Prevalence and Clinical Characteristics of Patients with Pause-Dependent Atrioventricular Block

Background: In patients with complete atrioventricular block (AVB), the prevalence and clinical characteristics of patients with pause-dependent AVB (PD-AVB) is not known. Our objective was to assess the prevalence of PD-AVB in a population of patients with complete (or high-grade) AVB. Methods: Twelve-lead electrocardiogram (ECG) and/or telemonitoring from patients admitted (from September 2020 to November 2021) for complete (or high-degree) AVB were prospectively collected at the University Hospital of Nice. The ECG tracings were analyzed by an electrophysiologist to determine the underlying mechanism of PD-AVB. Results: 100 patients were admitted for complete (or high-grade) AVB (men 55%; 82 ± 12 years). Arterial hypertension was present in 68% of the patients. Baseline QRS width was 117 ± 32 ms, and mean left ventricular ejection fraction was 56 ± 7%. Fourteen patients (14%) with PD-AVB were identified, and presented similar clinical characteristics in comparison with patients without PD-AVB, except for syncope (which was present in 86% versus 51% in the non-PD-AVB patients, p = 0.01). PD-AVB sequence was induced by: Premature atrial contraction (8/14), premature ventricular contraction (5/14), His extrasystole (1/14), conduction block in a branch (1/14), and atrial tachycardia termination (1/14). All patients with PD-AVB received a dual-chamber pacemaker during hospitalization. Conclusion: The prevalence of PD-AVB was 14%, and may be underestimated. PD-AVB episodes were more likely associated with syncope in comparison with patients without PD-AVB.

Outcome of Antibody‐Mediated Fetal Heart Disease With Standardized Anti‐Inflammatory Transplacental Treatment

Background Transplacental fetal treatment of immune‐mediated fetal heart disease, including third‐degree atrioventricular block (AVB III) and endocardial fibroelastosis, is controversial. Methods and Results To study the impact of routine transplacental fetal treatment, we reviewed 130 consecutive cases, including 108 with AVB III and 22 with other diagnoses (first‐degree/second‐degree atrioventricular block [n=10]; isolated endocardial fibroelastosis [n=9]; atrial bradycardia [n=3]). Dexamethasone was started at a median of 22.4 gestational weeks. Additional treatment for AVB III included the use of a β‐agonist (n=47) and intravenous immune globulin (n=34). Fetal, neonatal, and 1‐year survival rates with AVB III were 95%, 93%, and 89%, respectively. Variables present at diagnosis that were associated with perinatal death included an atrial rate <90 beats per minute (odds ratio [OR], 258.4; 95% CI, 11.5–5798.9; P <0.001), endocardial fibroelastosis (OR, 28.9; 95% CI, 1.6–521.7; P <0.001), fetal hydrops (OR, 25.5; 95% CI, 4.4–145.3; P <0.001), ventricular dysfunction (OR, 7.6; 95% CI, 1.5–39.4; P =0.03), and a ventricular rate <45 beats per minute (OR, 12.9; 95% CI, 1.75–95.8; P =0.034). At a median follow‐up of 5.9 years, 85 of 100 neonatal survivors were paced, and 1 required a heart transplant for dilated cardiomyopathy. Cotreatment with intravenous immune globulin was used in 16 of 22 fetuses with diagnoses other than AVB III. Neonatal and 1‐year survival rates of this cohort were 100% and 95%, respectively. At a median age of 3.1 years, 5 of 21 children were paced, and all had normal ventricular function. Conclusions Our findings reveal a low risk of perinatal mortality and postnatal cardiomyopathy in fetuses that received transplacental dexamethasone±other treatment from the time of a new diagnosis of immune‐mediated heart disease.

INSIGHTS ON ATRIAL ELECTROCARDIOGRAM IN SINUS RHYTHM AND ATRIOVENTRICULAR BLOCK FOR IMPROVED CLINICAL DIAGNOSIS

Objective: This study aims to characterize P and Ta wave of Modified Limb Lead (MLL) Electrocardiogram (ECG) in Normal Sinus Rhythm (NSR) and Atrioventricular Block (AVB). Methods: ECGs were recorded using MLL configuration from 100 NSR volunteers (mean age 31 years, 35 women) and 20 male AVB patients (mean age 72 years). Amplitudes and durations of P, Ta wave, and PTa Interval (PTaI) were measured, plotted, and analyzed for both the groups. Results: P-wave amplitudes were larger in AVB, and also P, Ta waves correlated significantly in both groups with higher correlation in AVB (NSR: [Formula: see text]; AVB: [Formula: see text]). Ta-wave duration ([Formula: see text] ms) was longer than P-wave duration ([Formula: see text] ms) in AVB patients and was opposite to P-wave polarity in all the leads. PP Interval (PPI) correlated significantly with P wave (NSR: [Formula: see text]; AVB: [Formula: see text]), Ta wave ([Formula: see text]; [Formula: see text]), PTaI ([Formula: see text]; [Formula: see text]), and corrected PTaI ([Formula: see text]; [Formula: see text]). Conclusion: P-wave right axis shift leads to the higher P-wave amplitude in AVB which may be due to the advancing age and atrial chamber enlargement. In NSR, the duration of observable Ta wave was longer than P wave, whereas in AVB, the Ta wave duration was 3–3.5 times longer than P wave.

Association of atrial septal defect and Brugada syndrome in a young woman

We report a 25-year-old woman who was diagnosed with atrial septal defect (ASD). An ECG showed only first-degree atrioventricular block and incomplete right bundle branch block. One day after the percutaneous ASD closure, she had a slight fever and an ECG showed a type 1 Brugada pattern. ECG characteristics of ASD are similar to those of a Brugada ECG. This case is rare combination of Brugada syndrome with ASD.

Adenosine Triphosphate (ATP)- A Safe and Effective Vasodilator for Stress Perfusion Cardiac Magnetic Resonance

Purpose The aim of this study was to evaluate the efficiency and safety of adenosine triphosphate (ATP) as a stress agent in a cohort of patients undergoing stress perfusion cardiac magnetic resonance imaging (CMR). Methods This retrospective study was conducted between December 2019 and October 2021 at the Beijing Friendship Hospital, Beijing, China. The study included 107 subjects (age range: 53±11 years; male: female, 62%:38%) with suspected non-obstructive coronary artery disease (NOCAD) that underwent stress CMR. These patients showed typical symptoms such as chest pain (stable and unstable angina pectoris) and <50% epicardial coronary artery stenosis based on coronary angiography. Adverse effects and splenic switch‑off (SSO) phenomenon was evaluated in the patients undergoing stress CMR. Moreover, qualitative and semi-quantitative analysis of inducible ischemia was performed by using stress CMR data. Results The qualitative and semi-quantitative analysis of stress CMR data showed 82 patients with reversible myocardial ischemia. The hemodynamic response was quick and observed within 2 minutes after ATP infusion. Scanning was stopped in three patients because of atrioventricular block. CMR images of seven out of 104 patients were excluded from the final analysis because of inferior quality. During ATP infusion, 31/107 patients (29%) experienced mild adverse effects such as chest pain, flushing, dyspnea, headache, and atrioventricular block. Myocardial infarction and bronchospasms were not observed during ATP infusion. SSO, a marker of adequate stress, was observed in 91% (94/103) of the patients that underwent stress CMR. Conclusion ATP is highly effective and safe to use in stress CMR as a coronary vasodilator.The hemodynamic response is observed within 2 minutes after ATP infusion.The adverse effects during ATP infusion were mild. SSO was observed in 91% of the patients undergoing stress CMR.