Incidence of Idiopathic Ventricular Arrhythmias: A Population-Based Study

The Incidence of Torsades de Pointes With Perioperative Triple Antiemetic Administration

BACKGROUND

The safety of triple antiemetic therapy consisting of ondansetron, haloperidol, and a steroid, to surgical patients is unknown.

OBJECTIVE

To determine the incidence of torsade de pointes (TdP) or death following perioperative administration of triple antiemetic therapy.

METHODS

A retrospective cohort study identified 19,874 patients who received 22,202 doses of triple antiemetics during the 2.5-year time frame from March 4, 2020 to September 7, 2022 for surgical nausea prophylaxis or treatment of nausea. These patients above were cross-matched with an electrocardiogram and adverse outcome database; this identified 226 patients with documentation of a QTc > 450 ms, all ventricular tachycardias including TdP within 48 hours of receiving triple antiemetic therapy, or death within 7 days of receiving ondansetron.

RESULTS

There were 3 patients who had documented VT (n = 3), but there were no documented incidents of TdP (n = 0). There were 9 codes called on patients within 48 hours of medication administration, and none of them were due to ventricular arrythmias (n = 0). A total of 11 patients died within 7 days of triple antiemetic therapy. Ten of the 11 deaths were determined to not be from the triple antiemetic. One patient died at home within 24 hours of the procedure of an unknown cause (n = 1).

CONCLUSIONS AND RELEVANCE

No episodes of TdP were identified in patients receiving triple antiemetic therapy perioperatively, though the cause of death in 1 patient could not be determined. This suggest that low-dose triple antiemetic therapy is low risk for the development of TdP.

Idiopathic ventricular tachycardia detected after coronavirus disease 2019

We present a 23-year-old woman with depression and long COVID in whom a diagnosis of idiopathic ventricular tachycardia (VT) was made. Although the relationship between idiopathic VT and long COVID remains unknown, this is the first report of idiopathic VT detected in a patient with long COVID.

Characteristics and incidence of cardiac events across spectrum of age in cardiac sarcoidosis

Background

Clinical characteristics and the risk of cardiovascular events in patients with cardiac sarcoidosis (CS) according to the age of initial diagnosis are unclear.

Methods

This study is a sub-analysis of the ILLUMINATE-CS registry, which is a retrospective, multicenter registry that enrolled patients with CS between 2001 and 2017. Patients were divided into three groups according to the tertile of age at the time of initial diagnosis of CS. The study compared the clinical background at the time of CS diagnosis and the incidence rate of cardiac events across age categories.

Results

A total of 511 patients were analyzed in this study. In baseline, older patients were more likely to be female. History of hypertension, heart failure admission, and atrioventricular block were more common in patients with older age. There was no significant difference in the history of ventricular arrhythmias and left ventricular ejection fraction among all age groups. During a median follow-up period of 3.2 [IQR: 1.7-4.2] years, 35 deaths, 56 heart failure hospitalization, and 98 fatal ventricular arrhythmias was observed. The incidence rate of all-cause death and heart failure hospitalization was significantly higher in patients with older age (p < 0.001), while there was no significant difference in the incidence rate of ventricular arrhythmia among age groups (p = 0.74).

Conclusions

In patients with CS, the risk of all-cause death and heart failure hospitalization was higher in older patients compared with other age groups; however, the risk of ventricular arrhythmia was comparable across all age groups.

Arrhythmias among Older Adults Receiving Comprehensive Geriatric Care: Prevalence and Associated Factors

BACKGROUND

Cardiovascular diseases and arrhythmias are medical conditions that increase with age and are associated with significant morbidities and mortality. The aim of the present study was to investigate the prevalence of arrhythmias and clinical associations in the collective of older adults receiving comprehensive geriatric care (CGC).

METHODS

Holter ECG monitoring (HECG) of older patients hospitalized for CGC was analyzed. The prevalence of arrhythmias and the associations between the presence of arrhythmias, patients' characteristics and the functional status regarding basic activities of daily living (assessed by the Barthel index (BI)), walking ability (assessed by the timed up and go test (TUG)), and balance and gait (assessed by the Tinetti balance and gait test (TBGT)) were examined.

RESULTS

In the presented study, 626 patients were included (mean age: 83.9 ± 6.6 years, 67.7% were female). The most common arrhythmias detected in HECG were premature ventricular contractions (87.2%), premature atrial contractions (71.7%), and atrial fibrillation (22.7%). Atrial flutter was found in 1.0%, paroxysmal supraventricular tachycardia in 5.8%, non-sustained ventricular tachycardia in 12.5%, first-degree AV block in 0.8%, second-degree AV block type Mobitz I in 0.8%, second-degree AV block type Mobitz II in 0.3%, pause > 2.5 s any cause in 3.5%, and pause > 3 s any cause in 1.6% of the cases. Premature atrial contractions were associated with the female sex (74.8% vs. 65.3%, p = 0.018), whereas in male patients, the following arrhythmias were more common: premature ventricular contractions (91.6% vs. 85.1%, p = 0.029), ventricular bigeminus (8.4% vs. 3.8%, p = 0.021), and non-sustained ventricular tachycardia (17.3% vs. 10.1%, p = 0.014). Atrial fibrillation detected in HECG was more frequent in patients at high risk of falls, indicated by their TBGT score ≤ 18 (24.7% vs. 12.0%, p = 0.006), and premature ventricular contractions were more common in patients unable to walk (TUG score 5) compared to those with largely independent mobility (TUG score 1 or 2) (88.0% vs. 75.0%, p = 0.023). In a logistic regression analysis, atrial fibrillation detected in HECG was identified as a risk factor for a high risk of falls (odds ratio (OR): 2.35, 95% confidence interval (CI): 1.23-4.46).

