Arrhythmic risk stratification in non-ischemic dilated cardiomyopathy: Where do we stand after DANISH?

Intracardiac electrophysiology to characterize susceptibility to ventricular arrhythmias in murine models

Introduction: Sudden cardiac death (SCD) and ventricular fibrillation are rare but severe complications of many cardiovascular diseases and represent a major health issue worldwide. Although the primary causes are often acute or chronic coronary diseases, genetic conditions, such as inherited channelopathies or non-ischemic cardiomyopathies are leading causes of SCD among the young. However, relevant experimental models to study the underlying mechanisms of arrhythmias and develop new therapies are still needed. The number of genetically engineered mouse models with cardiac phenotype is growing, making electrophysiological studies in mice essential tools to study arrhythmogenicity and arrhythmia mechanisms and to test novel treatments. Recently, intracardiac catheterization via the jugular vein was described to induce and record ventricular arrhythmias in living anesthetized mice. Several strategies have been reported, developed in healthy wild-type animals and based on aggressive right ventricular stimulation. Methods: Here, we report a protocol based on programmed electrical stimulation (PES) performed in clinical practice in patients with cardiac rhythm disorders, adapted to two transgenic mice models of arrhythmia - Brugada syndrome and cardiolaminopathy. Results: We show that this progressive protocol, based on a limited number of right ventricular extrastimuli, enables to reveal different rhythmic phenotypes between control and diseased mice. In this study, we provide detailed information on PES in mice, including catheter positioning, stimulation protocols, intracardiac and surface ECG interpretation and we reveal a higher susceptibility of two mouse lines to experience triggered ventricular arrhythmias, when compared to control mice. Discussion: Overall, this technique allows to characterize arrhythmias and provides results in phenotyping 2 arrhythmogenic-disease murine models.

Serum albumin and prognosis in elderly patients with nonischemic dilated cardiomyopathy

AIMS

Hypoalbuminemia was extensively used to diagnose malnutrition in older adults. Malnutrition was associated with mortality in elderly patients with cardiovascular diseases. The relationship between hypoalbuminemia and clinical outcomes in elderly patients with nonischemic dilated cardiomyopathy (NIDCM) remains unknown.

METHODS

A total of 1058 consecutive patients with NIDCM (age ≥60 years) were retrospectively enrolled from January 2010 to December 2019. Univariate and multivariate analyses were performed to assess the association of hypoalbuminemia with clinical outcomes.

RESULTS

Patients with hypoalbuminemia were older (69.29 ± 6.67 vs. 67.61 ± 5.90 years, P  < 0.001) and had higher prevalence of in-hospital and long-term death than those without (6.9 vs. 1.7%, 50.7 vs. 35.2%, P  < 0.001). Logistic regression analysis showed that hypoalbuminemia was significantly related to in-hospital death [odds ratio (OR): 4.334, 95% confidence interval (CI): 2.185-8.597, P  < 0.001]. Kaplan-Meier survival analysis showed that patients with hypoalbuminemia had worse prognosis than those with nonhypoalbuminemia (log-rank χ2 28.96, P  < 0.001). After adjusting for age, serum creatinine, HDL-C, AST/ALT hypoalbuminemia, LVEF and diabetes, hypoalbuminemia remained an independent predictor for long-term death (hazard ratio 1.322, 95% CI 0.046-1.670, P  = 0.019).

CONCLUSION

Hypoalbuminemia was associated with increased risk of in-hospital and long-term mortality in elderly patients with NIDCM.

Relationship between serum chloride and prognosis in non-ischaemic dilated cardiomyopathy: a large retrospective cohort study

OBJECTIVES

Serum chloride has a unique homeostatic role in modulating neurohormonal pathways. Some studies have reported that hypochloremia has potential prognostic value in cardiovascular diseases; thus, we aimed to investigate the association of baseline serum chloride with clinical outcomes in elderly patients with non-ischaemic dilated cardiomyopathy (NIDCM).

DESIGN

Retrospective study.

