Prolonged QT Interval in Cirrhosis: Twisting Time?

From genes to clinical management: A comprehensive review of long QT syndrome pathogenesis and treatment

Background

Long QT syndrome (LQTS) is a rare cardiac disorder characterized by prolonged ventricular repolarization and increased risk of ventricular arrhythmias. This review summarizes current knowledge of LQTS pathogenesis and treatment strategies.

Objectives

The purpose of this study was to provide an in-depth understanding of LQTS genetic and molecular mechanisms, discuss clinical presentation and diagnosis, evaluate treatment options, and highlight future research directions.

Methods

A systematic search of PubMed, Embase, and Cochrane Library databases was conducted to identify relevant studies published up to April 2024.

Results

LQTS involves mutations in ion channel-related genes encoding cardiac ion channels, regulatory proteins, and other associated factors, leading to altered cellular electrophysiology. Acquired causes can also contribute. Diagnosis relies on clinical history, electrocardiographic findings, and genetic testing. Treatment strategies include lifestyle modifications, β-blockers, potassium channel openers, device therapy, and surgical interventions.

Conclusion

Advances in understanding LQTS have improved diagnosis and personalized treatment approaches. Challenges remain in risk stratification and management of certain patient subgroups. Future research should focus on developing novel pharmacological agents, refining device technologies, and conducting large-scale clinical trials. Increased awareness and education are crucial for early detection and appropriate management of LQTS.

Therapies for Cirrhotic Cardiomyopathy: Current Perspectives and Future Possibilities

Cirrhotic cardiomyopathy (CCM) is defined as cardiac dysfunction associated with cirrhosis in the absence of pre-existing heart disease. CCM manifests as the enlargement of cardiac chambers, attenuated systolic and diastolic contractile responses to stress stimuli, and repolarization changes. CCM significantly contributes to mortality and morbidity in patients who undergo liver transplantation and contributes to the pathogenesis of hepatorenal syndrome/acute kidney injury. There is currently no specific treatment. The traditional management for non-cirrhotic cardiomyopathies, such as vasodilators or diuretics, is not applicable because an important feature of cirrhosis is decreased systemic vascular resistance; therefore, vasodilators further worsen the peripheral vasodilatation and hypotension. Long-term diuretic use may cause electrolyte imbalances and potentially renal injury. The heart of the cirrhotic patient is insensitive to cardiac glycosides. Therefore, these types of medications are not useful in patients with CCM. Exploring the therapeutic strategies of CCM is of the utmost importance. The present review summarizes the possible treatment of CCM. We detail the current status of non-selective beta-blockers (NSBBs) in the management of cirrhotic patients and discuss the controversies surrounding NSBBs in clinical practice. Other possible therapeutic agents include drugs with antioxidant, anti-inflammatory, and anti-apoptotic functions; such effects may have potential clinical application. These drugs currently are mainly based on animal studies and include statins, taurine, spermidine, galectin inhibitors, albumin, and direct antioxidants. We conclude with speculations on the future research directions in CCM treatment.

Propranolol can correct prolonged QT intervals in patients with cirrhosis

Background

Prolonged QT intervals are extremely common in patients with cirrhosis and affect their treatment outcomes. Propranolol is often used to prevent gastroesophageal variceal hemorrhage in patients with cirrhosis; however, it is uncertain whether propranolol exerts a corrective effect on QT interval prolongation in patients with cirrhosis.

Aim

The study aimed to investigate the therapeutic effects of propranolol on patients with cirrhosis and prolonged QT intervals.

Methods

A retrospective cohort study approach was adopted. Patients with cirrhosis complicated by moderate-to-severe gastroesophageal varices, who were hospitalized at the Affiliated Hospital of Guangdong Medical University between 1 December 2020 and 31 November 2022, were included in the study. The patients were divided into the propranolol and control groups based on whether they had received propranolol. Upon admission, the patients underwent tests on liver and kidney functions, electrolytes, and coagulation function, as well as abdominal ultrasonography and electrocardiography. In addition to conventional treatment, the patients were followed up after the use or non-use of propranolol for treatment and subsequently underwent reexamination of the aforementioned tests.

