Selective versus non-selective antiarrhythmic approach for prevention of atrial fibrillation after coronary surgery: is there a need for pre-operative risk stratification? A prospective placebo-controlled study using low-dose sotalol

Prevention of Atrial Fibrillation After Cardiac Surgery: A Review of Literature and Comparison of Different Treatment Modalities

Atrial fibrillation is the most common arrhythmia to occur after cardiac surgery, with an incidence of 10% to 50%. It is associated with postoperative complications including increased risk of stroke, prolonged hospital stays and increased costs. Despite new insights into the mechanisms of atrial fibrillation, no specific etiologic factor has been identified as the sole perpetrator of the arrhythmia. Current evidence suggests that the pathophysiology of atrial fibrillation in general, as well as after cardiac surgery, is multifactorial. Studies have also shown that new-onset postoperative atrial fibrillation following cardiac surgery is associated with a higher risk of short-term and long-term mortality. Furthermore, it has been demonstrated that prophylactic medical therapy decreases the incidence of postoperative atrial fibrillation after cardiac surgery. Of note, the incidence of postoperative atrial fibrillation has not changed during the last decades despite the numerous preventive strategies and operative techniques proposed, although the perioperative and postoperative care of cardiac patients as such has improved.

Left Volume Atrial Index and P-wave Dispersion as Predictors of Postoperative Atrial Fibrillation After Coronary Artery Bypass Graft: A Retrospective Cohort Study

Preoperative left atrial remodeling as Postoperative atrial fibrillation (POAF) predisposing factors could be measured by left atrial volume index (LAVI) and P-wave dispersion. This study aimed to assess P-wave dispersion and LAVI as preoperative predictors of POAF among patients who underwent Coronary Artery Bypass Graft (CABG). An analytical retrospective cohort study was performed on patients who underwent CABG. The P-wave dispersion and POAF were evaluated based on documented ECG results. LAVI size was collected from echocardiographic reports. Hazard ratios of P-wave dispersion and LAVI for POAF were analyzed using Cox proportional hazard model. A total of 42 subjects (57 ± 1 years) were included in this study. POAF occurred in 28.6% of patients at a median of 2 days after CABG. P-wave dispersion was significantly longer in patients in whom AF was developed (53.03 ± 3.82 ms vs 44.01 ± 1.98ms, p:0.028), while LAVI difference was not significant. The Cox proportional hazard model showed a significant association between P-wave dispersion and risk of POAF (HR 1.05, CI95%, 1.001-1.103; P = 0.048). There was no association between LAVI and risk of POAF (HR 1.003, CI 95%, 0.965-1.044; P = 0.864). P-wave dispersion is a predictor of POAF in patients who underwent CABG. Risk stratification using P-wave dispersion enables clinicians to identify high-risk patients before CABG surgery.

Predicting atrial fibrillation after cardiac surgery: a scoping review of associated factors and systematic review of existing prediction models

INTRODUCTION

Postoperative atrial fibrillation (POAF) is common after cardiac surgery and associated with increased hospital length of stay, patient morbidity and mortality. We aimed to identify factors associated with POAF and evaluate the accuracy of available POAF prediction models.

METHODS

We screened articles from Ovid MEDLINE® and PubMed Central® (PMC) and included studies that evaluated risk factors associated with POAF or studies that designed or validated POAF prediction models. We only included studies in cardiac surgical patients with sample size n ⩾ 50 and a POAF outcome group ⩾20. We summarised factors that were associated with POAF and assessed prediction model performance by reviewing reported calibration and discriminative ability.

RESULTS

We reviewed 232 studies. Of these, 142 fulfilled the inclusion criteria. Age was frequently found to be associated with POAF, while most other variables showed contradictory findings, or were assessed in few studies. Overall, 15 studies specifically developed and/or validated 12 prediction models. Of these, all showed poor discrimination or absent calibration in predicting POAF in externally validated cohorts.

CONCLUSIONS

Except for age, reporting of factors associated with POAF is inconsistent and often contradictory. Prediction models have low discrimination, missing calibration statistics, are at risk of bias and show limited clinical applicability. This suggests the need for studies that prospectively collect AF relevant data in large cohorts and then proceed to validate findings in external data sets.

The effect of recanalization of a chronic total coronary occlusion on P-wave dispersion

Introduction: P-wave dispersion (PWD) obtained from the standard 12-lead electrocardiography (ECG) is considered to reflect the homogeneity of the atrial electrical activity. The aim of this investigation was to evaluate the effect of percutaneous chronic total occlusion (CTO) revascularization on the parameters of P wave duration and PWD on ECG in cases before and after procedure at 12^th months.

Methods: We analyzed 90 consecutive CTO cases who were on sinus rhythm and underwent percutaneous coronary intervention (PCI). P-wave maximum (P_-max) and P-wave minimum (P_-min), P-wave time, and PWD were determined before and twelve months after the CTO intervention. The study population was categorized into two groups as successful and unsuccessful CTO PCI groups.

Results: The CTO PCI was successful in 71% of cases (n=64) and it was unsuccessful in 29% of cases (n=26). Both groups, except for age and hypertension, were similar in terms of demographic and clinical aspects. CRP levels were significantly elevated in the unsuccessful CTO PCI group. Pre-PCI ECG parameters showed no significant difference. Irrespective of the target vessel revascularization, we observed that PWD and P_-max values were significantly lower in the 12^th months follow-up. In all Rentrop classes, PWD values were significantly decreased at 12^th months follow-up in comparison to the pre-CTO PCI values.

Conclusion: This study has determined that PWD and P_-max, which are both risk factors for atrial arrhythmias, are significantly reduced within 12^th months after successful CTO PCI regardless of the target vessel.

P-wave dispersion: What we know till now?

P-wave dispersion is defined as the difference between the maximum and the minimum P-wave duration recorded from multiple different-surface ECG leads. It has been known that increased P-wave duration and P-wave dispersion reflect prolongation of intraatrial and interatrial conduction time and the inhomogeneous propagation of sinus impulses, which are well-known electrophysiologic characteristics in patients with atrial arrhythmias and especially paroxysmal atrial fibrillation. Extensive clinical evaluation of P-wave dispersion has been performed in the assessment of the risk for atrial fibrillation in patients without apparent heart disease, in hypertensives, in patients with coronary artery disease, in patients undergoing coronary artery bypass surgery, in patients with congenital heart diseases, as well as in other groups of patients suffering from various cardiac or non-cardiac diseases. In this paper, we aimed to summarize the measurement methods, current use in different clinical situations, strengths and limitations of the of P-wave dispersion.

Pharmacological strategies for prevention of postoperative atrial fibrillation

Atrial fibrillation (AF) complicating cardiac surgery continues to be a major problem that increases the postoperative risk of stroke, myocardial infarction, heart failure and costs and can affect long-term survival. The incidence of AF after surgery has not significantly changed over the last two decades, despite improvement in medical and surgical techniques. The mechanism and pathophysiology underlying postoperative AF (PoAF) is incompletely understood and results from a combination of acute and chronic factors, superimposed on an underlying abnormal atrial substrate with increased interstitial fibrosis. Several anti-arrhythmic and non-anti-arrhythmic medications have been used for the prevention of PoAF, but the effectiveness of these strategies has been limited due to a poor understanding of the basis for the increased susceptibility of the atria to AF in the postoperative setting. In this review, we summarize the pathophysiology underlying the development of PoAF and evidence behind pharmacological approaches used for its prevention in the postoperative setting.

Infliximab, an anti-TNF-alpha agent, improves left atrial abnormalities in patients with rheumatoid arthritis: preliminary results

Background

Rheumatoid arthritis (RA) is associated with increased cardiovascular morbidity and mortality. In the current prospective study, we addressed the impact of RA on left atrial (LA) function and electrical remodelling. Further, we tried to demonstrate the effects of infliximab, an anti-TNFalpha agent, on echocardiographical LA abnormality in RA patients with preserved left ventricular (LV) ejection fraction.

Methods

We compared 38 female RA patients without clinical evidence of heart disease and 30 female controls without RA and clinical evidence of heart disease. Further, we compared RA patients receiving infliximab and increasing doses of prednisolone over a three-month period. At baseline and post treatment, this study assessed (1) LA and LV parameters using conventional and speckle tracking echocardiography (STE), and (2) electrocardiographic P-wave changes.

