The clinical significance of premature atrial contractions: How frequent should they become predictive of new-onset atrial fibrillation

Postoperative electrocardiography changes: To worry or not to worry

Abnormal postoperative electrocardiograms are not uncommon, oftentimes leading to further cardiac workup especially when the findings are new and not easily explainable. A forty-year-old woman, with a history of left breast cancer status post bilateral mastectomies and reconstructions, presented for robot-assisted low-anterior resection secondary to rectal cancer. Postoperative electrocardiogram showed poor R wave progression, biphasic T waves in V2-4, and possible anterior wall ischemia. Her electrocardiogram from 6 years ago was normal. No recent electrocardiogram was available for comparison. Initially, the abnormal postoperative electrocardiogram appeared worrisome. However, the patient was completely asymptomatic, and all vital signs were normal. Cardiac point-of-care ultrasound showed normal parasternal long and short axis views. The biphasic T waves in V2-4 were suggestive of Wellens syndrome, but the accompanying poor R wave progression was not consistent with the diagnostic criteria. The anesthesiologist then remembered the patient's history of the presence of a left breast implant and suspected it might have caused the changes on the electrocardiogram. A literature search did find one publication that shows approximately 45% of patients with breast implants present with electrocardiogram changes, including poor R wave progression and negative T waves. Therefore, no further cardiac workup was ordered for our patient. She was discharged home 3 days later. Breast implants and electrocardiogram changes are a lesser-known topic. Obtaining a pre-operative electrocardiogram should be considered in patients with previous breast implants, to serve as a baseline for comparison if the patient were to need another electrocardiogram in the future.

Reduction in atrial and pulmonary vein stretch as a therapeutic target for prevention of atrial fibrillation

Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with increased mortality. Heart failure, hypertension, valvular disease, and obstructive sleep apnea are risk factors for incident AF. A common characteristic of these diseases is that they increase atrial wall stretch. Multiple experimental studies confirm a proarrhythmic effect of atrial stretch. Conversely, a reduction in stretch is antiarrhythmic. A therapeutic target for AF, therefore, lies in local reduction of atrial stretch. This review focuses on atrial stretch and its clinical associations in patients with AF and its downstream effects on electrophysiology. We discuss the possible application of targeted atrial stretch reduction in AF prevention. We conclude that a reduction in local atrial stretch should be considered an essential element in rhythm control.

Assessment of atrial conduction times in patients with frequent premature ventricular complex

Background

Premature ventricular complex (PVC) is a frequent finding in the general population. The atrial conduction time (ACT) is the period between the electrocardiographic P wave and the atrial mechanical contraction, and its prolongation indicates an atrial electromechanical delay (EMD). In our study, we compared atrial conduction parameters by echocardiographic methods between patients with frequent PVC and healthy control subjects.

Methods

The study included 54 patients with PVC and 54 healthy volunteers. Atrial conduction parameters were measured with echocardiographic examination. The time difference between the p wave and the Am wave was measured in the septal, lateral, and tricuspid annulus regions. The interatrial EMD, left atrial intra-atrial delay, and the right atrial intra-atrial delay were calculated from these measurements. The groups were compared for demographic and electrocardiographic features and echocardiographic parameters.

Results

Left intra-atrial EMD, right intra-atrial EMD, and interatrial EMD were significantly longer in the patient group (p = .001, p < .001, p < .001, respectively). PA lateral, PA septal, and PA tricuspid durations were significantly prolonged in the patient group (all p < .001). All ACT parameters were significantly prolonged in patients with PVC QRS duration of 150 ms and above (all p < .001). All ACT parameters were prolonged in PVCs of right ventricular origin than those of left ventricular origin (all p < .001). ACT parameters were prolonged in patients with a coupling interval time below 485 ms (all p < .001).

Conclusions

Atrial conduction times are prolonged in patients with frequent PVC.

A case of successful catheter ablation of blocked atrial bigeminy and bradycardia with the recovery of normal sinus rhythm and myocardial reverse remodeling

A 69-year-old man presented bradycardia with a constant blocked atrial bigeminy and heart failure. Successful catheter ablation of blocked atrial bigeminy with bradycardia resulted in myocardial reverse remodeling and restoration of the normal sinus rhythm from the ectopic atrial rhythm.

