODS

We utilized the KARDIO registry, which comprised data on demographics, prevalent diseases, including diabetes status, cardiovascular risk factors, coronary angiographies, and other interventions in 79,738 patients. Hazard ratios (HRs) (95% confidence intervals [CIs]) for the association between prevalent diabetes and all-cause mortality were estimated.

RESULTS

During a median follow-up of 5.5 years, 11,896 all-cause deaths occurred. In analyses adjusted for age, smoking status, hypertension, family history of CAD, dyslipidaemia, urgency of intervention, body mass index, sex, and sex-age interaction, the HR (95% CI) for mortality comparing diabetes with no diabetes was 1.44 (1.38, 1.50). Following additional adjustment for the degree of CAD (1-3 vessels disease) as confirmed by angiography, the HR (95% CI) for mortality remained similar 1.43 (1.36, 1.49). The association did not vary significantly across several relevant clinical characteristics except for a stronger association in those with a family history of CAD than those without (p = 0.034) and former smokers than nonsmokers (p = 0.046).

CONCLUSION

In patients undergoing coronary angiography, diabetes is associated with an increased mortality risk, independent of several risk factors including the degree of CAD. The association may be modified by family history of CAD and smoking status.

Effect of empagliflozin on ventricular arrhythmias in patients with type 2 diabetes treated with an implantable cardioverter-defibrillator: the EMPA-ICD trial

BACKGROUND

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of hospitalization for heart failure and cardiovascular death with type 2 diabetes; however, their effect on arrhythmias is unclear. The purpose of this study was to investigate the effects of empagliflozin on ventricular arrhythmias in patients with type 2 diabetes.

METHODS

A total of 150 patients with type 2 diabetes who were treated with an implantable cardioverter-defibrillator or cardiac resynchronization therapy defibrillator (ICD/CRT-D) were randomized to once-daily empagliflozin or placebo for 24 weeks. The primary endpoint was the change in the number of ventricular arrhythmias from the 24 weeks before to the 24 weeks during treatment. Secondary endpoints included the change in the number of appropriate device discharges and other values.

RESULTS

In the empagliflozin group, the number of ventricular arrhythmias recorded by ICD/CRT-D decreased by 1.69 during treatment compared to before treatment, while in the placebo group, the number increased by 1.79. The coefficient for the between-group difference was - 1.07 (95% confidence interval [CI] - 1.29 to - 0.86; P < 0.001). The change in the number of appropriate device discharges during and before treatment was 0.06 in the empagliflozin group and 0.27 in the placebo group, with no significant difference between the groups (P = 0.204). Empagliflozin was associated with an increase in blood ketones and hematocrit and a decrease in blood brain natriuretic peptide and body weight.

CONCLUSIONS

In patients with type 2 diabetes treated with ICD/CRT-D, empagliflozin reduces the number of ventricular arrhythmias compared with placebo. Trial registration jRCTs031180120.

Accuracy and Functionality of Select Continuous Glucose Monitoring Systems Are Not Impacted by Implantable Cardioverter Defibrillator Devices

BACKGROUND

Increasing numbers of individuals with diabetes are adopting use of continuous glucose monitoring (CGM) in their daily self-management. Many of these individuals have advanced heart disease. Implantable cardioverter defibrillator (ICD) devices can effectively reduce arrhythmic death and all-cause mortality in individuals with advanced heart disease. However, the potential impact of ICD devices on CGM system accuracy and functionality has not been well studied.

METHODS

This evaluation assessed whether FreeStyle Libre (FL) CGM systems can coexist and function within the same patient in the presence of wireless interference devices, including current ICD devices. Interferer sources included Wi-Fi devices, Bluetooth devices, cellular mobile devices, implantable medical devices, Bluetooth Low-Energy (BLE) devices, BLE accessory devices and BLE mobile devices, and ICD-programmer interferers. Five testing methodologies were used to evaluate the accuracy and functionality of the CGM systems when exposed to ICD functions: high-energy emergency shocking, pacing modes, anti-tachycardia pacing mode (ATP), and DC Fibber mode.

RESULTS

All acceptance criteria and testing requirements were met for the CGM and ICD system for wireless coexistence evaluation.

CONCLUSIONS

Our findings demonstrated that coexisting ICD devices and FL CGM systems provide safe and effective wireless communications with functional and accurate transfer of data during scenarios expected in clinical use.

Implantable cardioverter defibrillator and cardiac resynchronization treatment in people with type 2 diabetes: a comparison with age- and sex matched controls from the general population

BACKGROUND

Increased risk of severe tachyarrhythmias is reported in patients with type 2 diabetes mellitus (T2DM). The aim of this study was to explore if treatment with cardiac implantable electronic device (CIED) such as implantable cardioverter defibrillator (ICD), cardiac resynchronization therapy- pacemaker and -defibrillator (CRT-P/CRT-D) differed in patients with vs. without T2DM. A secondary aim was to identify patient characteristics indicating an increased CIED treatment.

METHOD

416 162 adult patients with T2DM from the Swedish National Diabetes Registry and 2 081 087 controls from the Swedish population, matched for age, sex and living area, were included between 1/1/1998 and 31/12/2012 and followed until 31/12/2013. They were compared regarding prevalence of ventricular tachycardia (VT) at baseline and the risk of receiving a CIED during follow-up. Multivariable Cox regression analysis was performed to estimate the risk of CIED-treatment and factors identifying patients with such risk.

RESULTS

Ventricular fibrillation (VF) (0.1% vs 0.0004%) and (VT) (0.2% vs. 0.1%) were more frequent among patients with T2DM compared to controls. CIED-treatment was significantly increased in patients with T2DM both in unadjusted and adjusted analyses. HR and 95% CI, after adjustment for sex, age, marital status, income, education, country of birth, coronary artery disease and congestive heart failure, were 1.32 [1.21-1.45] for ICD, 1.74 [1.55-1.95] for CRT-P and 1.69 [1.43-1.99] for CRT-D. Blood-pressure and lipid lowering therapies were independent risk factors associated to receiving CIED, while female sex was protective.

CONCLUSIONS

Although the proportion of VT/VF was low, patients with T2DM had a higher prevalence of these conditions and increased risk for treatment with CIED compared to controls. This underlines the importance of recognizing that T2DM patients have an increased need of CIED.

Normal-weight central obesity and risk of cardiovascular and microvascular events in adults with prediabetes or diabetes: Chinese and British cohorts

OBJECTIVE

To investigate the relationship between body fat distribution and risk of cardiometabolic and microvascular events among individuals with prediabetes or diabetes with normal body mass index (BMI).

METHODS

A total of 17,232 participants with prediabetes or diabetes from UK Biobank (UKB) with 12-year follow-up and 499 diabetic participants from China with 2-year follow-up with normal BMI were included. Anthropometric measurements of waist circumference (WC), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR), and body fat composition assessment of trunk-to-leg fat ratio (TLFR) were obtained. Outcomes included incident all-cause and cardiovascular mortality and macrovascular and microvascular diseases.

