Association between body mass index and results of cryoballoon ablation in Korean patients with atrial fibrillation: an analysis from the Korean Heart Rhythm Society Cryoablation registry

AIMS

Pulmonary vein isolation using cryoablation is effective and safe in patients with atrial fibrillation (AF). Although both obesity and underweight are associated with a higher risk for incident AF, there is limited data on the efficacy and safety following cryoablation according to body mass index (BMI) especially in Asians.

METHODS AND RESULTS

Using the Korean Heart Rhythm Society Cryoablation registry, a multicentre registry of 12 tertiary hospitals, we analysed AF recurrence and procedure-related complications after cryoablation by BMI (kg/m2) groups (BMI < 18.5, underweight, UW; 18.5-23, normal, NW; 23-25, overweight, OW; 25-30, obese Ⅰ, OⅠ; ≥30, obese Ⅱ, OⅡ). A total of 2648 patients were included (median age 62.0 years; 76.7% men; 55.6% non-paroxysmal AF). Patients were categorized by BMI groups: 0.9% UW, 18.7% NW, 24.8% OW, 46.1% OI, and 9.4% OII. Underweight patients were the oldest and had least percentage of non-paroxysmal AF (33.3%). During a median follow-up of 1.7 years, atrial arrhythmia recurred in 874 (33.0%) patients (incidence rate, 18.9 per 100 person-years). After multivariable adjustment, the risk of AF recurrence was higher in UW group compared with NW group (adjusted hazard ratio, 95% confidence interval; 2.55, 1.18-5.50, P = 0.02). Procedure-related complications occurred in 123 (4.7%) patients, and the risk was higher for UW patients (odds ratio, 95% confidence interval; 2.90, 0.94-8.99, P = 0.07), mainly due to transient phrenic nerve palsy.

CONCLUSION

Underweight patients showed a higher risk of AF recurrence after cryoablation compared with NW patients. Also, careful attention is needed on the occurrence of phrenic nerve palsy in UW patients.

Estimation of Supply and Demand for Cardiologists in Korea

BACKGROUND AND OBJECTIVES

The objective of this study was to estimate the supply and demand for cardiologists in Korea and provide evidence for healthcare policy to ensure a stable and adequate workforce for optimal cardiovascular disease management.

METHODS

Past trends of inflow and outflow of cardiologists were used to make crude projections, which were then adjusted based on demands of services to obtain final projections. Inflow of cardiologists was estimated using second-order polynomial regression and demand for cardiology care was estimated using linear regression.

RESULTS

There were 1,139 active cardiologists who were under the age of 65 in clinical practice in Korea. The estimated number of cardiologists from 2022 to 2040 showed that the number of cardiologists would peak at 1,344 in 2032 and gradually decrease thereafter. We also estimated an increase of 947,811 cases of heart-related procedures annually from 2023 to 2032. The number of heart-related procedures per cardiologist would increase 1.4 times from 12,964 in 2023 to 17,862 in 2032. The estimated number of emergency patients per cardiologist under 50 years old would almost double from 544 in 2022 to 987 in 2032.

CONCLUSIONS

We expect significant shortage of cardiologists in Korea within the next 10 years. The number of emergency patients per cardiologist will increase by nearly 50%, leading to high individual workload for cardiologists. To prevent this imbalance between supply and demand, an organized and collective approach by the specialty of cardiology is imperative to produce a balanced workforce.

Seven-day and In-hospital Mortality According to Left and Right Ventricular Dysfunction in Patients With Septic Shock

BACKGROUND AND OBJECTIVES

The prognostic implications of septic cardiomyopathy have not been clearly demonstrated. We evaluated serial changes in left ventricular (LV) and right ventricular (RV) function in patients with septic shock and their prognostic value on 7-day and in-hospital mortality.

METHODS

Transthoracic echocardiography was performed within 48 hours of the diagnosis of septic shock and 7 days after the initial evaluation. In addition to traditional echocardiographic parameters, LV and RV function was evaluated using global longitudinal strain (GLS), and tricuspid annular plane systolic excursion (TAPSE).

