Symptomatic tachydysrhythmias after esophagectomy: incidence and outcome measures

Evolving Perspectives on Esophagectomy Care: Clinical Update

Recent changes in perioperative care have led to new perspectives and important advances that have helped to improve outcomes among patients treated with esophagectomy for esophageal cancer.

Clinician preference instrumental variable analysis of the effectiveness of magnesium supplementation for atrial fibrillation prophylaxis in critical care

Atrial fibrillation is a frequently encountered condition in critical illness and causes adverse effects including haemodynamic decompensation, stroke and prolonged hospital stay. It is a common practice in critical care to supplement serum magnesium for the purpose of preventing episodes of atrial fibrillation. However, no randomised studies support this practice in the non-cardiac surgery critical care population, and the effectiveness of magnesium supplementation is unclear. We sought to investigate the effectiveness of magnesium supplementation in preventing the onset of atrial fibrillation in a mixed critical care population. We conducted a single centre retrospective observational study of adult critical care patients. We utilised a natural experiment design, using the supplementation preference of the bedside critical care nurse as an instrumental variable. Using routinely collected electronic patient data, magnesium supplementation opportunities were defined and linked to the bedside nurse. Nurse preference for administering magnesium was obtained using multilevel modelling. The results were used to define "liberal" and "restrictive" supplementation groups, which were inputted into an instrumental variable regression to obtain an estimate of the effect of magnesium supplementation. 9114 magnesium supplementation opportunities were analysed, representing 2137 critical care admissions for 1914 patients. There was significant variation in magnesium supplementation practices attributable to the individual nurse, after accounting for covariates. The instrumental variable analysis showed magnesium supplementation was associated with a 3% decreased relative risk of experiencing an atrial fibrillation event (95% CI - 0.06 to - 0.004, p = 0.03). This study supports the strategy of routine supplementation, but further work is required to identify optimal serum magnesium targets for atrial fibrillation prophylaxis.

Digital Predictors of Morbidity, Hospitalization, and Mortality Among Older Adults: A Systematic Review and Meta-Analysis

The widespread adoption of digital health technologies such as smartphone-based mobile applications, wearable activity trackers and Internet of Things systems has rapidly enabled new opportunities for predictive health monitoring. Leveraging digital health tools to track parameters relevant to human health is particularly important for the older segments of the population as old age is associated with multimorbidity and higher care needs. In order to assess the potential of these digital health technologies to improve health outcomes, it is paramount to investigate which digitally measurable parameters can effectively improve health outcomes among the elderly population. Currently, there is a lack of systematic evidence on this topic due to the inherent heterogeneity of the digital health domain and the lack of clinical validation of both novel prototypes and marketed devices. For this reason, the aim of the current study is to synthesize and systematically analyse which digitally measurable data may be effectively collected through digital health devices to improve health outcomes for older people. Using a modified PICO process and PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) framework, we provide the results of a systematic review and subsequent meta-analysis of digitally measurable predictors of morbidity, hospitalization, and mortality among older adults aged 65 or older. These findings can inform both technology developers and clinicians involved in the design, development and clinical implementation of digital health technologies for elderly citizens.

Implementation of evidence-based recommendations to reduce elective surgical case cancellations

BACKGROUND

Cancellation of elective surgical cases leads to a waste of resources, financial burden, patient dissatisfaction, extended hospital stay, and unnecessary repetition of preoperative preparations.

AIM

The objective of this study was to identify, analyze and manage the causes of cancellation of elective surgical cases in our institution.

METHODS

This quality improvement study compared preoperative cardiovascular event and case cancellation rates before and after implementing the practice of perioperative cardiovascular risk management. The study included the following phases: (1) Screening and identification of the most important reason for case cancellation; (2) Developing the strategy and internal protocol based on the international recommendations to minimize perioperative cardiovascular risk; (3) Implementing the internal protocol and monitoring preoperative cardiovascular events and case cancellation rate.

RESULTS

We achieved a reduction in surgical case cancellation rate: 83 (3.7%) out of 2242 in 2018 and 28 (1.1%) out of 2538 cases in 2019 were cancelled after the patient had been delivered to the operating room area.

CONCLUSION

Screening and identification of gaps in perioperative care as well as implementation of evidence-based recommendations can significantly improve the quality of patient care. In our case, implementing the internal protocol of cardiovascular risk management in perioperative period resulted in a reduction of preoperative hypertensive crisis, myocardial ischemia, heart rhythm disorder rates and in subsequently reduction in case cancellation rate.

Major Postoperative Complications in Esophageal Cancer After Minimally Invasive Esophagectomy Compared With Open Esophagectomy: An Updated Meta-analysis

BACKGROUND

To evaluate the existing literature comparing cardiopulmonary complications after minimally invasive esophagectomy (MIE) with open esophagectomy (OE) and conduct a meta-analysis based on the relevant studies.

METHODS

A systematic search for articles was performed in Medline, Embase, Wiley Online Library, and the Cochrane Library. The relative risks or odds ratios (ORs) were calculated by using fixed or random-effects models. The I² and X² tests were used to test for statistical heterogeneity. We performed a metaregression for the pulmonary complications with the adenocarcinoma proportion and tumor stage. Publication bias and small-study effects were assessed using Egger's test and Begg's funnel plot.

RESULTS

A total of 30,850 participants were enrolled in the 63 studies evaluated in the meta-analysis. Arrhythmia, pulmonary embolism, pulmonary complications, gastric tip necrosis, anastomotic leakage, and vocal cord palsy were chosen as outcomes. The occurrence rate of arrhythmia was significantly lower in patients receiving MIE than in patients receiving OE (OR = 0.69; 95% CI = 0.53-0.89), with heterogeneity (I² = 30.7%, P = 0.067). The incidence of pulmonary complications was significantly lower in patients receiving MIE (OR = 0.54, 95% CI = 0.45-0.63) but heterogeneity remained (I² = 72.1%, P = 0.000). The risk of gastric tip necrosis (OR = 1.48, 95% CI = 1.07-2.05) after OE was lower than that after MIE. Anastomotic leakage, pulmonary embolism, and vocal cord palsy showed no significant differences between the two groups.

CONCLUSIONS

MIE has advantages over OE, especially in reducing the incidence of arrhythmia and pulmonary complications. Thus, MIE can be recommended as the preferred alternative surgery method for resectable esophageal cancer.

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.

