Preoperative left atrial dysfunction and risk of postoperative atrial fibrillation complicating thoracic surgery

Relationship between postoperative atrial fibrillation and its recurrence after lung resection

PURPOSE

Atrial fibrillation (AF) frequently occurs after pulmonary resection and is commonly referred to as postoperative atrial fibrillation (POAF). This study explored whether or not POAF is related to the recurrence of AF in the chronic phase.

METHODS

A total of 1311 consecutive patients without a history of AF who underwent lung resection based on a diagnosis of lung tumor were retrospectively analyzed.

RESULTS

POAF occurred in 46 patients (3.5%), and a logistic regression analysis revealed that the age (p < 0.05), history of hyperthyroidism (p < 0.05), and major lung resection (p < 0.05) were independent predictors of POAF. AF events in the chronic phase were observed in 15 (32.6%) and 45 (3.6%) patients with and without POAF, respectively. A Cox regression analysis revealed that POAF was the only independent predictor of AF development in the chronic phase (p < 0.01). The Kaplan-Meier curve and log-rank test revealed that the cumulative incidence of AF in the chronic phase was significantly higher in patients with POAF than in those without POAF (p < 0.01).

CONCLUSION

POAF was an independent predictor for AF in the chronic phase after lung resection. Further investigations including cases of catheter ablation and optimal medical therapy for patients with POAF after lung resection are needed.

Functional and postoperative outcomes after high-intensity interval training in lung cancer patients: A systematic review and meta-analysis

Objective

The study evaluated the effects of high-intensity interval training (HIIT) on postoperative complications and lung function in patients with lung cancer compared to usual care.

Methods

We searched electronic databases in April 2022, including PubMed, Embase, the Cochrane Library, Web of Science, and the China National Knowledge Infrastructure (CNKI). Two authors independently applied the Cochrane Risk of Bias tool to assess the quality of RCTs. The postoperative complications, length of hospitalization, and cardiopulmonary functions from the studies were pooled for statistical analysis.

Results

A total of 12 randomized controlled trials were eligible for inclusion and were conducted in the meta-analysis. HIIT significantly increased VO_2peak (MD = 2.65; 95% CI = 1.70 to 3.60; I² = 40%; P <0.001) and FEV1 (MD = 0.12; 95% CI = 0.04 to 0.20; I² = 51%; P = 0.003) compared with usual care. A subgroup analysis of studies that applied HIIT perioperatively showed significant improvement of HIIT on FEV1 (MD = 0.14; 95% CI = 0.08 to 0.20; I² = 36%; P <0.0001). HIIT significantly reduced the incidence of postoperative atelectasis in lung cancer patients compared with usual care (RD = -0.16; 95% CI = -0.24 to -0.08; I² = 24%; P <0.0001). There was no statistically significant effect of HIIT on postoperative arrhythmias (RD = -0.05; 95% CI = -0.13 to 0.03; I² = 40%; P = 0.22), length of hospitalization (MD = -1.64; 95% CI = -3.29 to 0.01; P = 0.05), and the six-minute walk test (MD = 19.77; 95% CI = -15.25 to 54.80; P = 0.27) compared to usual care.

Conclusion

HIIT may enhance VO_2peak and FEV1 in lung cancer patients and reduce the incidence of postoperative atelectasis. However, HIIT may not reduce the incidence of postoperative arrhythmia, shorten the length of hospitalization, or improve the exercise performance of patients with lung cancer.

Systematic review registration

PROSPERO, CRD42022335441.

Peri-operative approach to esophagectomy: a narrative review from the anesthesiological standpoint

Objective

This review summarizes the peri-operative anesthesiological approaches to esophagectomy considering the best up-to-date, evidence-based medicine, discussed from the anesthesiologist’s standpoint.