CONCLUSION

In our study, investigation of HECG of older adults hospitalized for CGC revealed that premature atrial contractions, premature ventricular contractions, and atrial fibrillation were the most common arrhythmias. Premature atrial contractions were found to be more frequent in female patients, while male patients were more prone to premature ventricular contractions. In the investigated population, atrial fibrillation emerged as a risk factor associated with a high risk of falls.

Anatomy of the Ventricular Outflow Tracts: An Electrophysiology Perspective

Outflow tract ventricular arrhythmias are the most common type of idiopathic ventricular arrhythmia. A systematic understanding of the outflow tract anatomy improves procedural efficacy and enables electrophysiologists to anticipate and prevent complications. This review emphasizes the three-dimensional spatial relationships between the ventricular outflow tracts using seven anatomical principles. In turn, each principle is elaborated on from a clinical perspective relevant for the practicing electrophysiologist. The developmental anatomy of the outflow tracts is also discussed and reinforced with a clinical case.

Mechanisms and Risk Factors for Premature Ventricular Contraction Induced Cardiomyopathy

Frequent premature ventricular contractions (PVCs) can cause a reversible form of cardiomyopathy in patients without structural heart disease. Because of the challenging nature of PVC-induced cardiomyopathy (PVICM), the mechanisms and risk factors for PVICM are still unclear. Based on the evidence from retrospective and observational studies, the risk factors for the development of PVICM, in addition to PVC exposure, include QRS duration, coupling interval and male sex. Based on animal models, abnormal calcium handling and cardiac remodeling may be the crucial mechanism underlying the development of cardiomyopathy. We have summarized the current knowledge on PVICM in this review. Understanding these mechanisms and risk factors is important for the diagnosis and management of this condition, which can lead to heart failure if left untreated.

Electrocardiographic Characteristics, Identification, and Management of Frequent Premature Ventricular Contractions

Premature ventricular complexes (PVCs) are frequently encountered in clinical practice. The association of PVCs with adverse cardiovascular outcomes is well established in the context of structural heart disease, yet not so much in the absence of structural heart disease. However, cardiac magnetic resonance (CMR) seems to contribute prognostically in the latter subgroup. PVC-induced myocardial dysfunction refers to the impairment of ventricular function due to PVCs and is mostly associated with a PVC burden > 10%. Surface 12-lead ECG has long been used to localize the anatomic site of origin and multiple algorithms have been developed to differentiate between right ventricular and left ventricular outflow tract (RVOT and LVOT, respectively) origin. Novel algorithms include alternative ECG lead configurations and, lately, sophisticated artificial intelligence methods have been utilized to determine the origins of outflow tract arrhythmias. The decision to therapeutically address PVCs should be made upon the presence of symptoms or the development of PVC-induced myocardial dysfunction. Therapeutic modalities include pharmacological therapy (I-C antiarrhythmic drugs and beta blockers), as well as catheter ablation, which has demonstrated superior efficacy and safety.

Left ventricular remodeling in premature ventricular contraction-induced cardiomyopathy: Effect of coupling intervals and atrioventricular dissociation

Background

Left ventricular dyssynchrony (LVD) and postextrasystolic potentiation (PESP) associated with premature ventricular contractions (PVCs) may play a role in the development of premature ventricular contraction-induced cardiomyopathy (PVC-CM). Long-coupled (LC) PVCs have a greater LVD than short-coupled (SC) PVCs, whereas SC-PVCs have a stronger PESP than LC-PVCs.

Objective

The purpose of this study was to compare SC-PVCs and LC-PVCs to evaluate the roles of LVD, PESP, and atrioventricular dissociation (AVD) in the development of PVC-CM.

Methods

Thirty-six canines underwent pacemaker implantation to induce bigeminal right ventricular apical epicardial PVCs (50% burden) for 12 weeks. Telemetry assessed PVC burden and AVD. Animals were grouped as SC-PVC (coupling interval [CI] 200-220ms), LC-PVC (CI 330 ms), or sham (control). Echocardiographic changes, AVD, and hemodynamics were monitored for 12 weeks.

Results

PVC burden was similar between SC-PVC and LC-PVC groups but was statistically higher in the SC-PVC group (50% vs 47.5%; P = .028). After 12 weeks, left ventricular ejection fraction (LVEF) significantly decreased in both SC-PVC and LC-PVC groups (47.1% ± 1.4% and 45.5% ± 2%, respectively) compared to sham group (61% ± 1.6%; P <.001). Overall AVD was similar between SC-PVC and LC-PVC groups, and there was no significant correlation between AVD and reduction in LVEF at 12 weeks (r = 0.09, P = .5; and r = 0.06, P = .8, respectively). Additionally, both SC-PVC and LC-PVC groups experienced substantial declines in max and min dP/dt after 12 weeks compared to baseline.