Anticancer Therapy-Induced Atrial Fibrillation: Electrophysiology and Related Mechanisms

Some well-established immunotherapy, radiotherapy, postoperation, anticancer drugs such as anthracyclines, antimetabolites, human epidermal growth factor receptor 2 blockers, tyrosine kinase inhibitors, alkylating agents, checkpoint inhibitors, and angiogenesis inhibitors, are significantly linked to cardiotoxicity. Cardiotoxicity is a common complication of several cancer treatments. Some studies observed complications of cardiac arrhythmia associated with the treatment of cancer, including atrial fibrillation (AF), supraventricular arrhythmias, and cardiac repolarization abnormalities. AF increases the risk of cardiovascular morbidity and mortality; it is associated with an almost doubled risk of mortality and a nearly 5-fold increase in the risk of stroke. The occurrence of AF is also usually researched in patients with advanced cancer and those undergoing active cancer treatments. During cancer treatments, the incidence rate of AF affects the prognosis of tumor treatment and challenges the treatment strategy. The present article is mainly focused on the cardiotoxicity of cancer treatments. In our review, we discuss these anticancer therapies and how they induce AF and consequently provide information on the precaution of AF during cancer treatment.

Atrial fibrillation after transhiatal esophagectomy with transcervical endoscopic esophageal mobilization: one institution's experience

Background

There have been numerous studies regarding atrial fibrillation (AF) associated with cardiac and pulmonary surgery; however, studies looking at esophagectomy and atrial fibrillation are sparse. The goal of this study was to review our institution’s atrial fibrillation rate following esophagectomy in order to better define the incidence and predisposing factors in this patient population.

Methods

A retrospective chart review of all patients undergoing esophagectomy with transcervical endoscopic mobilization of the esophagus (TEEM) at the Medical College of Wisconsin and Affiliated Hospitals from July 2009 through December 2012.

Results

Seventy-one patients underwent TEEM esophagectomy during the study period. Of those, 23 (32.4%) patients developed new atrial fibrillation postoperatively. ICU (Intensive Care Unit) length of stay was 7.1 days for those that did not receive amiodarone, compared to 5.3 days for those that did receive amiodarone (p < 0.025). Those that went into AF spent on average 9.3 days in the ICU compared to 4.7 days for their counterparts that did not go into AF (p < 0.006). Total length of stay was not statistically different between populations [15.1 +/− 11.3 days compared to 13.5 +/− 9.4 days for those who did not go into AF (p < 0.281)]. Receiving preoperative amiodarone was found to reduce the overall incidence of AF. There was a trend towards decreased risk of going into AF in those who received preoperative amiodarone with an adjusted hazard ratio of 0.555 (p = 0.057).

Conclusion

Similar to data reported in previous literature, postoperative atrial fibrillation was found to increase ICU length of stay as well as overall length of hospital stay. Preoperative amiodarone administration displayed a trend toward decreasing the rates of atrial fibrillation in patients undergoing TEEM.

Impact of atrial arrhythmias after esophagectomy on recovery: A meta-analysis

BACKGROUND

Postoperative atrial arrhythmias (PAAs) are common complications after esophagectomy, however research findings are contradicted on the prognosis. Therefore this meta-analysis was conducted to determine whether PAAs after esophagectomy had an impact on prognosis.

METHODS

Studies comparing prognosis between patients with and without PAAs after esophagectomy were searched in EMBASE, MEDLINE, and the Cochrane Register. Primary prognosis was perioperative mortality, and secondary prognoses were postoperative complications, length of stay (LOS).

RESULTS

Ten studies including 2681 patients were included in this analysis, in which 508 patients (18.9%) experienced PAAs. Patients with PAAs resulted in significantly higher perioperative (odds ratio, OR 4.05[95% confidence interval, CI: 2.45-6.70], P = .40) mortality, longer hospital LOS (mean differences, MD: 1.49 [95% CI: 0.32-2.66]days, P = .01), more incidence of pulmonary pneumonia (OR 2.48 [95% CI: 1.71-3.59], P < .00001), and anastomotic leakage (OR 2.37 [95% CI: 1.39-4.03], P < .00001).

CONCLUSIONS

Atrial arrhythmias (AAs) after esophagectomy are associated with higher perioperative mortality, longer hospital LOS, and more incidences of complications. Therapeutic strategies against PAAs are pending for further researches.

Effects of dexmedetomidine on heart arrhythmia prevention in off-pump coronary artery bypass surgery: A randomized clinical trial

Background

Arrhythmia occurring during and after surgery is one of the major complications in open-heart surgery. Dexmedetomidine is an intravenous alpha-2 agonist and very specific short-acting drug to protect the various organs against ischemic injuries and blood reflow. However, the effect of dexmedetomidine for preventing intraoperative heart arrhythmias has not been recognized.

Objective

This study aimed to determine the effect of dexmedetomidine on the incidence rate of heart arrhythmias and anesthetic required in off-pump coronary artery bypass surgery.

Methods

This randomized clinical trial was conducted on patients who were candidates for off-pump coronary artery bypass referring to Imam Reza Hospital of Mashhad, Iran, from July 2016 through January 2017. The patients were randomly assigned to two groups of intervention (infusion of 0.5 mcg/kg/h dexmedetomidine together with induction followed by infusion of 0.5 mcg/kg/h by the end of the surgery) or control (saline infusion). Mean arterial pressure (MAP) and heart rate (HR) were measured before induction, during surgery operation and ICU admission. Data were analyzed by SPSS version 18 using Chi Square and independent-samples t-test.

Results

A total of 76 patients with a mean age of 59.8 ± 8.2 years (in two groups of 38) were studied. The two groups had no statistically significant difference in terms of background variables. The MAP and HR values before induction, during surgery and ICU admission were significantly higher in the control group than in the intervention group (p=0.001). Out of the studied arrhythmias, the values of PAC (55.2% vs. 15.7%), PVC (81.5% vs. 21.0%), AF (26.3% vs. 7.8%), VTAC (21.0% vs. 2.6%) were significantly lower in dexmedetomidine group (p=0.001).

Conclusion

It seems that dexmedetomidine administration during induction and surgery can cause significant reduction in most of the common arrhythmias in off-pump coronary bypass surgery. The use of dexmedetomidine maintains MAP and HR at significantly lower values, and changes compared to the control group as well as reduces the need for anesthetic compounds.