Background

Esophagectomy is the only curative therapy for esophageal cancer. Despite the many advancements made in the surgical treatment of this tumour, esophagectomy still carries a morbidity rate reaching 60%. Patients undergoing esophagectomy should be referred to high volume centres where they can receive a multidisciplinary approach to treatment, associated with better outcomes. The anesthesiologist is the key figure who should guide the peri-operative phase, from diagnosis through to post-surgery rehabilitation. We performed an updated narrative review devoted to the study of anesthesia management for esophagectomy in cancer patients.

Methods

We searched MEDLINE, Scopus and Google Scholar databases from inception to May 2021. We used the following terms: “esophagectomy”, “esophagectomy AND pre-operative evaluation”, “esophagectomy AND protective lung ventilation”, “esophagectomy AND hemodynamic monitoring” and “esophagectomy AND analgesia”. We considered only articles with abstract written in English and available to the reader. We excluded single case-reports.

Conclusions

Pre-operative anesthesiological evaluation is mandatory in order to stratify and optimize any medical condition. During surgery, protective ventilation and judicious fluid management are the cornerstones of intraoperative “protective anesthesia”. Post-operative care should be provided by an intensive care unit or high-dependency unit depending on the patient’s condition, the type of surgery endured and the availability of local resources. The provision of adequate post-operative analgesia favours early mobilization and rapid recovery. Anesthesiologist has an important role during the peri-operative care for esophagectomy. However, there are still some topics that need to be further studied to improve the outcome of these patients.

Predictive value of preoperative echocardiographic assessment for postoperative atrial fibrillation after esophagectomy for esophageal cancer

BACKGROUND

Postoperative atrial fibrillation (POAF) after esophagectomy for esophageal cancer is not uncommon. The aim of this study is to examine whether preoperative transthoracic echocardiography is useful for predicting new-onset POAF in esophageal cancer.

METHODS

In this prospective observational study, we evaluated 200 patients with esophageal cancer who underwent esophagectomy at our hospital between January 2016 and July 2019. Conventional echocardiographic assessment and tissue Doppler imaging were performed before surgery. We investigated the utility of preoperative transthoracic echocardiography for predicting new-onset POAF in esophageal cancer.

RESULTS

New-onset POAF occurred in 51 (25.5%) of 200 patients. POAF was significantly associated with older age (p = 0.007), higher body mass index (p = 0.020), preoperative hypertensive disease (p = 0.021), and lower hemoglobin level (p = 0.028). The incidence of postoperative complications was significantly higher in patients with POAF than in patients without POAF (43.1% vs. 24.2%, p = 0.013). Transthoracic echocardiography showed that left atrial diameter (LAD) and E wave/e' wave ratio (E/e') were significantly higher in patients with POAF than in patients without POAF (34.1 vs. 31.3 mm, p < 0.001 and 11.6 vs. 10.5, p = 0.003, respectively). Multivariate analysis showed that LAD ≥ 36.0 mm, E/e' ≥ 8.4 are independent risk factors for POAF (odds ratios 2.47 and 3.64; p values 0.035 and 0.027, respectively) CONCLUSIONS: Preoperative echocardiographic evaluation is useful for predicting the onset of POAF after esophagectomy for esophageal cancer. Risk stratification using LAD and E/e' enables clinicians to identify patients at high risk for POAF before esophagectomy.

The role of surgery type in postoperative atrial fibrillation and in-hospital mortality in esophageal cancer patients with preserved left ventricular ejection fraction

BACKGROUND

Postoperative atrial fibrillation (POAF) is one of the most common complications of esophagectomy, which may extend the inpatient hospital stay. Minimally invasive esophagectomy (MIE) has been increasingly used in clinical practice; however, its POAF risk and short-term mortality remain unclear. This study aimed to examine the POAF risk and in-hospital mortality rate between patients receiving MIE and open esophagectomy (OE).

METHODS

Esophageal cancer patients who underwent MIE or OE from a retrospective cohort study were evaluated. A multivariate logistic regression model was built to assess the associations between esophagectomy (MIE vs. OE) and various outcomes (POAF, in-hospital mortality). Covariates included age, sex, body mass index, neoadjuvant therapy, tumor stage, surgery incision type, comorbidities, cardia conditions, peri-operative medication, and complications.

