Prevalence and risk factors of acquired long QT syndrome in hospitalized patients with chronic kidney disease

Chronic Kidney Disease Induces Proarrhythmic Remodeling

BACKGROUND

Patients with chronic kidney disease (CKD) are at increased risk of developing cardiac arrhythmogenesis and sudden cardiac death; however, the basis for this association is incompletely known.

METHODS

Here, using murine models of CKD, we examined interactions between kidney disease progression and structural, electrophysiological, and molecular cardiac remodeling.

RESULTS

C57BL/6 mice with adenine supplemented in their diet developed progressive CKD. Electrocardiographically, CKD mice developed significant QT prolongation and episodes of bradycardia. Optical mapping of isolated-perfused hearts using voltage-sensitive dyes revealed significant prolongation of action potential duration with no change in epicardial conduction velocity. Patch-clamp studies of isolated ventricular cardiomyocytes revealed changes in sodium and potassium currents consistent with action potential duration prolongation. Global transcriptional profiling identified dysregulated expression of cellular stress response proteins RBM3 (RNA-binding motif protein 3) and CIRP (cold-inducible RNA-binding protein) that may underlay the ion channel remodeling. Unexpectedly, we found that female sex is a protective factor in the progression of CKD and its cardiac sequelae.

CONCLUSIONS

Our data provide novel insights into the association between CKD and pathologic proarrhythmic cardiac remodeling. Cardiac cellular stress response pathways represent potential targets for pharmacologic intervention for CKD-induced heart rhythm disorders.

The effects of peritoneal dialysis on QT interval in ESRD patients

BACKGROUND

Patients with chronic kidney disease (CKD) are at a high risk of fatal arrhythmias. The extended corrected QT (QTc) interval is a hallmark of ventricular arrhythmias and sudden cardiac death. Previous studies have shown that QT interval and QTc are prolonged with the decline in renal function. However, there were no available results for patients with peritoneal dialysis (PD). In this study, we examined changes in QT interval and QTc in patients with end-stage renal disease (ESRD) who underwent peritoneal dialysis.

METHODS

A total of 66 ESRD patients who received PD, including 50 males and 16 females, with an average age of 43.56 ± 15.15 years, were enrolled. The follow-up lasted 1 year. The demographics and the etiology of patients were recorded. QTc and clinical/biochemical indexes before dialysis and at 6 and 12 months were determined and analyzed. Dialysis adequacy and peritoneal transport function were assessed in each patient. Analysis of variance (ANOVA), least significant difference (LSD) or Tamhane's T2, Paired T-test, Chi-square test, multiple linear regression analysis, and Pearson correlation coefficient were used to analyze the data. P < 0.05 was considered as statistically significant.

RESULTS

With reference to etiology, 37 patients (56.06%) had chronic nephritis, and 11 (16.67%) had diabetic nephropathy. Most of the peritoneal transport functions were low average transport (25, 37.88%), while the least were high transport (2, 3.03%).During the follow-up period, all patients had adequate peritoneal dialysis. Compared with a baseline before dialysis, anemia, low albumin, blood pressure, blood urea nitrogen, creatinine, uric acid, potassium, calcium, phosphorus, and parathyroid hormone improved after 6 and 12 months, while the residual renal function gradually decreased during the follow-up. The mean QTc of all patients was stable during the follow-up period. According to gender, the QTc in males and female patients were similar. Before PD, diastolic blood pressure, calcium concentration, and hemoglobin level were negatively correlated with QTc in end-stage renal disease patients; After PD, the observed clinical indexes were no longer relevant to QTc.

CONCLUSION

Unlike hemodialysis-induced QTc prolongation, PD did not increase the patient's QT interval and QTc interval, which suggested that myocardial electrical activity might be more stable in patients with adequate peritoneal dialysis.

Metabolic and electrolyte abnormalities as risk factors in drug-induced long QT syndrome

Drug-induced long QT syndrome (diLQTS) is the phenomenon by which the administration of drugs causes prolongation of cardiac repolarisation and leads to an increased risk of the ventricular tachycardia known as torsades de pointes (TdP). In most cases of diLQTS, the primary molecular target is the human ether-à-go-go-related gene protein (hERG) potassium channel, which carries the rapid delayed rectifier current (I_Kr) in the heart. However, the proarrhythmic risk associated with drugs that block hERG can be modified in patients by a range of environmental- and disease-related factors, such as febrile temperatures, alterations in pH, dyselectrolytaemias such as hypokalaemia and hypomagnesemia and coadministration with other drugs. In this review, we will discuss the clinical occurrence of drug-induced LQTS in the context of these modifying factors as well as the mechanisms by which they contribute to altered hERG potency and proarrhythmic risk.

QT Interval Dynamics and Cardiovascular Outcomes: A Cohort Study in an Integrated Health Care Delivery System

Background

Long QT has been associated with ventricular dysrhythmias, cardiovascular disease (CVD) mortality, and sudden cardiac death. However, no studies to date have investigated the dynamics of within‐person QT change over time in relation to risk of incident CVD and all‐cause mortality in a real‐world setting.