RESULTS

In British cohort, participants with central obesity defined by WHR had 27%-54% higher risk of incident all-cause mortality (hazard ratio (HR) 1.42, 95% confidence interval (CI): 1.23-1.64), cardiovascular mortality (HR 1.54 [1.15-2.07]), myocardial infarction (HR = 1.43 [1.15, 1.78]), stroke (HR 1.26 [0.90, 1.75]), heart failure (HR = 1.27 [1.00, 1.61]), diabetic nephropathy (HR 1.33 [1.07, 1.65]), and diabetic retinopathy (DR) (HR = 1.48 [1.12, 1.96]) than those without obesity. Central obesity defined by WC and WHtR was associated with 40%-44% and 23%-98% higher risks of developing diabetic events, respectively. In the Chinese cohort, individuals with abdominal obesity, defined by WC (HR 1.44) or WHtR (HR 1.43) but not by WHR, carried more than 40% higher risk of developing DR than those without it. Higher TLFR carried 1.30-2.85 times higher risk of CVD and microvascular diseases among the dysglycemic population.

CONCLUSIONS

Body fat distribution diseases among individuals with prediabetes or diabetes are associated with an increased risk of cardiometabolic and microvascular diseases independent of BMI.

Type 2 diabetes and in-hospital sudden cardiac arrest in ST-elevation myocardial infarction in the US

Aims

We aimed to assess the impact of diabetes on sudden cardiac arrest (SCA) in US patients hospitalized for ST-elevation myocardial infarction (STEMI).

Methods

We used the National Inpatient Sample (2005-2017) data to identify adult patients with STEMI. The primary outcome was in-hospital SCA. Secondary outcomes included in-hospital mortality, ventricular tachycardia (VT), ventricular fibrillation (VF), cardiogenic shock (CS), acute renal failure (ARF), and the revascularization strategy in SCA patients.

Results

SCA significantly increased from 4% in 2005 to 7.6% in 2018 in diabetes patients and from 3% in 2005 to 4.6% in 2018 in non-diabetes ones (p < 0.001 for both). Further, diabetes was associated with an increased risk of SCA [aOR = 1.432 (1.336-1.707)]. In SCA patients with diabetes, the mean age (SD) decreased from 68 (13) to 66 (11) years old, and mortality decreased from 65.7% to 49.3% during the observation period (p < 0.001). Compared to non-diabetes patients, those with T2DM had a higher adjusted risk of mortality, ARF, and CS [aOR = 1.72 (1.62-1.83), 1.52 (1.43-1.63), 1.25 (1.17-1.33); respectively] but not VF or VT. Those patients were more likely to undergo revascularization with CABG [aOR = 1.197 (1.065-1.345)] but less likely to undergo PCI [aOR = 0.708 (0.664-0.754)].

Conclusion

Diabetes is associated with an increased risk of sudden cardiac arrest in ST-elevation myocardial infarction. It is also associated with a higher mortality risk in SCA patients. However, the recent temporal mortality trend in SCA patients shows a steady decline, irrespective of diabetes.

Diabetes mellitus and hemodynamics in advanced heart failure

BACKGROUND

The presence of diabetes in patients with heart failure (HF) is associated with a worse prognosis. It is unclear if hemodynamics in HF patients with DM differ from those of non-diabetic patients and how this might influence outcome. This study aims to discover the impact of DM on hemodynamics in HF patients.

METHODS

Consecutive patients (n = 598) with HF and reduced ejection fraction (LVEF ≤40%) undergoing invasive hemodynamic evaluation were included (non-DM: n = 473, DM: n = 125). Hemodynamic parameters included pulmonary capillary wedge pressure (PCWP), central venous pressure (CVP), cardiac index (CI) and mean arterial pressure (MAP). Mean follow-up was 9.5 ± 5.1 years.

RESULTS

Patients with DM (82.7% male, mean age 57.1 ± 10.1 years, mean HbA1c 60 ± 21 mmol/mol) had higher PCWP, mPAP, CVP and higher MAP. Adjusted analysis demonstrated that DM patients had higher PCWP and CVP. Increasing HbA1c-values were correlated with higher PCWP (p = 0.017) and CVP (p = 0.043).

CONCLUSION

Patients with DM, especially those with poor glycemic control, have higher filling pressures. This may be a feature of diabetic cardiomyopathy, however, other unknown mechanisms beyond hemodynamic factors are likely to explain the increased mortality associated with diabetes in HF.

Buffer glucose adjustment affects myocardial function after ischemia-reperfusion in long-term diabetic rat isolated hearts

Due to its comorbidities type 2 diabetes mellitus (T2DM) and hypertension, the Zucker Spontaneous Hypertensive Fatty (ZSF1) rat is a clinically relevant animal model when assessing ischemia-reperfusion (IR) injury. Most IR studies in hearts isolated from diabetic animals have been conducted at normal glucose concentrations, providing a different environment compared to in-vivo. We hypothesized IR injury to be attenuated in isolated hearts of diabetic ZSF1 rats when adjusting the Krebs-buffer (KB) to their in-vivo, i.e., elevated blood glucose (BG) levels. Diabetic and non-diabetic ZSF1 rats were anesthetized, hearts isolated and Langendorff-prepared. While standard KB was used for the non-diabetic and diabetic unadjusted groups, KB with glucose levels increased to each rat's prior BG level was used for the adjusted diabetic group. All hearts underwent 30 min ischemia and 120 min reperfusion. Diastolic contracture during ischemia and early reperfusion was delayed and temporarily attenuated in the adjusted compared to the unadjusted diabetic and the non-diabetic groups. The decrease in coronary flow on reperfusion was attenuated in diabetic animals. Left ventricular developed pressure and contractility were not different among the three groups. Infarct size was significantly lower in non-diabetic animals; buffer adjustment made no difference in diabetic animals. In our study, T2DM did not worsen myocardial function in ZSF1 rat isolated hearts. Since our results reveal that hearts with an adjusted glucose level exhibit an at least temporary improvement of function following IR, further studies should consider adapting glucose levels to create more realistic conditions in isolated, perfused hearts.

Diabesity phenotype and the risks of cardiovascular disease and subclinical atherosclerosis: A prospective cohort study

OBJECTIVE

The aim of this study was to investigate the associations of diabesity with incident cardiovascular disease (CVD) and subclinical atherosclerosis.

METHODS

The prospective cohort study included 8,006 participants without baseline CVD. Diabesity was categorized as (i) normal glucose tolerance (NGT) with nonobesity; (ii) NGT with obesity; (iii) prediabetes with nonobesity; (iv) prediabetes with obesity; (v) diabetes with nonobesity; and (vi) diabetes with obesity. The hazard ratios (HRs) for incident CVD and odds ratios (ORs) for subclinical atherosclerosis associated with diabesity categories were examined.