Conclusion

Neither PVC CI nor AVD played an independent role in the development or severity of PVC-CM. LVD and PESP make equal relative contributions to the development of PVC-CM.

Electrical and Structural Insights into Right Ventricular Outflow Tract Arrhythmogenesis

The right ventricular outflow tract (RVOT) is the major origin of ventricular arrhythmias, including premature ventricular contractions, idiopathic ventricular arrhythmias, Brugada syndrome, torsade de pointes, long QT syndrome, and arrhythmogenic right ventricular cardiomyopathy. The RVOT has distinct developmental origins and cellular characteristics and a complex myocardial architecture with high shear wall stress, which may lead to its high vulnerability to arrhythmogenesis. RVOT myocytes are vulnerable to intracellular sodium and calcium overload due to calcium handling protein modulation, enhanced CaMKII activity, ryanodine receptor phosphorylation, and a higher cAMP level activated by predisposing factors or pathological conditions. A reduction in Cx43 and Scn5a expression may lead to electrical uncoupling in RVOT. The purpose of this review is to update the current understanding of the cellular and molecular mechanisms of RVOT arrhythmogenesis.

[Should we treat asymptomatic premature ventricular contractions?]

Premature ventricular contractions (PVC) are a common arrhythmia. Therapy is indicated in case of frequent symptomatic PVC or deterioration of left ventricular function. Asymptomatic patients should be evaluated critically for possible PVC-associated symptoms. Catheter ablation of PVCs in patients with normal left ventricular ejection fraction (LVEF) is safe and effective. PVC-induced cardiomyopathy should be considered in unexplained LVEF dysfunction with a PVC burden of at least 10%. If ECG and echocardiography do not clearly rule out structural heart disease (SHD) or the clinical presentation raises suspicion of SHD, cardiac magnetic resonance imaging should be performed. If SHD has been excluded, the guidelines recommend catheter ablation as primary therapy in frequent monomorphic PVC, regardless of symptoms. To prevent PVC-induced cardiomyopathy, ablation can also be considered in asymptomatic patients with a PVC burden > 20%. Also, in patients with known SHD frequent PVC can aggravate LV dysfunction and catheter ablation should be considered.

Idiopathic Ventricular Tachycardia

Idiopathic ventricular tachycardia (VT) is an important cause of morbidity and less commonly, mortality in patients with structurally normal hearts. Appropriate diagnosis and management are predicated on an understanding of the mechanism, relevant cardiac anatomy, and associated ECG signatures. Catheter ablation is a viable strategy to adequately treat and potentially provide a cure in patients that are intolerant to medications or when these are ineffective. In this review, we discuss special approaches and considerations for effective and safe ablation of VT arising from the right ventricular outflow tract, left ventricular outflow tract, left ventricular fascicles, papillary muscles, and moderator band.

Ventricular arrhythmias and sudden death events following acalabrutinib initiation

Acalabrutinib, a next-generation Bruton's tyrosine kinase inhibitor (BTKi), associates with dramatic efficacy against B-cell malignancies. Recently, unexplained ventricular arrhythmias (VAs) with next-generation BTKi-therapy have been reported. Yet, whether acalabrutinib associates with VAs in long-term follow-up is unknown. Leveraging a large-cohort of 290 consecutive B-cell malignancy patients treated with acalabrutinib from 2014 to 2020, we assessed the incidence of VAs. The primary-endpoint was incident VA development (ventricular fibrillation, ventricular tachycardia, and symptomatic premature ventricular contractions). Probability-scores were assessed to determine likelihood of acalabrutinib-association. Incident rates as function of time-on-therapy were calculated. Weighted average observed incidence rates were compared with expected population rates using relative-risks. Absolute excess risk (AER) for acalabrutinib-associated VAs was estimated. Over 1063 person-years of follow-up, there were 8 cases of incident-VAs, including 6 in those without coronary disease (CAD) or heart failure (HF) and 1 sudden-death; median time-to-event 14.9 months. Among those without prior ibrutinib-use, CAD, or HF, the weighted average incidence was 394 per 100 000 person years compared with a reported incidence of 48.1 among similar-aged non-BTKi-treated subjects (relative risk, 8.2; P < .001; AER, 346). Outside of age, no cardiac or electrocardiographic variables associated with VA development. Collectively, these data suggest VAs may be a class-effect of BTKi therapies.

Training machine learning models with synthetic data improves the prediction of ventricular origin in outflow tract ventricular arrhythmias