Results

The propranolol group (26 patients) had an average baseline corrected QT (QTc) interval of 450.23 ± 37.18 ms, of which 14 patients (53.8%) exhibited QTc interval prolongation. Follow-up was continued for a median duration of 7.00 days after the administration of propranolol and conventional treatment. Electrocardiographic reexamination revealed a decrease in the QTc interval to 431.04 ± 34.64 ms (p = 0.014), and the number of patients with QTc interval prolongation decreased to five (19.2%; p < 0.001). After treatment with propranolol and multimodal therapy, QTc interval normalization occurred in nine patients with QTc interval prolongation, leading to a normalization rate of 64.3% (9/14). The control group (n = 58) had an average baseline QTc interval of 453.74 ± 30.03 ms, of which 33 patients (56.9%) exhibited QTc interval prolongation. After follow-up for a median duration of 7.50 days, the QTc interval was 451.79 ± 34.56 ms (p = 0.482), and the number of patients with QTc interval prolongation decreased to 30 (51.7%; p = 0.457). The QTc interval normalization rate of patients in the control group with QTc interval prolongation was merely 10.0% (3/33), which was significantly lower than that in the propranolol group (p < 0.001).

Conclusion

In patients with cirrhosis complicated by QT interval prolongation, the short-term use of propranolol aids in correction of a long QT interval and provides positive therapeutic value for cirrhotic cardiomyopathy.

Cardiomyopathy in cirrhosis: From pathophysiology to clinical care

Cirrhotic cardiomyopathy (CCM) is defined as systolic or diastolic dysfunction in the absence of prior heart disease or another identifiable cause in patients with cirrhosis, in whom it is an important determinant of outcome. Its underlying pathogenic/pathophysiological mechanisms are rooted in two distinct pathways: 1) factors associated with portal hypertension, hyperdynamic circulation, gut bacterial/endotoxin translocation and the resultant inflammatory phenotype; 2) hepatocellular insufficiency with altered synthesis or metabolism of substances such as proteins, lipids, carbohydrates, bile acids and hormones. Different criteria have been proposed to diagnose CCM; the first in 2005 by the World Congress of Gastroenterology, and more recently in 2019 by the Cirrhotic Cardiomyopathy Consortium. These criteria mainly utilised echocardiographic evaluation, with the latter refining the evaluation of diastolic function and integrating global longitudinal strain into the evaluation of systolic function, an important addition since the haemodynamic changes that occur in advanced cirrhosis may lead to overestimation of systolic function by left ventricular ejection fraction. Advances in cardiac imaging, such as cardiac magnetic resonance imaging and the incorporation of an exercise challenge, may help further refine the diagnosis of CCM. Over recent years, CCM has been shown to contribute to increased mortality and morbidity after major interventions, such as liver transplantation and transjugular intrahepatic portosystemic shunt insertion, and to play a pathophysiologic role in the genesis of hepatorenal syndrome. In this review, we discuss the pathogenesis/pathophysiology of CCM, its clinical implications, and the role of cardiac imaging modalities including MRI. We also compare diagnostic criteria and review the potential diagnostic role of electrocardiographic QT prolongation. At present, no definitive medical therapy exists, but some promising potential treatment strategies for CCM are reviewed.

How non-alcoholic fatty liver disease and cirrhosis affect the heart

Liver diseases affect the heart and the vascular system. Cardiovascular complications appear to be a leading cause of death in patients with non-alcoholic fatty liver disease (NAFLD) and cirrhosis. The predominant histological changes in the liver range from steatosis to fibrosis to cirrhosis, which can each affect the cardiovascular system differently. Patients with cirrhotic cardiomyopathy (CCM) and NAFLD are at increased risk of impaired systolic and diastolic dysfunction and for suffering major cardiovascular events. However, the pathophysiological mechanisms behind these risks differ depending on the nature of the liver disease. Accurate assessment of symptoms by contemporary diagnostic modalities is essential for identifying patients at risk, for evaluating candidates for treatment, and prior to any invasive procedures. This review explores current perspectives within this field.

Oxidative Mechanisms and Cardiovascular Abnormalities of Cirrhosis and Portal Hypertension