RESULTS

A total of 162 patients (men, 83, 51.5%; 70.7±13.4 years; Acute Physiology and Chronic Health Evaluation [APACHE] II, 30.6±9.2) were enrolled. Initial GLS and TAPSE were -14.9±5.2% and 16.9±5.5 mm, and improved in the follow-up evaluation (GLS, -17.6±4.9%; TAPSE, 19.2±5.4 mm). Seven-day and in-hospital mortality were 24 (14.9%) and 64 (39.8%). Seven-day mortality was significantly associated with initial GLS >-16% (odds ratio [OR], 14.066, 95% confidence interval [CI], 1.178-167.969, p=0.037) and APACHE II score (OR, 1.196, 95% CI, 1.047-1.365, p=0.008). The in-hospital mortality of 7-day survivors was associated with follow-up TAPSE <16 mm (OR, 10.109, 95% CI, 1.640-62.322, p=0.013) and Sequential Organ Failure Assessment score (OR, 1.340, 95% CI, 1.078-1.667, p=0.008). GLS was not associated with in-hospital mortality of 7-day survivors.

CONCLUSIONS

Fluctuation of both ventricular function was common in septic shock. Seven-day mortality of patients with septic shock was related to GLS, whereas in-hospital mortality of 7-day survivors was related to TAPSE, not to GLS.

Early Aortic Valve Replacement in Symptomatic Normal-Flow, Low-Gradient Severe Aortic Stenosis: A Propensity Score-Matched Retrospective Cohort Study

BACKGROUND AND OBJECTIVES

Aortic valve replacement (AVR) is considered a class I indication for symptomatic severe aortic stenosis (AS). However, there is little evidence regarding the potential benefits of early AVR in symptomatic patients diagnosed with normal-flow, low-gradient (NFLG) severe AS.

METHODS

Two-hundred eighty-one patients diagnosed with symptomatic NFLG severe AS (stroke volume index ≥35 mL/m², mean transaortic pressure gradient <40 mmHg, peak transaortic velocity <4 m/s, and aortic valve area <1.0 cm²) between January 2010 and December 2020 were included in this retrospective study. After performing 1:1 propensity score matching, 121 patients aged 75.1±9.8 years (including 63 women) who underwent early AVR within 3 months after index echocardiography, were compared with 121 patients who received conservative care. The primary outcome was a composite of all-cause death and heart failure (HF) hospitalization.

RESULTS

During a median follow-up of 21.9 months, 48 primary outcomes (18 in the early AVR group and 30 in the conservative care group) occurred. The early AVR group demonstrated a significantly lower incidence of primary outcomes (hazard ratio [HR], 0.52; 95% confidence interval [CI], 0.29-0.93; p=0.028); specifically, there was no significant difference in all-cause death (HR, 0.51; 95% CI, 0.23-1.16; p=0.110), although the early AVR group showed a significantly lower incidence of hospitalization for HF (HR, 0.43; 95% CI, 0.19-0.95, p=0.037). Subgroup analyses supported the main findings.

CONCLUSIONS

An early AVR strategy may be beneficial in reducing the risk of a composite outcome of death or hospitalization for HF in symptomatic patients with NFLG severe AS. Future randomized studies are required to validate and confirm our findings.

Machine Learning Prediction for the Recurrence After Electrical Cardioversion of Patients With Persistent Atrial Fibrillation

BACKGROUND AND OBJECTIVES

There is limited evidence regarding machine-learning prediction for the recurrence of atrial fibrillation (AF) after electrical cardioversion (ECV). This study aimed to predict the recurrence of AF after ECV using machine learning of clinical features and electrocardiograms (ECGs) in persistent AF patients.

METHODS

We analyzed patients who underwent successful ECV for persistent AF. Machine learning was designed to predict patients with 1-month recurrence. Individual 12-lead ECGs were collected before and after ECV. Various clinical features were collected and trained the extreme gradient boost (XGBoost)-based model. Ten-fold cross-validation was used to evaluate the performance of the model. The performance was compared to the C-statistics of the selected clinical features.