Trial Registration

The present study has been registered at the Iranian Registry of Clinical Trials (www.IRCT.IR) with a code of IRCT2016072413159N9 before starting the study.

Founding

This study was fully sponsored by the Research Deputy at Mashhad University of Medical Sciences, Iran (grant number 941413).

Randomized clinical trial of landiolol hydrochloride for the prevention of atrial fibrillation and postoperative complications after oesophagectomy for cancer

Background

Atrial fibrillation is common after oesophageal surgery. The aim of this study was to evaluate whether landiolol hydrochloride was effective and safe in the prevention of atrial fibrillation after oesophagectomy, and to see whether a reduction in incidence of atrial fibrillation would reduce other postoperative complications.

Methods

This single-centre study enrolled patients scheduled for transthoracic oesophagectomy in a randomized, double-blind, placebo-controlled trial between March 2013 and January 2016. Enrolled patients were randomized with a 1 : 1 parallel allocation ratio to either landiolol prophylaxis or placebo. The primary endpoint was the occurrence of atrial fibrillation after oesophagectomy. Secondary endpoints were incidence of postoperative complications, and effects on haemodynamic and inflammatory indices.

Results

One hundred patients were enrolled, 50 in each group. Postoperative atrial fibrillation occurred in 15 patients (30 per cent) receiving placebo versus five (10 per cent) receiving landiolol (P = 0·012). The overall incidence of postoperative complications was significantly lower in the landiolol group (P = 0·046). In the landiolol group, postoperative heart rate was suppressed effectively, but the decrease in BP was not harmful. The interleukin 6 level was significantly lower on days 3 and 5 after surgery in the landiolol group (P = 0·001 and P = 0·002 respectively).

Conclusion

Landiolol was effective and safe in preventing atrial fibrillation after oesophagectomy. Registration number: UMIN000010648 (http://www.umin.ac.jp/ctr/).

The suppressive effects of landiolol administration on the occurrence of postoperative atrial fibrillation and tachycardia, and plasma IL-6 elevation in patients undergoing esophageal surgery: A randomized controlled clinical trial

STUDY OBJECTIVE

To determine whether perioperative landiolol administration suppresses postoperative atrial fibrillation (AF) and the plasma cytokines elevation in patients undergoing esophageal cancer surgery.

DESIGN

A prospective, randomized controlled trial.

SETTING

Akita University Hospital, Akita, Japan, from April 2012 to January 2015.

PATIENTS

Forty American Society of Anesthesiologists grade I-II patients undergoing elective esophagectomy.

INTERVENTIONS

Patients were randomly divided into two groups, landiolol group (landiolol: 5μg/kg/min) and control group (the same volume of covered saline). Landiolol or saline was infused continuously from the induction of anesthesia until next morning.

MEASUREMENTS

We examined the new onset of AF and sinus tachycardia, and measured plasma concentrations of cytokines (IL-1β, IL-6, IL-8, IL-10, and TNF-α) just before surgery, at the end of surgery, the next day, and 2days after surgery. Data (mean±SD) were analyzed using two-way ANOVA followed by the Bonferroni"s test for post hoc comparison; a P<0.05 was considered statistically significant.

MAIN RESULTS

Demographic data were similar between the landiolol and the control groups. The incidence of AF was significantly lower in the landiolol group (1/19=5.3%) compared with the control group (7/20=35%) as well as sinus tachycardia (landiolol group, 0/19=0% vs. control group, 5/20=25%). Plasma IL-6 level at the end of surgery was significantly lower in the landiolol group compared with the control group, but the other plasma cytokines levels were similar between the two groups during the entire study period.

CONCLUSIONS

Perioperative landiolol administration suppressed the incidence of new-onset of AF as well as sinus tachycardia, and the plasma IL-6 elevation in patients undergoing esophageal cancer surgery.

Incidence and impact of postoperative atrial fibrillation after minimally invasive esophagectomy

Atrial fibrillation (AF) following open esophagectomy has been associated with increased rates of pulmonary and anastomotic complications, and mortality. This study seeks to evaluate effects of AF after minimally invasive esophagectomy (MIE). A retrospective review of patients consecutively treated with MIE for esophageal carcinoma, dysplasia. and benign disease from November 2006 to November 2011 was performed. One hundred twenty-one patients underwent MIE. Median age was 65 years (range 26-88) with 85% being male. Thirty-eight (31.4%) patients developed AF postoperatively. Of these 38 patients, 7 (18.4%) had known AF preoperatively. Patients with postoperative AF were significantly older than those without postoperative AF (68.7 vs. 62.8 years, P = 0.008) and more likely to be male (94.7% vs. 80.7%, P = 0.04). Neoadjuvant chemoradiation showed a trend toward increased risk of AF (73.7% vs 56.6%, P = 0.07). Sixty-day mortality was 2 of 38 (5.3%) in patients with AF and 4 of 83 (6.0%) in the no AF cohort (P = 1.00). The group with AF had increased length of hospitalization (13.4 days vs. 10.6 days P = 0.02). No significant differences in rates of pneumonia (31.6% vs. 21.7% P = 0.24), stricture (13.2% vs. 26.5% P = 0.10), or leak requiring return to operating room (13.2% vs. 8.4% P = 0.51) were noted between groups. We did not find an increased rate of AF in our MIE cohort compared with prior reported rates in open esophagectomy populations. AF did result in an increased length of stay but was not a predictor of other short-term morbidities including anastomotic leak, pulmonary complications, stenosis, or 60-day mortality.

Pathophysiology of cancer therapy-provoked atrial fibrillation

Atrial fibrillation (AF) occurs with increased frequency in cancer patients, especially in patients who undergo surgery or chemotherapy. AF disturbs the prognosis of cancer patients and challenges therapeutic outcomes of cancer treatment. Elucidating the mechanisms of cancer-induced AF would help identify specific strategies for preventing AF occurrence. In addition to concurrent risk factors of cancer and AF, cancer surgery, side effects of anticancer agents, and cancer-associated immune responses play critical roles in the genesis of AF. In this review, we provide succinct potential mechanisms of AF genesis in cancer patients.

Association between Postoperatively Developed Atrial Fibrillation and Long-Term Mortality after Esophagectomy in Esophageal Cancer Patients: An Observational Study

Background

Newly developed atrial fibrillation (AF) in patients who have undergone an esophagectomy increases the incidence of postoperative complications. However, the clinical implications of AF have not been fully elucidated in these patients. This retrospective observational study investigated the predictors for AF and the effect of AF on the mortality in esophageal cancer patients undergoing esophagectomy.