RESULTS

Compared with the category of NGT with nonobesity, the categories of NGT with obesity (HR 1.68; 95% CI: 1.10-2.57), diabetes with nonobesity (HR 1.42; 95% CI: 1.08-1.88), and diabetes with obesity (HR 1.78; 95% CI: 1.24-2.55) were associated with higher risks of CVD. Prediabetes with or without obesity conferred no excess risk for CVD but higher risks for subclinical atherosclerosis. The diabetes with obesity category was associated with the highest risk for elevated pulse pressure (OR 3.07; 95% CI: 2.06-4.58) and albuminuria (OR 3.39; 95% CI: 2.31-4.99), and diabetes with or without obesity showed comparable ORs for elevated brachial-ankle pulse wave velocity.

CONCLUSIONS

The association patterns between diabesity and CVD risks support the value of diabesity as a prevention target for CVD.

Diagnostic and therapeutic characteristics of diabetes mellitus and risk of out-of-hospital cardiac arrest

This study aimed to evaluate the risks of diabetes mellitus (DM) on out-of-hospital cardiac arrest (OHCA) and to investigate whether the risks of DM on OHCA varied according to the diagnostic and therapeutic characteristics of diabetes. We conducted a multicenter prospective case–control study in 17 University hospitals in Korea from September 2017 to December 2020. Cases were EMS-treated OHCA patients aged 20 to 79 with a presumed cardiac etiology. Community-based controls were recruited at a 1:2 ratio after matching for age, sex, and urbanization level of residence. A structured questionnaire and laboratory findings were collected from cases and controls. Multivariable conditional logistic regression analyses were conducted to estimate the risk of DM on OHCA by characteristics. A total of 772 OHCA cases and 1544 community-based controls were analyzed. A total of 242 (31.3%) OHCAs and 292 (18.9%) controls were previously diagnosed with DM. The proportions of type I DM (10.7% vs. 2.1%) and insulin therapy (15.3% vs. 6.5%) were higher in OHCAs with DM than in controls with DM. The duration of DM was longer in OHCAs than in controls (median 12 vs. 7 years). DM was associated with an increased risk of OHCA (aOR (95% CI), 2.13 (1.64–2.75)). Compared to the no diabetes group, the risks of OHCA increased in the diabetes patients with type I DM (5.26 (1.72–16.08)) and type II DM group (1.63 (1.18–2.27)), a long duration of DM prevalence (1.04 (1.02–1.06) per 1-year prevalence duration), and a high HbA1c level (1.38 (1.19–1.60) per 1% increase). By treatment modality, the aOR (95% CI) was lowest in the oral hypoglycemic agent (1.47 (1.08–2.01)) and highest in the insulin (6.63 (3.04–14.44)) groups. DM was associated with an increased risk of OHCA, and the risk magnitudes varied according to the diagnostic and therapeutic characteristics.

Temporal variation in out-of-hospital cardiac arrest occurrence in individuals with or without diabetes

Objective

Out-of-hospital cardiac arrest (OHCA) occurrence has been shown to exhibit a circadian rhythm, following the circadian rhythm of acute myocardial infarction (AMI) occurrence. Diabetes mellitus (DM) is associated with changes in circadian rhythm. We aimed to compare the temporal variation of OHCA occurrence over the day and week between OHCA patients with DM and those without.

Methods

In two population-based OHCA registries (Amsterdam Resuscitation Studies [ARREST] 2010-2016, n = 4163, and Danish Cardiac Arrest Registry [DANCAR], 2010-2014, n = 12,734), adults (≥18y) with presumed cardiac cause of OHCA and available medical history were included. Single and double cosinor analysis was performed to model circadian variation of OHCA occurrence. Stratified analysis of circadian variation was performed in patients with AMI as immediate cause of OHCA.

Results

DM patients (22.8% in ARREST, 24.2% in DANCAR) were older and more frequently had cardiovascular risk factors or previous cardiovascular disease. Both cohorts showed 24 h-rhythmicity, with significant amplitudes in single and double cosinor functions (P-range < 0.001). In both registries, a morning peak (10:00-11:00) and an evening peak (20:00-21:00) was observed in both DM and non-DM patients. No septadian variation was observed in either DM or non-DM patients (P-range 0.13-84).

Conclusions

In these two population-based OHCA registries, we observed a similar circadian rhythm of OHCA occurrence in DM and non-DM patients.

Association between sodium-glucose cotransporter-2 inhibitors and risk of sudden cardiac death or ventricular arrhythmias: a meta-analysis of randomized controlled trials

AIMS 

Sudden cardiac death (SCD) and ventricular arrhythmias (VAs) are important causes of mortality in patients with type 2 diabetes mellitus (T2DM), heart failure (HF), or chronic kidney disease (CKD). We evaluated the effect of sodium-glucose cotransporter-2 (SGLT2) inhibitors on SCD and VAs in these patients.

METHODS AND RESULTS 

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) that enrolled patients with T2DM and/or HF and/or CKD comparing SGLT2i and placebo or active control. PubMed and ClinicalTrials.gov were systematically searched until November 2020. A total of 19 RCTs with 55 ,590 participants were included. Sudden cardiac death events were reported in 9 RCTs (48 patients receiving SGLT2i and 57 placebo subjects). There was no significant association between SGLT2i therapy and SCD [risk ratio (RR) 0.74, 95% confidence interval (CI) 0.50-1.08; P = 0.12]. Ventricular arrhythmias were reported in 17 RCTs (126 patients receiving SGLT2i and 134 controls). SGLT2i therapy was not associated with a lower risk of VAs (RR 0.84, 95% CI 0.66-1.06; P = 0.14). Besides the subgroup of low-dosage SGLT2i therapy that demonstrated decreased VAs compared to control (RR 0.45, 95% CI 0.25-0.82; P = 0.009), or to placebo (RR 0.46, 95% CI 0.25-0.85; P = 0.01), further subgroup analysis did not demonstrate any significant differences.

CONCLUSION 

SGLT2i therapy was not associated with an overall lower risk of SCD or VAs in patients with T2DM and/or HF and/or CKD. However, further research is needed since the number of SCD and VA events were relatively few leading to wide confidence intervals, and the point estimates suggested potential benefits.

Impaired hypoxic ventilatory drive induced by diabetic autonomic neuropathy, a cause of misdiagnosed severe cardiac events: brief report of two cases

Background

Sudden cardiac deaths are twice more frequent in diabetic patients with cardiac autonomic neuropathy. Sudden cardiac death etiologies remain unclear and no recommendations are made to identify factors associated with cardiorespiratory arrest in diabetic patients. We hypothesized, from two clinical cases, that impaired hypoxic ventilatory drive, induced by diabetic autonomic neuropathy, is a cause of misdiagnosed severe cardiac events.