In order to determine the site of origin (SOO) in outflow tract ventricular arrhythmias (OTVAs) before an ablation procedure, several algorithms based on manual identification of electrocardiogram (ECG) features, have been developed. However, the reported accuracy decreases when tested with different datasets. Machine learning algorithms can automatize the process and improve generalization, but their performance is hampered by the lack of large enough OTVA databases. We propose the use of detailed electrophysiological simulations of OTVAs to train a machine learning classification model to predict the ventricular origin of the SOO of ectopic beats. We generated a synthetic database of 12-lead ECGs (2,496 signals) by running multiple simulations from the most typical OTVA SOO in 16 patient-specific geometries. Two types of input data were considered in the classification, raw and feature ECG signals. From the simulated raw 12-lead ECG, we analyzed the contribution of each lead in the predictions, keeping the best ones for the training process. For feature-based analysis, we used entropy-based methods to rank the obtained features. A cross-validation process was included to evaluate the machine learning model. Following, two clinical OTVA databases from different hospitals, including ECGs from 365 patients, were used as test-sets to assess the generalization of the proposed approach. The results show that V2 was the best lead for classification. Prediction of the SOO in OTVA, using both raw signals or features for classification, presented high accuracy values (>0.96). Generalization of the network trained on simulated data was good for both patient datasets (accuracy of 0.86 and 0.84, respectively) and presented better values than using exclusively real ECGs for classification (accuracy of 0.84 and 0.76 for each dataset). The use of simulated ECG data for training machine learning-based classification algorithms is critical to obtain good SOO predictions in OTVA compared to real data alone. The fast implementation and generalization of the proposed methodology may contribute towards its application to a clinical routine.

Prevalence and heart rate variability characteristics of premature ventricular contractions detected by 24-hour Holter among outpatients with palpitations in China: a cross-sectional study

OBJECTIVE

To analyse the prevalence and heart rate variability (HRV) characteristics of premature ventricular contraction (PVC) detected by 24-hour Holter among Chinese outpatients with palpitations.

DESIGN

A cross-sectional study.

SETTING

This study was conducted in a tertiary hospital.

PARTICIPANTS

A total of 4754 outpatients who received 24-hour Holter for palpitations.

MAIN OUTCOME MEASURES

Prevalence, HRV time-domain and frequency-domain analyses of 24-hour Holter, and echocardiographic parameters were assessed. Propensity score matching (PSM) was applied to balance baseline variables (age, gender) to decrease the bias between comparison groups.

RESULTS

The prevalence of PVC was 67.7% (3220/4754), and was higher in men than women (69.9% vs 66.0%, p=0.004); the prevalence of frequent PVCs (PVC burden≥5%) was 7.7% (368/4754). Older patients had the highest frequency of PVC among all patients. However, among 3220 patients with PVC, younger patients' PVC burden was much higher. Matched 1:1 by age and gender, the HRV time-domain parameters in patients with PVC were all lower than those in patients without PVC (all p<0.05); for the HRV frequency-domain parameters, the patients with frequent PVCs had a higher low frequency/high frequency (LF/HF) ratio (5.4 vs 2.8, p<0.001) than those with PVC burden less than 5%.

CONCLUSIONS

The prevalence of PVC and frequent PVCs were 67.7% and 7.7%, respectively, detected by 24-hour Holter among Chinese outpatients with palpitations. Decreased HRV time-domain parameters suggested the occurrence of PVC, and increased LF/HF ratio represented the imbalance of autonomic nervous system in patients with frequent PVCs. Further studies are needed to understand the HRV indexes in PVC patients.

The value of QRS onset of the outflow tract PVC in V1 and V2 leads recorded in fourth, third, and second intercostal spaces to differentiate main origins of premature ventricular contraction-A prospective cohort study

Background

Electrocardiography (ECG) is now proposed as a simple and cost-effective tool to determine the location of arrhythmias before ablation. We aimed to examine the value of the QRS onset of outflow tract PVC in V1 and V2 leads recorded in fourth, third, and second intercostal spaces to differentiate two main origins for premature ventricular contraction (PVC) including right ventricular outflow tract (RVOT) and left ventricular outflow tract (LVOT).

Methods

In this prospective cohort study, a total of 58 patients were studied, from whom a surface ECG was obtained using V1 and V2 leads in the fourth, third, and second intercostal spaces. ECG and Electrophysiology studie (EPS) data were then recorded and compared to determine the sensitivity and specificity of QRS onset in locating arrhythmias. The reciever operating characterictic (ROC) curve analysis was applied to test diagnostic performance.

Results

Based on the time of PVC initiation in each of the V1 and V2 leads in the fourth intercostal space, if PVC is recorded earlier in the V1 lead, its source in 95.8% of the patients is RVOT and if PVC preceded the V2 lead, 70.59% of the patients had PVC from LVOT. Comparing of QRS onset in V1 and V2 leadsrecorded from third% and and second intercostal spaces had considerable sensitivity and specificity to determine the origin of the outflow tract PVC (81.82 and 94.12%, respectively).

Conclusion

Simultaneous recording of outflow tract PVCs from second third and fourth intercostal spaces and comparing their onset can determine the left and right outflow tract PVCs with high sensitivity and specificity.

Management of Cardiovascular Disease in Patients With COVID-19 and Chronic Chagas Disease: Implications to Prevent a Scourge Still Larger

Cardiovascular diseases (CVD) are the most important cause of morbidity and mortality in the general population. Because the high prevalence of COVID-19 and chronic Chagas disease (CCD) where the latter is endemic, all such diseases will likely be observed in the same patient. While COVID-19 can provoke generalized endotheliitis, which can lead to a cytokine storm and a hyper-coagulable state culminating into in-site and at a distance thrombosis. Therefore, small-vessel coronary artery disease (CAD), cerebrovascular disease, thromboembolism, and arrhythmias are prominent findings in COVID-19. In CCD, small-vessel CAD, cardioembolic stroke, pulmonary embolism, heart failure and arrhythmias are frequently observed as a result of a similar but less intense mechanism. Consequently, the association of CCD and COVID-19 will likely increase the incidence of CVD. Thus, doctors on the frontline should be on the alert for this diagnostic possibility so that the proper treatment can be given without any delay.