RESULTS

Of the 484 patients with esophageal cancer, 63 received MIE. A total of 53 patients developed POAF. Compared to patients receiving OE, MIE patients had 81% reduced odds of POAF (adjusted odds ratio [aOR] 0.185, 95% CI 0.039-0.887, P = 0.035). No statistically significant association was found for in-hospital mortality (aOR 0.709, 95% CI 0.114-4.409, P = 0.712).

CONCLUSIONS

MIE is associated with a lower risk of POAF, compared to traditional surgery. No significant short-term survival benefit was found for MIE.

Atrial Fibrillation, Cancer and Echocardiography

Nonvalvular atrial fibrillation (AF) is a relatively frequent arrhythmia in cancer patients; it is possibly due to direct effect of cancer or consequence of cancer therapies. AF creates important problems for both therapeutic management and prognosis in cancer patients. The anticoagulation of cancer patients presenting AF is a main issue because of the difficult balance between thromboembolic and bleeding risks, both elevated in this clinical setting. A comprehensive echo Doppler examination is mandatory to identify the eventual sources of emboli in left atrial (LA) cavity, mainly the transesophageal echocardiography (TEE), but also to predict the subsequent development of heart failure. This evaluation is particularly important to graduate anticoagulation and to prevent and manage symptoms/signs of heart failure. The performance of a TEE precardioversion is highly encouraged to detect possible thrombi in LA appendage. A careful assessment of LA size (LA volume index) and function (LA emptying fraction and/or LA strain) should always be planned to predict the possible recurrence of AF paroxysmal episodes. This is in fact a key action, not only from the cardiologic point of view but also for the oncologic perspectives in individual situations. Patients with larger left atrium and more impaired LA function should be addressed toward a less aggressive cancer treatment, with drugs which are not associated or are poorly related with the risk of AF development. A correct and comprehensive echocardiographic assessment could even induce the oncologist to change the cancer management balancing the oncologic and the cardiac risk.

[Postoperative complications after major lung resection]

INTRODUCTION

The advent of the minimally invasive techniques has allowed an expansion of the indications for thoracic surgery, particularly in older patients and those with more comorbidities. However, the rate of postoperative complications has remained stable.

STATE OF THE ART

Postoperative complications are defined as any variation from the normal course. They occur in 30% but majority of them are minor. The 30-day mortality rate for lung resection varies range between 2 % and 3% in the literature. Complications can be classified as: (1) early (occurring in the first 24hours) including both "generic" surgical complications (especially postoperative bleeding) and complications more specific to lung surgery (Acute respiratory syndrome, atelectasis); (2) in-hospital complications and those occurring during the first 3 months; these are dominated by infectious events in particular pneumonia but also bronchial (bronchopleural fistula), pleural (pneumothorax, hydrothorax) or cardiac complications; (3) late complications are dominated by chronic pain, affecting 60% of patients having a thoracotomy at three months. Lobectomy is the most common lung resection. Pneumonectomy is a distinct procedure requiring a specific peri- and postoperative management. Right pneumonectomy is associated with a higher risk with a treatment related-mortality ranging between 7 and 10%.

CONCLUSION

Major lung resection has benefited from minimally invasive approaches and fast track to surgery. However, it is important to note the occurrence of new and specific complications related to those news surgical access.

Meta-analysis of risk factors and complications associated with atrial fibrillation after oesophagectomy

Background

Oesophagectomy is associated with high morbidity and mortality rates. New-onset atrial fibrillation (AF) is a frequent complication following oesophagectomy. Several studies have explored whether new-onset AF is associated with adverse events after oesophagectomy.

Methods

This review was performed according to PRISMA guidelines. Eligible studies were identified through a search of PubMed, Scopus and Cochrane CENTRAL databases up to 25 November 2018. A meta-analysis was conducted with the use of random-effects modelling. The I2 statistic was used to assess for heterogeneity.