Excessive Supraventricular Ectopic Activity and the Risk of Atrial Fibrillation and Stroke: A Systematic Review and Meta-Analysis

BACKGROUND

Excessive supraventricular ectopic activity (ESVEA) is correlated with the development of atrial fibrillation (AF) and is frequently observed in ischemic stroke patients. This meta-analysis aims to summarize the evidence on the association between ESVEA and the risk of AF and stroke.

METHODS

PubMed and Embase databases were systematically searched to identify all publications providing relevant data from inception to 23 August 2022. Hazard ratio (HR) and 95% confidence interval (CI) were pooled using fixed-effect or random-effect models.

RESULTS

We included 23,272 participants from 20 studies. Pooled results showed that ESVEA was associated with an increased risk of AF in the general population (HR: 2.57; 95% CI 2.16-3.05), increased risk of AF in ischemic stroke patients (HR: 2.91; 95% CI 1.80-4.69), new-onset ischemic stroke (HR: 1.91; 95% CI 1.30-2.79), and all-cause mortality (HR: 1.41; 95% CI 1.24-1.59). Pooled analysis indicated that ESVEA was not associated with recurrent ischemic stroke/transient ischemic attack (TIA) (HR: 1.24; 95% CI 0.91-1.67).

CONCLUSIONS

ESVEA is associated with AF, new-onset ischemic stroke, and all-cause mortality.

Could premature ventricular contractions lead to atrial remodeling?

BACKGROUND

Premature ventricular contraction (PVC) is a frequent kind of arrhythmia that affects around 1% of the general population. While PVC most frequently impairs ventricular function in structurally normal heart, retrograde ventriculo-atrial conduction can occur in people with PVC. These retrograde atrial activations may mimic pulmonary vein-derived atrial ectopies. As a result, PVC may raise the risk of atrial fibrillation (AF) by retrograde ventriculo-atrial conduction. The Four-Dimensional Automated Left Atrial Quantification (4D Auto LAQ) tool is a left atrial analytical approach that utilizes three-dimensional volume data to quantify the volume, as well as LA longitudinal and circumferential strains. The purpose of this study was to determine if clinical diagnosis of PVC is connected with abnormal LA function as determined by LA strain evaluation utilizing a 4D Auto LAQ compared to the healthy population.

METHODS

The 58 patients with frequent PVCs and 53 healthy volunteers as a control group were enrolled in the study. Imaging was performed using the GE Vivid E95 echocardiography equipment (GE Healthcare; Vingmed Ultrasound, Horten, Norway) equipped with an M5S probe (frequency range: 1.5-4.6 MHz) and a 4V probe (frequency range: 1.5-4.0 MHz). Images were imported into and were selected for analysis using the EchoPAC203 software (GE Healthcare). The analysis mode was selected, followed by the volume and 4D Auto LAQ submodes. Following that, the sample point was positioned in the center of the mitral orifice in each of the three planes. The review function was used to acquire the LA parameters measured by 4D Auto LAQ, including volume and strain parameters.

RESULTS

The maximum left atrial volume (LAVmax) and minimal left atrial volume (LAVmin) were significantly higher in the patient group (38.91 ± 9.72 vs. 46.31 ± 10.22, 17.75 ± 4.52 vs. 23.10 ± 7.13, respectively, all p values <.001). On the other hand left atrial reservoir longitudinal strain (LASr), conduit longitudinal strain (LAScd), contraction longitudinal strain (LASct), reservoir circumferential strain (LASr-c), conduit circumferential strain (LAScd-c), and contraction circumferential strain (LASct-c) were significantly lower in patient group (26.64 ± 5.64 vs.19.16 ± 4.58, -19.53 ± 3.72 vs. -11.28 ± 3.47, -10.34 ± 1.56 vs. -4.59 ± 1.49, 30.72 ± 4.04 vs. 19.31 ± 2.60, -19.91 ± 1.78 vs. -13.38 ± 2.85, -15.89 ± 6.37 vs. -9.24 ± 1.63, respectively, all p values <.001).

CONCLUSIONS

The present study found that premature ventricular complexes can lead to atrial remodeling as well as ventricular remodeling in patients with PVC and 4D LAQ technology can quantitatively examine left atrial function and determine these alterations early.

