Ventricular Ectopy as a Predictor of Heart Failure and Death

Temporal and Spatial Changes of Proarrhythmic Substrate in Premature Ventricular Contraction-Induced Cardiomyopathy

BACKGROUND

The changes in proarrhythmic substrates and malignant ventricular arrhythmia mechanisms caused by premature ventricular contraction-induced cardiomyopathy (PVCCM) remain unclear.

OBJECTIVES

The goal of this study was to establish the electrophysiological mechanism of how high-load PVC causes malignant arrhythmia.

METHODS

Thirteen swine were exposed to 50% paced PVC from the right ventricular apex for 12 weeks (PVCCM, n = 6) and no pacing for 12 weeks (control, n = 7). Cardiac function was quantified biweekly with echocardiography. Computed tomography scans and electrophysiological examinations were performed monthly to dynamically evaluate the changes in the cardiac structure and the arrhythmogenic substrate.

RESULTS

The decreases in the cardiac function and ventricular enlargement in the PVCCM group were significant after 12 weeks of PVC stimulation compared with the control group (P < 0.001). Electrophysiological examination found that the ventricular effective refractory period dispersion (0.071 ± 0.008), area of the low-voltage zone (9.41 ± 1.55 cm2), and malignant ventricular arrhythmia inducibility (33.3%) of the PVCCM group increased significantly at week 8 after pacing (P < 0.001 vs the control group); these changes slowed down after 8 weeks. Moreover, the distribution of the low-voltage zone presented obvious spatial heterogeneity, especially in the anterior wall of the right ventricle, accompanied by delayed activation in the sinus rhythm (67 ± 13 milliseconds). Consistently, the proportion of ventricular fibrosis- and expression-related proteins were significantly increased in the PVCCM group (P < 0.001), especially in the right ventricle. Moreover, proteomic analysis confirmed the spatial profile of these fibrotic changes in the PVCCM group.

CONCLUSIONS

High-burden PVC can cause significant temporal and spatial heterogeneity changes in proarrhythmic substrates, which are potentially related to the upregulation of calcium signaling caused by asynchronous activation.

Left and Right PVC-Induced Ventricular Dysfunction

BACKGROUND

Frequent premature ventricular complexes (PVCs) can result in a reversible form of cardiomyopathy that usually affects the left ventricle (LV).

OBJECTIVES

The objective of this study was to assess whether frequent PVCs have an impact on right ventricular (RV) function.

METHODS

Serial cardiac magnetic resonance (CMR) studies were performed in a series of 47 patients before and after ablation of frequent PVCs.

RESULTS

Patients with RV cardiomyopathy (ejection fraction [EF] <0.45) had more frequent PVCs than did patients without decreased RV function (23% ± 11% vs 15% ± 11%, P = 0.03). Likewise, patients with LV cardiomyopathy (EF <0.50) had more frequent PVCs than did patients without decreased LV function (23% ± 10% vs 14% ± 12%, P = 0.003). LV dysfunction was present in 21 patients (45%). In patients with LV dysfunction, 15 patients (32%) had biventricular dysfunction, and 6 patients (13%) had isolated LV dysfunction. A total of 19 patients (40%) had RV dysfunction, and 4 of the patients with RV dysfunction (9%) had isolated RV dysfunction. Cardiac magnetic resonance was repeated 1.9 ± 1.3 years after ablation. In patients with successful ablation, RV function improved, and in patients without successful ablation, RV function did not significantly change (before and after ablation RVEF 0.45 ± 0.09 and 0.52 ± 0.09; P < 0.001 vs. 0.46 ± 0.07 and 0.48 ± 0.04; P = 0.14, respectively).

CONCLUSIONS

Frequent PVCs can cause RV cardiomyopathy that parallels LV cardiomyopathy and is reversible with successful ablation.

Obstetric and fetal/neonatal outcomes in pregnant women with frequent premature ventricular complexes and structurally normal heart

BACKGROUND

High premature ventricular complex (PVC) burden may increase the risk of left ventricular dysfunction and all-cause mortality. We aimed to evaluate maternal and neonatal outcomes of pregnant women with structurally normal heart having PVC burden ≥1%.

METHODS

This retrospective cohort study used data from Chang Gung Research Database. Pregnancies from January 1, 2005, through June 30, 2020, with documented maternal PVC burden ≥1% by 24-h Holter monitor were identified. Pregnant women with a diagnosis of structural heart disease or arrhythmias other than PVC were excluded. We used propensity score matching (PSM) to balance the covariates between the PVC group and normal control group. The PVC group was classified into low-PVC (<10%) and high-PVC burden subgroups. The maternal and neonatal outcomes were assessed through 6 months after delivery or termination.

RESULTS

After PSM, there were 214, 61, and 46 pregnant women enrolled in the normal control group, low-PVC burden, and high-PVC burden subgroups, respectively. The high-PVC and low-PVC burden subgroups had composite adverse maternal and neonatal events similar to the control group without use of antiarrhythmic drugs (AADs), but a higher proportion of placental abruption was observed in the high-PVC burden subgroup. Maternal age, diabetes, and overweight were significant predictors of composite adverse maternal events, whereas only maternal age was a significant predictor of composite adverse neonatal events.

CONCLUSIONS

High PVC burden was not associated with poor composite adverse maternal and neonatal outcomes with no need of AADs therapy in pregnant women with structurally normal heart.

Age-related reference intervals for ambulatory electrocardiographic parameters in healthy individuals

Background

The advent of novel monitoring technologies has dramatically increased the use of ambulatory electrocardiography (AECG) devices. However, few studies have conducted detailed large-scale investigations on the incidence of arrhythmias over 24 h, especially ectopy, in healthy individuals over a wide age range.

Objectives

This study aimed to investigate the incidence of arrhythmias detected using AECG and associated factors, in healthy individuals, over a wide age range.

Methods

In this cross-sectional study, we performed AECG on 365 healthy volunteers (median [interquartile range]: 48 [36, 67], 20-89 years, 165 men) under free-running conditions for 24 h. Ultrasonic echocardiography and heart rate variability analysis were performed to explore the factors associated with the incidence of arrhythmias.

Results

The 97.5th percentile of single ventricular ectopy (VE) was 149/day, 254/day, and 1,682/day in the 20-39-, 40-59- and 60-89-year age groups, respectively; that of single supraventricular ectopy (SVE) was 131/day, 232/day, and 1,063/day, respectively. Multivariate analysis revealed that aging was the only independent significant factor influencing the frequency of VE (β = 0.207, P = 0.001). Age (β = 0.642, P < 0.001), body mass index (BMI) (β = -0.112, P = 0.009), and the root mean square of successive differences in RR intervals (β = 0.097, P = 0.035) were factors significantly associated with SVE frequency.

Conclusions

Age-specific reference intervals of VE and SVE in a large population of healthy participants over a wide age range were generated. VE and SVE increased with age; SVE was influenced by BMI and the aging-induced decrease in parasympathetic tone activity.