Case presentation

We describe the cases of two patients with isolated low blood saturation on pulse oximeter during the systematic nurse check-up (77% and 85% respectively) contrasting with the absence of any complaint such as dyspnea, polypnea or other respiratory insufficiency signs observed during the clinical examination. Arterial blood gas measurements subsequently confirmed that blood oxygen saturation was low and both patients were indeed hypoxemic. Patient 1 suffered from vascular overload complicated by cardiac arrest caused by hypoxemia in light of the quick recovery observed after ventilation. Pulmonary edema was diagnosed in patient 2. The common denominator of these 2 cases described in this brief report is the absence of respiratory failure clinical signs contrasting with the presence of confirmed hypoxemia. Also, in both cases, such absence of precursory signs seems to be induced by an impaired ventilatory drive to hypoxemia. This appears to be related to the autonomic diabetic neuropathy encountered in those 2 patients.

Conclusions

Therefore, we describe, in this brief report, cardiac autonomic neuropathy as a cause of impaired hypoxic ventilatory drive involved in severe acute cardiorespiratory events in two type 1 diabetic patients. We assume that altered response to hypoxemia due to cardiac autonomic neuropathy and non-functional central neurological breathing command could play a key role in sudden deaths among diabetic patients. An important point is that hypoxemia can be easily missed since no clinical signs of respiratory failure are reported in these two clinical cases. Systematic screening of cardiac autonomic neuropathy in diabetic patients and proactive detection of impaired hypoxic ventilatory drive for early management (e.g. treatment of hypoxemia) should be systematically undertaken in diabetic patients to prevent its dramatic consequences such as cardiorespiratory arrest and death.

High Prevalence of Diabetes Mellitus and Mental Illness Among Victims of Sudden Death

OBJECTIVES

Diabetes mellitus (DM) increases the risk of cardiovascular disease and is associated with sudden death. Mental illness among individuals with DM may confound medical care. This study assessed the association of mental illness with DM and poorly controlled DM in sudden death victims.

METHODS

We screened out-of-hospital deaths ages 18 to 64 years in Wake County, North Carolina from 2013 to 2015 to adjudicate sudden deaths. We abstracted demographics and clinical characteristics from health records. Mental illness included anxiety, schizophrenia, bipolar disorder, or depression. Poorly controlled DM was defined as a hemoglobin A1c >8 or taking ≥3 medications for glycemic control. Logistic regression assessed the association between DM and mental illness.

RESULTS

Among victims with available records, 109 (29.4%) had DM. Of those, 62 (56.9%) had mental illness. Mental illness was present in 53.42% and 63.89% of victims with mild and poorly controlled DM, respectively. Mental illness was associated with DM (adjusted odds ratio 2.46, 95% confidence interval 1.57-3.91). Victims with poorly controlled DM were more likely to have mental illness (adjusted odds ratio 2.66, 95% confidence interval 1.14-6.18).

CONCLUSIONS

DM is a common comorbid condition in sudden death victims. Among victims, mental illness is associated with the control of DM. Early management of comorbid mental illnesses may improve the care of patients with DM and reduce the incidence of sudden death.

Interleukin-1β, Oxidative Stress, and Abnormal Calcium Handling Mediate Diabetic Arrhythmic Risk

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Diabetes-induced arrhythmic risk involved activation of innate immunity, elevation of IL-1β, mitochondrial oxidative stress, SR calcium release channel oxidation, and QT prolongation.

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Diabetes-induced arrhythmic risk could be inhibited by IL-1β antagonism, mitoROS scavenging, and SR calcium release stabilization.

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The relationship of inflammation and arrhythmic risk may account for increased susceptibility of diabetic patients to the effects of COVID-19.

Diabetes mellitus (DM) is associated with increased arrhythmia. Type 2 DM (T2DM) mice showed prolonged QT interval and increased ventricular arrhythmic inducibility, accompanied by elevated cardiac interleukin (IL)-1β, increased mitochondrial reactive oxygen species (mitoROS), and oxidation of the sarcoplasmic reticulum (SR) Ca²⁺ release channel (ryanodine receptor 2 [RyR2]). Inhibiting IL-1β and mitoROS reduced RyR2 oxidation and the ventricular arrhythmia in DM. Inhibiting SR Ca2⁺ leak by stabilizing the oxidized RyR2 channel reversed the diabetic arrhythmic risk. In conclusion, cardiac IL-1β mediated the DM-associated arrhythmia through mitoROS generation that enhances SR Ca²⁺ leak. The mechanistic link between inflammation and arrhythmias provides new therapeutic options.

Baroreflex sensitivity with different lags and random forests for staging cardiovascular autonomic neuropathy in subjects with diabetes

Impaired baroreflex sensitivity (BRS) may indicate cardiovascular autonomic neuropathy (CAN), which often remains undiagnosed during the initial course of diabetes mellitus. The baroreflex mechanism can be considered negative feedback because of baroreflex delay, the time delay between a change in blood pressure and the counteracting heart rate response. This work sought to analyze BRS considering lags from 1 to 10 RR intervals. We hypothesized that diabetic patients with subclinical CAN (SCAN) have a detectable delay in autonomic nervous system activity and that this would differ from patients without CAN (NCAN) and with established CAN (ECAN). In the first stage, 30 patients were included in an exploratory analysis using the Principal Component Analysis. Six indexes related to the BRS delay were proposed and considered significant for staging diabetic patients. Three indexes allowed for the differentiating of patients with and without CAN, and three indexes distinguished subjects with SCAN from subjects with NCAN or ECAN. Then, in the second stage, a random forest model was developed with 72 subjects, using the variables selected in the first stage. It was possible to detect SCAN, and to point out those subjects with the potential to change the CAN stage, allowing for the tracking of CAN progression. The model achieved a sensitivity of 96% and specificity of 100% to detect SCAN. Thus, the BRS analysis considering delayed reaction in the dynamics of heart rate variability may contribute to an accurate screening tool to staging CAN, in addition to indicating patients with most insidious disease progress.

Sudden cardiac death among persons with diabetes aged 1-49 years: a 10-year nationwide study of 14 294 deaths in Denmark

AIMS

The aim of this study was to compare nationwide incidence rate (IR) of sudden cardiac death (SCD) in persons aged 1-49 years with and without diabetes mellitus (DM).

METHODS AND RESULTS

The study population consisted of all persons in Denmark aged 1-49 years in 2000-09, which equals 27.1 million person-years. All 14 294 deaths in the 10-year period were included. By using the highly descriptive Danish death certificates, 1698 cases of sudden and unexpected death were identified. Through review of autopsy reports, discharge summaries, and the Danish registries, we identified 1363 cases of SCD. The Danish Register of Medicinal Product Statistics was used to identify persons with type 1 DM and type 2 DM. Among the 14 294 decedents, there were 669 with DM, of which 118 suffered SCD (9% of all SCD), making SCD the leading cause of death among young persons with DM. Among those aged 1-35 years, the IR of SCD-DM was 21.9 per 100 000 person-years compared to 2.6 per 100 000 person-years among persons without DM [IR ratio 8.6, 95% confidence interval (CI) 5.8-28.6]. Within the age range 36-49 years, the IR among persons with DM was 119.8 per 100 000 person-years compared to 19.7 per 100 000 person-years among persons without DM (IR ratio 6.1, 95% CI 4.7-7.8).