Cardiopulmonary Exercise Testing in Repaired Tetralogy of Fallot: Multiparametric Overview and Correlation with Cardiac Magnetic Resonance and Physical Activity Level

Patients with repaired Tetralogy of Fallot (rToF) typically report having preserved subjective exercise tolerance. Chronic pulmonary regurgitation (PR) with varying degrees of right ventricular (RV) dilation as assessed by cardiac magnetic resonance imaging (MRI) is prevalent in rToF and may contribute to clinical compromise. Cardiopulmonary exercise testing (CPET) provides an objective assessment of functional capacity, and the International Physical Activity Questionnaire (IPAQ) can provide additional data on physical activity (PA) achieved. Our aim was to assess the association between CPET values, IPAQ measures, and MRI parameters. All rToF patients who had both an MRI and CPET performed within one year between March 2019 and June 2021 were selected. Clinical data were extracted from electronic records (including demographic, surgical history, New York Heart Association (NYHA) functional class, QRS duration, arrhythmia, MRI parameters, and CPET data). PA level, based on the IPAQ, was assessed at the time of CPET. Eighty-four patients (22.8 ± 8.4 years) showed a reduction in exercise capacity (median peak VO₂ 30 mL/kg/min (range 25–33); median percent predicted peak VO₂ 68% (range 61–78)). Peak VO₂, correlated with biventricular stroke volumes (RVSV: β = 6.11 (95%CI, 2.38 to 9.85), p = 0.002; LVSV: β = 15.69 (95% CI 10.16 to 21.21), p < 0.0001) and LVEDVi (β = 8.74 (95%CI, 0.66 to 16.83), p = 0.04) on multivariate analysis adjusted for age, gender, and PA level. Other parameters which correlated with stroke volumes included oxygen uptake efficiency slope (OUES) (RVSV: β = 6.88 (95%CI, 1.93 to 11.84), p = 0.008; LVSV: β = 17.86 (95% CI 10.31 to 25.42), p < 0.0001) and peak O₂ pulse (RVSV: β = 0.03 (95%CI, 0.01 to 0.05), p = 0.007; LVSV: β = 0.08 (95% CI 0.05 to 0.11), p < 0.0001). On multivariate analysis adjusted for age and gender, PA level correlated significantly with peak VO₂/kg (β = 0.02, 95% CI 0.003 to 0.04; p = 0.019). We observed a reduction in objective exercise tolerance in rToF patients. Biventricular stroke volumes and LVEDVi were associated with peak VO₂ irrespective of RV size. OUES and peak O₂ pulse were also associated with biventricular stroke volumes. While PA level was associated with peak VO₂, the incremental value of this parameter should be the focus of future studies.

Diagnosis and Treatment of Idiopathic Premature Ventricular Contractions: A Stepwise Approach Based on the Site of Origin

Premature ventricular contractions in the absence of structural heart disease are among the most common arrhythmias in clinical practice, with well-defined sites of origin in the right and left ventricle. In this review, starting from the electrocardiographic localization of premature ventricular contractions, we investigated the mechanisms, prevalence in the general population, diagnostic work-up, prognosis and treatment of premature ventricular contractions, according to current scientific evidence.

Frequency of cardiac arrhythmias in older adults: Findings from the Subclinical Atrial Fibrillation and Risk of Ischemic Stroke (SAFARIS) study

BACKGROUND

Prolonged monitoring of cardiac rhythm has been used to screen for subclinical atrial fibrillation (AF); little is known about other arrhythmias in the general population, especially in the elderly, who are at higher risk of arrhythmias.

METHODS

We evaluated the frequency of arrhythmias in the tri-ethnic (white, Black, Hispanic), community-based Subclinical Atrial Fibrillation and Risk of Ischemic Stroke (SAFARIS) study using a patch-based recorder for up to 14 days in 527 participants free of AF, congestive heart failure (CHF) or history of stroke. Differences according to gender, age, ethnicity and presence of hypertension, diabetes and pertinent ECG and echocardiographic variables were examined.

RESULTS

Mean age was 77.2 ± 6.8 years (37.2% men, 62.8% women). AF was present in 10 participants (1.9%), only 2 of them symptomatic. Supraventricular tachycardia (SVT) and ventricular tachycardia (VT) episodes were observed in 84.4% and 25.0% but only 13.5% and 10.6% of participants reported symptoms, respectively. Severe bradycardia (<40 bpm) was present in 12.5%. Sinus pauses and high-degree atrioventricular blocks were infrequent (2.1% and 1.5%, respectively). Most arrhythmias were more frequent in participants > 75 years; ventricular arrhythmias and severe bradycardia were more common in men. Whites had significantly more episodes of AF than Hispanics, SVT than Blacks and VT ≥ 10 beats than Hispanics and Blacks. Hypertensives had more episodes of severe bradycardia. LV hypertrophy or LVEF <55% were associated with more frequent ventricular and supraventricular arrhythmias.

CONCLUSIONS

Prolonged cardiac rhythm monitoring revealed moderate frequency of AF, but higher than expected frequencies of AF-predisposing arrhythmias. Ventricular arrhythmias were relatively frequent, whereas severe bradyarrhythmias were infrequent.