Dyssynchronous Heart Failure: A Clinical Review

PURPOSE OF THE REVIEW

Dyssynchrony occurs when portions of the cardiac chambers contract in an uncoordinated fashion. Ventricular dyssynchrony primarily impacts the left ventricle and may result in heart failure. This entity is recognized as a major contributor to the development and progression of heart failure. A hallmark of dyssynchronous heart failure (HF_d) is left ventricular recovery after dyssynchrony is corrected. This review discusses the current understanding of pathophysiology of HF_d and provides clinical examples and current techniques for treatment.

RECENT FINDINGS

Data show that HF_d responds poorly to medical therapy. Cardiac resynchronization therapy (CRT) in the form of conventional biventricular pacing (BVP) is of proven benefit in HF_d, but is limited by a significant non-responder rate. Recently, conduction system pacing (His bundle or left bundle branch area pacing) has also shown promise in correcting HF_d. HF_d should be recognized as a distinct etiology of heart failure; HF_d responds best to CRT.

Risk factors for the development of premature ventricular complex-induced cardiomyopathy: a systematic review and meta-analysis

Background

Premature ventricular complexes (PVCs) are a potentially reversible cause of heart failure. However, the characteristics of patients most likely to develop impaired left ventricular function are unclear. Hence, the objective of this study is to systematically assess risk factors for the development of PVC-induced cardiomyopathy.

Methods

We performed a structured database search of the scientific literature for studies investigating risk factors for the development of PVC-induced cardiomyopathy (PVC-CM). We investigated the reporting of PVC-CM risk factors (RF) and assessed the comparative association of the different RF using random-effect meta-analysis.

Results

A total of 26 studies (9 prospective and 17 retrospective studies) involving 16,764,641 patients were analyzed (mean age 55 years, 58% women, mean PVC burden 17%). Eleven RF were suitable for quantitative analysis (≥ 3 occurrences in multivariable model assessing a binary change in left ventricular (LV) function). Among these, age (OR 1.02 per increase in the year of age, 95% CI [1.01, 1.02]), the presence of symptoms (OR 0.18, 95% CI [0.05, 0.64]), non-sustained ventricular tachycardias (VT) (OR 3.01, 95% CI [1.39, 6.50]), LV origin (OR 2.20, 95% CI [1.14, 4.23]), epicardial origin (OR 4.72, 95% CI [1.81, 12.34]), the presence of interpolation (OR 4.93, 95% CI [1.66, 14.69]), PVC duration (OR 1.05 per ms increase in QRS-PVC duration [1.004; 1.096]), and PVC burden (OR 1.06, 95% CI [1.04, 1.08]) were all significantly associated with PVC-CM.

Conclusions

In this meta-analysis, the most consistent risk factors for PVC-CM were age, non-sustained VT, LV, epicardial origin, interpolation, and PVC burden, whereas the presence of symptoms significantly reduced the risk. These findings help tailor stringent follow-up of patients presenting with frequent PVCs and normal LV function.

Sustained Suppression of Premature Ventricular Contractions by a Three-Month Pacing Adjustment

Premature ventricular contractions (PVCs) that comprise more than 15% of total heartbeats can induce cardiomyopathy in patients with systolic dysfunction, and cardiac ablation is frequently used to reduce PVCs in this patient group. However, cardiac ablation is not entirely without hazards. We report a noninvasive method that dramatically reduced PVCs in a cardiac pacemaker patient from 31% to 3% in seven days by increasing the lower limit pacing rate from 50 beats per minute (bpm) to 60 bpm. Not only were our patient's PVCs reduced by the initial pacing elevation, but PVC levels were maintained below 5% even after the pacemaker's lower limit was returned to its original value of 50 bpm. This irreversible suppression of PVC activity following a three-month pacing elevation is a novel result that might be caused by ventricular remodeling of the original ectopic focus.

Prognostic implication of premature ventricular contractions in patients without structural heart disease

AIMS

Premature ventricular contractions (PVCs) are a common form of arrhythmia associated with an unfavourable prognosis in patients with structural heart disease. However, the prognostic significance in absence of heart disease is debated. With this study, we aim to investigate whether subjects with PVC, without structural heart disease, have a worse prognosis than the general population.

METHODS AND RESULTS

Patients evaluated for PVC at a secondary care centre in Stockholm County from January 2010 to December 2016 were identified. We included patients without history of previous heart disease who had undergone echocardiography and exercise test with normal findings. Based on sex and age, we matched the PVC cohort to a four times bigger control group from the general population and compared the outcome in terms of mortality and cardiovascular morbidity during a median follow-up time of 5.2 years. We included 820 patients and 3,264 controls. Based on a non-inferiority analysis, the PVC group did not have a higher mortality than the control group (0.44, CI 0.27-0.72). Sensitivity analysis with propensity score matching confirmed this result.

CONCLUSIONS

PVC patients, who after thorough evaluation showed no signs of structural heart disease, did not have a worse prognosis when compared to an age- and sex- control group based on the general population.

Cardiac Magnetic Resonance in the Evaluation of Patients With Frequent Premature Ventricular Complexes

BACKGROUND

The role of cardiac magnetic resonance (CMR) in the evaluation and management of patients with frequent premature ventricular complexes (PVCs) of unknown etiology remains unclear.

OBJECTIVES

This study evaluated the prevalence and prognostic significance of myocardial abnormalities detected with CMR among patients with frequent PVCs and no known structural heart disease.

METHODS

This prospective cohort study included consecutive patients with frequent PVCs and a negative initial diagnostic work-up who underwent CMR with late gadolinium enhancement imaging. The clinical outcome was a composite of mortality, ventricular fibrillation, sustained ventricular tachycardia, or reduction in left ventricular ejection fraction of ≥10%.

RESULTS

A total of 255 patients were included, of whom 35 (13.7%) had evidence of myocardial abnormality on CMR. Age ≥60 years (odds ratio [OR]: 6.96; 95% CI: 1.30-37.18), multifocal PVCs (OR: 10.90; 95% CI: 3.21-36.97), and non-outflow tract left ventricular PVC origin (OR: 3.00; 95% CI: 1.00-8.95) were independently associated with the presence of a myocardial abnormality on CMR. After a median follow-up of 36 months, the composite outcome occurred in 15 (5.9%) patients. The presence of a myocardial abnormality on CMR was independently associated with the composite outcome (HR: 4.35; 95% CI: 1.34-14.15; P = 0.014).

CONCLUSIONS

One in 7 patients with frequent PVCs with no known structural heart disease had myocardial abnormality detected on CMR, and these abnormalities were associated with adverse clinical outcomes. These findings highlight the important role of CMR in the evaluation of patients with frequent PVCs.

Premature Ventricular Contractions Are Presaged by a Mechanically Abnormal Sinus Beat

BACKGROUND

Frequent premature ventricular contractions (PVCs) can lead to cardiomyopathy; it is unclear if there are abnormal myocardial mechanics operative in the PVC and non-PVC beats.