SETTING AND PARTICIPANT

A total of 1088 patients (age ≥60 years) diagnosed with NIDCM were enrolled from January 2010 to December 2019.

RESULTS

Logistic regression analyses showed that serum chloride was significantly associated with in-hospital death. Receiver operating characteristic (ROC) curve analyses showed that serum chloride had excellent prognostic ability for in-hospital and long-term death (area under the curve (AUC)=0.690 and AUC=0.710, respectively). Kaplan-Meier survival analysis showed that the patients with hypochloremia had worse prognoses than those without hypochloremia (log-rank χ²=56.69, p<0.001). After adjusting for age, serum calcium, serum sodium, left ventricular ejection fraction, lg NT-proBNP and use of diuretics, serum chloride remained an independent predictor of long-term death (HR 0.934, 95% CI 0.913 to 0.954, p<0.001).

CONCLUSIONS

Serum chloride concentration was a prognostic indicator in elderly patients with NIDCM, and hypochloremia was significantly associated with both in-hospital and long-term poor outcomes.

Elevated α-hydroxybutyrate dehydrogenase is associated with in-hospital mortality in non-ischemic dilated cardiomyopathy

Background

Previous Study Found That Implantation of a Cardioverter-Defibrillator Likely Caused a Worse Prognosis in Older Patients With non-Ischemic Systolic Heart Failure. This Suggests That More Precise Risk Stratification Is Needed in Elderly Patients. We Conducted a Retrospective Study to Evaluate the Association of α-Hydroxybutyrate Dehydrogenase (α-HBDH) With Mortality During Hospitalization in Elderly Patients With non-Ischemic Dilated Cardiomyopathy (NIDCM).

Methods

1,019 Elderly Patients (age ≥60 Years) Diagnosed With NIDCM Were Retrospectively Enrolled From January 2010 to December 2019. Univariate and Multivariate Analyses Were Showed to Explore the Relationship Between α-HBDH and in- Hospital Death.

Results

Patients in elevated α-HBDH group (>182 U/L) had a longer hospital stays and higher in-hospital mortality. Univariate logistics regression analysis showed that elevated α-HBDH was significantly related to mortality (OR: 7.004, 95% CI: 3.583–13.693, p < 0.001). Receiver operator characteristic (ROC) curve analysis reflected that α-HBDH levels had excellent predictive power for in-hospital death (AUC = 0.810, 95% CI: 0.745–0.876, p < 0.001). After adjustment of age, serum creatine, albumin and LVEF, multivariate regression analysis validated the association of elevated α-HBDH with increased risk of in-hospital death (p < 0.05).

Conclusions

Elevated α-HBDH level is significantly related to in-hospital mortality in older patients with NIDCM.

Arrhythmic risk stratification in ischemic, non-ischemic and hypertrophic cardiomyopathy: A two-step multifactorial, electrophysiology study inclusive approach

Annual arrhythmic sudden cardiac death ranges from 0.6% to 4% in ischemic cardiomyopathy (ICM), 1% to 2% in non-ischemic cardiomyopathy (NICM), and 1% in hypertrophic cardiomyopathy (HCM). Towards a more effective arrhythmic risk stratification (ARS) we hereby present a two-step ARS with the usage of seven non-invasive risk factors: Late potentials presence (≥ 2/3 positive criteria), premature ventricular contractions (≥ 30/h), non-sustained ventricular tachycardia (≥ 1episode/24 h), abnormal heart rate turbulence (onset ≥ 0% and slope ≤ 2.5 ms) and reduced deceleration capacity (≤ 4.5 ms), abnormal T wave alternans (≥ 65μV), decreased heart rate variability (SDNN < 70ms), and prolonged QT_c interval (> 440 ms in males and > 450 ms in females) which reflect the arrhythmogenic mechanisms for the selection of the intermediate arrhythmic risk patients in the first step. In the second step, these intermediate-risk patients undergo a programmed ventricular stimulation (PVS) for the detection of inducible, truly high-risk ICM and NICM patients, who will benefit from an implantable cardioverter defibrillator. For HCM patients, we also suggest the incorporation of the PVS either for the low HCM Risk-score patients or for the patients with one traditional risk factor in order to improve the inadequate sensitivity of the former and the low specificity of the latter.