Methods

This study evaluated 583 patients undergoing esophagectomy, from January 2005 to April 2012. AF was defined as newly developed postoperative AF requiring treatment. The risk factors for AF and the association between AF and mortality were evaluated. The long-term mortality was the all-cause mortality, for which the cutoff date was May 31, 2014.

Results

AF developed in 63 patients (10.8%). Advanced age (odds ratio [OR] 1.099, 95% confidence interval [CI] 1.056–1.144, P < 0.001), preoperative calcium channel blocker (CCB) (OR 2.339, 95% CI 1.143–4.786, P = 0.020), and angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) (OR 0.206, 95% CI 0.067–0.635, P = 0.006) were associated with the incidence of AF. The Kaplan-Meier curve showed a significantly lower survival rate in the AF group compared to the non-AF group (P = 0.045), during a median follow-up of 50.7 months. The multivariable analysis revealed associations between AF and the 1-year mortality (hazard ratio [HR] 2.556, 95% CI 1.430–4.570, P = 0.002) and between AF and the long-term mortality (HR 1.507, 95% CI 1.003–2.266, P = 0.049).

Conclusions

In esophageal cancer patients, the advanced age and the preoperative medications (CCB, ACEI or ARB) were associated with the incidence of AF. Furthermore, postoperatively developed AF was associated with mortality in esophageal cancer patients after esophagectomy, suggesting that a close surveillance might be required in patients who showed AF during postoperative period.

The Influence of Perioperative Dexmedetomidine on Patients Undergoing Cardiac Surgery: A Meta-Analysis

Background

The use of dexmedetomidine may have benefits on the clinical outcomes of cardiac surgery. We conducted a meta-analysis comparing the postoperative complications in patients undergoing cardiac surgery with dexmedetomidine versus other perioperative medications to determine the influence of perioperative dexmedetomidine on cardiac surgery patients.

Methods

Randomized or quasi-randomized controlled trials comparing outcomes in patients who underwent cardiac surgery with dexmedetomidine, another medication, or a placebo were retrieved from EMBASE, PubMed, the Cochrane Library, and Science Citation Index.

Results

A total of 1702 patients in 14 studies met the selection criteria among 1,535 studies that fit the research strategy. Compared to other medications, dexmedetomidine has combined risk ratios of 0.28 (95% confidence interval [CI] 0.15, 0.55, P = 0.0002) for ventricular tachycardia, 0.35 (95% CI 0.20, 0.62, P = 0.0004) for postoperative delirium, 0.76 (95% CI 0.55, 1.06, P = 0.11) for atrial fibrillation, 1.08 (95% CI 0.74, 1.57, P = 0.69) for hypotension, and 2.23 (95% CI 1.36, 3.67, P = 0.001) for bradycardia. In addition, dexmedetomidine may reduce the length of intensive care unit (ICU) and hospital stay.

Conclusions

This meta-analysis revealed that the perioperative use of dexmedetomidine in patients undergoing cardiac surgery can reduce the risk of postoperative ventricular tachycardia and delirium, but may increase the risk of bradycardia. The estimates showed a decreased risk of atrial fibrillation, shorter length of ICU stay and hospitalization, and increased risk of hypotension with dexmedetomidine.

Incidence and Risk Factors of an Intraoperative Arrhythmia in Transhiatal Esophagectomy

BACKGROUND

Transhiatal esophagectomy (THE) is a widely used technique for carcinoma of the esophagus and other conditions, such as benign strictures and motility disorders.

OBJECTIVES

The aim of our study was to quantify the incidence, predisposing factors, as well as types of arrhythmias in transhiatal esophagectomy.

PATIENTS AND METHODS

In this prospective study, we selected 61 patients undergoing transhiatal esophagectomy during 2012 - 2013 in our hospital. The demographic information, site of the tumor, cardiopulmonary function, transfusion, preoperative and postoperative complications (i.e. arrhythmias, hypotension), operation time, duration of mediastinal manipulation, amount of hemorrhage, volume loss, volume intake, mean systolic and diastolic pressure, and death rate were evaluated by chi-square, Fisher's exact test, ANOVA, and t-tests.

RESULTS

The mean age of patients was 61.24 ± 11.48. In the study group, 8.2% of the patients before, 50.8% during, and 11.2% after mediastinal manipulation showed arrhythmia. Tumor location, the need for transfusion, pathology of the tumor, presence of arrhythmia before the operation, FEV1 (Forced Expiratory Volume) > 2 liters, and mean volume intake were significantly different between the patients with and without arrhythmia. Hypotension was shown in 8.2% of the patients before and 57.7% during mediastinal manipulation. Manipulation times, volume loss, mean systolic and diastolic blood pressure before the operation, and FEV1 > 2 liters were statistically significant in occurrence of hypotension.

CONCLUSIONS

Our data showed that the amount of hydration, transfusion, pre-manipulation arrhythmia, and pulmonary function should be controlled to decrease the risk of arrhythmias. Minor mediastinal manipulation, few intraoperative hemorrhages, improvement of pulmonary function, and careful blood pressure monitoring can reduce the risk of hypotension.

Predictive Factors of Supraventricular Arrhythmias after Noncardiac Thoracic Surgery: A Multicenter Study

<p><b>Background:</b> Supraventricular cardiac arrhythmias are the most common rhythm disturbances in patients following thoracic surgery. The purpose of our study was to determine which of the clinical parameters are the most valuable in predicting postoperative atrial fibrillation (AF) after lung surgery.</p><p><b>Methods:</b> Retrospective analysis was carried out on 987 patients after noncardiac thoracic surgery to define the prevalence, associated risk factors, and clinical course of postoperative arrhythmias. There were 822 men and 165 women, age 34 to 78 years (mean age: 61 � 8 years). The patients were divided into two groups depending on the occurrence or absence of supraventricular arrhythmia. Group I consisted of 876 patients who were free from rhythm disturbances. The remaining 111 patients exhibited episodes of supraventricular arrhythmia (29 supraventricular tachycardia; 82 AF). These 111 patients were placed in Group II. Preoperative, operative, and postoperative data were reviewed. Statistical analysis was performed.</p><p><b>Results:</b> A statistically significant difference was found between the two groups in age, previous history of heart disease, and lung resection, especially pneumonectomy. Conclusion: Age, history of prior heart disease, lung resection, and the extent of pulmonary resection are the main risk factors for postoperative supraventricular arrhythmia in patients undergoing major thoracic operations.</p>

Vagus-preserving technique during minimally invasive esophagectomy: the effects on cardiac parameters in a swine model

BACKGROUND

Cardiac complications are an important cause of morbidity and mortality observed after esophageal resections. We examined whether an high intrathoracic vagotomy during abdominothoracic esophagectomy would have an effect on intraoperative and early postoperative cardiac function in the setting of a minimally invasive resection. Two hypotheses were generated for this study: (1) Vagotomy would cause cardiac changes, and (2) vagus-preserving esophagectomy would prevent cardiac problems during resection and in the early postoperative phase.