OBJECTIVES

The aim of this study was to investigate regional and global myocardial mechanics, including dyssynchrony, in patients with frequent PVCs.

METHODS

Fifty-six consecutive patients referred for PVC ablation were prospectively studied. During sinus rhythm (SR) and PVC beats, left ventricular (LV) global longitudinal strain (GLS), LV dyssynchrony (measured as the SD of time to peak GLS), and dyssynergy (measured as maximum regional strain minus minimum regional strain at aortic valve closure) were quantified using 2-dimensional strain echocardiography. GLS, dyssynchrony, and dyssynergy were compared in remote SR, pre-PVC SR, PVC, and post-PVC SR beats.

RESULTS

In SR beats remote from the PVC, GLS was -17.3% ± 4%, dyssynchrony was 49 ± 14 ms, and dyssynergy was 22% ± 9%. Myocardial mechanics were significantly abnormal during PVCs compared with remote SR beats (GLS -7.7% ± 3% [P < 0.001], dyssynchrony 115 ± 37 milliseconds [P < 0.001], and dyssynergy 26% ± 10% [P < 0.001]). There were significant mechanical abnormalities in the SR beat preceding the PVC, which demonstrated significantly lower LV strain (pre-PVC SR, -13% ± 4%; P < 0.001) and more dyssynchrony (pre-PVC SR, 63 ± 19 milliseconds; P < 0.001) compared with remote SR beats. Dyssynergy was significantly higher for pre-PVC SR and PVC beats compared with remote SR (pre-PVC SR, 25% ± 8% [P < 0.001]; PVC, 26% ± 10% [P < 0.001]).

CONCLUSIONS

In patients with frequent PVCs, the SR beat preceding the PVC demonstrates significant mechanical abnormalities. This finding suggests that perturbations in cellular physiological processes such as excitation-contraction coupling may underlie the generation of frequent PVCs.

Electrocardiogram Parameters That Affect the Success Rate of Radiofrequency Ablation in Patients with Outflow Tract Ventricular Premature Complexes

Objectives. The objectives of this study are to assess the efficacy of radiofrequency catheter ablation (RFCA) in patients with outflow tract (OT) ventricular premature complexes (VPCs) and to explore the electrocardiographic (ECG) features of initially successful procedures. Methods. Based on the outcome of ablation, 154 consecutive patients with OT-VPCs who underwent RFCA from January 2017 to December 2019 were divided into two groups. The rate of successful procedures and the ECG features were analyzed and compared between the two groups. Results. The highest success rate was found in patients with VPCs from the right ventricular outflow tract (RVOT), and the lowest success rate was evident among patients with complexes from both the RVOT and the left ventricular OT (LVOT). The patients with successful procedures (136) reflected a lower pseudo delta wave ratio (16.2% vs. 44.4%, $P<0.01$ ), a smaller R-wave amplitude in lead V1 (V1) ( $0.23\pm 0.24$ mV vs. $0.35\pm 0.44$  mV, $P<0.05$ ), shorter intrinsicoid deflection time in lead V2 (V2) ( $44.00\pm 18.33$ ms vs. $57.41\pm 20.67$ ms, $P<0.01$ ), a shorter RS duration in V2 ( $93.67\pm 21.33$  ms vs. $106.93\pm 18.76$  ms, $\text{P}<0.01$ ), and smaller R/S-waveratios in V2. Furthermore, multivariate analysis demonstrated that RS duration in V2 was above 109.17 ms and R/S ratio in V2 was above 0.28, forecasting a failed procedure. Conclusions. The ECG predictors of failed ablation were characterized by RS duration and R/S ratio in V2.

FRONTAL QRS-T AÇISI İLE AMBULATUAR 24 SAAT HOLTERDE PREMATÜR VENTRİKÜLER KONTRAKSİYON YÜKÜ ARASINDAKİ İLİŞKİ

AMAÇ Sık prematür ventriküler kontraksiyonlar (PVK), ventriküler fonksiyonun bozulmasına veya ventriküler kavitelerin genişlemesine neden olabilir. Frontal düzlem QRS-T [f(QRS-T)] açısı, miyokardın elektrofizyolojik özelliklerindeki kararsızlığın bir göstergesidir ve aritmilerle ilişkilidir. Bu çalışma, ventriküler repolarizasyon heterojenitesinin bir belirteci olarak f(QRS-T) açısının, ambulatuar 24 saatlik holterde prematüre ventriküler kontraksiyon yükünü tahmin edip etmediğini araştırmayı amaçlamıştır. METHOD Çalışmada 100 hasta mevcuttu. Hastalar 24 saatlik Holter izleminde PVK yüklerine göre “sık PVK” ve “nadir PVK” olarak iki gruba ayrıldı. Laboratuar ve frontal plan QRS-T açısı dahil olmak üzere bazı ambulatuar elektrokardiyografi parametreleri iki grup arasında karşılaştırıldı. BULGULAR Frontal QRS-T açısı (63.34±37.86°'ye karşı 23.46±14.29° p

A Heartbeat Classifier for Continuous Prediction Using a Wearable Device

Heartbeat monitoring may play an essential role in the early detection of cardiovascular disease. When using a traditional monitoring system, an abnormal heartbeat may not appear during a recording in a healthcare facility due to the limited time. Thus, continuous and long-term monitoring is needed. Moreover, the conventional equipment may not be portable and cannot be used at arbitrary times and locations. A wearable sensor device such as Polar H10 offers the same capability as an alternative. It has gold-standard heartbeat recording and communication ability but still lacks analytical processing of the recorded data. An automatic heartbeat classification system can play as an analyzer and is still an open problem in the development stage. This paper proposes a heartbeat classifier based on RR interval data for real-time and continuous heartbeat monitoring using the Polar H10 wearable device. Several machine learning and deep learning methods were used to train the classifier. In the training process, we also compare intra-patient and inter-patient paradigms on the original and oversampling datasets to achieve higher classification accuracy and the fastest computation speed. As a result, with a constrain in RR interval data as the feature, the random forest-based classifier implemented in the system achieved up to 99.67% for accuracy, precision, recall, and F1-score. We are also conducting experiments involving healthy people to evaluate the classifier in a real-time monitoring system.