Methods and Results

A cohort study among members of an integrated health care delivery system in Northern California including 61 455 people (mean age, 62 years; 60% women, 42% non‐White) with 3 or more ECGs (baseline in 2005–2009; mean±SD follow‐up time, 7.6±2.6 years). In fully adjusted models, tertile 3 versus tertile 1 of average QT corrected (using the Fridericia correction) was associated with cardiac arrest (hazard ratio [HR], 1.66), heart failure (HR, 1.62), ventricular dysrhythmias (HR, 1.56), all CVD (HR, 1.31), ischemic heart disease (HR, 1.28), total stroke (HR, 1.18), and all‐cause mortality (HR, 1.24). Tertile 3 versus tertile 2 of the QT corrected linear slope was associated with cardiac arrest (HR, 1.22), ventricular dysrhythmias (HR, 1.12), and all‐cause mortality (HR, 1.09). Tertile 3 versus tertile 1 of the QT corrected root mean squared error was associated with ventricular dysrhythmias (HR, 1.34), heart failure (HR, 1.28), all‐cause mortality (HR, 1.20), all CVD (HR, 1.14), total stroke (HR, 1.08), and ischemic heart disease (HR, 1.07).

Conclusions

Our results demonstrate improved predictive ability for CVD outcomes using longitudinal information from serial ECGs. Long‐term average QT corrected was more strongly associated with CVD outcomes than the linear slope or the root mean squared error. This new evidence is clinically relevant because ECGs are frequently used, noninvasive, and inexpensive.

Genetic and Molecular Aspects of Drug-Induced QT Interval Prolongation

Long QT syndromes can be either acquired or congenital. Drugs are one of the many etiologies that may induce acquired long QT syndrome. In fact, many drugs frequently used in the clinical setting are a known risk factor for a prolonged QT interval, thus increasing the chances of developing torsade de pointes. The molecular mechanisms involved in the prolongation of the QT interval are common to most medications. However, there is considerable inter-individual variability in drug response, thus making the application of personalized medicine a relevant aspect in long QT syndrome, in order to evaluate the risk of every individual from a pharmacogenetic standpoint.

Electrocardiographic abnormalities among late-stage non-dialysis chronic kidney disease patients

OBJECTIVES

Cardiovascular disease (CVD) complication is common among chronic kidney disease (CKD) patients. Thus, knowledge about CVD and ECG abnormalities in CKD are essential due to progressive nature of the disease and increased risk of sudden cardiac death. This study aims to scrutinize the ECG abnormalities among nondialysis late-stage CKD patients.

METHODS

A descriptive observational study was conducted at Dr. Soetomo General Hospital, Surabaya, Indonesia. Subjects were hospitalized patients with late-stage CKD between 1 January and 31 December 2019, who were consulted at the department of cardiology and vascular medicine during their initial admission at emergency room. ECG interpretation for this study was done by qualified cardiologist.

RESULTS

There were 191 patients included in this study. Mean ages were 52.2 ± 11.8 years old and 51% were males. Total 143 (74.9%) patients had anemia, 111 (58.1%) had hypertension and 75 (39.3%) had type 2 diabetes mellitus. Mean serum creatinine was 10.5 ± 8.0 mg/dL. There were 176 (92.1%) patients with at least one form of ECG abnormalities. Prolonged QTc interval (36.6%), fragmented QRS complex (29.8%), poor R wave progression (24.6%), peaked T wave (22.0%) and left ventricular hypertrophy (16.7%) were the most common abnormalities.

CONCLUSIONS

ECG abnormalities are common among nondialysis late-stage CKD patients. Given the fact that long-term CKD influences the pathogenesis cardiovascular diseases and substantial cardiovascular mortality, there is a need to screen Indonesian CKD patients who are at risks of getting earlier complications.

Acquired long QT syndrome in chronic kidney disease patients

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in chronic kidney disease (CKD) patients. QT interval prolongation is a congenital or acquired condition that is associated with an increased risk of torsade de pointes (TdP), sudden cardiac death (SCD), and all-cause mortality in the general population. The prevalence of acquired long QT syndrome (aLQTS) is high, and various acquired conditions contribute to the prolonged QT interval in patients with CKD. More notably, the prolonged QT interval in CKD is an independent risk factor for SCD and all-cause mortality. In this review, we focus on the epidemiological characteristics, risk factors, underlying mechanisms and treatments of aLQTS in CKD, promoting the management of aLQTS in CKD patients.

[Long and short QT syndromes : Emergency treatment and secondary prophylaxis]

Long QT syndrome (LQTS) is a rare inherited or acquired channelopathy associated with a relevant mortality if left untreated. Therapy can reduce the sudden cardiac death (SCD) rate significantly. Of 17 subtypes, LQTS1-3 are the most common. Clinical presentation ranges from asymptomatic patients to torsade de pointes (TdP) and SCD. Emergency therapy includes defibrillation, administration of magnesium, betablockers and temporary pacing and sedation. Secondary prevention is based on betablocker therapy and implantation of an implantable cardioverter-defibrillator (ICD), if appropriate. Short QT syndrome (SQTS) is a rare channelopathy that manifests as SCD in 34%. So far 250 cases with mutations in 8 genes have been reported. ICDs are the only reliable protection against SCD. Drug therapy is based on hydroquinidine. Further therapeutic options exist for certain subtypes of both diseases. Patients should be referred to specialized centers.