Results

The values of C-reactive protein (CRP), isovolumic relaxation time (IVRT), A wave, and deceleration time (DT) were significantly higher in RA patients compared to the control group (p < 0.05), whereas E/E′ and E/A values were found to be lower (p < 0.05) in RA patients. E/E′ values were lower in prednisolone- compared to infliximab-treated patients (p < 0.05). After three months of infliximab and prednisolone treatment, CRP and disease activity score (DAS 28) values decreased in both groups (p < 0.05), and Duke activity status index (DASI) increased (p < 0.05). Maximal left atrial volume index (LAVI_max), pre-contraction left atrial volume index (LAVI_preA) and maximum P wave (P_max) of the RA patients were higher compared to the control group (p < 0.05), whereas LA global strain was found to be lower (p < 0.05). There was no difference in P_max values between groups before and after the treatment period. E/E′, LAVI_max and LAVI_preA values of infliximab-treated patients decreased and LA global strain increased after three months of therapy compared to baseline (p < 0.05). At baseline in both treatment groups, E/E′ and LA global late diastolic strain rate were lower in prednisolone-compared to infliximab-treated patients (p < 0.05).

Conclusion

There was echocardiographic LA abnormality in these RA patients. In this patient group there was also a meaningful increase in maximum P wave assessed by electrocardiography. Infliximab therapy for a period of three months improved LA abnormality.

Postoperative hyperglycemia and atrial fibrillation after coronary artery bypass graft surgery

BACKGROUND

Postoperative atrial fibrillation (AF) is a common complication following coronary artery bypass grafting (CABG). We investigated the risk factors for postoperative AF and analyzed the relationship between blood sugar concentration (BS) and AF after CABG.

METHODS AND RESULTS

A total of 199 consecutive patients who underwent isolated CABG were retrospectively examined and classified according to the presence (n=95) or absence (n=104) of postoperative AF. On univariate analysis mean postoperative BS (P<0.001), postoperative drainage volume (P<0.001), age (P=0.034), presence of diabetes mellitus (DM; P=0.004), and postoperative estimated glomerular filtration rate (P=0.032) were significant risk factors for postoperative AF. On multivariate analysis mean postoperative BS (OR, 1.041; 95% CI: 1.008-1.079; P<0.001), postoperative drainage volume (OR, 1.003; 95% CI: 1.001-1.006; P=0.001), and age (OR, 1.040; 95% CI: 1.002-1.083; P=0.041) were significant risk factors for postoperative AF. Postoperative AF often occurred in patients with high postoperative BS, irrespective of DM. The BS cut-off that predicted postoperative AF occurrence was 180 mg/dl. A strong positive correlation existed between the time of the maximum postoperative BS and AF onset time (ρ=0.746).

CONCLUSIONS

Mean postoperative BS and postoperative drainage volume are risk factors for AF after CABG. AF was strongly associated with maximum postoperative BS. Intensive glycemic control could reduce AF occurrence after CABG.

Postoperative atrial fibrillation: incidence, mechanisms, and clinical correlates

Atrial fibrillation is the most commonly encountered arrhythmia after cardiac surgery. Although usually self-limiting, it represents an important predictor of increased patient morbidity, mortality, and health care costs. Numerous studies have attempted to determine the underlying mechanisms of postoperative atrial fibrillation (POAF) with varied success. A multifactorial pathophysiology is hypothesized, with inflammation and postoperative β-adrenergic activation recognized as important contributing factors. The management of POAF is complicated by a paucity of data relating to the outcomes of different therapeutic interventions in this population. This article reviews the literature on epidemiology, mechanisms, and risk factors of POAF, with a subsequent focus on the therapeutic interventions and guidelines regarding management.

Electrocardiographic P-wave Indices as a Useful Tool to Predict Successful Percutaneous Balloon Mitral Valvotomy in Patients with Mitral Stenosis

Introduction : Patients with hemodynamically significant mitral stenosis (MS) have prolonged P-wave duration and increased P-wave dispersion (PWD) that decrease after successful percutaneous balloon mitral valvotomy (PBMV). The purpose of this study was to investigate if the changes in these indices may predict a successful procedure. Methods : Fifty two patients with MS in sinus rhythm underwent PBMV (90.4% female; mean age 38±10 years). Mitral valve area (MVA), valve score, mean diastolic mitral gradient (mMVG), mitral regurgitation severity, and systolic pulmonary artery pressure (sPAP) were evaluated by echocardiography before PBMV and repeated after one month. P-wave duration (Pmax /Pmin) and PWD were measured before and immediately after PBMV, at discharge, and at the end of the first month after discharge. Results : Among all procedures, 38 (73.1%) were defined as successful. Mean age, valve score, mMVG, and MVA before PBMV were similar for both groups. MVA was significantly greater in the successful PBMV group (1.65±0.27 vs. 1.41±0.22; P= 0.003). sPAP was reduced after PBMV in all patients and there were no significant differences in the mean sPAP before and after PBMV in both successful and unsuccessful groups. Pmax and PWD were significantly decreased immediately after the procedure (P= 0.035), the next day (P= 0.005) and at one month (P= 0.002) only in patients with successful PBMV. Pmin did not change significantly in either group. Conclusion : Only is successful PBMV associated with a decrease in Pmax and PWD. These simple electrocardiographic indices may predict the success of the procedure immediately after PBMV.

Bedside tool for predicting the risk of postoperative atrial fibrillation after cardiac surgery: the POAF score

Background

Atrial fibrillation (AF) remains the most common complication after cardiac surgery. The present study aim was to derive an effective bedside tool to predict postoperative AF and its related complications.

Methods and Results

Data of 17 262 patients undergoing adult cardiac surgery were retrieved at 3 European university hospitals. A risk score for postoperative AF (POAF score) was derived and validated. In the overall series, 4561 patients (26.4%) developed postoperative AF. In the derivation cohort age, chronic obstructive pulmonary disease, emergency operation, preoperative intra‐aortic balloon pump, left ventricular ejection fraction <30%, estimated glomerular filtration rate <15 mL/min per m² or dialysis, and any heart valve surgery were independent AF predictors. POAF score was calculated by summing weighting points for each independent AF predictor. According to the prediction model, the incidences of postoperative AF in the derivation cohort were 0, 11.1%; 1, 20.1%; 2, 28.7%; and ≥3, 40.9% (P<0.001), and in the validation cohort they were 0, 13.2%; 1, 19.5%; 2, 29.9%; and ≥3, 42.5% (P<0.001). Patients with a POAF score ≥3, compared with those without arrhythmia, revealed an increased risk of hospital mortality (5.5% versus 3.2%, P=0.001), death after the first postoperative day (5.1% versus 2.6%, P<0.001), cerebrovascular accident (7.8% versus 4.2%, P<0.001), acute kidney injury (15.1% versus 7.1%, P<0.001), renal replacement therapy (3.8% versus 1.4%, P<0.001), and length of hospital stay (mean 13.2 versus 10.2 days, P<0.001).

Conclusions

The POAF score is a simple, accurate bedside tool to predict postoperative AF and its related or accompanying complications.

How valuable is P-wave dispersion in the determination of carboxyhemoglobin levels?

Objective:

To determine whether or not wave/interval dispersions in electrocardiography (ECG) are increased, and to define whether wave and interval dispersions are correlated with carboxyhemoglobin (COHb) levels.

Methods:

ECG, complete blood count, and biochemical parameters were taken from 87 patients with carbon monoxide (CO) poisoning as well as 90 control patients with similar age, gender, and body mass index distribution. COHb levels were recorded in CO-poisoning patients. The COHb levels and the relationships with ECG parameters were studied.