Prognostic implications of structural heart disease and premature ventricular contractions in recovery of exercise

Premature ventricular contractions (PVCs) during recovery of exercise stress testing are associated with increased cardiovascular mortality, but the cause remains unknown. We aimed to evaluate the association of PVCs during recovery with echocardiographic abnormalities, and their combined prognostic performance. Echocardiographic abnormalities [reduced left ventricular (LV) ejection fraction, valvular heart disease, LV dilatation, LV hypertrophy, or increased filling pressures] and PVCs during recovery were identified among patients having undergone both echocardiography and exercise stress test. Among included patients (n = 3106, age 59 ± 16 years, 55% males), PVCs during recovery were found in 1327 (43%) patients, among which the prevalence of echocardiographic abnormalities was increased (58% vs. 43%, p < 0.001). Overall, PVCs during recovery were associated with increased cardiovascular mortality (219 total events, 7.9 [5.4–11.1] years follow-up; adjusted hazard ratio (HR [95% confidence interval]) 1.6 [1.2–2.1], p < 0.001). When analyzed in combination with either presence or absence of echocardiographic abnormalities, PVCs during recovery were associated with increased risk when such were present (HR 3.3 [1.9–5.5], p < 0.001) but not when absent (HR 1.5 [0.8–2.8], p = 0.22), in reference to those with neither. Our findings provide mechanistic insights to the increased CV risk reported in patients with PVCs during recovery.

Premature ventricular complexes during continuous electrocardiographic monitoring in the intensive care unit: Occurrence rates and associated patient characteristics

AIMS AND OBJECTIVES

This study examined the occurrence rate of specific types of premature ventricular complex (PVC) alarms and whether patient demographic and/or clinical characteristics were associated with PVC occurrences.

BACKGROUND

Because PVCs can signal myocardial irritability, in-hospital electrocardiographic (ECG) monitors are typically configured to alert nurses when they occur. However, PVC alarms are common and can contribute to alarm fatigue. A better understanding of occurrences of PVCs could help guide alarm management strategies.

DESIGN

A secondary quantitative analysis from an alarm study.

METHODS

The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist was followed. Seven PVC alarm types (vendor-specific) were described, and included isolated, couplet, bigeminy, trigeminy, run PVC (i.e. VT >2), R-on-T and PVCs/min. Negative binomial and hurdle regression analyses were computed to examine the association of patient demographic and clinical characteristics with each PVC type.

RESULTS

A total of 797,072 PVC alarms (45,271 monitoring hours) occurred in 446 patients, including six who had disproportionately high PVC alarm counts (40% of the total alarms). Isolated PVCs were the most frequent type (81.13%) while R-on-T were the least common (0.29%). Significant predictors associated with higher alarms rates: older age (isolated PVCs, bigeminy and couplets); male sex and presence of PVCs on the 12-lead ECG (isolated PVCs). Hyperkalaemia at ICU admission was associated with a lower R-on-T type PVCs.

CONCLUSIONS

Only a few distinct demographic and clinical characteristics were associated with the occurrence rate of PVC alarms. Further research is warranted to examine whether PVCs were associated with adverse outcomes, which could guide alarm management strategies to reduce unnecessary PVC alarms.

RELEVANCE TO CLINICAL PRACTICE

Targeted alarm strategies, such as turning off certain PVC-type alarms and evaluating alarm trends in the first 24 h of admission in select patients, might add to the current practice of alarm management.

Electrical management of heart failure: from pathophysiology to treatment

Electrical disturbances, such as atrial fibrillation (AF), dyssynchrony, tachycardia, and premature ventricular contractions (PVCs), are present in most patients with heart failure (HF). While these disturbances may be the consequence of HF, increasing evidence suggests that they may also cause or aggravate HF. Animal studies show that longer-lasting left bundle branch block, tachycardia, AF, and PVCs lead to functional derangements at the organ, cellular, and molecular level. Conversely, electrical treatment may reverse or mitigate HF. Clinical studies have shown the superiority of atrial and pulmonary vein ablation for rhythm control and AV nodal ablation for rate control in AF patients when compared with medical treatment. Ablation of PVCs can also improve left ventricular function. Cardiac resynchronization therapy (CRT) is an established adjunct therapy currently undergoing several interesting innovations. The current guideline recommendations reflect the safety and efficacy of these ablation therapies and CRT, but currently, these therapies are heavily underutilized. This review focuses on the electrical treatment of HF with reduced ejection fraction (HFrEF). We believe that the team of specialists treating an HF patient should incorporate an electrophysiologist in order to achieve a more widespread use of electrical therapies in the management of HFrEF and should also include individual conditions of the patient, such as body size and gender in therapy fine-tuning.

A High-Precision Deep Learning Algorithm to Localize Idiopathic Ventricular Arrhythmias

Background: An accurate prediction of ventricular arrhythmia (VA) origins can optimize the strategy of ablation, and facilitate the procedure. Objective: This study aimed to develop a machine learning model from surface ECG to predict VA origins. Methods: We obtained 3628 waves of ventricular premature complex (VPC) from 731 patients. We chose to include all signal information from 12 ECG leads for model input. A model is composed of two groups of convolutional neural network (CNN) layers. We chose around 13% of all the data for model testing and 10% for validation. Results: In the first step, we trained a model for binary classification of VA source from the left or right side of the chamber with an area under the curve (AUC) of 0.963. With a threshold of 0.739, the sensitivity and specification are 90.7% and 92.3% for identifying left side VA. Then, we obtained the second model for predicting VA from the LV summit with AUC is 0.998. With a threshold of 0.739, the sensitivity and specificity are 100% and 98% for the LV summit. Conclusions: Our machine learning algorithm of surface ECG facilitates the localization of VPC, especially for the LV summit, which might optimize the ablation strategy.

Intramural Needle Ablation for Refractory Premature Ventricular Contractions

BACKGROUND

Frequent premature ventricular contractions (PVCs) are often amenable to catheter ablation. However, a deep intramural focus may lead to failure due to inability of standard ablation techniques to penetrate the focus. We sought to assess the efficacy and safety of infusion needle ablation (INA) for PVCs that are refractory to standard radiofrequency ablation.

METHODS

Under 2 Food and Drug Administration approved protocols, INA was evaluated in patients with frequent PVCs that were refractory to standard ablation. Initial targets for ablation were selected by standard mapping techniques. INA was performed with a deflectable catheter equipped with an extendable/retractable needle at the tip that can be extended up to 12 mm into the myocardium and is capable of pacing and recording. After contrast injection for location assessment, radiofrequency ablation was performed with the needle tip using a temperature-controlled mode (maximum temperature 60 °C) with saline infusion from the needle. The primary end point was a decrease in PVC burden to <5000/24 hours at 6 months. The primary safety end point was incidence of procedure- or device-related serious adverse events.

RESULTS

At 4 centers, 35 patients (age 55.3±16.9 years, 74.2% male) underwent INA. The baseline median PVC burden was 25.4% (interquartile range, 18.4%-33.9%) and mean left ventricular ejection fraction was 37.7±12.3%. Delivering 10.3±8.0 INA lesions/patient (91% had adjunctive standard radiofrequency ablation also) resulted in acute PVC elimination in 71.4%. After a mean follow-up of 156±109 days, the primary efficacy end point was met in 73.3%. The median PVC burden decreased to 0.8% (interquartile range, 0.1%-6.0%; P<0.001). The primary safety end point occurred in 14.3% consisting of 1 (2.9%) heart block, 1 (2.9%) femoral artery dissection, and 3 (8.6%) pericardial effusions (all treated percutaneously).

