Criteria for the electrocardiographic diagnosis of atrial flutter improve diagnostic accuracy

Purpose

We previously developed and validated diagnostic criteria for the differentiation of atrial flutter from atrial fibrillation. In this study we examine if the criteria (F waves in the frontal plane and a partially or completely regular ventricular response) can improve the diagnostic accuracy of internists.

Methods

Two groups of 10 internists (1 group given the criteria and 1 not) read a set of electrocardiograms (ECGs) selected from the hospital database with cardiologist-confirmed diagnoses of atrial fibrillation, atrial flutter, or “atrial fibrillation-flutter” (100 each). The final diagnoses of all ECGs were provided by a consensus of electrophysiologists. The criteria also were used to establish the criteria-based diagnoses.

Results

Of the 298 ECGs analyzed, the electrophysiologist diagnosis was atrial fibrillation in 71% and atrial flutter in 29%. The concordance of the internists’ diagnoses with the electrophysiologist consensus diagnoses was 66 ± 12% for those not given the criteria and 81 ± 4% (P <.01) for those given the criteria. The concordance of the internists’ diagnoses with the criteria based diagnoses was 66 ± 12% for those not given the criteria and 83 ± 4% (P <.01) for those given the criteria.

Conclusions

The simple criteria of F waves in the frontal plane and a partially or completely regular ventricular response can be used to improve the differentiation of atrial flutter from atrial fibrillation based on the ECG.     

Do baseline atrial electrocardiographic and infarction patterns predict new-onset atrial fibrillation after ST-elevation myocardial infarction? Insights from the Assessment of Pexelizumab in Acute Myocardial Infarction Trial

Background

Atrial infarction reportedly occurs in 0.7% to 52% of ST-elevation myocardial infarctions (STEMIs), up to two thirds of whom develop atrial fibrillation and flutter (AF). Prospective validation of electrocardiographic atrial infarction patterns is lacking. Hence, in STEMI patients treated with primary percutaneous coronary intervention, we examined whether baseline atrial electrocardiographic changes or atrial infarction patterns predicted new AF or mortality.

Methods

Within the Assessment of Pexelizumab in Acute Myocardial Infarction trial, a nested case-control study was conducted. Patients with new AF were matched 1:1 with controls, and baseline atrial electrocardiographic variables were examined.

Results

Abnormal P wave morphology (Liu minor criterion for atrial infarction) was significantly associated with new AF (adjusted odds ratio, 1.68; 1.03-2.73). This was also independently associated with 90-day mortality in the overall case-control cohort (adjusted hazard rate, 1.90; 1.04-3.46) and among patient with new-onset AF (adjusted hazard rate, 2.43; 1.22-4.84).

Conclusions

Abnormal P wave morphology significantly predicted new AF and 90-day mortality in STEMI patients.     

The impact of rapid atrial pacing on ADMA and endothelial NOS

Background

The endothelial nitric oxide synthase (eNOS) inhibitor asymmetric dimethylarginine (ADMA) is a well-established risk factor for oxidative stress, vascular dysfunction, and congestive heart failure. The aim of the present study was to determine the impact of rapid atrial pacing (RAP) on ADMA levels and eNOS expression.

Methods and results

ADMA levels were studied in 60 age- and gender-matched patients. Thirty five patients had persistent atrial fibrillation (AF) ≥ 4 months. In AF-patients, parameters were studied before and 24 h after electrical cardioversion. Moreover, ADMA, eNOS expression, and calcium-handling proteins were studied in pigs subjected to RAP as well as in endothelial cell (EC) cultures. ADMA level was significantly higher in AF compared to sinus rhythm patients (p = 0.024). ADMA was highest in AF-patients, who also showed elevated troponin T (TnT) levels. Moreover, ADMA showed a significant linear correlation to TnT (r = 0.47; p < 0.01). After electrical cardioversion ADMA returned to normal within 24 h. In pigs, RAP for 7 h increased ADMA levels (p = 0.018) and TnI (p < 0.05), and reduced mRNA expression of ventricular and aortic eNOS (− 80%; p < 0.05) compared to sham-control. However, ADMA per se did not affect eNOS mRNA level in EC cultures.