METHODS AND RESULTS

Thirty male pigs were operated on while cardiac parameters (heart rate [HR], cardiac index [CI], preload recruitable stroke work [PRSW], contractility speed [dp/dtmax], relaxation speed [dp/dtmin], and relaxation time [tau]) were monitored using a conductance catheter and the thermodilution method. Animals were randomized into 4 groups (each n = 7): (1) control, thoracoscopy only, (2) thoracoscopy with vagotomy, (3) esophageal resection with vagotomy, and (4) esophageal resection with vagus nerve preservation. To evaluate the first hypothesis, we compared groups 1 and 2; to evaluate the second hypothesis, we compared groups 3 and 4. HR, CI, PRSW, dp/dtmax, and tau were different in the 2 groups without resection (area under the curve; each P < .05). Vagotomy with esophagectomy resulted in nonsignificant differences between groups 3 and 4. The requirement for metoprolol administration to avoid severe tachycardia was greater in the groups that underwent vagotomy (P < .05; Fisher's exact test).

CONCLUSION

An high intrathoracic vagotomy results in loss of vagal tone and a greater rate of tachycardia during thoracoscopy and esophagectomy. There were no differences, however, in cardiac dynamics between the esophagectomy groups. Thus, vagal injury is not the sole reason for cardiac dysfunction after esophagectomy.

Anesthetic management for esophageal resection

Surgical resection remains a standard treatment option for localized esophageal cancer. Surgical approaches to esophagectomy include transhiatal and transthoracic techniques as well as minimally invasive techniques that have been developed to reduce the morbidities associated with laparotomy and thoracotomy incisions. The perioperative mortality for esophagectomy remains high with cardiopulmonary and anastomotic complications as the most frequent and serious morbidities. This article reviews the management of patients presenting for esophagectomy, with a focus on evidence-based anesthetic and perioperative approaches for improving outcomes.

Patterns of operative mortality following esophagectomy

Esophagectomy has one of the highest mortality rates among all surgical procedures. We investigated the type and frequency of complications associated with perioperative mortality after esophagectomy. We performed a retrospective review of all perioperative deaths following esophagectomy for esophageal cancer at the Mayo Clinic, Rochester from 1993 through 2009. Of 1522 esophagectomies, perioperative mortality occurred in 45 (3.0%). The majority who died were male (82%); median age was 72 years (range 46-92). The median age-adjusted Charlson comorbidity score was 6. Twenty-three (51%) underwent neoadjuvant chemoradiotherapy. The type of esophagectomy was transthoracic in 27 patients (60%), transhiatal in eight (18%), tri-incisional in seven (16%), left thoracoabdominal in one (2%), and transabdominal in one (2%). A mean of 3.2 major complications occurred prior to death (median 2.5, range 1-8), with the most common being pulmonary complications occurring in 30 patients (67%) and anastomotic complications in 20 (44%). The primary underlying cause of death was pulmonary complications and anastomotic complications in 18 patients (40%) each, respectively, abdominal sepsis in three (7%), fatal hemorrhage in three (7%), and pulmonary embolism, stroke and multisystem organ failure in one each (2%), respectively. Patients died a median of 19 days (range 3-98) following esophagectomy. Most patients who died following esophagectomy experienced multiple serious complications rather than a single causative event. Major pulmonary and anastomotic complications were implicated in the vast majority of perioperative mortality, and should remain the focus of efforts to improve clinical outcomes.

Atrial fibrillation after esophagectomy: an indicator of postoperative morbidity

PURPOSE

The relevance of new-onset atrial fibrillation (AF) after esophagectomy remains poorly defined. This study's primary goal is to better define the incidence, clinical patterns, and outcomes associated with the development of AF after esophagectomy.

METHODS

The study is a retrospective review of patients undergoing esophagectomy at a single academic center between May 1996 and December 2007. Patients with new-onset AF were evaluated by univariate and multivariate analyses for risk factors associated with AF onset and outcomes.

RESULTS

New-onset AF was noted in 32 of 156 (20.5%) patients after esophagectomy. Most (16/32, 50%) developed AF within 48 h, and 28 of 32 (87.5%) developed new AF within 72 h of surgery. Pulmonary complications were more frequent in patients with AF than those without AF (59.4% vs. 15.3%, P < 0.01) and usually immediately preceded or occurred concurrently with AF. Anastomotic leaks were significantly more common in patients with AF than those without (28.1% vs. 6.45%, P < 0.01) and were identified, on average, 4.2 days after the onset of AF. In the multivariate analysis, anastomotic leaks, pulmonary complications, and number of complications were significantly associated with AF. Although 60-day survival was worse for patients developing AF (P < 0.01), multivariate analysis suggests that non-AF complications were the independent predictor of mortality.

CONCLUSION

New-onset AF after esophagectomy is associated with anastomotic leaks, pulmonary complications, and decreased 60-day survival. Although pulmonary complications typically occurred coincident with the onset of AF, anastomotic leaks were usually diagnosed 4 days after AF onset. New postesophagectomy AF should prompt vigilance for the presence of other concurrent complications.

Does the prophylactic administration of magnesium sulphate to patients undergoing thoracotomy prevent postoperative supraventricular arrhythmias? A randomized controlled trial

BACKGROUND

Supraventricular arrhythmias (SVA) are common after thoracic surgery and are associated with increased morbidity and mortality. This prospective, randomized, double-blind, placebo-controlled trial examined the effects of perioperative magnesium on the development of postoperative SVA.