CONCLUSIONS

INA is effective for the elimination of frequent PVCs that are refractory to conventional ablation and is associated with an acceptable safety profile.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT01791543 and NCT03204981.

Elevated Premature Ventricular Complex counts on 24-hour ECG predict incident atrial fibrillation and heart failure - A prospective population-based cohort study

Background

Objectives

Methods

Results

Conclusion

Life's Simple 7 Cardiovascular Health Score in Relation to Arrhythmias on Extended Ambulatory Electrocardiographic Monitoring (from the Multi-Ethnic Study of Atherosclerosis)

The Life's Simple 7 (LS7) metric consists of 7 modifiable health behaviors and measures that are known health factors for cardiovascular wellness. Relatively little is known about the association of LS7 score with cardiac arrhythmias. In the setting of the Multi-Ethnic Study of Atherosclerosis, we studied the LS7 score (range 0 to 14), assessed at the 2010 to 2102 study visit, in relation to cardiac arrhythmias assessed by Zio Patch ambulatory electrocardiographic monitoring in 2016 to 2018. In participants free of clinically recognized cardiovascular disease and atrial fibrillation, we used logistic and linear regression to examine the association of total LS7 score with atrial fibrillation, supraventricular ectopy, and ventricular ectopy. In 1,329 participants in the analysis, the mean (SD) age was 67 (8) years and 48% were men. A more favorable total LS7 score was associated with fewer premature ventricular contractions (PVCs) per hour (ratio of geometric means for optimal [11 to 14] versus inadequate [0 to 7] score 0.52 [95% confidence interval 0.34 to 0.81]). After adjustment for sociodemographic characteristics, the association was attenuated (0.66 [0.43 to 1.01]). =Among the LS7 components, a more favorable body mass index was associated with less ventricular ectopy. We did not detect associations of total LS7 score with atrial arrhythmias. In conclusion, in this longitudinal study of older participants free of clinically recognized cardiovascular disease, there was little evidence of association of the LS7 cardiovascular health score with subclinical cardiac arrhythmias. However, there was a suggestion that a more favorable LS7 score was associated with fewer PVCs and specifically, that a more favorable body mass index was associated with fewer PVCs.

Ventricular Premature Complexes and Their Associated Factors in a General Population of Japanese Men

Increased ventricular premature complexes (VPCs) are associated with a higher risk of cardiac morbidities. However, little information is available on the risk factors of Western general populations. Therefore, we aimed to assess the frequency and associated factors of VPCs in healthy general Japanese men. We conducted a population-based cross-sectional study in 517 men, aged 40 to 79 years, using 24-hour Holter electrocardiography. Age, body mass index, height, low-density lipoprotein cholesterol, triglycerides, high-density lipoprotein cholesterol, resting heart rate, diabetes mellitus, hypertension, physical activity, smoking, alcohol consumption, lipid-lowering therapy were included in multivariable negative binomial regression to assess independent correlates for the number of VPCs per hour. We observed at least 1 VPC in 1 hour in 429 men (83%). In multivariable negative binomial regression adjusted for all covariates simultaneously, age (risk ratio [95% confidence interval] 1.91 [1.56 to 2.33] per 1-SD increment), height (1.17 [1.04 to 1.49] per 1-SD increment), resting heart rate(1.34 [1.02 to 1.77] per 1-SD increment), diabetes mellitus (2.36 [1.17 to 4.76] ), hypertension (1.90 [1.03 to 3.50]), physical activity (0.67 [0.47 to 0.97] ), current smoking (4.23 [1.86 to 9.60] ), past smoking (2.08 [1.03 to 4.19] ), current light alcohol consumption (0.16 [0.04 to 0.64] ), and lipid-lowering therapy (0.47 [0.23 to 0.96] ) were independently associated with VPCs frequency. In conclusion, VPCs frequency was independently associated with age, height, resting heart rate, diabetes mellitus, hypertension, physical activity, smoking, alcohol consumption, and lipid-lowering therapy.

Left Ventricular Remodeling in Non-syndromic Mitral Valve Prolapse: Volume Overload or Concomitant Cardiomyopathy?

Mitral valve prolapse (MVP) is a common valvular disorder that can be associated with mitral regurgitation (MR), heart failure, ventricular arrhythmias and sudden cardiac death. Given the prognostic impact of these conditions, it is important to evaluate not only mitral valve morphology and regurgitation, but also the presence of left ventricular (LV) function and remodeling. To date, several possible hypotheses have been proposed regarding the underlying mechanisms of LV remodeling in the context of non-syndromic MVP, but the exact pathophysiological explanation remains elusive. Overall, volume overload related to severe MR is considered the main cause of LV dilatation in MVP. However, significant LV remodeling has been observed in patients with MVP and no/mild MR, particularly in patients with bileaflet MVP or Barlow's disease, generating several new hypotheses. Recently, the concept of "prolapse volume" was introduced, adding a significant volume load to the LV on top of the transvalvular MR volume. Another possible hypothesis is the existence of a concomitant cardiomyopathy, supported by the link between MVP and myocardial fibrosis. The origin of this cardiomyopathy could be either genetic, a second hit (e.g., on top of genetic predisposition) and/or frequent ventricular ectopic beats. This review provides an overview of the different mechanisms and remaining questions regarding LV remodeling in non-syndromic MVP. Since technical specifications of imaging modalities impact the evaluation of MR severity and LV remodeling, and therefore might influence clinical decision making in these patients, this review will also discuss assessment of MVP using different imaging modalities.

A High Precision Machine Learning-Enabled System for Predicting Idiopathic Ventricular Arrhythmia Origins

Background

Radiofrequency catheter ablation (CA) is an efficient antiarrhythmic treatment with a class I indication for idiopathic ventricular arrhythmia (IVA), only when drugs are ineffective or have unacceptable side effects. The accurate prediction of the origins of IVA can significantly increase the operation success rate, reduce operation duration and decrease the risk of complications. The present work proposes an artificial intelligence-enabled ECG analysis algorithm to estimate possible origins of idiopathic ventricular arrhythmia at a clinical-grade level accuracy.

Method

A total of 18,612 ECG recordings extracted from 545 patients who underwent successful CA to treat IVA were proportionally sampled into training, validation and testing cohorts. We designed four classification schemes responding to different hierarchical levels of the possible IVA origins. For every classification scheme, we compared 98 distinct machine learning models with optimized hyperparameter values obtained through extensive grid search and reported an optimal algorithm with the highest accuracy scores attained on the testing cohorts.

Results

For classification scheme 4, our pioneering study designs and implements a machine learning-based ECG algorithm to predict 21 possible sites of IVA origin with an accuracy of 98.24% on a testing cohort. The accuracy and F1-score for the left three schemes surpassed 99%.

Conclusion

In this work, we developed an algorithm that precisely predicts the correct origins of IVA (out of 21 possible sites) and outperforms the accuracy of all prior studies and human experts.