Association of single nucleotide polymorphisms in the 3'UTR region of TPM1 gene with dilated cardiomyopathy: A case-control study

Tropomyosin 1 (TPM1) is a protein that constitutes the sarcomere filaments and is encoded by the TPM1 gene. The aim of the present study is to investigate the correlation between the 3' untranslated region (3'UTR) single nucleotide polymorphisms (SNPs) of the TPM1 gene and dilated cardiomyopathy (DCM).A total of 245 patients with DCM and 245 healthy controls were recruited with 5 ml of venous blood. Genomic DNA was extracted to analyze the TPM1 gene rs12148828, rs11558748, rs707602, rs6738, rs7178040 loci genotypes, and the plasma miR-21 level was analyzed by reverse transcription-PCR (RT-PCR).The risk of DCM development in the rs6738 locus G allele carriers were 1.69 times more than A allele carriers (95% CI: 1.22-2.33, P = .001). Age and gender had no effect on the association of TPM1 gene SNPs with DCM risk (P > .05). The plasma miR-21 level of TPM1 gene rs6738 locus AA carriers was significantly higher than that of the AG and GG genotypes (P < .001).The SNPs of TPM1 gene rs6738 locus is associated with the risk of DCM, which may be related to the abnormal increase of miR-21 level in DCM patients, but further research is needed to prove the causal relationship between miR-21 level and DCM risk.

Anti-arrhythmic therapy in patients with non-ischemic cardiomyopathy

Implantable cardiac defibrillators (ICD) are the foundation of therapy for the prevention of sudden cardiac death. While ICDs prevent SCD, they do not prevent the occurrence of ventricular arrhythmias which are usually symptomatic. Though catheter ablation has been successful in substrate modification of ventricular tachycardia in patients with ischemic cardiomyopathy, there is much less evidence to support its use in non-ischemic cardiomyopathy. Therefore, anti-arrhythmic drugs (AADs) are an essential adjunctive therapy for secondary prevention of ventricular arrhythmias in patients with non-ischemic cardiomyopathy. In patients with hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM), the prevalence of ventricular arrhythmias correlates with the volume of scar as characterized by late gadolinium enhancement. Beta-blockers forms the cornerstone of treatment to prevent ventricular arrhythmias in both HCM and DCM. Disopyramide is an important therapeutic option in HCM as it provides both negative inotropy which reduces obstruction as well as lass I anti-arrhythmic action. In DCM sotalol, through is combined beta-blocking and class III AD effects, significantly reduces the burden of ventricular arrhythmias. Though amiodarone is efficacious in the prevention of ventricular arrhythmias in both HCM and DCM, its use is limited by its side-effects profile. Evidence for AAD therapy for arrhythmogenic right ventricular dysplasia (ARVD) is limited by its low prevalence and lack of studies. ICDs have been shown to reduce SCD regardless of whether patients are receiving AAD therapy.

Signal-averaged electrocardiography: Past, present, and future

Signal-averaged electrocardiography records delayed depolarization of myocardial areas with slow conduction that can form the substrate for monomorphic ventricular tachycardia. This technique has been examined mostly in patients with coronary artery disease, but its use has been declined over the years. However, several lines of evidence, derived from hitherto clinical data in patients with healed myocardial infarction, indicate that signal-averaged electrocardiography remains a valuable tool in risk stratification, especially when incorporated into algorithms encompassing invasive and noninvasive indices. Such an approach can aid the more precise identification of candidates for device therapy, in the context of primary prevention of sudden cardiac death. This article reappraises the value of signal-averaged electrocardiography as a predictor of arrhythmic outcome in patients with ischemic heart disease and discusses potential future indications.