Results:

Pmax, Pmin, Pd, PRmax, PRmin, PRd, QTmax, QTmin, QTd, cQTmax, cQTmin, cQTd, Tmax, Tmin, and Td in ECG were higher in intoxicated patients than the control group ( p < 0.05 for all). Pearson’s correlation analyses showed moderately significant positive correlations between COHb level and Pmax ( r = 0.224; p = 0.037) and Pd ( r = 0.222; p = 0.039). The receiver–operator characteristic (ROC) curve showed that a Pd value of 38 ms determined by ECG separates patients with a COHb ≥ 20% with area under the ROC curve of 0.78 (95%CI = 0.71–0.83), a sensitivity of 67.9% (95%CI = 59.4–75.6), a specificity of 95% (95%CI = 83.0–99.2], a positive predictive value of 97.9% (95%CI = 92.5–99.7), and a negative predictive value of 46.3% (95%CI = 35.3–57.7.)

Conclusion:

A significant increase in wave/interval dispersions in the ECG of CO-poisoning patients compared with controls may show that not only a part is affected but both atrium and the ventricles as a whole are affected by hypoxic ischemia. When COHb levels of the patients are unavailable, P dispersion on ECG may show CO poisoning level of the patient.

Evaluation of atrial conduction features with tissue Doppler imaging in patients with chronic obstructive pulmonary disease

BACKGROUND

The electrical activity of atria can be demonstrated by P waves on surface electrocardiogram (ECG). Atrial electromechanical delay (AEMD) measured with tissue Doppler imaging (TDI) echocardiography can be a useful non-invasive method for evaluating atrial conduction features. We investigated whether AEMD is prolonged in patients with chronic obstructive pulmonary disease (COPD).

PATIENTS AND METHODS

Study consisted of 41 (15 female, 26 male, mean age 62 + 12 years) patients with COPD and 41 healthy subjects. Pulmonary function tests,12 lead surface ECG and echocardiographic examination were performed and recorded. P wave changes on surface ECG, minimum (P (min)) and maximum (P (max)) duration of P wave and its difference as P wave dispersion (P (wd)) were measured and recorded. Atrial electromechanic delay (AEMD) was calculated from colored-TDI recordings.

RESULTS

Pulmonary functions were significantly lower in COPD group than the control group as expected. Right atrial areas and pulmonary arterial systolic pressures (PAP) were significantly higher in COPD group than the controls (right atrial area: 11.9 ± 3.4 cm(2) and 8.2 ± 2.2 cm(2), p < 0.0001 and PAP: 38.4 ± 12.2 and 19.0 ± 3.2 mmHg p < 0.0001, respectively). P wave intervals on surface ECG were significantly increased in COPD patients than the control group (P (max): 105 ± 11 and 90 ± 12 ms, p < 0.0001; P (min): 60 ± 12 and 51 ± 10 ms, p = 0.003 and P (wd): 39 ± 10 and 31 ± 7 ms, p < 0.0001). According to the AEMD measurements from different sites by TDI, there was a significant delay between the onset of the P wave on surface ECG and the onset of the late diastolic wave in patients with COPD when compared with controls measured from tricuspid lateral septal annulus (TAEMD) (COPD: 41.3 ± 9.8 ms, control: 36 ± 4.5 ms; p = 0.005). There was a positive correlation between TAEMD and right atrial area (r = 0.63, p < 0.0001) and also between TAEMD and PASP (r = 0.43, p < 0.0005) and a negative correlation between TAEMD and forced expiratory volume (FEV1) (r = -0.44, p = 0.04).

CONCLUSIONS

Right atrial electromechanical delay is significantly prolonged in patients with COPD. The right atrial area, PAP and FEV1 levels are important factors of this prolonged delay. Also the duration of atrial depolarization is significantly prolonged and propagation of depolarization is inhomogeneous in patients with COPD. These may be the underlying mechanisms to explain the atrial premature beats, multifocal atrial tachycardia, atrial flutter and fibrillation often seen in patients with COPD secondary to these changes.

Evaluation of the relationship between atrial septal aneurysm and cardiac arrhythmias via P-wave dispersion and signal-averaged P-wave duration

OBJECTIVE

The aim of the study was to investigate the relationship between atrial septal aneurysms (ASAs) and cardiac arrhythmias via signal-averaged P-wave duration (SAPWD) and P-wave dispersion (Pd).

METHODS

Sixty-six patients with ASA served as the study group (group 1; 28 men and 38 women; mean age, 34 +/- 10 years) and 62 healthy volunteers served as the control group (group 2; 29 men and 33 women; mean age, 31 +/- 8 years) in the current study. ASAs were diagnosed by transthoracic echocardiography based on the criteria of a minimal aneurysmal base of > or =15 mm; and an excursion of > or =10 mm. All subjects were evaluated by 24-hour Holter monitoring, 12 lead body surface electrocardiogram for P-wave analysis, and signal-averaged electrocardiogram for P-wave duration (PWD).

RESULTS

There was no significant difference between the study and control groups in terms of age, gender, left atrium diameter, and left ventricular ejection fraction. Supraventricular arrhythmias (SVAs) were detected in 29 patients with ASA (43.9%) and 5 controls (8.1%; P < 0.001). The mean Pd in patients with ASA was significantly longer compared to the control group (14.1 +/- 8 ms vs 7.0 +/- 2.9 ms; P < 0.001). Similarly, the mean SAPWD in group 1 was significantly longer compared to group 2 (127.4 +/- 17.6 ms vs 99.8 +/- 12.3 ms; P < 0.001).

CONCLUSION

Prolonged SAPWD and Pd were determined to indicate electrical disturbances in the atrial myocardium, and predict the increase in the prevalence of SVA in patients with ASA.

Left-ventricular electromechanical delay is prolonged in patients with postoperative atrial fibrillation

OBJECTIVE

Although several risk factors for postoperative atrial fibrillation (AF) have been proposed, it remains the most common complication after cardiac surgery, even in low-risk patients. There is still no single reliable and reproducible parameter for predicting AF, and no standardized recommendation exists for this issue. Electromechanical delay (excitation-contraction coupling delay) is the time delay from the electrical activation to the actual systolic motion, and it reflects abnormality in calcium-handling proteins, which is considered one mechanism of postoperative AF. We hypothesized that left-ventricular electromechanical delay (LVEMD) is correlated to postoperative AF and serially examined it by echocardiography.

METHODS

We prospectively included 16 patients with relatively low risk for AF, who underwent cardiac surgery. The inclusion criteria were younger than 80 years, an ejection fraction greater than 45%, a left-atrial dimension less than 50mm, and a brain natriuretic peptide (BNP) value less than 250 pg ml⁻¹. Postoperative AF for 10 postoperative days was monitored by 24-h electrocardiogram. The LVEMD was assessed by pulse-wave tissue Doppler echocardiography before and 1, 3, and 7 days after the operation. Serum BNP, adrenalin, and noradrenalin levels were also examined at the same time.

RESULTS

Postoperative AF was detected in six (37.5%) patients. There was no significant difference in heart rate, QRS duration, and serum hormones between the non-AF (n = 10) and AF (n = 6) groups. Although the preoperative LVEMD was comparable, that on postoperative day 1 of the AF group was significantly longer than that of the non-AF group (in the septal wall, 174 ± 50 vs 101 ± 36 ms, p = 0.020; in the lateral wall, 195 ± 71 and 111 ± 37 ms, p = 0.029). A LVEMD on postoperative day 1 greater than 150 ms well predicted postoperative AF (sensitivity, 75% and 75%; specificity, 100% and 86%, in septal and lateral LVEMDs, respectively).

CONCLUSIONS

LVEMD is prolonged in patients with postoperative AF. This could be a new predicting parameter for AF in low-risk patients.

Effect of low-dose landiolol, an ultrashort-acting beta-blocker, on postoperative atrial fibrillation after CABG surgery

OBJECTIVE

Postoperative atrial fibrillation is the most common complication after coronary artery bypass grafting (CABG). This complication is associated with prolongation of the intensive care unit stay and hospitalization time with attendant increased hospitalization costs, and it is an important risk factor for perioperative cerebrovascular accidents. Landiolol is a newly developed ultrashort-acting beta-adrenoceptor antagonist with a half-life of 3 min that is eight times more cardioselective than esmolol. The purpose of this study was to investigate the prophylactic effect of continuous administration of low-dose landiolol on postoperative atrial fibrillation.