Recent trends in cardiac electrophysiology and catheter ablation in New Zealand

BACKGROUND

Catheter ablation has rapidly become an integral part of the management of many arrhythmias.

AIMS

To provide a history of clinical cardiac electrophysiology (EP) in New Zealand (NZ) and analysis of recent trends in EP procedures and catheter ablations across NZ, which has not previously been reported.

METHODS

EP case type and volume were obtained from the EP databases from each of the four public and four private EP centres in NZ from 1 January 2014 to 31 December 2018. Procedure rates were expressed as per million population.

RESULTS

A total of 7695 EP cases was performed, including 5929 (77%) in the public sector. Atrial fibrillation (AF) ablation was the most common procedure at 29%. EP procedure rates increased by 21% (to 353 per million in 2018), predominantly due to AF ablation rates increasing by 46%. Ventricular tachycardia ablation rates increased by 41% but only comprised 8% of procedures. There was a striking difference in the growth of EP procedure rates in the public compared to the private sector (4% vs 106%), as well as considerable differences in EP procedure and AF ablation rates across the public EP centres. NZ had lower ablation rates compared to countries with similar healthcare expenditure.

CONCLUSION

There has been a substantial increase in EP procedure and AF ablation rates in NZ and international trends suggest this growth will continue. However, there is considerable variation in procedure rates and growth trends between EP centres, highlighting inequities in access within the country.

Therapeutic Inefficacy and Proarrhythmic Nature of Metoprolol Succinate and Carvedilol Therapy in Patients With Idiopathic, Frequent, Monomorphic Premature Ventricular Contractions

BACKGROUND

Antiarrhythmic drugs remain the first-line therapy for treatment of idiopathic ventricular arrhythmias.

STUDY QUESTION

The aim of this study was to assess the therapeutic efficacy of extended-release metoprolol succinate (MetS) and carvedilol for idiopathic, frequent, monomorphic premature ventricular contractions (PVCs).

STUDY DESIGN

Study population consisted of 114 consecutive patients: 71 received MetS and 43 received carvedilol.

MEASURES AND OUTCOMES

All patients underwent 24-hour Holter monitoring at baseline and during drug therapy. PVC-burden response to drug therapy was categorized as "good" (≥80% reduction), "poor" (either <80% reduction or ≤50% increase), and "proarrhythmic" responses (>50% increase) based on change in PVC burden compared with baseline.

RESULTS

Most common presenting symptom was palpitations (65.8%), followed by coincidental discovery (29%). The mean MetS and carvedilol dosages were 65.57 ± 30.67 mg/d and 23.66 ± 4.26 mg/d, respectively. "Good," "poor," and "proarrhythmic" responses were observed in 11.3% and 16.3%, 63.4% and 67.4%, and 25.3% and 16.3% of patients treated with MetS and carvedilol, respectively. In patients with relatively high (≥16%) PVC burden, the sum of "poor"/"proarrhythmic" response was observed in 95.5% and 86.4% of patients treated with MetS and carvedilol, respectively. "Proarrhythmic" response was observed in 21.9% of the patients, particularly in the presence of relatively lower (≤10%) baseline PVC burden. Patients with "good" response during beta-blocker therapy had higher baseline daily average intrinsic total heart beats compared with patients with "poor"/"proarrhythmic" response combined (96,437 ± 26,488 vs. 86,635 ± 15,028, P = 0.047, respectively). Side effects and intolerance were observed in 5.6% and 18.6% of patients treated with MetS and carvedilol, respectively.

CONCLUSIONS

MetS and carvedilol for idiopathic, frequent, monomorphic PVCs are frequently inefficient. Therapeutic efficacy decreases further in patients with relatively high (≥16%) PVC burden. Relatively higher baseline daily intrinsic total heart beats may be used to predict "good" response before beta-blocker therapy.

Incidence of outflow tract ventricular tachycardia long after surgical aortic valve replacement

BACKGROUND

The peri-outflow tract region could be the origin of ventricular tachycardia (VT) after aortic valve replacement (AVR). However, the clinical characteristics of outflow tract ventricular tachycardias (OTVTs) after AVR are yet to be clarified. This study investigated the incidence, risk factors, and clinical characteristics of patients with OTVTs after AVR.

METHODS

We retrospectively analyzed the clinical course of 120 patients who had undergone surgical AVR (SAVR) between April 1980 and October 2018. The patients had no ischemic or diagnosed cardiomyopathies other than primary aortic valve diseases.

RESULTS

Six patients (5.0%) developed OTVTs after SAVR. The average onset was at 10.8 ± 5.7 years after SAVR. All cases of VT arose from the inferior axis and included left and right bundle branch block configuration. Two patients who underwent cardiac magnetic resonance imaging (MRI) had late gadolinium enhancement (LGE) in the midlayer of the left ventricle basal anteroseptal wall. Patients with periaortic VTs had significantly larger left ventricular (LV) diameter at systole, lower LV ejection fraction, higher positive rates of signal-averaged electrocardiogram (SAECG), and nonsustained VTs on Holter monitoring. On ablation, local fragmented potentials with low voltage zones were observed in accordance with the LGE distribution. Multiple VTs originating from the periaortic region were provoked in the sessions.