Automaticity in ventricular myocyte cell pairs with ephaptic and gap junction coupling

Spontaneous electrical activity, or automaticity, in the heart is required for normal physiological function. However, irregular automaticity, in particular, originating from the ventricles, can trigger life-threatening cardiac arrhythmias. Thus, understanding mechanisms of automaticity and synchronization is critical. Recent work has proposed that excitable cells coupled via a shared narrow extracellular cleft can mediate coupling, i.e., ephaptic coupling, that promotes automaticity in cell pairs. However, the dynamics of these coupled cells incorporating both ephaptic and gap junction coupling has not been explored. Here, we show that automaticity and synchronization robustly emerges via a Hopf bifurcation from either (i) increasing the fraction of inward rectifying potassium channels (carrying the I_K1 current) at the junctional membrane or (ii) by decreasing the cleft volume. Furthermore, we explore how heterogeneity in the fraction of potassium channels between coupled cells can produce automaticity of both cells or neither cell, or more rarely in only one cell (i.e., automaticity without synchronization). Interestingly, gap junction coupling generally has minor effects, with only slight changes in regions of parameter space of automaticity. This work provides insight into potentially new mechanisms that promote spontaneous activity and, thus, triggers for arrhythmias in ventricular tissue.

Heart Disease and Stroke Statistics-2022 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2022 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population and an enhanced focus on social determinants of health, adverse pregnancy outcomes, vascular contributions to brain health, and the global burden of cardiovascular disease and healthy life expectancy.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

The Burden of Ventricular Premature Complex Is Associated With Cardiovascular Mortality

Background

Ventricular premature complex (VPC) is one of the most common ventricular arrhythmias. The presence of VPC is associated with an increased risk of heart failure (HF).

Method

We designed a single-center, retrospective, and large population-based cohort to clarify the role of VPC burden in long-term prognosis in Taiwan. We analyzed the database from the National Cheng Kung University Hospital-Electronic Medical Record (NCKUH-EMR) and NCKUH-Holter (NCKUH-Holter). A total of 19,527 patients who underwent 24-h Holter ECG monitoring due to palpitation, syncope, and clinical suspicion of arrhythmias were enrolled in this study.

Results

The clinical outcome of interests involved 5.65% noncardiovascular death and 1.53% cardiovascular-specific deaths between 2011 and 2018. Multivariate Cox regression analysis, Fine and Gray's competing risk model, and propensity score matching demonstrated that both moderate (1,000–10,000/day) and high (>10,000/day) VPC burdens contributed to cardiovascular death in comparison with a low VPC burden (<1,000/day).

Conclusion

A higher VPC burden via Holter ECG is an independent risk factor of cardiovascular mortality.

Contemporary clinical management of monomorphic idiopathic premature ventricular contractions: results of the European Heart Rhythm Association Survey

On behalf of the European Heart Rhythm Association, we designed a survey, whose aim was to understand the trend(s) in the clinical management of idiopathic monomorphic premature ventricular contractions (PVCs) among European cardiologists and cardiac electrophysiologists. A total of 202 participants in the survey answered 27 multiple-choice questions on the clinical presentation, diagnosis and treatment of idiopathic monomorphic PVCs. The most common symptom in patients with idiopathic monomorphic PVCs is palpitations, according to the majority of responders (87%), followed by fatigue (29%) and dizziness (18%). Complete blood cell count, renal function with electrolytes levels, and thyroid function are the blood tests requested by the majority of respondents (65%, 92%, and 93%, respectively). Coronary artery disease and structural heart disease needs to be ruled out, according to the vast majority of participants (99%). A 24-h Holter ECG is the preferred ECG modality to assess the burden of PVCs (86% of respondents). Among the different option treatments, beta-blockers and class I antiarrhythmic drugs are by far (81% of respondents) the preferred pharmacological option in comparison with calcium antagonists and class III antiarrhythmic drugs. Catheter ablation has also a good reputation: 99% of responders are keen to use it, especially in patients with high burden of PVCs and when signs of cardiomyopathy occur.

The use of ivabradine in a patient with idiopathic ventricular arrhythmia originating from the left ventricular summit

Idiopathic ventricular arrhythmias (VA) are common and treatment options include anti-arrhythmic drugs (AAD) or catheter ablation. Patients presenting with idiopathic VA which is originating from the left ventricular summit (LVS) poses a particular challenge as the success for catheter ablation is low and AAD's may not be used long-term due to side effects. Ivabradine is an inhibitor of funny current (If) in cardiac pacemaker cells by blocking hyperpolarization-activated cyclic nucleotide-gated (HCN). In the present case, we reported the use of ivabradine in treatment of idiopathic VA which was originated from LVS and was resistant to multiple AAD's and catheter ablation.

Premature ventricular complexes and development of heart failure in a community-based population

OBJECTIVE

A higher premature ventricular complex (PVC) frequency is associated with incident congestive heart failure (CHF) and death. While certain PVC characteristics may contribute to that risk, the current literature stems from patients in medical settings and is therefore prone to referral bias. This study aims to identify PVC characteristics associated with incident CHF in a community-based setting.

METHODS

The Cardiovascular Health Study is a cohort of community-dwelling individuals who underwent prospective evaluation and follow-up. We analysed 24-hour Holter data to assess PVC characteristics and used multivariable logistic and Cox proportional hazards models to identify predictors of a left ventricular ejection fraction (LVEF) decline and incident CHF, respectively.

RESULTS

Of 871 analysed participants, 316 participants exhibited at least 10 PVCs during the 24-hour recording. For participants with PVCs, the average age was 72±5 years, 41% were women and 93% were white. Over a median follow-up of 11 years, 34% developed CHF. After adjusting for demographics, cardiovascular comorbidities, antiarrhythmic drug use and PVC frequency, a greater heterogeneity of the PVC coupling interval was associated with an increased risk of LVEF decline and incident CHF. Of note, neither PVC duration nor coupling interval duration exhibited a statistically significant relationship with either outcome.

CONCLUSIONS

In this first community-based study to identify Holter-based features of PVCs that are associated with LVEF reduction and incident CHF, the fact that coupling interval heterogeneity was an independent risk factor suggests that the mechanism of PVC generation may influence the risk of heart failure.

Diagnostic and prognostic significance of premature ventricular complexes in community and hospital-based participants: A scoping review

BACKGROUND

While there are published studies that have examined premature ventricular complexes (PVCs) among patients with and without cardiac disease, there has not been a comprehensive review of the literature examining the diagnostic and prognostic significance of PVCs. This could help guide both community and hospital-based research and clinical practice.

METHODS

Scoping review frameworks by Arksey and O'Malley and the Joanna Briggs Institute (JBI) were used. A systematic search of the literature using four databases (CINAHL, Embase, PubMed, and Web of Science) was conducted. The review was prepared adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Extension for Scoping Review (PRISMA-ScR).