CONCLUSION

We found that young persons with DM aged 1-35 years had >8-fold higher SCD IR compared to young persons without DM. Our study highlights the need for early cardiovascular risk monitoring and assessment in young persons with DM.

End stage renal disease modifies the effect of targeted temperature management after out-of-hospital cardiac arrest

INTRODUCTION

Kidney function can affect the permeability of the blood-brain barrier; thus, end-stage renal disease (ESRD) may alter the effects of targeted temperature management (TTM) on the neurological outcomes of out-of-hospital cardiac arrest (OHCA) patients. We aimed to investigate whether the interaction effect of TTM on outcomes after OHCA was observed among patients with and without ESRD.

METHODS

Adult OHCA patients with presumed cardiac etiology who attained sustained return of spontaneous circulation from 2013 to 2017 were included using nationwide OHCA registry. The main exposure variable was TTM. The primary endpoint was survival with good neurological recovery. Multivariable logistic regression analysis was performed after adjustment for potential confounders. To compare the effect of ESRD on TTM, an interaction term (TTM × ESRD) was added to the model.

RESULTS

A total of 21,250 patients were included in the analysis; 2693 (12.7%) patients underwent TTM. ESRD was observed in 128 (4.8%) in the TTM group and 767 (4.1%) in the no-TTM group. The TTM group showed better outcomes than the no-TTM group (32.4% vs. 17.2%, p < 0.01). The adjusted odds ratio of TTM for good neurological recovery in the entire study group was 1.15 (95% CI, 1.03-1.29). In the interaction model, the adjusted odds ratio of TTM for good neurological recovery was 0.47 (95% CI, 0.23-0.98) in the ESRD group vs. 1.54 (95% CI, 1.00-2.39) in the no-ESRD group.

CONCLUSIONS

The interaction effect between ESRD and TTM on neurologic outcome was positive in adult OHCA initial survivors with presumed cardiac etiology.

Heart failure and its complications in patients with diabetes: Mounting evidence for a growing burden

Heart failure (HF) is one of the major challenges in the management of diabetes patients. Among subjects with diabetes, up to 20% could have HF. Conversely, diabetes prevalence in HF patients varies greatly from more than 10% up to 50%. When it is present, the risk of mortality and rehospitalization increases substantially. In addition, current evidence points to an increased risk of atrial fibrillation and sudden cardiac death in patients with diabetes. The inter-relation between diabetes cardiomyopathy, left ventricular hypertrophy, coronary artery disease and renal dysfunction indicates complex and intricate pathways. Despite the great value of clinical assessment and echocardiography, there is insufficient data to suggest systematic screening for HF in asymptomatic patients with diabetes. There is little evidence to indicate that improved glycaemic control improves HF outcome in this population. In the case of established HF, the general guidelines apply in diabetes patients. However, recent advances concerning glucose-lowering treatment in patients with cardiovascular disease suggest that the choice of glucose-lowering agent is of crucial interest and should be based on the patient’s phenotype. New drug classes, such as SGLT2 inhibitors, seem to be of particular benefit in these patients. In the future, new personalized strategies should aim at not only good control of the glycaemic level but also the reduction and possibly the prevention of HF onset.

Nocturnal ventricular arrhythmias are associated with the severity of cardiovascular autonomic neuropathy in type 2 diabetes

BACKGROUND

Cardiovascular autonomic neuropathy (CAN) is a risk factor for arrhythmias and adverse cardiovascular events, but the relationship between CAN severity and nocturnal arrhythmias needs to be clarified. This study evaluated the association between nocturnal arrhythmias and CAN severity in patients with type 2 diabetes (T2D).

METHODS

In all, 219 T2D patients were recruited from January 2017 to May 2018. Subjects were classified into no CAN (NCAN), early CAN (ECAN), definite CAN (DCAN), or advanced CAN (ACAN) based on cardiovascular autonomic reflex tests (CARTs). A 24-hour electrocardiogram was recorded and daytime (0700-2300 hours) and night-time (2300-0700 hours) heartbeats were analyzed separately.

RESULTS

After adjusting for age, the incidence of ventricular arrhythmias increased with CAN severity at night-time (18.6%, 29.9%, 36.2%, and 60.0% in the NCAN, ECAN, DCAN, and ACAN groups, respectively; P_trend  = 0.034). Patients with nocturnal ventricular arrhythmias (NVAs) had higher CART scores (2.0 ± 1.0 vs 1.5 ± 0.9; P < 0.001) and lower heart rate variability (HRV) during deep breathing (9.5 ± 5.7 vs 11.6 ± 6.6 b. p. m; P = 0.021), HRV during the Valsalva maneuver (1.2 ± 0.1 vs 1.2 ± 0.2; P = 0.006), and postural blood pressure change (-8.8 ± 15.5 vs -4.1 ± 11.2 mmHg; P = 0.023). Multivariate regression analysis revealed that CAN stage (odds ratio 1.765; 95% confidence interval 1.184-2.632; P = 0.005) was independently associated with NVAs.

CONCLUSIONS

In T2D, CAN stage was independently associated with the presence of NVAs. Early detection, diagnosis, and treatment of CAN may help predict and prevent adverse cardiovascular events and cardiovascular mortality in diabetes.

[Cardiac arrhythmias in patients with chronic autoimmune diseases]

Chronic inflammation due to autoimmune diseases is associated with a higher rate of supraventricular and ventricular arrhythmias leading to an increased risk for cardiovascular morbidity and mortality. Involvement of the cardiac conduction system is common in patients with chronic autoimmune diseases, although the penetrance of clinical signs and symptoms is variable and complete heart block with need for therapy is rare. The combination of the increased prevalence of structural cardiovascular disease and the direct impact of inflammatory mechanisms on cardiac electrophysiology seems to be responsible for the higher rate of tachyarrhythmias. In particular, fibroblast activation, gap junction impairment via changes in connexin composition and abnormalities in intracellular calcium-handling are mentioned. Electrocardiographic markers of an increased arrhythmogenic potential in patients with chronic autoimmune disorders may include prolonged P‑wave duration as well as abnormal QTc interval and reduced heart rate variability. Thus, minimizing the inflammatory burden through tight control of disease activity may help reduce the arrhythmic load.