In patients with portal hypertension, there are many complications including cardiovascular abnormalities, hepatorenal syndrome, ascites, variceal bleeding, and hepatic encephalopathy. The underlying mechanisms are not yet completely clarified. It is well known that portal hypertension causes mesenteric congestion which produces reactive oxygen species (ROS). ROS has been associated with intestinal mucosal injury, increased intestinal permeability, enhanced gut bacterial overgrowth, and translocation; all these changes result in increased endotoxin and inflammation. Portal hypertension also results in the development of collateral circulation and reduces liver mass resulting in an overall increase in endotoxin/bacteria bypassing detoxication and immune clearance in the liver. Endotoxemia can in turn aggravate oxidative stress and inflammation, leading to a cycle of gut barrier dysfunction → endotoxemia → organ injury. The phenotype of cardiovascular abnormalities includes hyperdynamic circulation and cirrhotic cardiomyopathy. Oxidative stress is often accompanied by inflammation; thus, blocking oxidative stress can minimize the systemic inflammatory response and alleviate the severity of cardiovascular diseases. The present review aims to elucidate the role of oxidative stress in cirrhosis-associated cardiovascular abnormalities and discusses possible therapeutic effects of antioxidants on cardiovascular complications of cirrhosis including hyperdynamic circulation, cirrhotic cardiomyopathy, and hepatorenal syndrome.

Corrected QT interval in cirrhosis: A systematic review and meta-analysis

BACKGROUND

Corrected QT (QTc) interval is prolonged in patients with liver cirrhosis and has been proposed to correlate with the severity of the disease. However, the effects of sex, age, severity, and etiology of cirrhosis on QTc have not been elucidated. At the same time, the role of treatment, acute illness, and liver transplantation (Tx) remains largely unknown.

AIM

To determine the mean QTc in patients with cirrhosis, assess whether QTc is prolonged in patients with cirrhosis, and investigate whether QTc is affected by factors such as sex, age, severity, etiology, treatment, acute illness, and liver Tx.

METHODS

In the present systematic review and meta-analysis, the searching protocol "{[QTc] OR [QT interval] OR [QT-interval] OR [Q-T syndrome]} AND {[cirrhosis] OR [Child-Pugh] OR [MELD]}" was applied in PubMed, EMBASE, and Google Scholar databases to identify studies that reported QTc in patients with cirrhosis and published after 1998. Seventy-three studies were considered eligible. Data concerning first author, year of publication, type of study, method used, sample size, mean age, female ratio, alcoholic etiology of cirrhosis ratio, Child-Pugh A/B/C ratio, mean model for end-stage liver disease (MELD) score, treatment with β-blockers, episode of acute gastrointestinal bleeding, formula for QT correction, mean pulse rate, QTc in patients with cirrhosis and controls, and QTc according to etiology of cirrhosis, sex, Child-Pugh stage, MELD score, and liver Tx status (pre-Tx/post-Tx) were retrieved. The Newcastle-Ottawa quality assessment scale appraised the quality of the eligible studies. Effect estimates, expressed as proportions or standardized mean differences, were combined using the random-effects, generic inverse variance method of DerSimonian and Laird. Subgroup, sensitivity analysis, and meta-regressions were applied to assess heterogeneity. The study has been registered in the PROSPERO database (CRD42023416595).

RESULTS

QTc combined mean in patients with cirrhosis was 444.8 ms [95% confidence interval (CI): 440.4-449.2; P < 0.001 when compared with the upper normal limit of 440 ms], presenting high heterogeneity (I2 = 97.5%; 95%CI: 97.2%-97.8%); both Egger's and Begg's tests showed non-significance. QTc was elongated in patients with cirrhosis compared with controls (P < 0.001). QTc was longer in patients with Child-Pugh C cirrhosis when compared with Child-Pugh B and A (P < 0.001); Child-Pugh B patients presented longer QTc when compared with Child-Pugh A patients (P = 0.003). The MELD score was higher in patients with cirrhosis with QTc > 440 ms when compared with QTc ≤ 440 ms (P < 0.001). No correlation of QTc with age (P = 0.693), sex (P = 0.753), or etiology (P = 0.418) was detected. β-blockers shortened QTc (P< 0.001). QTc was prolonged during acute gastrointestinal bleeding (P = 0.020). Tx tended to improve QTc (P < 0.001). No other sources of QTc heterogeneity were revealed.

CONCLUSION

QTc is prolonged in cirrhosis independently of sex, age, and etiology but is correlated with severity and affected by β-blockers and acute gastrointestinal bleeding. QTc is improved after liver Tx.

