Cardiovascular Effects of Immune Checkpoint Inhibitors: More Than Just Myocarditis

PURPOSE OF REVIEW

Immune checkpoint inhibitors have reshaped the treatment of cancer, but they are characterized by peculiar toxicity consisting of immune-related adverse events that may potentially affect any organ or system. In this review, we summarize data on clinical presentation, diagnosis, pathogenesis, and management of the main immune-related cardiovascular toxicities of immune checkpoint inhibitors.

RECENT FINDINGS

The most relevant immune-related cardiovascular toxicity is myocarditis, but other non-negligible reported events include non-inflammatory heart failure, conduction abnormalities, pericardial disease, and vasculitis. More recently, growing evidence suggests a role for immune checkpoint inhibitors in accelerating atherosclerosis and promoting plaque inflammation, thus leading to myocardial infarction. Immune checkpoint inhibitors are associated with several forms of cardiovascular toxicity; thus, an accurate cardiovascular baseline evaluation and periodical monitoring are required. Furthermore, the optimization of cardiovascular risk factors before, during, and after treatment may contribute to mitigating both short-term and long-term cardiovascular toxicity of these drugs.

Lifestyle habits associated with cardiac conduction disease

AIMS

Cardiac conduction disease can lead to syncope, heart failure, and death. The only available therapy is pacemaker implantation, with no established prevention strategies. Research to identify modifiable risk factors has been scant.

METHODS AND RESULTS

Data from the Cardiovascular Health Study, a population-based cohort study of adults ≥ 65 years with annual 12-lead electrocardiograms obtained over 10 years, were utilized to examine relationships between baseline characteristics, including lifestyle habits, and conduction disease. Of 5050 participants (mean age 73 ± 6 years; 52% women), prevalent conduction disease included 257 with first-degree atrioventricular block, 99 with left anterior fascicular block, 9 with left posterior fascicular block, 193 with right bundle branch block (BBB), 76 with left BBB, and 102 with intraventricular block at baseline. After multivariable adjustment, older age, male sex, a larger body mass index, hypertension, and coronary heart disease were associated with a higher prevalence of conduction disease, whereas White race and more physical activity were associated with a lower prevalence. Over a median follow-up on 7 (interquartile range 1-9) years, 1036 developed incident conduction disease. Older age, male sex, a larger BMI, and diabetes were each associated with incident conduction disease. Of lifestyle habits, more physical activity (hazard ratio 0.91, 95% confidence interval 0.84-0.98, P = 0.017) was associated with a reduced risk, while smoking and alcohol did not exhibit a significant association.

CONCLUSION

While some difficult to control comorbidities were associated with conduction disease as expected, a readily modifiable lifestyle factor, physical activity, was associated with a lower risk.

One gene, two modes of inheritance, four diseases: A systematic review of the cardiac manifestation of pathogenic variants in JPH2-encoded junctophilin-2

Rare variants in JPH2 have been associated with a range of cardiac disease, including hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), arrhythmias, and sudden cardiac death (SCD); however, our understanding of how variants in JPH2 correspond to specific modes of inheritance and correlate clinical phenotypes has not been comprehensively explored. In this systematic review, we assess current case reports and series that describe patients with JPH2 variants and cardiac disease. We identified a total of 61 variant-positive individuals, approximately 80% of whom had some form of cardiac disease, including 47% HCM, 18% DCM, and 14% arrhythmia/SCD. In analyzing the 24 probands described in the studies, we found that autosomal recessive, loss-of-function variants are associated with severe, early onset DCM, while autosomal dominant missense variants are associated with a wider range of cardiac disease, including HCM, arrhythmia, SCD, and cardiac conduction disease.

Management of Cardiac Symptoms in Amyloidosis

Cardiac amyloidosis (CA) results in symptoms of heart failure, atrial and ventricular arrhythmias, conduction disturbances, and profound autonomic dysfunction. These symptoms present unique management challenges as compared with patients without CA, and can be very debilitating. Thus, management of the cardiovascular symptoms of these patients plays a central role in their care. This review presents an overview of the typical cardiovascular manifestations encountered in patients with CA and highlights the key management considerations for each.