METHODS

Two hundred patients undergoing thoracotomy for lobectomy, bi-lobectomy, pneumonectomy, or oesophagectomy were recruited and randomly allocated into two groups. The treatment group received magnesium (5 g daily) intraoperatively, and on days 1 and 2 after operation, the control group received placebo. The primary outcome of the study was the development of SVA within the first 5 days after operation.

RESULTS

There were 100 patients in each arm of the study, with one withdrawal and three lost to follow-up in the treatment group and four withdrawals in the control group. Ninety-six patients received magnesium and 96 received placebo. There was no difference in the incidence of SVA between the treatment and control groups, 16.7% (16/96) vs 25% (24/96), P=0.16. In the predefined subgroup analysis, patients at highest risk of arrhythmias (those undergoing pneumonectomy) had a significant reduction in the frequency of SVA, 11.1% (2/18) vs 52.9% (9/17), P=0.008. There were no differences in hospital length of stay or mortality. Patients receiving i.v. magnesium experienced a higher frequency of minor side-effects (stinging at injection site). The treatment was otherwise well tolerated.

CONCLUSIONS

Overall, prophylactic magnesium did not reduce the incidence of SVA in patients undergoing thoracotomy. However, it reduced the incidence of SVA in the high-risk cohort of patients undergoing pneumonectomy. (ISRCTN22028180.).

Multi-factor investigation of early postoperative cardiac arrhythmia for elderly patients with esophageal or cardiac carcinoma

BACKGROUND

The purpose of the present study was to analyze the risk multi-factors of postoperative cardiac arrhythmia for elderly patients with esophageal or cardiac carcinoma.

METHODS

A total of 756 operations for elderly patients (>65 years of age) with esophageal or cardiac carcinoma were performed in our department from January 1997 to December 2006. These included 197 cases (26.1%) of various types of cardiac arrhythmia after operation. Logistic regression was adopted to analyze the risk multi-factors of postoperative cardiac arrhythmia.

RESULTS

It showed that complications of other diseases before operation, selection of operation method, duration of anesthesia and operation, postoperative pain, anoxia, hypovolemia, acid-alkali disequilibrium, and electrolyte imbalance might be the risk factors of postoperative cardiac arrhythmia in elderly patients with esophageal or cardiac carcinoma, whereas minimally invasive endoscopic operation might be a protective factor.

CONCLUSIONS

In order to decrease the risk factors leading to postoperative cardiac arrhythmia for elderly patients with esophageal or cardiac carcinoma, it was necessary to completely evaluate the functions of heart and lung, improve the nutrition and metabolism of heart muscle, conduct effective breathing exercises, and correct the existing cardiac arrhythmia of such patients before operation, and perform the minimally invasive operation, shorten operation duration, relieve pain efficiently during the perioperative period, and correct hypovolemia and acid-alkali disequilibrium and electrolyte imbalance.

Atrial fibrillation following elective open abdominal aortic aneurysm repair

BACKGROUND

Atrial fibrillation is a common complication following major vascular surgery. It is often considered to be relatively benign but may represent the first sign of cardiac and non-cardiac complications. We conducted a retrospective study to determine the incidence and clinical associations of atrial fibrillation following open elective abdominal aortic aneurysm repair as well as its effect on prognosis.

METHODS

The case-notes of 200 consecutive patients undergoing open aneurysm repair were reviewed. Known pre-operative and intra-operative risk factors and potential post-operative associations with new-onset AF were recorded. Significant univariate correlates with AF were entered into a forward stepwise logistic regression model to test for independence. The effect of new-onset AF on long-term prognosis was assessed.

RESULTS

AF developed in 20 patients (10%) post-operatively. Previous cerebrovascular disease, aneurysm size and post-operative cardiac failure were associated with post-operative AF in univariate analyses. Cerebrovascular disease and post-operative cardiac failure were independently associated with new-onset AF. AF patients had a longer hospital stay. There was no difference in survival between those patients with and without new-onset AF.

CONCLUSION

New-onset AF is a common complication of open abdominal aortic aneurysm surgery and may indicate an underlying myocardial infarction. It is associated with a longer hospital stay and an increased risk of cardiac failure. Assessed and treated appropriately, it appears to have no effect on long-term prognosis.

Prevention and management of perioperative arrhythmias in the thoracic surgical population

Although bradyarrhythmias or malignant ventricular tachyarrhythmias have been reported in less than 1% of patients following noncardiac surgery, rapid atrial arrhythmias more frequently affect the elderly who undergo thoracic operations. This article focuses on new issues leading to the improved understanding of the pathophysiology and mechanisms of postoperative atrial arrhythmias. It discusses new risk factors and a prediction rule for postthoracotomy atrial fibrillation (AF), reviews prophylaxis and acute therapeutic interventions for postthoracotomy AF, and highlights the most recent recommendations of the American Heart Association Task Force on the management of patients who have AF with emphasis on preventing thromboembolic events.

Perioperative anesthetic management for esophagectomy

Esophageal resection is a formidable operation associated with high morbidity and mortality. Anesthetic management may contribute to the containment of respiratory failure and anastomotic leakage by the use of thoracic epidural analgesia, protective ventilation strategies, prevention of tracheal aspiration, and judicious fluid management.

Risk factors for an intraoperative arrhythmia during esophagectomy

PURPOSE

Arrhythmias after an esophagectomy (most commonly atrial fibrillation) are a significant contributing factor to patient morbidity. However, the significance of an intraoperative arrhythmia is not completely understood. The aim of this retrospective study was to determine the occurrence and risk factors for developing intraoperative arrhythmias in patients undergoing an esophagectomy.

MATERIALS AND METHODS

We reviewed the records of 427 patients who underwent a transthoracic esophagectomy between 2001 and 2005. Variables such as age, sex, hypertension, diabetes, cardiac disease, preoperative pulmonary function test (PFT) results, cancer level, combined radiochemotherapy, intrathoracic cavity adhesions and anastomosis site, hemoglobin, central venous pressure (CVP), fluid balance, serum potassium level, dose of vasopressors, temperature, and combined general and epidural anesthesia were analyzed as risk factors for the occurrence of an arrhythmia. We defined this arrhythmia as one not originating from the sinus node.

RESULTS

The incidence of intraoperative arrhythmia in this subset of patients was 17.1%, with a 37.2% reoccurrence rate during the first three postoperative days. Univariate and multivariate analysis revealed the presence of heart disease, poor PFTs, cervical anastomosis, elevated CVP, and higher ephedrine doses to be independent predictors of the development of an intraoperative arrhythmia.