Acute intramyocardial lipid accumulation in rats does not slow cardiac conduction per se

Diabetic patients suffer from both cardiac lipid accumulation and an increased risk of arrhythmias and sudden cardiac death. This correlation suggests a link between diabetes induced cardiac steatosis and electrical abnormalities, however, the underlying mechanism remains unknown. We previously showed that cardiac conduction velocity slows in Zucker diabetic fatty rats and in fructose-fat fed rats, models that both exhibit prominent cardiac steatosis. The aim of this study was to investigate whether acute cardiac lipid accumulation reduces conduction velocity per se. Cardiac lipid accumulation was induced acutely by perfusing isolated rat hearts with palmitate-glucose buffer, or subacutely by fasting rats overnight. Subsequently, longitudinal cardiac conduction velocity was measured in right ventricular tissue strips, and intramyocardial triglyceride and lipid droplet content was determined by thin layer chromatography and BODIPY staining, respectively. Perfusion with palmitate-glucose buffer significantly increased intramyocardial triglyceride levels compared to perfusion with glucose (2.16 ± 0.17 (n = 10) vs. 0.92 ± 0.33 nmol/mg WW (n = 9), P < 0.01), but the number of lipid droplets was very low in both groups. Fasting of rats, however, resulted in both significantly elevated intramyocardial triglyceride levels compared to fed rats (3.27 ± 0.43 (n = 10) vs. 1.45 ± 0.24 nmol/mg WW (n = 10)), as well as a larger volume of lipid droplets (0.60 ± 0.13 (n = 10) vs. 0.21 ± 0.06% (n = 10), P < 0.05). There was no significant difference in longitudinal conduction velocity between palmitate-glucose perfused and control hearts (0.77 ± 0.025 (n = 10) vs. 0.75 m/sec ± 0.029 (n = 9)), or between fed and fasted rats (0.75 ± 0.042 m/sec (n = 10) vs. 0.79 ± 0.047 (n = 10)). In conclusion, intramyocardial lipid accumulation does not slow cardiac longitudinal conduction velocity per se. This is true for both increased intramyocardial triglyceride content, induced by palmitate-glucose perfusion, and increased intramyocardial triglyceride and lipid droplet content, generated by fasting.

Microvascular complications in diabetes: A growing concern for cardiologists

Randomized, cross-sectional, and prospective studies have demonstrated that microvascular complications in patients with diabetes are not only the cause of blindness, renal failure and non-traumatic amputations, but also powerful predictors of cardiovascular complications. Beside the metabolic theory, the pathophysiology of diabetic microvascular complications is determined by the interaction among several factors, including epigenetic modifications and the reduced release of progenitor cells by the bone marrow, that contribute simultaneously to damage and impaired vascular protection against hyperglycemia. Identifying and preventing microvascular complications has the significant potential to reduce major adverse cardiovascular events. For these reasons, there may no longer be a rational to consider microangiopathy and macroangiopathy as entirely separate entities, but they should most likely be viewed as a continuum of the widespread vascular damage determined by diabetes mellitus.

Association between diabetes mellitus and poor patient outcomes after out-of-hospital cardiac arrest: A systematic review and meta-analysis

Diabetes mellitus (DM) serves as an important prognostic indicator in patients with cardiac-related illness. Our objective is to compare survival and neurological outcomes among diabetic and non-diabetic patients who were admitted to the hospital after an out-of-hospital cardiac arrest (OHCA). We searched MEDLINE and EMBASE for relevant articles from database inception to July 2018 without any language restriction. Studies were included if they evaluated patients who presented with OHCA, included mortality and neurological outcome data separately for DM patients and Non-DM patients and reported crude data, odds ratio (OR), relative risk (RR) or hazard ratio (HR). Two investigators independently reviewed the retrieved citations and assessed eligibility. The quality of included studies was evaluated using Newcastle-Ottawa quality assessment scale for cohort studies. Random-effect models using the generic variance method were used to create pooled odds ratios (OR) and 95% confidence intervals (CI). Heterogeneity was assessed using the I2 value. Survival and neurological outcomes (using modified rankin scale and cerebral performance category scale) after OHCA in hospitalized patients with DM compared with patients without DM. Out of 57 studies identified, six cohort studies met the inclusion criteria. In an analysis of unadjusted data, patients with DM had lower odds of survival, pooled OR 0.64; 95% CI, 0.52-0.78, [I2 = 90%]. When adjusted ORs were pooled, the association between DM and survival after OHCA was still significantly reduced, pooled OR 0.78, 95% CI, 0.68-0.89 [I2 = 55%]. Unadjusted pooled OR revealed poor neurological outcomes in patients with DM, pooled OR 0.55, 95% CI, 0.38-0.80 [I2 = 90%]. The result demonstrates significant poor outcomes of in-hospital survival and neurological outcomes among DM patients after OHCA.

FUNCTIONAL CONDITION OF THE CARDIOVASCULAR SYSTEM IN CHILDREN WITH TYPE 1 DIABETES DEPENDING ON THE LEVEL OF GLYCEMIA

Purpose of the study: to determine main parameters of the heart rhythm in children with type 1 diabetes, depending on the night level of glycemia. We performed bifunctional monitoring of glycemia and ECG in 50 patients with type 1 diabetes from 10 to 17 years. Depending on the glycemic parameters summarized in all patients we divided 3 groups: Group 1 (n=11) – sites of hypoglycemia (≤3.9 mmol/l), Group 2 (n=35) – optimal level of glycemia (4.0-9.0 mmol/l) and Group 3 (n=45) – sites of hyperglycemia (> 9 mmol/l). According to the results of glycemic monitoring, 96% of children do not have glycemic target marks at night and 20% of patients have asymptomatic night hypoglycemia. When analyzing the parameters of Holter ECG monitoring, the greatest value of heart rate, duration of the QTc interval, as well as atrial ectopic activity were often recorded during periods of hypoglycemia. Hyperglycemia also causes pathologic elongation of the ventricular electric systole and a greater number of ventricular extrasystoles. Thus, night hypo- and hyperglycemia in children and adolescents with type 1 diabetes leads to an extension of the QTc interval, an increase in the number of extrasystoles with the highest severity and frequency in hypoglycemia. We noted a high level of functioning of the sympathetic department of the autonomic nervous system and the central contour of heart rhythm regulation in children and adolescents with type 1 diabetes mellitus in hypoglycemia.