Results

In total, 53 studies including 9087 patients were eligible for analysis. The overall incidence of postoperative AF was 16·5 per cent. Coronary artery disease and hypertension were associated with AF, whereas diabetes, smoking and chronic obstructive pulmonary disease were not. Patients with AF had a significantly higher risk of overall postoperative adverse events than those without fibrillation (odds ratio (OR) 5·50, 95 per cent c.i. 3·51 to 8·30), including 30-day mortality (OR 2·49, 1·70 to 3·64), anastomotic leak (OR 2·65, 1·53 to 4·59) and pneumonia (OR 3·42, 2·39 to 4·90).

Conclusion

Postoperative AF is frequently observed in patients undergoing oesophagectomy for cancer. It is associated with an increased risk of death and postoperative complications.

Risk factors of atrial fibrillation occurring after radical surgery of esophageal carcinoma

Background

Atrial fibrillation (AF) is a common complication after radical surgery of esophageal cancer. The aim of this study was to explore AF risk factors after radical surgery of esophageal carcinoma.

Method

The data of 335 patients with esophageal cancer who were admitted in our hospital from January 2014 to August 2016 for the first time were retrospectively analyzed. We retrieved the papers in some data banks using the search terms including English and Chinese search terms, and obtained 13 factors which were mentioned in more than 6 papers. The 13 factors including age, gender, history of smoking, history of hypertension, history of peripheral vascular disease, history of cardiac stents or angina pectoris, preoperative pulmonary infection, preoperative brain natriuretic peptide (BNP) level, preoperative left ventricular diastolic dysfunction, operative method, lesion location, intraoperative blood transfusion, adhesion between lymph nodes and pericardium, underwent univariate and multivariate analyses.

Results

Of the 335 patients with esophageal cancer, 48 had AF within one week after operation. Univariate analysis indicated that the age (OR: 4.89; CI: 2.53–9.47, P: 0.000), gender (OR: 2.26; CI: 1.17–4.37, P: 0.013), history of peripheral vascular disease (OR: 2.29; CI: 1.06–4.92, P: 0.030), history of cardiac stents or angina pectoris (OR: 27.30; CI: 12.44–59.91, P: 0.000), preoperative BNP level (OR: 27.13; CI: 10.97–67.06, P: 0.000), preoperative left ventricular diastolic dysfunction (OR: 2.22; CI: 1.19–4.14, P: 0.012), operative method (OR: 2.09; CI: 1.002–4.380, P: 0.046), intraoperative blood transfusion (OR: 20.24; CI: 8.39–48.82, P: 0.000), and adhesion between lymph nodes and pericardium were risk factors (OR: 2.05; CI: 1.08–3.87, P: 0.024). Furthermore, multivariate analysis displayed that advanced age (OR: 5.044; CI: 1.748–14.554, P: 0.003), male (OR: 6.161; CI: 2.143–17.715, P: 0.001), history of cardiac stents or angina pectoris (OR: 48.813; CI: 13.674–174.246, P: 0.000), preoperative BNP > 100 (OR: 41.515; CI: 9.380–183.732, P: 0.000), open surgery (OR: 3.357; CI: 1.026–10.983, P: 0.045), intraoperative blood transfusion (OR: 58.404; CI: 10.777–316.509, P: 0.000), and adhesion between lymph nodes and pericardium (OR: 3.954; CI: 1.364–11.459, P: 0.011) were risk factors which could increase the incidence of postoperative AF.

Conclusion

We should pay attention to the above risk factors in order to reduce the incidence of postoperative AF.

Amiodarone for prevention of atrial fibrillation following esophagectomy

OBJECTIVES

Atrial fibrillation (AF) is a common complication after esophagectomy and is associated with symptoms, hemodynamic instability, prolonged hospital stay, and an increased incidence of mortality. Our objective was to determine the efficacy and safety of intravenous amiodarone for prophylaxis of postesophagectomy AF.