METHODS

We reviewed all patients who underwent CABG alone at our hospital from April 2002 and September 2006. Patients with a previous history of atrial arrhythmias were excluded. The remaining patients were divided to two groups: landiolol group (n = 20), and control group (n = 35). Administration of landiolol started after cardiopulmonary bypass with a loading dose of 1.5-2.5 mug.kg(t-1).min(-1) and continued for the first 2 days after surgery. The incidence of postoperative atrial fibrillation was noted. Continuous variables were compared between groups by means of Student's t-test. Categorical variables were compared by means of the chi(2) test or Fisher's exact test.

RESULTS

The occurrence of atrial fibrillation after CABG in the control group was statistically more than in the landiolol group (P = 0.04). There were no statistical differences between the groups regarding the cardiac index or the dose of inotropic agents during the perioperative period.

CONCLUSION

Intraoperative and perioperative administration of low-dose landiolol has a preventive effect on the appearance of atrial fibrillation after CABG surgery.

Global T-wave inversion: limited QT dispersion despite QTc prolongation--a correlate of benignity in patients with strikingly abnormal electrocardiograms

BACKGROUND

The global T-inversion (GTI) electrocardiogram (ECG) is strikingly abnormal with major QTc prolongation, but with a surprisingly good prognosis by Kaplan-Meier curve. This contrasts with most significant QTc prolongations.

HYPOTHESIS

This study was undertaken to ascertain QT interval dispersion (QTd) in global T wave inversion, a clinically benign long QTc ECG.

METHODS

Longest and shortest QT intervals in all 12 leads in 35 consecutive patients with GTI were determined by two mutually blinded observers. QTd was determined by subtraction (maximum-minimum) and QTc was calculated using the Bazett formula.

RESULTS

There was a 2:1 female preponderance QTc was prolonged and equal for men (0.471) and women (0.469). Observer variability of under 2% permitted averaging of QT measurements. Composite mean QTd was 55 ms. The literature revealed a range of QTd in normal subjects of 39 to 59 ms (mostly 49 to 59 ms). Patient series with abnormal QTd were well above this level.

CONCLUSION

Despite a strikingly abnormal ECG with marked QTc prolongation, QT dispersion was limited in global T inversion, consistent with its previously demonstrated benignity.

Assessment of P-wave duration and dispersion in patients with isolated coronary artery ectasia

INTRODUCTION

Coronary artery ectasia (CAE) is defined as localized or diffuse dilatation of the epicardial coronary arteries. We sought to determine whether isolated CAE may alter P-wave duration and dispersion (PD).

METHODS

The study population consisted of 26 patients (mean age: 61.6+/-11.0 years) with isolated CAE (group 1) and sex- and age-matched 26 control subjects (group 2). Both groups underwent a standard 12-lead surface electrocardiogram recorded at 50 mm/s. Maximal (P(max)) and minimal P-wave durations (P(min)) are measured. PD was defined as the difference between P(max) and P(min).

RESULTS

In group 1, P(max) (114.2+/-10.4 ms vs 104.8+/-10.6 ms, p<0.002) and PD (34.0+/-12.7 ms vs 24+/-10.6, p<0.004) were significantly higher than those of group 2. Moreover a significant correlation was found between P(max) and PD with ectatic segment number (r=0.625, r=0.626, respectively; p=<0.001); and P(max) and PD with ectatic vessel number (r=0.698, r=0.704 respectively; p=<0.0001).

CONCLUSION

Isolated CAE and the degree of the ectasia were found to be associated with prolonged P(max) and PD.

The increase in P-wave dispersion is associated with the duration of disease in patients with Behçet's disease

AIM

P-wave dispersion (PD) has been reported to be associated with inhomogeneous and discontinuous propagation of sinus impulses. Behçet's disease (BD) is a chronic multi-system disease presenting with recurrent oral and genital ulceration, and relapsing uveitis. Left ventricular diastolic dysfunction, ventricular arrhythmia and sudden cardiac death have been documented in Behçet's disease. The aim of this study was to evaluate myocardial involvement noninvasively in patients with BD by measuring PD.

METHODS

Study population included 29 patients with BD (group I), (16 males, mean age: 60.4+/-10.1 years), and 45 normal (group II), (23 males, mean age: 61.2+/-12.0 years). The maximum and minimum P-wave duration (Pmax and Pmin) and PD were measured from the 12-lead surface electrocardiogram. Echocardiographic examination was also performed.

RESULTS

There was no statistically significant difference between two groups in respect to age, gender, hypertension, diabetes mellitus, hyperlipidemia and cigarette smoking (p>0.05). Pmax and PD of patients with BD were found to be significantly higher than those of control subjects (116.2+/-14.0 ms vs. 102.0+/-16.5 and 49.3+/-12.7 ms vs. 29.3+/-8.5 ms, respectively p<0.0001). Moreover, we found a significant positive correlation between PD with BD duration (r=0.78, p<0.0001).

CONCLUSION

Pmax and PD are found to be greater in patients with BD than in controls and are related with the duration of the disease.

The effect of diabetes mellitus on the P-wave dispersion

BACKGROUND

P-wave dispersion (PD), a measure of heterogeneity of atrial refractoriness, is defined as the difference between the minimum (P min) and maximum P-wave (P max) durations on standard 12-lead electrocardiography (ECG). Increase in PD shows the intra-atrial and inter-atrial non-uniform conduction. In the present study the evaluation of the effect of diabetes mellitus (DM) on PD in patients without coronary artery disease and hypertension was carried out.

METHODS AND RESULTS

Seventy-six diabetic patients who had no coronary artery disease or hypertension (group 1; mean age 48+/-9) and 40 healthy volunteer individuals (group 2; mean age 46+/-13) were enrolled in the study. After obtaining 12-lead surface ECG of all cases, P max and P min P-wave durations were measured and the differences between them were taken as PD (PD=P max-P min). Left atrium diameter, left ventricular end systolic and end diastolic diameters were measured and left ventricular ejection fraction was determined by echocardiography. Pulse wave mitral flow velocities were measured from the apical 4-chamber view. Mitral early diastolic velocity (E), late diastolic velocity (A), E/A, E deceleration time and isovolumetric relaxation time were determined. In comparison of the 2 groups there was no statistically significant difference among age, sex, systolic and diastolic blood pressure, resting heart rate and body mass index of the cases. Although PD and P max were significantly higher in diabetic patients, there was no difference between P min values (33+/-12 vs 28+/-10, p=0.02; 99+/-12 vs 93+/-10, p=0.011; 66+/-9 vs 65+/-10, p=NS; respectively).

CONCLUSIONS

DM might increase PD even without ischemia, hypertension and left ventricular hypertrophy.

Prevention of atrial fibrillation after cardiac surgery

Atrial fibrillation is the most common arrhythmia occurring after heart surgery. Its prevalence after coronary artery bypass surgery is 17-33%. Atrial fibrillation requires additional treatment, lengthens hospitalization and increases the overall expenses of cardiac surgery. Atrial fibrillation can cause hemodynamic problems, predispose to congestive heart failure and increase the risk of stroke. Beta-blockers have been shown to effectively prevent atrial fibrillation, and beta-blockers should be a part of the medication of every patient undergoing cardiac surgery, if there are no contraindications. Amiodarone therapy can also be considered for especially high-risk patients.

The effect of VVI pacing on P-wave dispersion in patients with dual-chamber pacemakers

The incidence of atrial fibrillation is higher in patients with VVI pacing mode than DDD pacing mode, but the likely mechanism is not clearly understood. We aimed to evaluate whether short-term VVI pacing increases inhomogeneous atrial conduction by using P-wave dispersion. Forty-seven patients (32 men, 15 women, mean age 54 +/- 13 years) with DDD pacemakers were enrolled in this study. Twelve-lead surface ECGs were obtained in all patients during VDD pacing after an observation period of 1 week. The mode was then changed to VVI and 12 lead surface ECGs were obtained after another 1-week observation period. P-wave durations were calculated in all 12 leads in both VDD and VVI pacing modes. The difference between the maximum and the minimum P-wave duration was defined as the P-wave dispersion (PWD = P(max) - P(min)). P-wave maximum duration (P(max)) calculated in VVI pacing mode was significantly longer than in VDD pacing mode (128 +/- 19 vs 113 +/- 16 ms, P < 0.001). There was no significant difference in the P-wave minimum durations (80 +/- 13 ms vs 79 +/- 12 ms, P = 0.7) between VVI pacing and VDD pacing. The P-wave dispersion value was higher in the VVI pacing mode than in the VDD pacing mode (48 +/- 8 ms vs 34 +/- 7 ms, P < 0.001). Short-term VVI pacing induces prolongation of P(max) and results in increased P-wave dispersion, which might be responsible for the development of atrial fibrillation more frequently in these patients than in those with the VDD pacing mode.