CONCLUSION

The incidence of intraoperative arrhythmia during esophagectomy was 17.1% with a 37.2% of reoccurrence rate.

Postthoracotomy atrial fibrillation

PURPOSE OF REVIEW

Rapid atrial arrhythmias affect the elderly who undergo cardiac or noncardiac operations annually and have been associated with prolonged hospital stays. This article focuses on new issues leading to the improved understanding of the pathophysiology and mechanisms of postoperative atrial arrhythmias.

RECENT FINDINGS

New risk factors and a prediction rule for postthoracotomy atrial fibrillation are discussed. Settings in which amiodarone prophylaxis against atrial fibrillation after cardiac surgery is appropriate are contrasted with evidence for postthoracotomy atrial fibrillation. Once atrial fibrillation develops, rate versus rhythm control strategies are reviewed. The most recent recommendations of the American Heart Association Task Force on the management of patients with atrial fibrillation are highlighted.

SUMMARY

Recent approaches directed at prophylaxis and acute therapy of atrial arrhythmias are discussed as are recommendations to prevent thromboembolic events.

Cancer of the esophagus: the value of preoperative patient assessment

In the past few years, major improvements and new technologies have been proposed and applied in esophageal surgery. Its evolution depended not only on a thorough knowledge of surgical anatomy and technique, but also on important developments in pre- and postoperative care. Esophageal resection for cancer is still associated with high morbidity and mortality. Postoperative complications may be either patient or surgeon related. Patient-related factors include age, malnutrition, immunodepression and associated diseases. The surgeon-related factors are surgical experience, hospital volume and multidisciplinary approach. Preoperative evaluation is defined as the process of clinical assessment that precedes the delivery of anesthesia. The principle is to gain information concerning patients that leads to modification of their management, and improves the outcome from surgery.

Incidence and Types of Arrhythmias After Mediastinal Manipulation During Transhiatal Esophagectomy

BACKGROUND

Transhiatal esophagectomy (THE) is a common operative procedure for carcinoma esophagus. Complications of this procedure include arrhythmias and hypotension during blunt dissection of the esophagus from posterior mediastinum. In the literature, exact incidence and type of arrhythmias have not been reported. We employed Holter monitoring during mediastinal manipulation in patients undergoing THE, for this purpose.

METHODS

This prospective study was carried out in 20 consecutive American Society of Anesthesiologists grade I-II patients undergoing THE. Anesthetic technique included induction with thiopentone and maintenance with morphine, vecuronium, and isoflurane. In addition to routine parameters, Holter monitoring was undertaken to record the exact incidence and types of arrhythmias. "Premanipulation" or control period included duration of 30 minutes preceding mediastinal manipulation, while "during manipulation" or study period included the duration of mediastinal manipulation. The incidence of arrhythmias was studied for 48 hours in the postoperative period. The Fisher exact test was applied to analyze incidence of arrhythmias and hypotension.

RESULTS

Out of 20 patients, only 2 had arrhythmias in the premanipulation period, while 13 had arrhythmias during the manipulation period (p < 0.01). During the manipulation period, arrhythmias included supraventricular ectopics and ventricular ectopics in 2 patients each and a combination of both in 9 patients. Arrhythmias were transient and had no correlation with either duration or degree of hypotension in all the patients. However, there was a linear relationship between hypotension and duration of mediastinal manipulation. Two patients (10%) had atrial arrhythmias in the postoperative period.

CONCLUSIONS

In transhiatal esophagectomy, there is a significant incidence of both arrhythmias and hypotension during mediastinal manipulation. The incidence of arrhythmias can be minimized by limiting the duration of the manipulation. The incidence of postoperative arrhythmias was not significant.

Atrial fibrillation after surgery for esophageal carcinoma: Clinical and prognostic significance

AIM: To retrospectively evaluate the clinical relevance, perioperative risk factors, outcome of different pharmacological prophylaxis, and short-term prognostic value of atrial fibrillation (AF) after surgery for esophageal carcinoma.

METHODS: We retrospectively studied 63 patients with AF after surgery for esophageal carcinoma in comparison with 126 patients without AF after esophagectomy during the same time. Postoperative AF incidence was related to different clinical factors possibly involved in its occurrence and short-term survival.

RESULTS: A strong relationship was observed between AF and postoperative hypoxia, history of chronic obstructive pulmonary disease (COPD), postoperative thoracic–gastric dilatation, age older than 65 years, male sex and history of cardiac disease. No difference was observed between the two groups with regard to short-term mortality and length of hospital stay.

CONCLUSIONS: AF occurs more frequently after esophagectomy in aged and male patients. Other factors contributing to postoperative AF are history of COPD and cardiac disease, postoperative hypoxia and thoracic–gastric dilatation.

Supraventricular tachyarrhythmia as early indicator of a complicated course after esophagectomy

In a group of 89 consecutive patients with a standardized operative procedure, the incidence of supraventricular tachyarrhythmia (SVT), predisposing risk factors (preoperative and intraoperative factors and parameters of intensive care strategy) and therapeutic strategies were evaluated. Operative treatment consisted of transthoracic esophagectomy, gastric interposition and intrathoracic anastomosis. Overall hospital mortality was 6.7%. In 32 (37%) patients a new onset SVT occurred. Age and elevated body temperature were the only significant risk factor for SVT in the multivariate analysis, their odds ratios being 1.3 for each year above 58 and 5.6 for each degree above 37.8 degrees C, respectively. Secondary risk factors were history of hypertension and use of epinephrine, the corresponding odds ratios being 6.6 and 10.2. Digitalis (2/32) and calcium-antagonists (2/9) were unsatisfactory, while beta-blockers (13/20) and amiodarone (12/12) were efficient therapeutic agents. Incidence of SVT was significantly correlated with the development of postoperative septic complications.

Risk factors associated with atrial fibrillation after noncardiac thoracic surgery: analysis of 2588 patients

OBJECTIVE

The purpose of this study was to identify risk factors associated with the onset of atrial fibrillation after thoracic surgery to allow more targeted interventions in patients with the highest risk.

METHODS

A comprehensive prospective database was used to identify patients undergoing major thoracic surgery from January 1, 1998, through December 31, 2002. Data collection was performed at point of contact: at preoperative evaluation, the time of the operation, discharge, and postoperative visits. All patients undergoing resection of a lung, the esophagus, the chest wall, or a mediastinal mass were included in this study. Univariate and multivariate analyses of factors associated with the development of atrial fibrillation were analyzed.