Comparison of Long-Term Survival Benefits With Cardiac Resynchronization Therapy in Patients With Mild Heart Failure With Versus Without Diabetes Mellitus (from the Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy [MADIT-CRT])

We have previously shown a reduction in HF events with cardiac resynchronization therapy with defibrillator (CRT-D) in patients with mild heart failure (HF) and diabetes mellitus (DM). It remains unknown whether HF remission in DM patients with CRT-D translates into reduced mortality. The effects of CRT-D versus an implantable cardioverter-defibrillator (ICD) alone to reduce long-term mortality were assessed in patients with left bundle branch block with DM (n = 386) and without DM (n = 982), enrolled in the Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy (MADIT-CRT). We further subdivided DM patients by insulin and noninsulin therapy. Kaplan-Meier survival analyses and multivariate cox proportional hazards regression models were utilized. At the 7-year follow-up, CRT-D was associated with a lower mortality in DM patients compared with ICD alone (21% vs 42%, p = 0.02), similar to non-DM patients (16 vs 24%, p = 0.014). CRT-D was associated with a 41% reduction in the risk of long-term all-cause mortality in DM patients (hazard ratio [HR] 0.59, 95% confidence interval 0.36 to 0.96, p = 0.033) and a similar reduction in non-DM patients (HR 0.69, 95% confidence interval 0.48 to 0.99, p = 0.045, treatment-diabetes interaction p = 0.611). Among DM patients, mortality benefit was evident in insulin-treated patients only (HR 0.40, p = 0.030). Reductions in HF events were present in all groups. In the MADIT-CRT, patients with mild HF with DM derive significant long-term survival benefit from CRT-D, similar to those without DM. The mortality benefit from CRT-D within the DM subgroup seems to be confined to patients with insulin treated diabetes.

Diabetes mellitus and the risk of sudden cardiac death: A systematic review and meta-analysis of prospective studies

BACKGROUND

Although diabetes mellitus is an established risk factor for myocardial infarction and stroke, data on the association with sudden cardiac death are less extensive and the findings have not been entirely consistent. We therefore conducted a systematic review and meta-analysis of prospective studies on diabetes mellitus and risk of sudden cardiac death.

METHODS AND RESULTS

PubMed and Embase databases were searched up to July 18th 2017. Prospective studies that reported adjusted relative risk (RR) estimates and 95% confidence intervals (CIs) for the association between a diabetes diagnosis or pre-diabetes and risk of sudden cardiac death were included. Summary RRs were estimated by use of a random effects model. Nineteen population-based prospective studies (11 publications) (3610 cases, 249,225 participants) and 10 patient-based prospective studies (2713 cases, 55,098 participants) were included. The summary RR for diabetes patients vs. persons without diabetes was 2.02 (95% CI: 1.81-2.25, I² = 0%, p_{heterogeneity} = 0.91) in the population-based studies. The summary RR was 1.23 (95% CI: 1.05-1.44, I² = 6%, p_{heterogeneity} = 0.34) for the association between pre-diabetes and sudden cardiac death (n = 3 studies, 1000 sudden cardiac deaths, 18,360 participants). In the patient-based studies, the summary RR of sudden cardiac death for diabetes patients vs. patients without diabetes was 1.75 (95% CI: 1.51-2.03, I² = 39%, p_{heterogeneity} = 0.10) for all patients combined, 1.63 (95% CI: 1.36-1.97, I² = 39%, n = 5) for coronary heart disease patients, and 1.85 (95% CI: 1.48-2.33, I² = 0%, n = 3) for heart failure patients.

CONCLUSIONS

These results suggest that diabetes patients are at an increased risk of sudden cardiac death both in the general population and among different patient groups.

Systemic inflammation and arrhythmic risk: lessons from rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic immuno-mediated disease primarily affecting the joints, characterized by persistent high-grade systemic inflammation. Cardiovascular morbidity and mortality are significantly increased in RA, with >50% of premature deaths attributable to cardiovascular disease. In particular, RA patients were twice as likely to experience sudden cardiac death compared with non-RA subjects, pointing to an increased propensity to develop malignant ventricular arrhythmias. Indeed, ventricular repolarization (QT interval) abnormalities and cardiovascular autonomic nervous system dysfunction, representing two well-recognized risk factors for life-threatening ventricular arrhythmias in the general population, are commonly observed in RA. Moreover, large population-based studies seem to indicate that also the prevalence of atrial fibrillation is significantly higher in RA subjects than in the general population, thus suggesting that these patients are characterized by an abnormal diffuse myocardial electrical instability. Although the underlying mechanisms accounting for the pro-arrhythmogenic substrate in RA are probably intricate, the leading role seems to be played by chronic systemic inflammatory activation, able to promote arrhythmias both indirectly, by accelerating the development of ischaemic heart disease and congestive heart failure, and directly, by affecting cardiac electrophysiology. In this integrated mechanistic view, lowering the inflammatory burden through an increasingly tight control of disease activity may represent the most effective intervention to reduce arrhythmic risk in these patients. Intriguingly, these considerations could be more generally applicable to all the diseases characterized by chronic systemic inflammation, and could help elucidate the link between low-grade chronic inflammation and arrhythmic risk in the general population.

Combined cardiovascular and sweating autonomic testing to differentiate multiple system atrophy from Parkinson's disease

OBJECTIVES

It can be difficult to differentiate multiple system atrophy (MSA) with predominant parkinsonism (MSA-P), a very disabling but rare disease, from Parkinson's disease (PD). Autonomic dysfunction, particularly cardiovascular autonomic neuropathy (CAN), is classically more pronounced in MSA. We investigated whether testing for CAN combined with sweat function assessment was helpful to differentiate patients with MSA from those with PD.

METHODS

In this retrospective study, 62 patients with MSA-P and 96 with PD, comparable in age, BMI and sex ratio with disease duration of 4.3±2.5 years for MSA vs. 11.5±6 years for PD (P<0.0001) were tested for CAN using heart rate changes with deep breathing (HR-DB), stand test (HR-ST) and Valsalva maneuver (HR-VM) and blood pressure changes during stand test (BPs-ST and BPd-ST), Valsalva maneuver (BPs-VM-II and IV), hand grip (BPd-HG) and the total "Ewing" score tests (EwS), and for sweating function using electrochemical skin conductance for hands and feet (HESC and FESC).

RESULTS

In MSA-P abnormal EwS, HR-DB, BP-ST and ESC were more frequent compared to PD, despite longer disease duration for PD. Using a model adjusted for sex, BMI, age, disease duration and treatment, the Odds Ratio for having MSA-P vs. PD based on EwS was 2.71, on HR-DB 2.36, on BP-ST 2.87 and on ESC 4.94 while it was 11.68 (2.17-62.79) for the combination of the three last tests.

CONCLUSION

Assessment of HR-DB, BP-ST and ESC, that is, rapid and non-invasive could be helpful in combination as a first simple screening to differentiate MSA-P from PD.

Cardiac biomarkers in diabetes mellitus: New dawn for risk stratification?

Type 2 diabetes mellitus (T2DM) remains a leading cause of cardiovascular (CV) events and diseases worldwide. The aim of the review is to summarize our knowledge regarding clinical implementation of the biomarker-based strategy of the CV risk assessment in T2DM patient population. There is large body of evidence regarding use of the cardiac biomarkers to risk stratification at higher CV risk individuals who belongs to general population and cohort with established CV disease. Although T2DM patients have higher incidence of macrovascular and microvascular CV complications than the general population, whether cardiac biomarkers would be effective to risk stratification of the T2DM is not fully understood. The role of natriuretic peptides, galectin-3, interleukins, growth differentiation factor-15, as well as biomarkers of endothelial dysfunction are widely discussed. In conclusion, future directions, which associate with discovering of novel biomarkers and their best combinations to provide additional predictive information beyond other traditional CV risk factors, are discussed.