Does Intermittent Aortic Cross Clamping Decrease the Incidence of Atrial Fibrillation after Coronary Bypass Surgery?

Atrial fibrillation (AF) is the most common arrhythmia after coronary artery bypass grafting (CABG). AF is a vexing problem that causes morbidity, prolongs hospital stay, and increases costs. Numerous factors have been suggested to play a role in the development of AF. The aim of this study was to evaluate the effect of intermittent aortic cross clamping (IACC) compared with hypothermic cardioplegic solution (HCS) in the development of postoperative AF. We evaluated data obtained from 345 patients undergoing CABG with HCS (HCS group, n = 212) and IACC (IACC group, n = 173) between April 2004 and August 2005. Diabetes mellitus was observed more often in the HCS group (P < .05), otherwise both groups had similar preoperative characteristics including sex, age, the number of distal anastomoses, left ventricle ejection fraction, history of myocardial infarction, and use of beta-blocker medication. The only statistically significant difference between the groups was higher postoperative Ca-antagonist use in the HCS group. Rates of postoperative AF, however, were significantly lower in the IACC group (21.52%) than that in the HCS group (11.05%; P < .01). Postoperative Ca-antagonist use in the HCS group and smoking in the IACC group were independent predictors of AF after CABG. The incidence of postoperative AF after CABG with IACC was reduced compared with HCS. IACC with ventricular fibrillation may exert a counteractive effect against AF.

The Clinical Noncompliance of Oral Sotalol/Magnesium for Prophylactic Treatment of Atrial Fibrillation After Coronary Artery Bypass Grafting

BACKGROUND

Postoperative atrial fibrillation has been refractory to many attempted pharmacologic prevention methods and, when effective, side effects have been described. The present aim was to study the clinical compliance of a suggested prophylactic treatment, oral sotalol, and magnesium.

METHODS

Coronary-bypass patients without clinical contraindications to receive oral sotalol (80 mg twice daily) and magnesium supplementation were enrolled (n = 49) with an intention-to-treat strategy and being compared with a matched control group (n = 844). A protocol listed exclusion criteria of clinical compliance that was postoperatively evaluated prior to and during treatment.

RESULTS

Twenty-seven of the 49 enrolled patients (55%) were compliant to sustain the treatment according to the protocol. The remaining patients were postoperatively excluded, mainly because of hemodynamic reasons, of whom 14 were noncompliant to initiate any treatment. The AF occurrence in the compliant group was 7% versus 36% in noncompliant patients (p = 0.035), and 24% in the control group (p = 0.076). However, with an intention-to-treat policy the overall AF incidence became 18%. The subgroups of enrolled patients demonstrated skewing phenomena. The noncompliant group had higher requirement for inotropic support (p = 0.029) and longer aortic cross-clamp time (p = 0.048) compared to compliant patients. Further, the body weight of noncompliant patients was markedly lower than in the compliant counterpart (p = 0.015).

CONCLUSIONS

The tested treatment protocol showed limited compliance among routine cardiac-surgery patients, and further, introduced a biased selection of patients that skewed the results and may have partly explained the treatment effect.

Differences in the morphology and duration between premature P waves and the preceding sinus complexes in patients with a history of paroxysmal atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Experimental and human mapping studies have demonstrated that perpetuation of AF is due to the presence of multiple reentrant wavelets with various sizes in the right and left atria.

HYPOTHESIS

Atrial fibrillation may be induced by atrial ectopic beats originating in the pulmonary veins, and premature P-wave (PPW) patterns may help to identify the source of firing.

METHODS

To evaluate the morphology and duration of PPWs, 12-lead digital electrocardiogram (ECG) strips containing clearly definable PPWs not merging with the preceding T waves were obtained in 25 patients with AF history (9 men, mean age 59.5 +/- 2.2 years) and 25 subjects without any previous AF history (11 men, mean age 53.6 +/- 25 years). The polarity of PPWs was evaluated in all 12 ECG leads. Previously described indices, such as P maximum, P dispersion (= P maximum-P minimum), P mean, and P standard deviation were also calculated.

RESULTS

Premature P-wave patterns were characterized by more positive P waves in lead V1. All P-wave analysis indices were significantly higher in patients with AF than in controls when calculated in the sinus beat, whereas they did not differ between the two groups when calculated in the PPW. P-wave indices did not differ between the PPW and the sinus either patients with AF or controls, except for P mean, which was significantly higher in the sinus (110.1 +/- 1.7 ms) than in the PPW (100 +/- 2 ms) only in patients with AF (p = 0.001).

CONCLUSION

The evaluation of PPW patterns is only feasible in a small percentage of short-lasting digital 12-lead ECG recordings containing ectopic atrial beats. Premature P wave patterns characterized by more positive P waves in lead V1, which indicates a left atrial origin in the ectopic foci. The observed differences in P-wave analysis indices between patients with AF and controls and between sinus beats and PPWs may be attributed to the presence of electrophysiologic changes in the atrial substrate.

P-wave signal-averaged electrocardiogram predicts atrial fibrillation after coronary artery bypass grafting

BACKGROUND

AF is one of the most common complications after CABG. The aim of the study was to identify the risk factors for postoperative AF.

METHODS

Between June and December 2000, 129 consecutive patients (72 men, 47 women; mean age 67 +/- 6 years) underwent preoperative signal-averaged electrocardiogram (SAECG) with assessment of filtered P-wave duration (fPWD) and of the root mean square voltage of the last 10 and 20 ms of atrial depolarization (RMSV10 and RMSV20, respectively) before CABG.

RESULTS

Fifty-six (43%) patients developed one episode of AF lasting > 30 seconds at a mean distance of 2.6 +/- 1.8 days after surgery (group A), while 73 patients remained in sinus rhythm (group B). No differences between the two groups were found in terms of age, sex, P-wave duration on the standard ECG, left atrial dimensions, and operative characteristics. In contrast, group A patients showed a significantly longer fPWD (138 +/- 10 vs 111 +/- 9 ms; P < 0.001) and smaller RMSV10 and RMSV20 (2.8 +/- 1.0 vs 4.3 +/- 1.1 microV, P < 0.001; 4.2 +/- 2.1 vs 6.2 +/- 2.0 microV, P < 0.001). Multivariate analysis indicated only fPWD as an independent predictor of AF (P = 0.009). With a cut-off value of 135 ms for fPWD, the occurrence of AF could be predicted with a sensitivity of 84%, a specificity of 73%, a negative predictive value of 85%, and a positive predictive value of 70%.

CONCLUSION

Preoperative SAECG is a simple exam that correctly identifies patients at higher risk of AF after CABG. A more widespread use of this technique can be suggested.

P-wave dispersion: a novel predictor of paroxysmal atrial fibrillation

BACKGROUND

The prolongation of intraatrial and interatrial conduction time and the inhomogeneous propagation of sinus impulses are well known electrophysiologic characteristics in patients with paroxysmal atrial fibrillation (AF). Previous studies have demonstrated that individuals with a clinical history of paroxysmal AF show a significantly increased P-wave duration in 12-lead surface electrocardiograms (ECG) and signal-averaged ECG recordings.

METHODS

The inhomogeneous and discontinuous atrial conduction in patients with paroxysmal AF has recently been studied with a new ECG index, P-wave dispersion. P-wave dispersion is defined as the difference between the longest and the shortest P-wave duration recorded from multiple different surface ECG leads. Up to now the most extensive clinical evaluation of P-wave dispersion has been performed in the assessment of the risk for AF in patients without apparent heart disease, in hypertensives, in patients with coronary artery disease and in patients undergoing coronary artery bypass surgery. P-wave dispersion has proven to be a sensitive and specific ECG predictor of AF in the various clinical settings. However, no electrophysiologic study has proven up to now the suspected relationship between the dispersion in the atrial conduction times and P-wave dispersion. The methodology used for the calculation of P-wave dispersion is not standardized and more efforts to improve the reliability and reproducibility of P-wave dispersion measurements are needed.