RESULTS

There were 2588 patients who met the inclusion criteria. The overall incidence of atrial fibrillation was 12.3% (n = 319). Categories of disease were primary lung cancer, pulmonary metastasis, esophageal cancer, intrathoracic metastasis, benign lung disease, other mediastinal tumors, mesothelioma, chest wall tumors, benign esophagus, and "other." Patients with atrial fibrillation had increased mean lengths of hospital stay, mortality rates, and mean hospital charges. Univariate analysis evaluated age, sex, disease category, comorbidities, preoperative therapy, and procedure, and significant variables were entered into the multivariate analysis. Significant variables (relative risk; 95% confidence interval) in the multivariate analysis were male sex (1.72; 1.29-2.28), age 50 to 59 years (1.70; 1.01-2.88), age 60 to 69 years (4.49; 2.79-7.22), age 70 years or greater (5.30; 3.28-8.59), history of congestive heart failure (2.51; 1.06-6.24), history of arrhythmias (1.92; 1.22-3.02), history of peripheral vascular disease (1.65; 0.93-2.92), resection of mediastinal tumor or thymectomy (2.36; 0.95-5.88), lobectomy (3.89; 2.19-6.91), bilobectomy (7.16; 3.02-16.96), pneumonectomy (8.91; 4.59-17.28), esophagectomy (2.95; 1.55-5.62), and intraoperative transfusions (1.39; 0.98-1.98).

CONCLUSIONS

The significant variables identified by means of multivariate analysis were associated with the occurrence of atrial fibrillation. Preventive therapies in selected populations might reduce the incidence of atrial fibrillation.

The effects of advanced age on the incidence of supraventricular arrhythmias after pneumonectomy in dogs

Because advanced age is the strongest independent risk factor for the development of supraventricular arrhythmias after lung resection, we compared the incidence and premorbid events of supraventricular arrhythmias after pneumonectomy in young and elderly dogs with the aim of better understanding potential age-related arrhythmogenic mechanisms. Right pneumonectomy was performed in 15 male mongrel dogs ("old" > or =8 yr [n = 8], "young" <4 yr [n = 7]) and the electrocardiogram continuously recorded by an implantable telemetry system for 1 wk before euthanizing. After surgery, 7 of 8 older animals (88%) developed a total of 23 episodes of sustained (>30 s) paroxysmal supraventricular tachycardia (SVT), compared with 0 of 7 (0%) young dogs, P = 0.0014. Analysis of heart rate over the 60 min preceding the onset of SVT revealed a progressive increase in sinus rhythm beginning 15 min before the arrhythmia. Comparison of the heart rate and rhythm obtained in younger animals from the corresponding postoperative hour demonstrated that although older animals developed more atrial (P = 0.03) and ventricular premature contractions (P = 0.056) and episodes of nonsustained ventricular tachycardia (P = 0.01), heart rate was similar for both groups until the increase in elderly dogs preceding the onset of SVT. Histologic examination of the atria showed interstitial fibrosis in old but not young animals. In addition, 4 of 8 (50%) elderly animals exhibited an inflammatory response within the atria consistent with acute myo- and epicarditis. We conclude that elderly dogs have an increased supraventricular arrhythmogenic potential within the first week after pneumonectomy than younger animals, perhaps because of increased atrial fibrosis and inflammation. Heart rate analysis before SVT onset suggests that adrenergic predominance was a probable responsible trigger.

IMPLICATIONS

In this canine pneumonectomy model, advanced age was associated with an increased incidence of supraventricular arrhythmias, perhaps because of increased atrial fibrosis and inflammation.

Cardiac arrhythmias in cardiothoracic surgery

Most patients with cardiopulmonary disease are predisposed to develop perioperative arrhythmias with the individual patient risk depending upon the type of operative procedure performed, the risk profile of the patient, and the complexity of the post-operative course. There are several management options that may tend to prevent perioperative arrhythmias that should be considered in certain patient subsets. Most important of these is the use of beta-blocker therapy before and after operation in patients with coronary risks factors undergoing non-cardiac thoracic procedures and in patients having coronary artery bypass grafting. The common supraventricular arrhythmias including atrial fibrillation and flutter, multifocal atrial tachycardia, and paroxysmal supraventricular tachycardia must be properly diagnosed and treated appropriately. Placement of atrial pacing wires for use after open cardiac surgery is of great value both for diagnosis, and in some cases, for treatment of arrhythmias. Fortunately, serious life threatening ventricular arrhythmias occurs less commonly but the clinician must recognize and correct important predisposing factors and know how to treat these when they occur. A specific protocol for arrhythmia management that sets guidelines for drug choice and therapies for each of the common arrhythmias is useful for clinicians and adds predictability to patient care.

Postoperative atrial fibrillation

Postoperative atrial fibrillation is associated with significant morbidity, longer hospital stay, and higher related costs. Although the etiologic mechanism of postoperative atrial fibrillation and its optimum method of prophylaxis or management are not well defined, progress has been made during the past decade. This review focused on recent findings leading to a better understanding of the mechanisms and management of atrial fibrillation after surgery and current approaches directed at prevention of thromboembolic sequelae. Because postoperative atrial fibrillation is a frequent complication, preoperative risk assessment algorithms are being proposed to minimize the number of patients in whom an intervention to prevent atrial fibrillation is undertaken, and thus, reduce toxicity due to antiarrhythmic drug therapy. Finally, current data suggest that once atrial fibrillation has occurred, a rate-control strategy during the first 8 to 12 hours is reasonable because 50% of those episodes will resolve during this period. Beyond this period, a more aggressive approach using class IC or III antiarrhythmic drugs will hopefully reduce the number of patients requiring anticoagulation and prolonged drug therapy.

Postoperative arrhythmias and conduction disorders

Cardiac arrhythmias are common in the perioperative period. Most arrhythmias are clinically benign. Occasionally, cardiac arrhythmias and conduction disturbances can pose a major additional risk to the patient in the perioperative and postoperative periods. The current availability of a wide array of techniques for controlling serious arrhythmias--pharmacologic, electrical, and interventional--enable the physician to manage most arrhythmias and conduction disturbances successfully. The added risks posed by arrhythmias and conduction disturbances in the perioperative period now can be minimized.