Conclusion

The current study shows that acute and persistent episodes of atrial tachyarrhythmia are associated with elevated ADMA levels accompanied by increased ischemic myocardial markers. Moreover, RAP increases ADMA and down-regulates eNOS expression in an ADMA-independent manner. We conclude that the combination of these two separate and potentially synergistic mechanisms may contribute to long-term vascular injury during atrial tachyarrhythmia.     

Measuring health related quality of life in coronary heart disease: The importance of feeling well

Background

Atrial tachyarrhythmias are associated with patent foramen ovale. The objective was to determine the anti-arrhythmic effect of patent foramen ovale closure on pre-existing atrial tachyarrhythmias.

Methods

Medline, EMBASE, Cochrane Library, and Google Scholar databases were searched between 1967 and 2010. The search was expanded using the ‘related articles’ function and reference lists of key studies. All studies reporting pre- and post-closure incidence (or prevalence) of atrial tachyarrhythmia in the same patient population were included. Random and fixed effect meta-analyses were used to aggregate the data.

Results

Six studies were identified including 2570 patients who underwent percutaneous closure. Atrial fibrillation was in fact the only AT reported in all studies. Meta-analysis using a fixed effects model demonstrated a significant reduction in the prevalence of atrial fibrillation with an OR of 0.43 (95% CI 0.26-0.71). When using the random-effects model, OR was 0.44 (95% CI 0.18-1.04) with a statistically significant trend demonstrated (test for overall effect: Z = 1.87, p = 0.06).

Conclusion

Closure of a patent foramen ovale may be associated with reduction in the prevalence of atrial fibrillation.     

Development of a toolbox for electrocardiogram-based interpretation of atrial fibrillation

Background

Atrial fibrillation (AF) develops as a consequence of an underlying heart disease such as fibrosis, inflammation, hyperthyroidism, elevated intra-atrial pressures, and/or atrial dilatation. The arrhythmia is initiated by, or depends on, ectopic focal activity. Autonomic dysfunction may also play a role. However, in most patients, the actual cause of AF is difficult to establish, which hampers the selection of the optimal mode of treatment. This study aims to develop tools for assisting the physician's decision-making process.

Methods

Signal analytical methods have been developed for optimizing the assessment of the complexity of AF in all of the standard 12-lead signals. The development involved an evaluation of methods for reducing the signal components stemming from the electric activity of the ventricles (QRST suppression). The methods were tested on simulated recordings, on clinical recordings on patients in AF, and on patients exhibiting atrial flutter (AFL) and atrial tachycardia. The results have been published previously. Subsequently, the implementation of the algorithms in a commercially available electrocardiogram (ECG) recorder, an implementation referred to as its AF-Toolbox, has been carried out. The performance of this implementation was tested against those observed during the development stage. In addition, an improved visualization of the specific ECG components was implemented. This was enabled by providing a separate view on ventricular and atrial activity, which resulted from the steps implied in the QRST suppression. Furthermore, a search was initiated for identifying meaningful features in the cleaned up atrial signals.

Results

When testing the implementation of the previously developed methods in the Toolbox on simulated and clinical data, the suppression of ventricular activity in the ECG produced residuals down to the level of physiologic background noise, in agreement with those reported on previously. The QRST suppression resulted in a better visualization of the atrial signals in AF, atrial AFL, sinus rhythm in the presence of atrioventricular blocks, or ectopic beats. Classifiers for AF and AFL that have been defined so far include the distinct spectral components (multiple basic frequencies), exhibiting distinct dominance in specific leads. The annotations of ventricular and atrial activities, ventricular and atrial trigger, as well as ratio between atrial and ventricular rates were greatly facilitated. The time diagram of ventricular and atrial triggers provides an additional view on rhythm disturbances.