RESULTS

A total of 71 relevant articles were identified, 66 (93%) were observational, and five (7%) were secondary analyses from randomized clinical trials. Three studies (4%) examined the diagnostic importance of PVC origin (left/right ventricle) and QRS morphology in the diagnosis of acute myocardial ischemia (MI). The majority of the studies examined prognostic outcomes including left ventricular dysfunction, heart failure, arrhythmias, ischemic heart diseases, and mortality by PVCs frequency, burden, and QRS morphology.

CONCLUSIONS

Very few studies have evaluated the diagnostic significance of PVCs and all are decades old. No hospital setting only studies were identified. Community-based longitudinal studies, which make up most of the literature, show that PVCs are associated with structural and coronary heart disease, lethal arrhythmias, atrial fibrillation, stroke, all-cause and cardiac mortality. However, a causal association between PVCs and these outcomes cannot be established due to the purely observational study designs employed.

Sarcomeres Morphology and Z-Line Arrangement Disarray Induced by Ventricular Premature Contractions through the Rac2/Cofilin Pathway

The most common ventricular premature contractions (VPCs) originate from the right ventricular outflow tract (RVOT), but the molecular mechanisms of altered cytoskeletons of VPC-induced cardiomyopathy remain unexplored. We created a RVOT bigeminy VPC pig model (n = 6 in each group). Echocardiography was performed. The histopathological alternations in the LV myocardium were analyzed, and next generation sequencing (NGS) and functional enrichment analyses were employed to identify the differentially expressed genes (DEGs) responsible for the histopathological alternations. Finally, a cell silencing model was used to confirm the key regulatory gene and pathway. VPC pigs had increased LV diameters in the 6-month follow-up period. A histological study showed more actin cytoskeleton disorganization and actin accumulation over intercalated disc, Z-line arrangement disarray, increased β-catenin expression, and cardiomyocyte enlargement in the LV myocardium of the VPC pigs compared to the control pigs. The NGS study showed actin cytoskeleton signaling, RhoGDI signaling, and signaling by Rho Family GTPases and ILK Signaling presented z-scores with same activation states. The expressions of Rac family small GTPase 2 (Rac2), the p-cofilin/cofilin ratio, and the F-actin/G-actin ratio were downregulated in the VPC group compared to the control group. Moreover, the intensity and number of actin filaments per cardiomyocyte were significantly decreased by Rac2 siRNA in the cell silencing model. Therefore, the Rac2/cofilin pathway was found to play a crucial role in the sarcomere morphology and Z-line arrangement disarray induced by RVOT bigeminy VPCs.

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.

Cardiac Arrhythmias and Impaired Heart Rate Variability in Older Patients With Ventricular Septal Defects

Background

Congenital ventricular septal defects (VSDs) are considered to have benign long‐term outcome when treated correctly in childhood. However, abnormal parameters are described in younger adults, including impaired heart rate variability (HRV). It is not known whether such abnormalities will deteriorate with age. Therefore, HRV and cardiac events, such as premature ventricular contraction, were evaluated in patients aged >40 years with congenital VSDs and compared with healthy peers.

Methods and Results

A total of 30 surgically closed VSDs (51±8 years, repair at median age 6.3 years with total range 1.4–54 years) with 30 healthy controls (52±9 years) and 30 small, unrepaired VSDs (55±12 years) with 30 controls (55±10 years) were all equipped with a Holter monitor for 24 hours. Compared with healthy peers, surgically closed patients had lower SD of the normal‐to‐normal (NN) interbeat interval (129±37 versus 168±38 ms; P<0.01), SD of the average NN intervals for each 5‐minute segment of a 24‐hour HRV recording (116±35 versus 149±35 ms; P<0.01) and 24‐hour triangular index (31±9 versus 44±11; P<0.01). SD of the NN intervals, SD of the average NN intervals for each 5‐minute segment of a 24‐hour HRV recording, and triangular index were comparable between unrepaired VSDs and healthy peers. SD of the NN intervals was <100 ms in 22% of surgically closed and 10% of unrepaired VSDs, whereas controls were within normal ranges. A high number of premature ventricular contractions (>200 events) was registered in 57% of surgical patients compared with 3% of controls (P<0.01), and 53% of unrepaired VSDs compared with 10% in controls (P<0.01).

Conclusions

Adults aged >40 with congenital VSDs demonstrate impaired HRV, mainly among surgically closed VSDs. More than half demonstrated a high number of premature ventricular contractions. These novel findings could indicate long‐term cardiovascular disturbances. This necessitates continuous follow‐up of VSDs throughout adulthood.

Prevalence and prognostic association of ventricular arrhythmia in non-ischaemic heart failure patients: results from the DANISH trial

AIMS

Improved risk stratification to identify non-ischaemic heart failure patients who will benefit from primary prophylactic implantable cardioverter-defibrillator (ICD) is needed. We examined the potential of ventricular arrhythmia to identify patients who could benefit from an ICD.

METHODS AND RESULTS

A total of 850 non-ischaemic systolic heart failure patients with left ventricle ≤35% and elevated N-terminal pro-brain natriuretic peptides had a 24-h Holter monitor recording performed. We examined present non-sustained ventricular tachycardia (NSVT), defined as ≥3 consecutive premature ventricular contractions (PVCs) with a rate of ≥100/min, and number of PVCs per hour stratified into low (<30) and high burden (≥30) groups. Outcome measures were overall mortality, sudden cardiac death (SCD), and cardiovascular death (CVD). In total, 193 patients died, 49 from SCD and 125 from CVD. Non-sustained ventricular tachycardia (365 patients) was significantly associated with increased all-cause mortality [hazard ratio (HR) 1.47; 95% confidence interval (CI) 1.07-2.03; P = 0.02] and to CVD (HR 1.89; CI 1.25-2.87; P = 0.003). High burden PVC (352 patients) was associated with increased all-cause mortality (HR1.38; CI 1.00-1.90; P = 0.046) and with CVD (HR 1.78; CI 1.19-2.66; P = 0.005). There was no statistically significant association with SCD for neither NSVT nor PVC. In interaction analyses, neither NSVT (P = 0.56) nor high burden of PVC (P = 0.97) was associated with survival benefit from ICD implantation.

CONCLUSION

Ventricular arrhythmia in non-ischaemic heart failure patients was associated with a worse prognosis but could not be used to stratify patients to ICD implantation.