METHODS

In this retrospective cohort study, 309 patients who underwent esophagectomy formed the initial cohort. Following propensity score-matching, 110 patients who received prophylactic amiodarone 43.75 mg/hour via continuous intravenous infusion over 96 hours (total dose, 4200 mg) were matched to a control group of patients who did not undergo amiodarone prophylaxis (n = 110). The propensity score was obtained using a multivariate logistic regression model with amiodarone as the variable and the following covariates: age, sex, surgical approach, history of neoadjuvant chemotherapy and/or radiation, chronic obstructive pulmonary disease, heart failure, cardiovascular disease, alcohol use (>7 drinks/week), preadmission β-blockers discontinued during hospitalization, preoperative use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, preoperative use of corticosteroids, postoperative use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, postoperative use of corticosteroids, postoperative use of statins, and preoperative Charlson comorbidity index.

RESULTS

The incidence of AF requiring treatment due to rapid ventricular rate and symptoms was lower in the amiodarone group (17 out of 110 [15.5%] vs 32 out of 110 [29.1%]; odds ratio, 0.45; 95% confidence interval, 0.23-0.86; P = .015). There were no significant differences between the groups in median postoperative length of hospital stay, incidence of pulmonary complications, or mortality. The incidences of hypotension requiring treatment (42.7% vs 21.8%; P = .001), bradycardia (8.2% vs 0.0%; P = .002), and corrected QT interval prolongation (10.9% vs 0.0%; P ≤ .0001) were significantly higher in the amiodarone group.

CONCLUSIONS

Prophylactic intravenous amiodarone is associated with a reduction in the incidence of AF following esophagectomy, but is not associated with shorter postoperative length of hospital stay. Intravenous amiodarone for prophylaxis of postesophagectomy AF is associated with hypotension, bradycardia, and corrected QT interval prolongation.

A brain natriuretic peptide-based prediction model for atrial fibrillation after thoracic surgery: Development and internal validation

OBJECTIVE

Postoperative atrial fibrillation (POAF) is common after anatomic thoracic surgery. Elevated preoperative brain natriuretic peptide (BNP) level is strongly associated with risk of POAF. We describe the development and internal validation of a clinical prediction model for POAF that includes BNP and other clinical factors.

METHODS

Clinical and preoperative BNP data were collected for 635 patients in sinus rhythm before anatomic lung (n = 540) or esophageal (n = 95) resection. The primary outcome was new onset of POAF (>5 minutes) during hospitalization. A prediction model was developed using multivariable logistic regression analysis and internally validated using a bootstrap-resampling approach.

RESULTS

POAF occurred in 20% of patients (124 out of 635). BNP level was higher among patients with than without POAF (median, 45 vs 23 pg/mL; P < .0001). The final prediction model included 5 factors: age (odds ratio [OR], 1.05; 95% confidence interval [CI], 1.02-1.08; P = .001), body mass index (OR, 1.05; 95% CI, 1.00-1.09; P = .016), BNP level (75th vs 25th percentile, 57.5 vs 12.5 pg/mL; OR, 2.08; 95% CI, 1.26-3.43; P = .0003), history of atrial fibrillation (OR, 5.91; 95% CI, 2.47-14.11; P < .0001), and extent of surgery (compared with segmentectomy [reference]: pneumonectomy OR, 6.70; 95% CI, 1.91-24.70; esophagectomy OR, 4.93; 95% CI, 1.94-14.06; lobectomy OR, 1.88; 95% CI, 4.90-8.34; overall P = .0002). The model had good calibration and discrimination (C statistic, 0.736). After internal validation, optimism-corrected measures showed similarly good calibration and discrimination (C statistic, 0.720; 95% CI, 0.664-0.765).

CONCLUSIONS

Our novel prediction model-based interactive calculator can be used to identify patients at high risk of POAF and could be incorporated into practice prevention guidelines.