Role of Galectin in Cardiovascular Conditions including Cirrhotic Cardiomyopathy

Abnormal cardiac function in the setting of cirrhosis and in the absence of a primary cardiac disease is known as cirrhotic cardiomyopathy. The pathogenesis of cirrhotic cardiomyopathy is multifactorial but broadly is comprised of two pathways. The first is due to cirrhosis and synthetic liver failure with abnormal structure and function of many substances, including proteins, lipids, hormones, and carbohydrates such as lectins. The second is due to portal hypertension which invariably accompanies cirrhosis. Portal hypertension leads to a leaky, congested gut with resultant endotoxemia and systemic inflammation. This inflammatory phenotype comprises oxidative stress, cellular apoptosis, and inflammatory cell infiltration. Galectins exert all these pro-inflammatory mechanisms across many different tissues and organs, including the heart. Effective therapies for improving cardiac function in patients with cirrhosis are not available. Conventional strategies for other noncirrhotic heart diseases, including vasodilators, are not feasible because of the significant baseline vasodilation in cirrhotic patients. Therefore, exploring new treatment modalities for cirrhotic cardiomyopathy is of great importance. Galectin-3 inhibitors such as modified citrus pectin, N-acetyllactosamine, TD139 and GB0139 exert anti-apoptotic, anti-oxidative and anti-inflammatory effects and thus have potential therapeutic interest. This review briefly summarizes the physiological and pathophysiological role of galectin and specifically examines its role in cardiac disease processes. We present a more detailed discussion of galectin in cardiovascular complications of cirrhosis, particularly cirrhotic cardiomyopathy. Finally, therapeutic studies of galectin-3 inhibitors in cirrhotic cardiomyopathy are reviewed.

Dysregulated Calcium Handling in Cirrhotic Cardiomyopathy

Cirrhotic cardiomyopathy is a syndrome of blunted cardiac systolic and diastolic function in patients with cirrhosis. However, the mechanisms remain incompletely known. Since contractility and relaxation depend on cardiomyocyte calcium transients, any factors that impact cardiac contractile and relaxation functions act eventually through calcium transients. In addition, calcium transients play an important role in cardiac arrhythmias. The present review summarizes the calcium handling system and its role in cardiac function in cirrhotic cardiomyopathy and its mechanisms. The calcium handling system includes calcium channels on the sarcolemmal plasma membrane of cardiomyocytes, the intracellular calcium-regulatory apparatus, and pertinent proteins in the cytosol. L-type calcium channels, the main calcium channel in the plasma membrane of cardiomyocytes, are decreased in the cirrhotic heart, and the calcium current is decreased during the action potential both at baseline and under stimulation of beta-adrenergic receptors, which reduces the signal to calcium-induced calcium release. The study of sarcomere length fluctuations and calcium transients demonstrated that calcium leakage exists in cirrhotic cardiomyocytes, which decreases the amount of calcium storage in the sarcoplasmic reticulum (SR). The decreased storage of calcium in the SR underlies the reduced calcium released from the SR, which results in decreased cardiac contractility. Based on studies of heart failure with non-cirrhotic cardiomyopathy, it is believed that the calcium leakage is due to the destabilization of interdomain interactions (dispersion) of ryanodine receptors (RyRs). A similar dispersion of RyRs may also play an important role in reduced contractility. Multiple defects in calcium handling thus contribute to the pathogenesis of cirrhotic cardiomyopathy.

Review article: diagnosis, pathophysiology and management of atrial fibrillation in cirrhosis and portal hypertension

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia and its management in cirrhosis can be challenging due to the altered hepatic metabolism of medications and increased risk of bleeding.

AIMS

To provide a comprehensive overview of the diagnosis, pathophysiology and management of AF in patients with cirrhosis from both a cardiology and a hepatology perspective.

METHODS

An extensive literature search was performed using the terms 'atrial fibrillation' and 'cirrhosis'. Guideline documents and consensus statements were explored.

RESULTS

The prevalence of AF in patients with cirrhosis ranges between 6.6% and 14.2%, while the incidence of new-onset AF in the post-operative period after liver transplant ranged between 6.8% and 10.2%. AF in patients with cirrhosis is associated with adverse outcomes in both pre-transplant and post-transplant settings, including an increased risk of stroke when compared to the general population. We review the pathogenesis of AF in general and in cirrhosis. This review also provides guidance on the management of AF, including the use of anticoagulation and rate versus rhythm control. In the absence of strict contraindications, all patients with cirrhosis and AF should be anticoagulated. The use of DOACs is preferred over vitamin K antagonists. In patients with a high bleeding risk, a DOAC with an approved antidote may be preferred.

CONCLUSIONS

Atrial fibrillation is increased in patients with cirrhosis. AF management requires careful consideration of treatment options. Since patients with cirrhosis were excluded from all major randomised clinical trials, dedicated research on the pathophysiology and management of AF in cirrhosis is needed.