An overview of heart rhythm disorders and management in myotonic dystrophy type 1

Myotonic dystrophy type 1 (DM1) is the most common adult form of muscular dystrophy, presenting with a constellation of systemic findings secondary to a CTG triplet expansion of the noncoding region of the DMPK gene. Cardiac involvement is frequent, with conduction disease and supraventricular and ventricular arrhythmias being the most prevalent cardiac manifestations, often developing from a young age. The development of cardiac arrhythmias has been linked to increased morbidity and mortality, with sudden cardiac death well described. Strategies to mitigate risk of arrhythmic death have been developed. In this review, we outline the current knowledge on the pathophysiology of rhythm abnormalities in patients with myotonic dystrophy and summarize available knowledge on arrhythmic risk stratification. We also review management strategies from an electrophysiological perspective, attempting to underline the substantial unmet need to address residual arrhythmic risks for this population.

Case report: third-degree atrioventricular block secondary to septic coronary artery embolism following infective endocarditis

Background

Coronary artery emboli can occur from a number of rare causes such as arterial thrombo-embolus or septic embolus. This diagnosis generally requires multi-modal imaging including echocardiography, computed tomography, or invasive coronary angiography. Septic coronary emboli is an extremely rare consequence of infective endocarditis (IE), having been reported in <1% of all cases.

Case summary

A 54-year-old previously healthy Tibetan monk presented feeling generally unwell and lethargic. Electrocardiogram demonstrated sinus rhythm, third-degree atrioventricular block with a left bundle branch escape. Initial transthoracic and transoesophageal echocardiography demonstrated vegetations on the aortic and tricuspid valve as well as intra-myocardial abscess. Coronary angiography revealed septic embolus involving the septal perforator coronary artery. He underwent surgical replacement of the infected valves and debridement and repair of a ventricular septal defect.

Discussion

Infective endocarditis can predispose to a range of cardiac pathology. This case demonstrates that patients can present with cardiac conduction disease from a septic embolus involving a coronary artery as a complication of IE.

Predictors of conduction recovery after permanent pacemaker implantation following transcatheter aortic valve replacement

PURPOSE

Conduction disturbances after transcatheter aortic valve replacement (TAVR) requiring pacemaker (PPM) implantation are a known complication and may be reversible. Therefore, we sought to evaluate the incidence and predictors for atrioventricular (AV) conduction recovery after TAVR.

METHODS

A single-center, retrospective study of patients undergoing PPM implantation for conduction disorders after TAVR between June 2011 and March 2019. Conduction recovery was defined as ≤ 1% ventricular pacing (VP) on follow-up PPM interrogation.

RESULTS

A total of 110 patients (mean age 83.6 ± 6.6 years, 46.8% female) were included. At a median follow-up of 438 days (interquartile range [IQR] 111-760 days), 35 patients (32%) had conduction recovery, with 50% of these occurring within the first 6 months. On multivariate analysis, predictors of conduction recovery include female sex (hazard ratio [HR] 2.5, 95% confidence interval [CI] 1.01-6.4, p = 0.048), non-VP/non-complete heart block rhythm immediately post-TAVR (HR 5.2, 95% CI 1.5-18.1, p = 0.011), normal sinus rhythm 7 days post-TAVR (HR 3.9, 95% CI 1.7-9.2, p = 0.002), and smaller valve size (mm) (HR 0.81, 95% CI 0.7-0.996, p = 0.045). Significant narrowing of the QRS and resolution of new-onset left bundle branch block within 1 month post-TAVR occurred in those with conduction recovery on PPM interrogation.

CONCLUSIONS

One-third of patients receiving new PPM implantation have conduction recovery after TAVR, with 50% occurring within the first 6 months. Patient gender, valve size, and rhythm on serial ECGs after TAVR can help identify patients that may recover AV conduction. A conservative approach rather than immediate PPM implantation may be considered in these patients.

Negative screening of Fabry disease in patients with conduction disorders requiring a pacemaker

Identification of Fabry disease (FD) in cardiac patients has been restricted so far to patients with left ventricular hypertrophy. Conduction problems are frequent in FD and could precede other manifestations, offering a possible earlier diagnosis.

We studied the prevalence of FD in 188 patients < 70 years with conduction problems requiring pacemaker implantation. Although classical manifestations of FD were not rare, no patient with FD was identified. Screening efforts should not be conducted in this population.

