The correlation of pulmonary arterial hypertension with late recurrence of paroxysmal atrial fibrillation after catheter ablation

Mechanisms of stretch-induced electro-anatomical remodeling and atrial arrhythmogenesis

Atrial fibrillation (AF) is the most common cardiac rhythm disorder, often occurring in the setting of atrial distension and elevated myocardialstretch. While various mechano-electrochemical signal transduction pathways have been linked to AF development and progression, the underlying molecular mechanisms remain poorly understood, hampering AF therapies. In this review, we describe different aspects of stretch-induced electro-anatomical remodeling as seen in animal models and in patients with AF. Specifically, we focus on cellular and molecular mechanisms that are responsible for mechano-electrochemical signal transduction and the development of ectopic beats triggering AF from pulmonary veins, the most common source of paroxysmal AF. Furthermore, we describe structural changes caused by stretch occurring before and shortly after the onset of AF as well as during AF progression, contributing to longstanding forms of AF. We also propose mechanical stretch as a new dimension to the concept "AF begets AF", in addition to underlying diseases. Finally, we discuss the mechanisms of these electro-anatomical alterations in a search for potential therapeutic strategies and the development of novel antiarrhythmic drugs targeted at the components of mechano-electrochemical signal transduction not only in cardiac myocytes, but also in cardiac non-myocyte cells.

Unraveling the Complex Relationship-Atrial Fibrillation and Pulmonary Hypertension

PURPOSE OF REVIEW

In this article, we underscore the importance of identifying risk factors and monitoring pulmonary hypertension patients for signs of arrhythmias, as this proactive approach can reduce morbidity and mortality.

RECENT FINDINGS

Atrial fibrillation is the most prevalent among cardiac arrhythmias and is associated with an increased risk of stroke, morbidity, and mortality. Smoking, obesity, hypertension, a sedentary lifestyle, and diabetes mellitus are some of the modifiable risk factors for atrial fibrillation. Recent studies show that the risk of atrial fibrillation is rising in patients with parenchymal and vascular lung disease. Stretching in the atria and pulmonary veins may lead to the onset of atrial fibrillation in cardiac conditions like hypertension, heart failure, and valvular disease. Atrial fibrillation in patients with pulmonary hypertension (PH) denotes a more advanced disease. Patients with PH are more susceptible to hemodynamic stress caused by tachycardia and an uncoordinated atrioventricular contraction. Therefore, atrial arrhythmias need to be treated because inadequate control of cardiac arrhythmias may result in poor clinical outcomes and lead to disease progression in PH patients. Aside from being a sign of severe disease, AF can also speed up and exacerbate the condition.

Association of Right Ventricular Afterload With Atrial Fibrillation Risk in Older Adults: The Atherosclerosis Risk in Communities Study

BACKGROUND

Atrial fibrillation (AF) is widely perceived to originate from the left atrium (LA). Whether increases in right ventricular (RV) afterload in older adults play an etiological role in AF genesis independent of LA and left ventricular (LV) remodeling is unknown.

RESEARCH QUESTION

Is higher RV afterload associated with greater AF risk independent of LA and LV remodeling?

STUDY DESIGN AND METHODS

In this observational prospective study, we included 2,246 community-dwelling older adults (mean age, 75 years) without known cardiovascular disease, with LV ejection fraction > 50%, LA volume index < 34 mL/m2, and E/e' ratio < 14 and a measurable functional tricuspid regurgitation jet velocity. From 2D-echocardiograms, we estimated pulmonary artery systolic pressure (PASP) and pulmonary vascular resistance (PVR). We ascertained incident AF (through 2018) from hospital discharge codes and death certificates. We estimated hazard ratios (HR) by Cox regression.

RESULTS

During follow-up (median, 6.3 years; interquartile interval, 5.5-6.9 years), 215 participants developed AF. AF risk was significantly higher in the third (vs first) tertile of PASP (HR, 1.65; 95% CI, 1.08-2.54) and PVR (HR, 1.38; 95% CI, 1.00-2.08) independent of LA and LV structure and function, heart rate, BMI, prevalent sleep apnea, systemic BP, antihypertensive medications, and lung, kidney, and thyroid function. These associations persisted after further exclusion of participants with tricuspid regurgitation jet velocity > 2.8 m/s and lateral and septal mitral annular velocity above age- and sex-specific reference limits.

INTERPRETATION

In older adults, higher RV afterload is associated with greater AF risk independent of LA and LV remodeling. Future research should focus on confirming this novel association and elucidate underlying mechanisms.

The spectrum and prevalence of arrhythmia in different clinical pulmonary hypertension groups in Chinese population

BACKGROUND

Arrhythmia is not uncommon among pulmonary hypertension (PH) population, and may be associated with disease severity.

HYPOTHESIS

To investigate different spectrums and prevalence of arrhythmias in different clinical PH groups in Chinese population.

METHODS

Patients diagnosed with PH between April 15, 2019, and August 2, 2021, were enrolled prospectively. The prevalence of different types of arrhythmias in PH patients were calculated. Logistic regression analyses were conducted to determine independent predictors for arrhythmia.

RESULTS

One thousand patients were enrolled. The prevalence of any arrhythmia, sinus node dysfunction, sinus tachycardia, atrial fibrillation, atrial flutter, other types of atrial tachycardia, atrioventricular block, and ventricular tachycardia is 44.4%, 12.2%, 15.2%, 8.1%, 4.1%, 10.2%, 7.1%, and 2.5%. Logistic regression analyses revealed that older age and larger right ventricle (odds ratio: 1.111 and 1.095, p < .05) were independently related with higher probability of supraventricular arrhythmia; Complicating with coronary artery disease, larger right ventricle, and increased left ventricular end-diastolic diameter (odds ratio: 19.540, 1.106, and 1.085, p < .05) were independently correlated with sinus node dysfunction/atrioventricular block in patients with pulmonary arterial hypertension.