Landing on the spot: Approaches to outflow tract PVCs; from ECG to EGMs to intracardiac echocardiography

Premature ventricular complexes (PVCs) are increasingly recognized, as the use of ECG wearables becomes more widespread. In particular, PVCs arising from both the right ventricular outflow tract (RVOT) and left ventricular outflow tract (LVOT) comprise the majority of these arrhythmias and form a significant component of an electrophysiology practice. A keen understanding of the correlative anatomy of the outflow tracts, in addition to recognizing key ECG indices illustrating PVC sites of origin, are fundamental in preparing for a successful ablation. Patient selection, incorporating symptomatology, structural disease, and PVC burden can pose a challenge, though tools such as the ABC-VT risk score may help identify those patients with a higher risk of clinical deterioration. Utilizing intracardiac echocardiography to highlight salient anatomic features not visible with fluoroscopy allows for a more precise and safer ablation. Interpretation of intracardiac EGMs, and the careful examination for low amplitude highly fractionated pre-potentials, enhanced by the advent of new developed mapping/ablation catheters, remains crucial. Utilizing these tools will guide the electrophysiologist to an efficient and effective outflow tract PVC ablation.

Premature ventricular contraction increases the risk of heart failure and ventricular tachyarrhythmia

Premature ventricular contraction (PVC), a common arrhythmia affecting 1–2% of the general population, has been considered to have a benign clinical course. However, people with PVC often develop heart failure and ventricular arrhythmias such as ventricular tachycardia. We aimed to clarify the risk of heart failure and lethal ventricular arrhythmias in people with PVC. The Korean National Health Insurance Service database was used for this study. People who underwent nationwide health check-ups in 2009 were enrolled in this study and clinical follow-up data until December 2018 were analyzed. Newly diagnosed PVC in 2009 (≥ 1 inpatient or outpatient claim) were identified and cumulative incidence of heart failure (≥ 1 inpatient claim) and ventricular arrhythmias (≥ 1 inpatient or outpatient claim) were compared. A total of 4515 people were first diagnosed with PVC in 2009 among 9,743,582 people without prior history of PVC, heart failure, or ventricular arrhythmias. People with newly diagnosed PVC in 2009 had a significantly higher incidence of heart failure compared to those without PVC [adjusted hazard ratio (HR)  1.371; 95% confidence interval (CI)  1.177–1.598; p  < 0.001]. Significant interaction was observed between age and PVC with young age people at greater risk of developing heart failure for having PVC. The incidence of ventricular arrhythmia was also significantly increased in people with PVC (HR  5.588; 95% CI  4.553–6.859; p  < 0.001). Age and chronic kidney disease had significant interactions with PVC. In conclusion, the incidence of heart failure and ventricular arrhythmia was significantly increased in people with PVC. Outpatient follow-up of people with PVC can be helpful to detect early signs of heart failure or advanced forms of ventricular arrhythmia.

The Mitral Annular Disjunction of Mitral Valve Prolapse: Presentation and Outcome

OBJECTIVES

The aim of this study was to assess in patients with mitral valve prolapse (MVP) mitral annular disjunction (MAD) prevalence, phenotypic characteristics, and long-term outcomes (clinical arrhythmic events and excess mortality).

BACKGROUND

Clinical knowledge regarding MAD of MVP remains limited and controversial, and its potential link with untoward outcomes is unsubstantiated.

METHODS

A cohort of 595 (278 women, mean age 61 ± 16 years) consecutive patients with isolated MVP, with comprehensive clinical, rhythmic, Doppler echocardiographic, and consistent MAD assessment, were examined. MAD prevalence, associated MVP phenotypes, and outcomes (survival, clinical arrhythmic events) starting at diagnostic echocardiography were analyzed. To balance important baseline differences, propensity scoring matching was conducted among patients with and those without MAD.

RESULTS

The presence of MAD was common (n = 186 [31%]) in patients with MVP, generally in younger patients, and was not random but was independently associated with severe myxomatous disease involving bileaflet MVP and marked leaflet redundancy (both P ≤ 0.0002). The presence of MAD was also independently associated with a larger left ventricle (P = 0.005). Age-matched cohort survival after MVP diagnosis was not worse with MAD (10-year survival 93% ± 2% for patients without MAD and 97% ± 1% for those with MAD; P = 0.40), even adjusted comprehensively for MVP characteristics (P = 0.80) and accounting for time-dependent mitral surgery (P = 0.60). During follow-up, 170 patients had clinical arrhythmic events (ventricular tachycardia, n = 159; arrhythmia ablation, n = 14; cardioverter-defibrillator implantation, n = 14; sudden cardiac death, n = 3). MAD was independently associated with higher risk for arrhythmic events (adjusted HR: 2.60; 95% CI: 1.87-3.62; P < 0.0001). The link between MAD and arrhythmic events persisted with time-dependent mitral surgery (adjusted HR: 2.54; 95% CI: 1.84-3.50; P < 0.0001), was strong under medical management (adjusted HR: 3.21; 95% CI: 2.03-5.06; P < 0.0001) but was weaker after mitral surgery (adjusted HR: 2.07; 95% CI: 1.24-3.43; P = 0.005).

CONCLUSIONS

This large cohort with MVP comprehensively characterized shows that MAD is frequent at MVP diagnosis and is strongly linked to advanced myxomatous degeneration. The presence of MAD was independently associated with long-term excess incidence of clinical arrhythmic events. However, within the first 10 years post-diagnosis, MAD was not linked to excess mortality, and although reassurance should be provided from the survival point of view, careful monitoring for arrhythmias is in order for MAD.

Age-Related Changes in Cardiac Autonomic Modulation and Heart Rate Variability in Mice

Objective

The aim of this study was to assess age-related changes in cardiac autonomic modulation and heart rate variability (HRV) and their association with spontaneous and pharmacologically induced vulnerability to cardiac arrhythmias, to verify the translational relevance of mouse models for further in-depth evaluation of the link between autonomic changes and increased arrhythmic risk with advancing age.

Methods

Heart rate (HR) and time- and frequency-domain indexes of HRV were calculated from Electrocardiogram (ECG) recordings in two groups of conscious mice of different ages (4 and 19 months old) (i) during daily undisturbed conditions, (ii) following peripheral β-adrenergic (atenolol), muscarinic (methylscopolamine), and β-adrenergic + muscarinic blockades, and (iii) following β-adrenergic (isoprenaline) stimulation. Vulnerability to arrhythmias was evaluated during daily undisturbed conditions and following β-adrenergic stimulation.

Results

HRV analysis and HR responses to autonomic blockades revealed that 19-month-old mice had a lower vagal modulation of cardiac function compared with 4-month-old mice. This age-related autonomic effect was not reflected in changes in HR, since intrinsic HR was lower in 19-month-old compared with 4-month-old mice. Both time- and frequency-domain HRV indexes were reduced following muscarinic, but not β-adrenergic blockade in younger mice, and to a lesser extent in older mice, suggesting that HRV is largely modulated by vagal tone in mice. Finally, 19-month-old mice showed a larger vulnerability to both spontaneous and isoprenaline-induced arrhythmias.

Conclusion

The present study combines HRV analysis and selective pharmacological autonomic blockades to document an age-related impairment in cardiac vagal modulation in mice which is consistent with the human condition. Given their short life span, mice could be further exploited as an aged model for studying the trajectory of vagal decline with advancing age using HRV measures, and the mechanisms underlying its association with proarrhythmic remodeling of the senescent heart.

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.