[Sudden cardiac death in diabetes mellitus]

Sudden cardiac death (SCD) represents one of the most frequent causes of death in patients with diabetes. In contrast to patients without diabetes it has not been significantly reduced despite improvements in the treatment of acute myocardial infarction and long-term treatment of cardiovascular diseases as well as diabetes mellitus. Several mechanisms can be responsible for the high incidence of SCD in diabetics: 1. arrhythmogenic effects mediated via cardiac autonomic neuropathy, repolarization disturbances or sympathetic tone activation (hypoglycemia), 2. myocardial ischemia due to atherosclerosis, endothelial dysfunction, platelet aggregation or thrombophilic effects, 3. myocardial disease due to inflammation, fibrosis, associated hypertension or uremia and 4. potassium imbalance due to diabetic nephropathy or hypoglycemia. This review introduces concepts of mechanisms that are responsible for SCD in patients with diabetes. Treatment of patients with diabetes should primarily consider a systematic assessment of any deterioration of this chronic disease and of complications at an early stage. Cardiovascular drug treatment corresponds to that of non-diabetics. In antidiabetic treatment drugs with a low risk of hypoglycemia should be preferred. Treatment with implantable cardioverter defibrillators (ICD) also combined with cardiac resynchronization therapy () demonstrated a high life-saving potential particularly in patients with diabetes.

Epidemiology of Obesity and Diabetes and Their Cardiovascular Complications

Obesity and diabetes mellitus have reached epidemic proportions in the past few years. During 2011 to 2012, more than one-third of the US population was obese. Although recent trend data indicate that the epidemic has leveled off, prevalence of abdominal obesity continues to rise, especially among adults. As seen for obesity, the past few decades have seen a doubling of the diabetes mellitus incidence with an increasing number of type 2 diabetes mellitus cases being diagnosed in children. Significant racial and ethnic disparities exist in the prevalence and trends of obesity and diabetes mellitus. In general, in both adults and children, non-Hispanic blacks and Mexican Americans seem to be at a high risk than their non-Hispanic white counterparts. Secular changes in agricultural policies, diet, food environment, physical activity, and sleep have all contributed to the upward trends in the diabesity epidemic. Despite marginal improvements in physical activity and the US diet, the food environment has changed drastically to an obesogenic one with increased portion sizes and limited access to healthy food choices especially for disadvantaged populations. Interventions that improve the food environment are critical as both obesity and diabetes mellitus raise the risk of cardiovascular disease by ≈2-fold. Among those with type 2 diabetes mellitus, significant sex differences occur in the risk of cardiovascular disease such that diabetes mellitus completely eliminates or attenuates the advantages of being female. Given the substantial burden of obesity and diabetes mellitus, future research efforts should adopt a translational approach to find sustainable and holistic solutions in preventing these costly diseases.

Diabetes, glucose tolerance, and the risk of sudden cardiac death

BACKGROUND

Diabetes predisposes to sudden cardiac death (SCD). However, it is uncertain whether greater proportion of cardiac deaths are sudden among diabetes patients than other subjects. It is also unclear whether the risk of SCD is pronounced already early in the course of the disease. The relationship of impaired glucose tolerance (IGT) and SCD is scarcely documented.

METHODS

A general population cohort of 10594 middle-aged subjects (mean age 44 years, 52.6 % male, follow-up duration 35-41 years) was divided into diabetes patients (n = 82), subjects with IGT (n = 3806, plasma glucose ≥9.58 mmol/l in one-hour glucose tolerance test), and controls (n = 6706).

RESULTS

Diabetes patients had an increased risk of SCD after adjustment confounders (hazard ratio 2.62, 95 % confidence interval 1.46-4.70, p = 0.001) but risk for non-sudden cardiac death was similarly increased and the proportion of SCD of cardiac deaths was not increased. The SCD risk persisted after exclusion of subjects with baseline cardiac disease or non-fatal cardiac events during the follow-up. Subjects with IGT were at increased risk for SCD (univariate hazard ratio 1.51; 95 % confidence interval 1.31-1.74; p < 0.001) and also for non-sudden cardiac deaths and non-fatal cardiac events but adjustments for other risk factors attenuated these effects.

CONCLUSIONS

Diabetes was associated with increased risk of SCD but also the risk of non-sudden cardiac death was similarly increased. The proportion of cardiac deaths being sudden in subjects with diabetes was not increased. The higher SCD risk in diabetes patients was independent of known cardiac disease at baseline or occurrence of non-fatal cardiac event during the follow-up.

Implantable cardioverter defibrillators in diabetics: efficacy and safety in patients at risk of sudden cardiac death

Diabetes mellitus is a major risk factor for arrhythmogenesis and is associated with a two-fold increase in all-cause mortality and a four-fold increase in cardiovascular mortality including sudden cardiac death when compared with nondiabetics. Implantable cardioverter defibrillators (ICD) have been shown to effectively reduce arrhythmic death and all-cause mortality in patients with severe myocardial dysfunction. With a high competing risk of nonarrhythmic cardiac and noncardiac death, survival benefit of ICD in patients with diabetes mellitus could be reduced, but the subanalysis of diabetic patients in randomized clinical trials provides reassurance regarding a similar beneficial survival effect of ICD and cardiac resynchronization therapy in diabetics, as observed in the overall population with advanced heart disease. In this article, the authors highlight some of the clinical issues related to diabetes, summarize the data on the efficacy of ICD in diabetics when compared with nondiabetics and discuss concerns related to ICD implantation in patients with diabetes.

Identification of coronary heart disease in asymptomatic individuals with diabetes mellitus: to screen or not to screen

Coronary heart disease (CHD) is highly prevalent in patients with diabetes mellitus (DM), and remains the single most common cause of death among this population. Regrettably, a significant percentage of diabetics fail to perceive the classic symptoms associated with myocardial ischemia. Among asymptomatic diabetics, the prevalence of abnormal cardiac testing appears to be high, ranging between 10% and 62%, and mortality is significantly higher in those with abnormal scans. Hence, the potential use of screening for CHD detection among asymptomatic DM individuals is appealing and has been recommended in certain circumstances. However, it was not until recently, that this question was addressed in clinical trials. Two studies randomized a total of 2,023 asymptomatic diabetics to screening or not using cardiac imaging with a mean follow up of 4.4 ± 1.4 years. In combination, both trials showed lower than expected annual event rates, and failed to reduce major cardiovascular events in the screened group compared to the standard of care alone. The results of these trials do not currently support the use of screening tools for CHD detection in asymptomatic DM individuals. However, these studies have important limitations, and potential explanations for their negative results that are discussed in this manuscript.