RESULTS

Among 718 patients (mean age 63.5±9.3 years, men 78.8%), AF recurred in 435 (60.6%) patients after 1 month. With the XGBoost-based model, the areas under the receiver operating characteristic curves (AUROCs) were 0.57, 0.60, and 0.63 if the model was trained by clinical features, ECGs, and both (the final model), respectively. For the final model, the sensitivity, specificity, and F1-score were 84.7%, 28.2%, and 0.73, respectively. Although the AF duration showed the best predictive performance (AUROC, 0.58) among the clinical features, it was significantly lower than that of the final machine-learning model (p<0.001). Additional training of extended monitoring data of 15-minute single-lead ECG and photoplethysmography in available patients (n=261) did not significantly improve the model's performance.

CONCLUSIONS

Machine learning showed modest performance in predicting AF recurrence after ECV in persistent AF patients, warranting further validation studies.

Major Adverse Cardiovascular Events in Korean Congenital Heart Disease Patients: A Nationwide Age- and Sex-Matched Case-Control Study

PURPOSE

Congenital heart disease (CHD) is a known risk factor for acquired cardiovascular and cerebrovascular diseases. However, available evidence on CHD is limited mostly to Western populations. This study aimed to evaluate the prevalence of vascular events and all-cause mortality in Korean patients with CHD and to further corroborate CHD as a predictor of vascular events and all-cause mortality.

MATERIALS AND METHODS

The claims data of the Korean National Health Insurance Service (NHIS) were retrospectively reviewed. Information regarding diagnostic codes, comorbidities, medical services, income level, and residential area was also collected. Outcomes of interest included stroke, myocardial infarction (MI), all-cause mortality, and major adverse cardiovascular events (MACE).

RESULTS

We included 232203 patients with CHD and 3024633 individuals without CHD as a control group through age- and sex-matched 1:10 random sampling. The prevalences of hypertension, congestive heart failure, ischemic heart disease, hyperlipidemia, and atrial fibrillation were significantly higher in the CHD group, which had a more than two-fold higher incidence of vascular events and all-cause mortality, than in the group without CHD. Multivariable models demonstrated that CHD was a significant risk factor for stroke, MI, all-cause mortality, and MACE.

CONCLUSION

In conclusion, this nationwide study demonstrates that Korean patients with CHD have a high incidence of comorbidities, vascular events, and mortality. CHD has been established as an important predictor of cardiovascular events. Further studies are warranted to identify high-risk patients with CHD and related factors to prevent vascular events.

Cardiovascular Complications of Novel Anti-Cancer Immunotherapy: Old Problems from New Agents?

Many novel anti-cancer therapies have dramatically improved outcomes of various cancer patients. However, it also poses a risk for cardiovascular complications as well. For the novel anti-cancer agent with which physicians does not have enough clinical experiences to determine the characteristics of cardiovascular complications, it is important to assess risk factors for cardiotoxicity before starting anti-cancer therapy. High-risk patient should be consulted to cardiologist before initiating anti-cancer therapy and pre-emptive cardiac function monitoring plan might be prepared in advance. The biomarkers, electrocardiography and echocardiography are useful tools for the detection of subclinical cardiotoxicity during anti-cancer therapy. This review article tried to suggest the cardiac function monitoring strategies for newly encountered potential cardiotoxic anti-cancer agents and to summarize the cardiovascular complications of novel anti-cancer immunotherapies including immune checkpoint inhibitor (ICI) and chimeric antigen receptor (CAR) T-cell therapy. ICIs can cause fatal myocarditis, which usually occurs early after initiation, and prompt treatment with high-dose corticosteroid is necessary. CAR T-cell therapy can cause cytokine release syndrome, which may result in circulatory collapse. Supportive treatment as well as tocilizumab, an anti-interleukin-6 receptor antibody are cornerstones of treatment.