CONCLUSIONS

Acute OTVT was found in 5% of patients after SAVR. Arrhythmia risk stratification by SAECG, Holter ECG, and cardiac MRI should be considered for a long period in patients after SAVR.

Outcomes of Premature Ventricular Contraction-Cardiomyopathy in the Veteran Population: A Secondary Analysis of the CHF-STAT Study

OBJECTIVES

This study sought to assess the rate and outcomes of premature ventricular contractions (PVC)-cardiomyopathy from the CHF-STAT (Survival Trial of Antiarrhythmic Therapy in Congestive Heart Failure) trial, a population with cardiomyopathy (left ventricular [LV] ejection fraction of <40%) and frequent PVCs (>10 PVCs per hour).

BACKGROUND

PVCs are associated with heart failure and PVC-cardiomyopathy. The prevalence of PVC-cardiomyopathy and outcome benefits of PVC suppression are not clear.

METHODS

A secondary analysis of the CHF-STAT study was performed to compare the rate of successful PVC suppression (≥80% PVC reduction), LV recovery (defined as improvement in LV ejection fraction of ≥10% points), and PVC-cardiomyopathy between amiodarone and placebo groups at 6 months. PVC-cardiomyopathy was defined if both PVC reduction of ≥80% and LV ejection fraction improvement of ≥10% were present at 6 months. Cardiac events (death or resuscitated cardiac arrest) were compared between PVC-cardiomyopathy versus non-PVC-cardiomyopathy during a 5-year follow-up.

RESULTS

The rates of successful PVC suppression and LV recovery were significantly higher in the amiodarone (72% and 39%, respectively) when compared to the placebo group (12% and 16%, respectively; p < 0.001), regardless of cardiomyopathy etiology. PVC-cardiomyopathy was present in 29% and 1.8% of patients in the amiodarone and placebo groups, respectively (p < 0.001). Similar PVC-cardiomyopathy rates were found in ischemic (24% amiodarone vs. 2% placebo; p < 0.001) and nonischemic populations (41% amiodarone vs. 1.5% placebo; p < 0.001). Death and resuscitated cardiac arrest were significantly lower in patients with PVC-cardiomyopathy and those treated with amiodarone.

CONCLUSIONS

The overall prevalence of PVC-cardiomyopathy in the CHF-STAT study was significant regardless of ischemic substrate (29%, overall population; 41%, nonischemic cardiomyopathy). Treatment of PVC-cardiomyopathy with amiodarone is likely to improve survival in this high-risk population.

Prediction of Paroxysmal Atrial Fibrillation From Complexity Analysis of the Sinus Rhythm ECG: A Retrospective Case/Control Pilot Study

Paroxysmal atrial fibrillation (PAF) is the most common cardiac arrhythmia, conveying a stroke risk comparable to persistent AF. It poses a significant diagnostic challenge given its intermittency and potential brevity, and absence of symptoms in most patients. This pilot study introduces a novel biomarker for early PAF detection, based upon analysis of sinus rhythm ECG waveform complexity. Sinus rhythm ECG recordings were made from 52 patients with (n = 28) or without (n = 24) a subsequent diagnosis of PAF. Subjects used a handheld ECG monitor to record 28-second periods, twice-daily for at least 3 weeks. Two independent ECG complexity indices were calculated using a Lempel-Ziv algorithm: R-wave interval variability (beat detection, BD) and complexity of the entire ECG waveform (threshold crossing, TC). TC, but not BD, complexity scores were significantly greater in PAF patients, but TC complexity alone did not identify satisfactorily individual PAF cases. However, a composite complexity score (h-score) based on within-patient BD and TC variability scores was devised. The h-score allowed correct identification of PAF patients with 85% sensitivity and 83% specificity. This powerful but simple approach to identify PAF sufferers from analysis of brief periods of sinus-rhythm ECGs using hand-held monitors should enable easy and low-cost screening for PAF with the potential to reduce stroke occurrence.

[Telemedicine and ECG monitoring : Technical prerequisites and clinical workflow]

Classic telemonitoring for the detection of arrhythmias is well established. The advent of wearable ECG devices is associated with great potential and significant challenges. New data collection pathways have to be integrated into clinical workflows. Preliminary studies indicate that positive effects are to be expected from this new form of telemonitoring.

Premature Ventricular Contractions and Cardiomyopathy

Premature ventricular contractions (PVCs) are a common arrhythmia that may cause symptoms of variable severity. PVCs have recently garnered interest in their ability to induce adverse structural heart remodeling in an entity known as PVC-induced cardiomyopathy. This entity is a retrospective diagnosis that likely remains under-recognized and may occur concurrently with other forms of cardiomyopathy. The appropriate identification and management of PVCs in the setting of associated cardiomyopathy may have a significant impact on cardiac function and the clinical course, including recovery of left ventricular ejection fraction and improvement in patient functional status. Treatment consists of catheter ablation and/or antiarrhythmic drug therapy, but continued monitoring and follow-up are required, as the recurrence of high PVC burden may lead to redevelopment of cardiomyopathy.