CONCLUSIONS

P-wave dispersion constitutes a recent contribution to the field of noninvasive electrocardiology and seems to be quite promising in the field of AF prediction.

Effect of Low-Dose Amiodarone and Magnesium Combination on Atrial Fibrillation After Coronary Artery Surgery

BACKGROUND

To evaluate whether postoperative administration of intravenous low-dose amiodarone and magnesium sulfate (MgSO(4)) combination would reduce the incidence of atrial fibrillation following coronary artery bypass grafting (CABG) in normomagnesemic high-risk patients for postoperative atrial fibrillation (POAF).

METHODS

A total of 136 patients undergoing elective CABG and had > or =3 risk factors for POAF were prospectively randomized to one of three groups, to receive a single dose of amiodarone (5 mg/kg) and MgSO(4) (1.5 g) (combination group, n = 44), or an equal dose of amiodarone (amiodarone group, n = 44) or equal volumes of saline (control group, n = 48) at early postoperative period. Continuous electrocardiographic (ECG) monitoring was performed for the first 48 hours and an ECG was recorded every 8 hours later. POAF longer than 30 minutes or for any length requiring treatment, and the drug-related side effects were recorded.

RESULTS

The study population showed a homogeneous distribution regarding risk factors for POAF and there was no significant difference in patient characteristics, echocardiographic variables, or operative variables among three groups. POAF developed in 4 patients in combination group, in 16 patients in amiodarone group and in 16 patients in control group, representing a 24% relative risk reduction between the combination group and control group (p = 0.023). No statistically significant difference regarding incidence of POAF was observed between amiodarone and control groups.

CONCLUSIONS

Combined prophylactic therapy with amiodarone and MgSO(4) at the early postoperative period without a maintenance phase is an effective, simple, well-tolerated, and possibly cost-effective regimen to prevent POAF in normomagnesemic, high-risk patients.

P-wave duration and dispersion in patients with coronary slow flow and its relationship with Thrombolysis in Myocardial Infarction frame count

AIM

P-wave dispersion (PD), and duration has been reported to be associated with inhomogeneous and discontinuous propagation of sinus impulses. The aim of this study was to investigate the PD in patients with coronary slow flow (CSF) phenomenon.

METHODS

Study population included 48 patients with angiographically proven normal coronary arteries and slow coronary flow in all 3 coronary vessels (group I, 36 men; mean age, 54 +/- 9 years) and 32 subjects with angiographically proven normal coronary arteries without associated slow coronary flow (group II, 24 men, mean age, 53 +/- 10 years). Coronary flow rates of all patients and control subjects were documented by Thrombolysis In Myocardial Infarction (TIMI) frame count. All patients in group I had TIMI frame counts greater than 2 SD above those of control subjects (group II). The mean TIMI frame count for each patient and control subject was calculated by adding the TIMI frame counts for each major epicardial coronary artery and then dividing the obtained value into 3. The maximum and minimum P-wave duration (P(max) and P(min)) and PD were measured from the 12-lead surface electrocardiogram. Echocardiographic examination was also performed.

RESULTS

There was no statistically significant difference between the 2 groups with respect to age, sex, hypertension, diabetes mellitus, hyperlipidemia, and cigarette smoking (P > .05). P-wave dispersion and P(max) of patients with CSF were found to be significantly higher than those of control subjects (39.4 +/- 17 vs 21.2 +/- 10 milliseconds and 121.6 +/- 17.1 vs 104.3 +/- 10.4 milliseconds, respectively; P < .0001). Moreover, we found a significant positive correlation between both P(max) and PD with mean TIMI frame count (r = 0.836 and r = 0.806, respectively; P < .0001).

CONCLUSIONS

P-wave dispersion and P-wave duration both were found to be greater in patients with CSF than in controls.

Determination of histopathologic risk factors for postoperative atrial fibrillation in cardiac surgery

BACKGROUND

Postoperative atrial fibrillation is one of the most common complications after coronary artery bypass grafting. This study aimed to identify preoperative histopathologic risk factors for the development of postoperative atrial fibrillation.

METHODS

One hundred elective coronary artery bypass grafting patients were enrolled into the study. Right atrial tissue from all patients was sampled before cardiopulmonary bypass. Patients were monitored for the occurrence of the postoperative atrial fibrillation. Right atrial tissue samples from the atrial fibrillation group were compared with samples belonging to the patients who remained in sinus rhythm postoperatively. Evaluation for atrial histopathology and myocyte apoptosis included light microscopic and immunohistochemical studies.

RESULTS

Fourteen of 100 patients (14%) developed postoperative atrial fibrillation. On univariate analysis, the only predictor for the development of postoperative atrial fibrillation was chronic obstructive pulmonary disease (p = 0.014). Histologically, larger sized myolytic vacuoles were more common in patients who developed postoperative atrial fibrillation (p = 0.001). The percentage of apoptotic myocytes in each specimen was significantly higher in patients with atrial fibrillation (p = 0.000). Most of the specimens with positive apoptotic staining were also severely myolytic in patients with postoperative atrial fibrillation.

CONCLUSIONS

Our results suggest that degree of myolysis and increased apoptotic pattern in right atrial myocardium are significant predictors for the development of postoperative atrial fibrillation. The improvement of preoperative metabolic status of the myocardial cells may reduce the incidence of this common complication.

Atrial fibrillation following cardiac surgery: a retrospective cohort series

Atrial fibrillation (AF) is a common postoperative complication of cardiac surgery, yet the prevention and treatment of postoperative AF remains controversial and varies among practitioners. The purpose of this study was to document the incidence and time of onset of postoperative AF in a cardiac surgical cohort, examine risk factors implicated in the occurrence of postoperative AF, and assess effectiveness of current treatment strategies implemented for postoperative AF. A retrospective health record review was conducted on 1078 adults following cardiac surgery. Data on demographic, preoperative, perioperative, and postoperative risk factors for postoperative AF, documented episodes of AF, and clinical outcomes were recorded. Overall incidence of postoperative AF was 39.6%: 57.6% after cardiac valve surgery, 69.3% after combined coronary artery bypass graft and valve surgery, and 33% after bypass graft surgery alone. The peak onset of postoperative AF occurred on the second postoperative day. Advancing age, history of AF, combined cardiac valve and coronary artery bypass graft surgery, and high Mg+2 levels on the third postoperative day were significant predictors of postoperative AF in this cohort. Length of hospitalization increased with the presence of postoperative AF. Findings corroborate that multiple factors play a role in the development of AF following cardiac surgery.

Anxiety and P Wave Dispersion in a Healthy Young Population

BACKGROUND

P wave dispersion (P(d)), defined as the difference between the maximum (P(max)) and the minimum P wave duration (P(min)), and P(max) are electrocardiographic (ECG) markers that have been used to evaluate the discontinuous propagation of sinus impulses and the prolongation of atrial conduction time. P(d) in normal subjects has been reported to be influenced by the autonomic tone, which induces changes in atrial size and the velocity of impulse propagation. However, the association between P(d) and anxiety has not been studied in normal subjects.

METHODS AND RESULTS

P(max), P(min) and P(d) were measured in 726 physically and mentally healthy young male volunteers, aged 21.23 +/- 1.25 years (range 20-26). The Spielberger State-Trait Anxiety Inventory (STAI) was scored concomitantly. Blinded intra- and interobserver reproducibility of the P wave duration and P(d) measurement were evaluated, and comparison revealed a Pearson correlation coefficient of 0.87 and 0.89 for the P wave duration, and 0.93 and 0.90 for P(d), respectively (p < 0.001). P(max) and P(d) were significantly correlated with the state anxiety (STAI-1) subscale (r = 0.662, p < 0.001, and r = 0.540, p < 0.001, respectively) and the trait anxiety (STAI-2) subscale (r = 0.583, p < 0.001, and r = 0.479, p < 0.001, respectively). P(min) did not show any significant correlation with anxiety. Across 3 variables included in a multiple linear regression analysis, STAI-1 and STAI-2 were the significant independent determinants of P(max) and P(d). Beta coefficients indicated that the contribution of STAI-1 to P(max) (66.3 and 33.7%) and P(d) (65 and 35%) was much greater than that of STAI-2.