Development and Validation of an Algorithm for the Digitization of ECG Paper Images

The electrocardiogram (ECG) signal describes the heart's electrical activity, allowing it to detect several health conditions, including cardiac system abnormalities and dysfunctions. Nowadays, most patient medical records are still paper-based, especially those made in past decades. The importance of collecting digitized ECGs is twofold: firstly, all medical applications can be easily implemented with an engineering approach if the ECGs are treated as signals; secondly, paper ECGs can deteriorate over time, therefore a correct evaluation of the patient's clinical evolution is not always guaranteed. The goal of this paper is the realization of an automatic conversion algorithm from paper-based ECGs (images) to digital ECG signals. The algorithm involves a digitization process tested on an image set of 16 subjects, also with pathologies. The quantitative analysis of the digitization method is carried out by evaluating the repeatability and reproducibility of the algorithm. The digitization accuracy is evaluated both on the entire signal and on six ECG time parameters (R-R peak distance, QRS complex duration, QT interval, PQ interval, P-wave duration, and heart rate). Results demonstrate the algorithm efficiency has an average Pearson correlation coefficient of 0.94 and measurement errors of the ECG time parameters are always less than 1 mm. Due to the promising experimental results, the algorithm could be embedded into a graphical interface, becoming a measurement and collection tool for cardiologists.

Association of Longitudinal Changes in Cardiac Biomarkers With Atrial and Ventricular Arrhythmias (from the Atherosclerosis Risk in Communities [ARIC] Study)

We evaluated the association of longitudinal changes in circulating levels of N-terminal pro B-type natriuretic peptide (NT-proBNP) and high sensitivity cardiac troponin T (hs-cTnT) with the burden of arrhythmias as captured by 2-week ambulatory ECG monitoring. This study included 1,930 Atherosclerosis Risk in Communities Study participants who wore a leadless, ambulatory ECG monitor (Zio XT Patch) at visit 6 (2016 to 2017) and had cardiac biomarkers measured at visit 6 and visit 4 (median of 19 years earlier). The mean age of participants at V6 was 79 ± 5 years, 41% were men, and 22% were black. Adjusting for demographics, body mass index, smoking, diabetes, hypertension, stroke, left ventricular mass, cardiac medications, patch wear time, visit 4 levels of NT-proBNP and hs-cTnT, and relative change in hs-cTnT, each log-transformed unit relative increase in NT-proBNP was associated with a higher likelihood of nonsustained ventricular tachycardia (odds ratio 1.29, 95% confidence interval [CI] 1.12 to 1.48), a higher number of daily atrial tachycardia episodes (geometric mean ratio [GMR] 1.16, 95% CI 1.10 to 1.21), and a higher daily ectopic burden (premature ventricular contractions -GMR 1.42, 95% CI 1.25 to 1.62; premature atrial contractions -GMR 1.40, 95% CI 1.25 to 1.57). In fully adjusted analyses, each log-transformed unit relative increase in hs-cTnT was only found to be weakly associated with a higher daily premature ventricular contraction burden (GMR 1.31, 95% CI 1.01 to 1.70). In conclusion, longitudinal change in NT-proBNP was associated with an increased atrial and ventricular arrhythmia burden.

The clinical significance of premature atrial contractions: How frequent should they become predictive of new-onset atrial fibrillation

Background

Although previous studies reported frequent premature atrial contractions(fPACs) increased the risk of adverse cardiovascular outcomes, especially atrial fibrillation(AF), there is a substantial inconsistency between reports concerning the definition of fPAC. In this study, we aimed to investigate the relationship between fPAC and cardiovascular outcomes, especially AF. We further searched for a cutoff value of fPAC for prediction of AF.

Methods

We retrospectively analyzed the ambulatory 24‐hr Holter monitoring records and 392 patients included. Frequent PAC was defined as more than 720 PAC/24 hr as used for frequent ventricular premature beats. Patients’ baseline characteristics, echocardiographic variables and medical history were recorded.

Results

There were 189 patients with fPAC and 203 patients without fPAC. Patients with fPAC had more comorbidities in terms of hypertension, diabetes mellitus, coronary artery disease and congestive heart failure. CHA2DS2‐VaSc was higher in patients with fPAC. Mean follow‐up duration was 31 months, and the number of patients with new‐onset AF during follow‐up was significantly higher in fPAC group (22% vs. 5%, p < .001). fPAC was significantly and independently associated with new‐onset AF and predicted AF with a cutoff value of 3,459 PAC/24 hr, and the risk of AF was 11‐fold higher than those with <3,000 PAC/24 hr. In addition, an increased CHA2DS2‐VaSc score was also associated with new‐onset atrial fibrillation.

Conclusion

In our study, we have demonstrated that fPAC is significantly associated with new‐onset AF, and this association is the strongest among those patients who have more than 3,000 PAC in 24 hr.