CONCLUSIONS

Nearly half of PH patients experienced at least one type of arrhythmia. The most common seen arrhythmias were supraventricular arrhythmia, sinus tachycardia, and sinus node dysfunction. Older age and larger right ventricle were independently related with higher probability of supraventricular arrhythmia; Complicating with coronary artery disease, larger right ventricle and increased left ventricular end-diastolic diameter were independently correlated with higher probability of sinus node dysfunction/atrioventricular block in patients with pulmonary arterial hypertension.

Assessment of cardiac arrhythmias using long-term continuous monitoring in patients with pulmonary hypertension

BACKGROUND

Cardiac arrhythmias are considered a prominent phenomenon in patients with pulmonary hypertension (PH). Older studies reported that 8% to 35% of patients with PH had supraventricular tachycardia (SVT), associated with adverse outcomes. Still, these arrhythmias have only been investigated via short-term monitoring or limited electrocardiogram recordings.

METHODS

Patients without previous arrhythmias diagnosed with PH at a tertiary facility received an insertable cardiac monitor as part of a prospective cohort study. Baseline assessments included World Health Organization functional class, six-minute walk test, echocardiography, and cardiac magnetic resonance imaging.

RESULTS

Thirty-four patients with PH were included. Twenty-four patients had pulmonary arterial hypertension (PAH) and 10 had chronic thromboembolic PH (CTEPH). During 46 patient-years of continuous monitoring (median: 594 (range: 334-654) days per patient), 70 arrhythmia episodes were recorded in 13 patients (38%), with a median of two (range: 1-3) episodes and an arrhythmic burden median of 1.6 (range: 0.1-228) minutes per patient. SVTs were the most common arrhythmias, with 16% of episodes being atrial fibrillation and 84% being other types of SVTs. Additionally, three patients experienced bradycardias, including one resulting in syncope and subsequent pacemaker implantation. None of the patients had sustained ventricular arrhythmias.

CONCLUSIONS

Arrhythmias were seen in 38% of contemporary patients with PH during long-term continuous monitoring; however, the vast majority of episodes were short and self-limiting. Modern therapy may alleviate the development of arrhythmias in stable patients with PH. This study is the first study to deploy long-term continuous monitoring in patients with PH.

Association of clinical predictors with recurrence of atrial fibrillation after catheter ablation

BACKGROUND

Recurrence rate after radiofrequency catheter ablation (RFCA) remains high, and further investigation on predictors of recurrence is needed.

OBJECTS

To identify risk factors of atrial fibrillation (AF) recurrence in patients undergoing RFCA.

METHODS

We retrospectively studied 257 patients with AF who underwent RFCA preceded by transthoracic echocardiographic and pulmonary vein CT examination from 2016 to 2019. Electrocardiogram examination was performed at baseline, 1, 3, 6 months, and 1 year after RFCA. We divided patients into two groups based on AF recurrence including recurrence group (n = 79) and nonrecurrence group (n = 178). The crude and independent association between clinical variables and AF recurrence was evaluated with logistic regression analysis. Specificity and positive predictive value of relevant factors for AF recurrence were performed by ROC curve.

RESULTS

Of these AF patients, 174 (68%) was paroxysmal AF and 83 (32%) was persistent AF. The multivariate logistic regression demonstrated that AF duration (OR = 1.008, 95% CI 1.002-1.013, p = .008), pulmonary arterial hypertension (PAH; OR = 2.313, 95% CI 1.031-5.192, p = .042), and low-density lipoprotein cholesterol (LDL-C; OR = 1.646, 95% CI 1.129-2.398, p = .010) were independently correlated with recurrence of AF. For predicting AF recurrence, the specificity and sensitivity of AF duration were 30.1% and 87.3%, and for LDL-C, the specificity and sensitivity of AF duration were 60.6% and 60.5%, respectively.

CONCLUSIONS

Atrial fibrillation duration, PAH, and LDL-C might be independent risk factors for the recurrence of AF after RFCA.

Arrhythmic Burden and Outcomes in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a devastating, life-limiting disease driven by small vessel vascular remodeling leading to a rise in pulmonary vascular resistance (PVR). Patients present with a range of symptoms including shortness of breath, exercise intolerance, palpitations or syncope. Symptoms may be related to vascular disease progression or arrhythmia secondary to the adaptation of the right heart to pressure overload. Arrhythmic burden is high in patients with left heart disease and guideline-based treatment of arrhythmias improves quality of life and prognosis. In PAH the incidence and prevalence of arrhythmias is less well-defined and there are no PAH-specific guidelines for arrhythmia management. We undertook a literature search identifying 13 relevant papers; detection of arrhythmias was acquired from 12-lead electrocardiogram (ECG) or Holter monitors. In all forms of pulmonary hypertension (PH) the prevalence of supraventricular arrhythmias (SVA) was 26-31%, ventricular arrhythmias (VA) 24% and a 5-year incidence of SVA ~13.2-25.1%. Prevalence and incidence of arrhythmias in PAH is less clear due to limited study numbers and the heterogenous nature of the patient population studied. For arrhythmia treatment, only single-arm studies of therapeutic strategies were reported using antiarrhythmic drugs (AAD), direct current cardioversion (DCCV) and ablation. Periods between ECG or Holter have not been investigated, highlighting the possibility that significant arrhythmias may be undetected. Advances in monitoring allow long-term surveillance via implanted/non-invasive monitors. Use of such technologies may provide an accurate estimate of incidence and prevalence of arrhythmias in patients with PAH, further defining relationships to adverse outcomes, and therapeutic options.