Ventricular tachycardia in patients with type 1 myotonic dystrophy: a case series

Background

Type 1 myotonic dystrophy (DM1) is associated with a variety of cardiac conduction abnormalities and the frequent need for permanent pacing. However, the role of ventricular tachycardia (VT) and the implied risk of sudden cardiac death (SCD) is poorly understood.

Case summary

This study examined a 56-patient DM1 cohort of men and women, and identified five patients (two females and three males) with ventricular arrhythmias (8.9%). Patients were reviewed on a case-by-case basis, with their clinical presentation and management of VT and the associated cardiomyopathy indicated. Patient cardiac function was determined by 12-lead electrocardiogram, 48-h Holter monitor, and transthoracic echocardiography. These patients were therefore suitable candidates for implantable cardioverter-defibrillator implantation and received these devices; four of the five patients also received cardiac resynchronization therapy. Medical therapies included angiotensin converting enzyme inhibition, mineralocorticoid receptor antagonist, and following device implantation, beta-blocker therapy was initiated.

Discussion

Our case series demonstrates the prevalence of VT in patients with DM1 highlighting the associated risks of SCD in this patient population. The burden of ventricular arrhythmias, advanced conduction disease, and cardiomyopathy are best treated with a combination of device and medical therapies.

ANK2 functionally interacts with KCNH2 aggravating long QT syndrome in a double mutation carrier

Pathogenic long QT mutations often comprise high phenotypic variability and particularly variants in ANK2 (long QT syndrome 4) frequently lack QT prolongation. We sought to elucidate the genetic and functional background underlying the clinical diversity in a 3-generation family with different cardiac arrhythmias. Next-generation sequencing-based screening of patients with QT prolongation identified the index patient of the family carrying an ANK2-E1813K variant and a previously uncharacterized KCNH2-H562R mutation in a double heterozygous conformation. The patient presented with a severe clinical phenotype including a markedly prolonged QTc interval (544 ms), recurrent syncope due to Torsade de Pointes tachycardias, survived cardiopulmonary resuscitation, progressive cardiac conduction defect, and atrial fibrillation. Evaluation of other family members identified a sister and a niece solely carrying the ANK2-E1813K variant, who showed age-related conduction disease. An asymptomatic second sister solely carried the KCNH2-H562R mutation. Voltage-clamp recordings in Xenopus oocytes revealed that KCNH2-H562R subunits were non-functional but did not exert dominant-negative effects on wild-type subunits. Expression of KCNH2-H562R in HEK293 cells showed a trafficking deficiency. Co-expression of the C-terminal regulatory domain of ANK2 in Xenopus oocytes revealed that ANK2-E1813K diminished currents mediated by the combination of wild-type and H562R KCNH2 subunits. Our data suggest that ANK2 functionally interacts with KCNH2 leading to a stronger current suppression and marked aggravation of long QT syndrome in the patient carrying variants in both proteins.

Supraventricular tachycardias, conduction disease, and cardiomyopathy in 3 families with the same rare variant in TNNI3K (p.Glu768Lys)

BACKGROUND

Rare genetic variants in TNNI3K encoding troponin-I interacting kinase have been linked to a distinct syndrome consisting primarily of supraventricular tachycardias and variably expressed conduction disturbance and dilated cardiomyopathy in 2 families.

OBJECTIVE

The purpose of this study was to identify new genetic variants associated with inherited supraventricular tachycardias, cardiac conduction disease, and cardiomyopathy.

METHODS

We conducted next generation sequencing in 3 independent multigenerational families with atrial/junctional tachycardia with or without conduction disturbance, dilated cardiomyopathy, and sudden death. We also assessed the effect of identified variant on protein autophosphorylation.

RESULTS

In this study, we uncovered the same ultra-rare genetic variant in TNNI3K (c.2302G>A, p.Glu768Lys), which co-segregated with disease features in all affected individuals (n = 23) from all 3 families. TNNI3K harboring the TNNI3K-p.Glu768Lys variant displayed enhanced kinase activity, in line with expectations from previous mouse studies that demonstrated increased conduction indices and procardiomyopathic effects with increased levels of Tnni3k.

CONCLUSION

This study corroborates further the causal link between rare genetic variation in TNNI3K and this distinct complex phenotype, and points to enhanced kinase activity of TNNI3K as the underlying pathobiological mechanism.