CONCLUSIONS

STAI-1 and STAI-2 are associated with an increase in P(max) and P(d). The association of P(d) resulted from an augmentation of P(max). This is the first study to show the relation between P(max), P(d) and anxiety.

Pharmacologic Strategies for Prevention of Atrial Fibrillation After Open Heart Surgery

Postoperative atrial fibrillation is a common complication after open heart surgery; it increases morbidity, hospital stay, and costs. In an analysis of 8 large cardiac surgery trials totaling 20,193 patients, the incidence of postoperative atrial fibrillation was estimated to be 26% and ranged from 17% to 35%. We reviewed the results of 52 studies published between 1966 and 2003 that evaluated pharmacologic strategies to prevent postoperative atrial fibrillation in nearly 10,000 patients undergoing open heart operations. Supraventricular tachyarrhythmias, including atrial fibrillation, after open heart operations occurred in 29% of patients who did not receive prophylactic drugs, compared with 12% in patients who received intravenous followed by oral amiodarone, 15% in those given sotalol, 16% in those given oral amiodarone, and 19% in those given beta-blockers. Pharmacologic strategies and regimens aimed at preventing postoperative atrial fibrillation are necessary to optimize the postoperative care of patients undergoing open heart operations. Although no strategy has consistently been shown to be superior to another, the most effective approach to preventing postoperative atrial fibrillation likely involves multiple interventions. In the absence of contraindications, all patients should receive beta-blocker therapy before and after the operation. For patients with 1 or more risk factors for postoperative atrial fibrillation, regimens consisting of either sotalol (beta-blocker with class III antiarrhythmic properties) alone or beta-blockers in combination with amiodarone seem to be the safest, most effective pharmacologic strategies for preventing postoperative atrial fibrillation.

Influence of high-dose leucovorin and 5-fluorouracil chemotherapy regimen on P wave duration and dispersion

BACKGROUND

Although 5-fluorouracil (5-FU)-related cardiotoxicity is well known, atrial arrhythmia, as a potentially serious complication has not been studied in detail. The aim of this study was to determine the P max and Pd in the electrocardiograms (ECG) of patients receiving 5-FU treatment.

METHODS

Twenty-five patients (mean age: 62 years) receiving a 5-FU bolus plus continuous infusion with calcium leucovorin over 48 h and with normal pre-treatment cardiac physical examinations, ECG and echocardiography were enrolled. P maximum (P max), P minimum (P min) and P dispersion (Pd) (maximum minus minimum P wave duration) were measured from the 12-lead ECG at the 0th and 48th hour of the first chemotherapy cycle. Echocardiography was also obtained in all patients at the same times.

RESULTS

Clinical cardiotoxicity was observed in two patients. P max and Pd were both significantly longer after 5-FU treatment at the 48th hour (P < 0.001). P min did not change (P > 0.05).

CONCLUSION

Treatment with 5-FU based regimens may increase Pd and prolong the P max in cancer patients. These alterations may be predictive of patients at risk of atrial arrhythmias during 5-FU treatment.

Maximum p wave duration and p wave dispersion in adult patients with secundum atrial septal defect: the impact of surgical repair

BACKGROUND

Patients with atrial septal defect (ASD) have an increased risk for atrial fibrillation (AF). Previously it was shown that maximum P wave duration and P wave dispersion in 12-lead surface electrocardiograms are significantly increased in individuals with a history of paroxysmal AF. We studied P maximum and P dispersion in adult patients with ASD during normal sinus rhythm. In addition, the impact of surgical closure of ASD on these variables within 1 year after surgery was evaluated.

METHODS

Thirty-four patients (21 women, 13 men; mean age: 35 +/- 11 years) operated on for ostium secundum type ASD and 24 age-matched healthy subjects (13 women, 11 men; mean age: 37 +/- 10 years) were investigated. P maximum, P minimum, and P dispersion (maximum - minimum P wave duration) were measured from the 12-lead surface electrocardiography.

RESULTS

P maximum was found to be significantly longer in patients with ASD as compared to controls (115.2 +/- 9 vs 99.3 +/- 14 ms; P < 0.0001). In addition, P dispersion of the patients was significantly higher than controls (37 +/- 9 vs 29.8 +/- 10 ms; P = 0.003). P minimum was not different between the two groups (P = 0.074). After surgical repair of ASD, 10 patients (29%) experienced one or more episodes of paroxysmal AF. Patients with postoperative AF were older (45 +/- 6 vs 30 +/- 10 years; P = 0.001), and had a higher preoperative pulmonary artery peak systolic pressure as compared to those without postoperative AF (51 +/- 11 vs 31 +/- 9 mmHg; P < 0.0001). No significant difference in the pulmonary-to-systemic flow ratio was observed preoperatively between the two groups (P = 0.56). P maximum and P dispersion were significantly higher in patients with postoperative paroxysmal AF at baseline and at postoperative first month, sixth month, and first year as compared to those without it (for P maximum P = 0.027, P = 0.014, P = 0.001, P < 0.0001, respectively; for P dispersion P = 0.037, P = 0.026, P = 0.001, P < 0.0001, respectively). In addition, in patients with postoperative AF, no significant changes were detected in both of these P wave indices during postoperative follow-up. However, in the other group, P maximum and P dispersion were found to be significantly decreased at postoperative 6 months and 1 year as compared to baseline. P minimum was similar throughout the postoperative follow-up as compared to baseline in both groups.

CONCLUSIONS

Mechanical and electrical changes in atrial myocardium may cause greater P maximum and P dispersion in patients with ASD. Surgical closure of the ASD can regress these pathological changes of atrial myocardium with a result in decreased P maximum and P dispersion. However, higher P maximum and P dispersion at baseline, which have not decreased after surgery, may be associated with postoperative paroxysmal AF, especially for older patients.

Interventions for preventing post-operative atrial fibrillation in patients undergoing heart surgery

BACKGROUND

Post-operative atrial fibrillation is a common complication of cardiac surgery and has been associated with increased incidence of other complications including post-operative stroke, increased hospital length of stay and increased cost of hospitalisation. Prevention of atrial fibrillation is a reasonable clinical goal and, consequently, many randomised trials have evaluated the effectiveness of pharmacological and non-pharmacological interventions. We systematically reviewed the literature and prepared meta-analyses to better understand the role and effects of various prophylactic therapies against post-operative atrial fibrillation.

OBJECTIVES

To assess the effects of pharmacological and non-pharmacological interventions for preventing post-cardiac surgery atrial fibrillation.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE and CINAHL from earliest achievable date to June 2003. We hand searched references from reports and earlier reviews. We searched abstract books and CD-ROMs from annual scientific meetings of American College of Cardiology, American Heart Association, North American Society of Pacing and Electrophysiology and European Heart Organization between 1997-2003. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials comparing pharmacological interventions or non-pharmacological interventions with control treatment, placebo or usual care for the prevention of post-operative atrial fibrillation in post-coronary artery bypass grafting or combined CABG and valvular surgery.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Fifty eight studies were included with a total of 8565 participants. Interventions included were amiodarone, beta blockers, solatol and pacing. Results favoured treatment for post-operative atrial fibrillation. The data for stroke favoured treatment by a non-significant effect size of 0.81, 95% confidence interval 0.51 to 1.28. Similarly, a positive indication for length of stay was derived but it too was not significant with a weighted mean difference of -0.66, 95% confidence interval -0.95 to -0.37. A positive result for cost of hospitalisation in favour of treatment was achieved, but the statistic is not significant due to low power and large standard deviations: a weighted mean difference of -2717, 95% confidence interval 7518 to 2084. Beta-blockers had the greatest magnitude of effect across 28 trials (4074 patients) with an odds ratio (random) of 0.35, 95% confidence interval 0.26 to 0.49. Across all treatment, the odds ratio favoured treatment with a ratio (random) of 0.43, 95% confidence interval 0.37 to 0.51.