Ten-year trends in catheter ablation for ventricular tachycardia vs other interventional procedures in Australia

AIMS

Major technological and procedural advancements have reinvigorated catheter ablation as adjunctive therapy for drug-refractory ventricular tachycardia (VT). We examined temporal trends in VT ablations as compared to other interventional cardiovascular procedures namely, percutaneous coronary intervention (PCI) and atrial fibrillation (AF) ablation in Australia.

METHODS AND RESULTS

A retrospective review of procedural numbers for VT ablations, AF ablations, and PCI was performed from 2008/09-2016/17 the Australian Institute of Health, Welfare and Aging (AIHW), and Medicare Australia (MA) databases. Linear regression models were fitted to compare the trends in population-adjusted procedural numbers over the 10-year period. Data from the AIHW and MA sources respectively showed that (a) PCI had a 1.3% (AIHW data P = .15) and 1.8% (MA data P < .001) population-adjusted increment per year, (b) AF ablations had a 12.7% (P < .001) and 11.7% (P < .001) per year population-adjusted increment, and (c) VT ablations showed an 18% (P < .001) and 12.7% (P < .001) per year population-adjusted increment. Growth of PCI was increasing at a lower rate than AF ablations (P < .001 for both AIHW and MA sources). Growth of VT ablation was significantly higher than AF ablations and PCI (AIHW: 18% vs 12.7% [P = .004] and 1.3% per year [P < .001]).

CONCLUSION

Catheter-based VT ablation has increased significantly in Australia over the last decade, consistent with worldwide trends, and now surpassing all ablation procedures, including AF ablation and PCI for CAD. This data highlight the provision of additional resources to match the increasing demand for VT ablation procedures in Australia.

Ventricular Arrhythmias

Ventricular tachycardia is commonly seen in medical practice. It may be completely benign or portend high risk for sudden cardiac death. Therefore, it is important that clinicians be familiar with and able to promptly recognize and manage ventricular tachycardia when confronted with it clinically. In many cases, curative therapy for a given ventricular arrhythmia may be provided after a thorough understanding of the underlying substrate and mechanism. In this article, the authors broadly review the current classification of the different ventricular arrhythmias encountered in medical practice, provide brief background regarding the different mechanisms, and discuss practical diagnosis and management scenarios.

[Premature ventricular contractions and tachycardia in a structurally normal heart : Idiopathic PVC and VT]

Premature ventricular contractions (PVC) are a common, often incidental and mostly benign finding. Treatment is indicated in frequent and symptomatic PVC or in cases of worsening of left ventricular function. Idiopathic ventricular tachycardia (VT) is mostly found in patients with a structurally healthy heart. These PVC/VT usually have a focal origin. The most likely mechanism is delayed post-depolarization. Localization of the origin is based on the creation of an activation map with or without combination of pace mapping. Idiopathic PVC/VT are most frequently located on the outflow tracts of the right and left ventricles, including the aortic root. Other typical locations include the annulus of the tricuspid or mitral valve, papillary muscles and Purkinje fibers. Catheter ablation is an alternative to antiarrhythmic medication in symptomatic monomorphic PVC/VT. The success rate is good whereby mapping and ablation can often represent a challenge. This article is the fifth part of a series dedicated to specific advanced training in the field of special rhythmology and invasive electrophysiology. It describes the pathophysiological principles, types and typical findings that can be obtained during an electrophysiological investigation.

Premature Ventricular Complex-induced Cardiomyopathy

Premature ventricular complex-induced cardiomyopathy is a potentially reversible condition in which left ventricular dysfunction is induced by the occurrence of frequent premature ventricular complexes (PVCs). Various cellular and extracellular mechanisms and risk factors for developing cardiomyopathy in this context have been suggested but the exact pathophysiological mechanism remains unclear. The suppression of PVCs is usually indicated in symptomatic patients with frequent PVCs and also those with left ventricular dysfunction. Antiarrhythmic drugs are a useful non-invasive treatment to eliminate PVCs, but the side effect profile, including the risk of pro-arrhythmia, along with suboptimal clinical effectiveness, should be weighed against the usually more effective but not risk-free treatment with catheter ablation. The latter has progressively become first line therapy in many patients with PVC-induced cardiomyopathy and should be particularly considered in specific scenarios.

Epidemiology of ventricular tachyarrhythmia : Any changes in the past decades?

Ventricular tachyarrhythmias include potentially lethal episodes of sustained ventricular tachycardia (VT) and ventricular fibrillation (VF) as well as hemodynamically tolerated ventricular ectopic activity. Sustained VT or VF may develop in the setting of acute myocardial infarction or as clinical sequelae of advanced cardiomyopathy. The incidence of these serious arrhythmias is estimated from retrospective and observational studies and registries of sudden cardiac arrest and sudden cardiac death. Over the past few decades, there has been a gradual decline in the incidence of life-threatening ventricular tachyarrhythmias which has been largely driven by upstream treatments for and prevention of coronary artery disease and its sequelae. In addition primary prevention implantable cardioverter-defibrillators (ICDs) have improved survival in patients at risk for malignant ventricular arrhythmias and sudden cardiac death. Improved understanding, and improved diagnostic and imaging methods have elucidated many of the previously classified "idiopathic" ventricular arrhythmias as inherited arrhythmic syndromes and occult cardiomyopathies. In addition, improved sensitivity and duration of ECG monitoring has allowed increased detection of ventricular ectopic activity.