Landiolol for managing post-operative atrial fibrillation

Beta-blockers are a potential option to manage peri-operative atrial fibrillation. Landiolol is a new ultra-short beta-blocker with a half-life of only 4 minutes and very high beta-1 selectivity which has been used for treatment and prevention of atrial fibrillation in pulmonary surgery and gastro-intestinal surgery. Due to its limited negative inotropic effect and high beta-1 selectivity landiolol allows for control of heart rate with minimal impact on blood pressure. Landiolol is well tolerated by the respiratory system. Additional benefits are related to the regulation of the inflammatory response and blunting of the adrenergic pathway. There is a limited number of trials with total of 61 patients undergoing lung resection or oesophagectomy who developed post-operative atrial fibrillation and were treated with landiolol. The experience with landiolol for prevention is more documented than landiolol application for treatment of post-operative atrial fibrillation. There are 9 comparative studies with a total of 450 patients administered landiolol for prevention of post-operative atrial fibrillation. The use of low dosage (5-10mcg/kg/min) is usually sufficient to rapidly control heart rate which is associated with earlier and higher rate of conversion to sinus rhythm as compared to the controls. The excellent tolerance of landiolol at lower dosage (3-5mcg/kg/min) allows to initiate prophylactic use during surgery and postoperatively. Landiolol prophylaxis is associated with reduced incidence of post-operative atrial fibrillation without triggering adverse events related to a beta-blockade.

Short-Term Preoperative High-Intensity Interval Training in Patients Awaiting Lung Cancer Surgery: A Randomized Controlled Trial

INTRODUCTION

Impairment in aerobic fitness is a potential modifiable risk factor for postoperative complications. In this randomized controlled trial, we hypothesized that a high-intensity interval training (HIIT) program enhances cardiorespiratory fitness before lung cancer surgery and therefore reduces the risk of postoperative complications.

METHODS

Patients with operable lung cancer were randomly assigned to usual care (UC) (n = 77) or preoperative rehabilitation based on HIIT (Rehab) (n = 74). Maximal cardiopulmonary exercise testing and the 6-minute walk test were performed twice before surgery. The primary outcome measure was a composite of death and in-hospital postoperative complications.

RESULTS

The groups were well balanced in terms of patient characteristics. During the preoperative waiting period (median 25 days), the peak oxygen consumption and the 6-minute walking distance increased (median +15%, interquartile range, 25th to 75 percentile [IQR25%-75%, %] = +9% to +22%, p = 0.003 and +15%, IQR25%-75% = +8% to +28%, p < 0.001, respectively) in the Rehab group, whereas peak oxygen consumption declined in the UC group (median -8%, IQR25%-75% = -16% to 0%], p = 0.005). The primary end point did not differ significantly between the two groups: at least one postoperative complication developed in 27 of the 74 patients (35.5%) in the Rehab group and 39 of 77 patients (50.6%) in the UC group (p = 0.080). Notably, the incidence of pulmonary complications was lower in the Rehab compared with in the UC group (23% versus 44%, p = 0.018), owing to a significant reduction in atelectasis (12.2% versus 36.4%, p < 0.001), and this decrease was accompanied by a shorter length of stay in the postanesthesia care unit (median -7 hours, IQR25%-75% = -4 to -10).

CONCLUSIONS

In this randomized controlled trial, preoperative HIIT resulted in significant improvement in aerobic performances but failed to reduce early complications after lung cancer resection.

Evaluation of left and right ventricular myocardial function after lung resection using speckle tracking echocardiography

The impact of major lung resections on myocardial function has not been well-investigated. We aimed to identify this impact through the use of speckle tracking echocardiography (STE) to evaluate the right and left ventricular myocardial function in patients who underwent lung resections.Thirty patients who had lung resections were recruited for this study. Ten patients who underwent pneumonectomies were matched by age and sex, with 20 patients who underwent lobectomies. STE was performed on both right and left ventricle (RV and LV). Strain values of pre and postlung resections were compared in both the pneumonectomy group and the lobectomy group. Comparison between the pneumonectomy group and the lobectomy group was also studied.Left ventricular ejection fraction remained normal (>55%), but significantly decreased after lung resection in both the pneumonectomy group and the lobectomy group. An accelerated heart rate was observed in both groups after lung resection, with the pneumonectomy group demonstrating extra rapid heart rate (P < 0.05). Strain values in the RV and LV decreased in both groups after lung resection, with the pneumonectomy group exhibiting a further decrease in longitudinal strain in LV and RV when compared with the lobectomy group (P < 0.05).Right and left ventricular dysfunction can occur after lung resection regardless of pneumonectomy or lobectomy, and lobectomy may have a less significant impact on myocardial functions. This study demonstrated that STE is able to detect acute cardiac dysfunction after lung resection.