REVIEWERS' CONCLUSIONS

Intervention is favoured across the three pharmacological interventions studied and the one non-pharmacological intervention, pacing. The length of stay data favoured treatment (-0.66, 95% confidence interval -0.95 to -0.37).

Antithrombotic Therapy in Atrial Fibrillation

This chapter about antithrombotic therapy in atrial fibrillation (AF) is part of the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following (all vitamin K antagonist [VKA] recommendations have a target international normalized ratio [INR] of 2.5; range, 2.0 to 3.0): In patients with persistent or paroxysmal AF (PAF) [intermittent AF] at high risk of stroke (ie, having any of the following features: prior ischemic stroke, transient ischemic attack, or systemic embolism, age > 75 years, moderately or severely impaired left ventricular systolic function and/or congestive heart failure, history of hypertension, or diabetes mellitus), we recommend anticoagulation with an oral VKA, such as warfarin (Grade 1A). In patients with persistent AF or PAF, age 65 to 75 years, in the absence of other risk factors, we recommend antithrombotic therapy with either an oral VKA or aspirin, 325 mg/d, in this group of patients who are at intermediate risk of stroke (Grade 1A). In patients with persistent AF or PAF < 65 years old and with no other risk factors, we recommend aspirin, 325 mg/d (Grade 1B). For patients with AF and mitral stenosis, we recommend anticoagulation with an oral VKA (Grade 1C+). For patients with AF and prosthetic heart valves, we recommend anticoagulation with an oral VKA (Grade 1C+); the target INR may be increased and aspirin added depending on valve type and position, and on patient factors. For patients with AF of > or = 48 h or of unknown duration for whom pharmacologic or electrical cardioversion is planned, we recommend anticoagulation with an oral VKA for 3 weeks before and for at least 4 weeks after successful cardioversion (Grade 1C+). For patients with AF of > or = 48 h or of unknown duration undergoing pharmacologic or electrical cardioversion, an alternative strategy is anticoagulation and screening multiplane transesophageal echocardiography (Grade 1B). If no thrombus is seen and cardioversion is successful, we recommend anticoagulation for at least 4 weeks (Grade 1B). For patients with AF of known duration < 48 h, we suggest cardioversion without anticoagulation (Grade 2C). However, in patients without contraindications to anticoagulation, we suggest beginning IV heparin or low molecular weight heparin at presentation (Grade 2C).

Increased P wave dispersion and maximum P wave duration after hemodialysis

BACKGROUND

Atrial fibrillation is a frequent arrhythmia in patients undergoing hemodialysis. The consequences of hemodialysis on P wave durations and P wave dispersion have not been fully understood. The objective of this study was to study the effect of dialysis on P wave maximum (Pmax), P wave minimum (Pmin), and P wave dispersion (Pd).

METHODS

We studied Pmax, Pmin, and Pd in 32 patients (17 men and 15 women, mean age 54 +/- 18 years) with chronic renal failure undergoing hemodialysis. The difference between maximum and minimum P wave duration was calculated and defined as P wave dispersion (Pd= Pmax- Pmin).

RESULTS

There was a significant increase in Pmax at the end of dialysis compared to the beginning (98 +/- 13 ms vs. 125 +/- 12 ms, P < 0.001). Pmin did not show any significant change (71 +/- 11 ms vs. 73 +/- 10 ms, P = 0.42). Pd was significantly increased at the end of dialysis (27 +/- 9 ms vs. 52 +/- 11 ms, P < 0.001). There was a negative correlation between serum potassium, magnesium, phosphate, blood urea nitrogen, and creatinin at the end of dialysis and Pmax and Pd, respectively (P < 0.05). A weak positive correlation was found between serum calcium, bicarbonate at the end of dialysis and Pmax and Pd (P < 0.05).

CONCLUSION

Hemodialysis ends with significant increase in P wave maximum duration and P wave dispersion, which might be responsible for the increased occurrence of atrial fibrillation in these groups of patients.

Efficacy of nonsteroidal anti-inflammatory medications for prevention of atrial fibrillation following coronary artery bypass graft surgery

This study was designed to test whether nonsteroidal anti-inflammatory medications could reduce the frequency of atrial fibrillation after coronary artery bypass graft surgery. The study was designed as an open-label, randomized trial. Patients undergoing first-time coronary artery bypass graft surgery were considered eligible. Patients with a history of atrial fibrillation, serum creatinine >2.0 mg/dL, on antiarrhythmic treatment, and those undergoing concomitant valvular surgery were excluded. The study was conducted in a single, university-affiliated community hospital. The researchers' role in the study was restricted to randomizing the patients and collecting data. The primary clinical care team made all decisions regarding patient care. One hundred patients were randomized to two groups: one received 30 mg ketorolac intravenously every 6 hours until able to take oral medications, at which point the patients were switched to 600 mg ibuprofen orally three times a day; the other group received conventional treatment. The primary end point of the study was incidence of atrial fibrillation in the immediate postoperative period. Atrial fibrillation occurred in 14 patients (28.6%) in the conventional treatment group vs. five patients (9.8%) in the ibuprofen group (p<0.017). Nonsteroidal anti-inflammatory medications were relatively safe and effective in significantly reducing the incidence of atrial fibrillation after coronary artery bypass graft surgery.

Prevention of atrial fibrillation after cardiac valvular surgery by epicardial, biatrial synchronous pacing

OBJECTIVE

Postoperative atrial fibrillation (AF) after cardiac surgery is a frequent complication after valvular surgery (30-60%). The purpose of this prospective, randomized study was to determine if biatrial synchronous pacing reduces postoperative AF after cardiac valvular surgery as compared to conventional therapy.

METHODS

Eighty patients subjected to valvular surgery (52 men, age 66 +/- 10 years) were randomized to one of two groups: one group was treated with biatrial, synchronous pacing (BAP) for 72 h postoperatively (n=40) the other group received no atrial pacing (controls; n=40). All patients had one pair of epicardial wires attached to the right atrium. An additional electrode was placed to the left atrium in the BAP group. These patients were continuously paced at a rate of 10 beats per minute higher than the intrinsic rate starting immediately after surgery. All patients were monitored with full disclosure telemetry or Holter monitors to identify onset of AF.

RESULTS

Eighteen of the 40 patients in the control group (45%) developed AF within the first 3 days postoperatively as compared to eight patients (20%) in the BAP group (P=0.02). No complications occurred associated with the placement, maintenance and removal of the atrial pacing electrodes.

CONCLUSIONS

Temporary, biatrial synchronous pacing during the first 3 postoperative days is safe and has a significant rhythm-stabilizing effect in patients undergoing valvular cardiac surgery.

Does impaired left ventricular relaxation affect P wave dispersion in patients with hypertension?

OBJECTIVE

P wave dispersion (PD) is considered to reflect the heterogeneous conduction in atria. We investigated whether there was a correlation between the left ventricular (LV) relaxation and PD.

METHOD AND RESULTS

Fifty-three hypertensive patients < or =60 years old were divided into two groups: Group A, 27 patients, aged 54+/-5 years with the impaired LV relaxation and Group B, 26 patients, aged 51+/-8 years with normal LV relaxation. The P wave durations were measured in all 12 leads of ECG and PD was defined as the difference between maximum and minimum P wave duration (Pmax-Pmin). Mitral inflow velocities (E and A), E deceleration time (DT), isovolumic relaxation time (IVRT), left atrial and ventricular diameters, and wall thickness of LV were obtained by echocardiography. Clinical characteristics of both groups were comparable. The wall thickness of LV, Pmax, and left atrial dimension were not different in both groups. A velocity was higher (P<0.001), but E velocity (P=0.03) and E/A ratio (P<0.001) were lower in group A than in group B. IVRT and DT were also significantly longer in group A. PD was significantly higher in group A compared to group B (51+/-9 vs 41+/-11 ms, P=0.01). This difference resulted from the Pmin (61+/-10 vs 67+/-9 ms, P=0.03, respectively). Multivariate analysis revealed a significant correlation between PD and A velocity (r=0.46, P=0.01), E/A ratio (r=-0.53, P=0.001), DT (r=0.65, P<0.001), and IVRT (r=0.73, P<0.001).

CONCLUSION

This study suggests that impaired LV relaxation contributes to the heterogeneous atrial conduction in hypertensive patients.