Comparison of Risk of Atrial Fibrillation in Black Versus White Patients After Coronary Artery Bypass Grafting

Obesity has been identified as a risk factor for postoperative atrial fibrillation (POAF) after coronary artery bypass grafting (CABG). However, no studies have addressed the influence of race on this association. A total of 13,594 patients undergoing first-time, isolated CABG without preoperative AF between 1992 and 2011 were included in our study. The association between body mass index and POAF was compared by race. Relative risk and 95% CIs were computed using maximum likelihood log-binomial regression. Increasing levels of body mass index were associated with higher POAF risk after CABG in black but not white patients (pinteraction = 0.0009).

Prognostic utility of right atrial emptying fractions in pulmonary arterial hypertension

Although left atrial function has been extensively studied in patients with heart failure, the determinants and clinical correlates of impaired right atrial (RA) function have been poorly studied. We investigated measures of RA function in pulmonary arterial hypertension (PAH). We identified all treatment-naive patients with World Health Organization category 1 PAH seen at our center during 2000-2011 who had right heart catheterization and 6-minute walk test (6MWT) within 1 month of initial echocardiographic examination. Atrial size was measured using the monoplane area-length method, and atrial function was quantified using total, passive, and active RA emptying fractions (RAEFs). We compared measures of RAEF with known prognostic clinical, echocardiographic, and hemodynamic parameters. For the subset of patients with follow-up echocardiographic examination/6MWT within 6-18 months, we investigated the change in RAEF. In an exploratory analysis, we investigated the association between RAEF and mortality. Our population consisted of 39 patients with treatment-naive (incident) PAH, 30 of whom had follow-up testing. The mean total, passive, and active RAEFs were 24.4% ± 15.1%, 8.5% ± 6.9%, and 17.6% ± 13.9%, respectively. Total and active RAEFs correlated with tricuspid annular plane systolic excursion (P = 0.004 and P = 0.005) and cardiac output (P = 0.02 and P = 0.01). The change in active RAEF correlated with change in 6-minute walk distance (P = 0.02). In our Cox regression analysis, low active and total RAEF were associated with mortality, with hazard ratios of 5.6 (95% confidence interval [CI], 1.2-26.2; P = 0.03) and 4.2 (95% CI, 1.1-15.5; P = 0.03), respectively. Passive RAEF was poorly reproducible and not associated with outcome. Measures of RAEF appear to have prognostic importance in PAH and warrant further study.

Electrophysiological changes preceding the onset of atrial fibrillation after coronary bypass grafting surgery

BACKGROUND

The incidence of Post-CABG atrial fibrillation (AF) lies between 25% and 40%. It worsens morbidity and raises post-operative costs. Detection of incoming AF soon enough for prophylactic intervention would be helpful. The study is to investigate the electrophysiological changes preceding the onset of AF and their relationship to the preoperative risk.

METHODS AND RESULTS

Patients were recorded continuously for the first four days after coronary artery bypass grafting surgery (CABG) with three unipolar electrodes sutured to the atria (AEG). The patients experiencing an AF lasting more than 10 minutes were selected and the two hours before the onset were analyzed. Four variables were found to show significant changes in the two hours prior to the first prolonged AF: increasing rate of premature atrial activation, increasing incidence of short transient arrhythmias, acceleration of heart rate, and rise of low frequency content of heart rate. The main contrast was between the first and last hour before AF onset. Preoperative risk was not predictive of the onset time of AF and did not correlate with the amplitude of changes prior to AF.

CONCLUSIONS

Post-CABG AF were preceded by electrophysiological changes occurring in the last hour before the onset of the arrhythmia, whereas none of these changes was found to occur in all AF patients. The risk was a weighted sum of factors related to the density of premature activations and the state of atrial substrate reflected by the sinus rhythm and its frequency content prior to AF. Preoperative risk score seems unhelpful in setting a detection threshold for the AF onset.

Left atrial expansion index predicts all-cause mortality and heart failure admissions in dyspnoea

AIMS

The power of left atrial (LA) parameters for predicting adverse events in relatively low-risk groups is not fully understood. This study investigated whether the LA expansion index predicts heart failure (HF) and all-cause mortality in subjects with dyspnoea.

METHODS AND RESULTS

Echocardiography was performed to identify causes of dypnoea in 1735 patients. The LA expansion index was calculated as (Volmax - Volmin) × 100%/Volmin, where Volmax was defined as the maximal LA volume and Volmin was defined as the minimal LA volume. The endpoints were 2-year frequencies of HF hospitalization and all-cause mortality. Over a median follow-up of 2.7 years, 91 participants reached endpoints. Rates of adverse events were exponentially proportional to the LA expansion index. For predicting adverse events, the LA expansion index was better than the maximal indexed LA volume and tissue Doppler parameters. Hospitalization for HF was independently associated with age, LVEF, pulmonary artery systolic pressure, LA expansion index, and history of prior HF. All-cause mortality was associated with age, pulmonary artery systolic pressure, and LA expansion index. Compared with the highest quartile of the LA expansion index, the lowest quartile had a 3.1-fold higher hazard of HF events and a 17.8-fold higher hazard of all-cause mortality.

CONCLUSIONS

The LA expansion index predicts adverse events in patients with dyspnoea. The prognostic power of the index exceeds that of other well-established echocardiographic parameters such as E/e' and maximal indexed LA volume. Trial registration NCT01171040.

Transcriptomic analysis reveals atrial KCNE1 down-regulation following lung lobectomy

Lone atrial fibrillation (AF) is associated with various ion channel gene sequence variants, notably the common S38G loss-of-function polymorphism in the KCNE1 K(+) channel ancillary subunit gene. New-onset postoperative AF (POAF) generally occurs 48-72 h after major surgery, particularly following procedures within the chest, but its molecular bases remain poorly understood. To begin to address this gap in knowledge, we analyzed molecular changes in the left atrium (LA) in relation to simultaneous changes in hemodynamics, LA effective refractory period (ERP), and the capacity to sustain electrically-induced AF following left upper lung lobectomy in swine. Relative to control pigs (no previous surgery), 3 days after lobectomy higher values for mean pulmonary artery pressure (16 ± 1 vs 22 ± 2 mmHg; P=0.045) and pulmonary vascular resistance (273 ± 47 vs 481 ± 63 dyns/cm(5); P=0.025) were evident, whereas other hemodynamic variables were unchanged. LA ERP trended toward reduction in lobectomy animals (187 ± 16 vs 170 ± 20 ms, P>0.05). None of the lobectomy pigs developed spontaneous POAF as assessed by telemetric ECG. However, all lobectomy pigs, but none of the controls, were able to sustain AF induced by a 10s burst of rapid pacing for ≥ 30 s (P=0.0079), independent of LA ERP; AF was sustained ≥ 60s in 3/5 postoperative pigs versus 0/5 controls and correlated with a shorter ERP overall (P=0.023). Transcriptomic analysis of LA tissue revealed 23 up-regulated and 10 down-regulated transcripts (≥ 1.5-fold, P<0.05) in lobectomy pigs. Strikingly, of the latter, KCNE1 down-regulation showed the statistically strongest link to surgery (2.0-fold, P=0.009), recapitulated at the protein level with Western blotting (P=0.039), suggesting KCNE1 down-regulation as a possible common mechanistic factor in POAF and lone AF. Of the up-regulated transcripts, while Teneurin-2 was the strongest linked (1.5-fold change, P=0.001), DSCR5 showed the highest induction (2.7-fold, P=0.02); this and other hits will be targeted in future functional studies.