Conclusions

The AF-Toolbox that is currently developed for clinical applications has the potential of reliably detecting and classifying AF, as well as to correctly describe atrioventricular conduction, propagation blocks and/or ectopic beats. Based on the results obtained, a first industrial prototype has been built, which will be used to assess its performance in a routine clinical environment. The availability of this tool will facilitate the search for meaningful signal features for identifying the source of AF in individual patients.     

Efficiency of radiofrequency ablation for surgical treatment of chronic atrial fibrillation in rheumatic valvular disease

Background

It remains unclear whether concomitant radiofrequency ablation procedure in valvular surgery could offer additional benefits to patients with rheumatic valvular disease. We designed a prospective and randomized control study to evaluate the efficacy of surgical radiofrequency ablation in patients with rheumatic heart disease.

Methods

From June 2008 to July 2011, 210 patients with chronic atrial fibrillation and rheumatic heart disease were randomized: (1) control group, patients underwent only valve replacement followed by amiodarone for rhythm control, (2) left atrial group (LA group), patients underwent valve replacement and left atrial mono-polar radiofrequency ablation, (3) bi-atrial group (BA group), patients underwent valve replacement and bi-atrial mono-polar radiofrequency ablation. The primary endpoints included: cardiac death, stroke, and recurrent AF after discharge.

Results

There was no perioperative death. One patient died 4 months after MVR in BA group. In univariate Cox analysis, the two ablation groups were associated with less AF (BA group vs control group: P < 0.001; LA group vs control group: P < 0.001) as well as atrial tachycardia arrhythmia (AF/AT/AFL) recurrent (BA group vs control group: P < 0.001; LA group vs control group: P = 0.02). The comparison between BA and LA groups revealed no differences in terms of AF (P = 0.06) or AF/AT/AFL (P = 0.09). Atrial transport function restoration rate 12 months after operation was 31.4% in LA group, 32.9% in BA group, and 8.6% in control group respectively (P < 0.01).

Conclusions

Radiofrequency ablation concurring with valvular surgery can bring a higher sinus rhythm restoration rate when compared with medical anti-arrhythmic drug therapy in low-medium risk rheumatic heart disease.The trial was registered on Clinicaltrials.gov (registry number NCT01013688).     

Spatial characteristics of atrial fibrillation electrocardiograms

Background

The present study investigates spatial properties of atrial fibrillation (AF) by analyzing vectorcardiogram loops synthesized from 12-lead electrocardiograms (ECGs).

Methods

After atrial signal extraction, spatial properties are characterized through analysis of successive, fixed-length signal segments and expressed in loop orientation, that is, azimuth and elevation, as well as in loop morphology, that is, planarity and planar geometry. It is hypothesized that more organized AF, expressed by a lower AF frequency, is associated with decreased variability in loop morphology. Atrial fibrillation frequency is determined using spectral analysis.

Results

Twenty-six patients with chronic AF were analyzed using 60-second ECG recordings. Loop orientation was similar when determined from either entire 60- or 1-second segments. For 1-second segments, the correlation between AF frequency and the parameters planarity and planar geometry were 0.608 (P < .001) and 0.543 (P < .005), respectively.

Conclusions

Quantification of AF organization based on AF frequency and spatial characteristics from the ECG is possible. The results suggested a relatively weak coupling between loop morphology and AF frequency when determined from the surface ECG.     

Association between aortic calcification and stable obstructive coronary artery disease

Aims

Atrial fibrillation and flutter remain an important cause of morbidity in adults with atrial septal defect (ASD). This study aimed at investigating predictors for late (≥ 1 month after repair) atrial arrhythmia.

Methods

Patients who underwent ASD closure after the age of 18 years, were selected through the databases of three medical centres in Belgium. Preprocedural, periprocedural and follow-up data were extracted. Univariate and multivariate Cox-regression analysis was performed. Kaplan-Meier analysis was performed for any independent predictor of late atrial arrhythmia.

Results

A total of 155 patients (38 men and 117 women) was included. Twenty-four patients (median age 48.3 years, range 19.9-79.8) underwent surgical and 131 (median age 57.6 years, range 18.2-86.9) underwent transcatheter closure. Thirty-nine patients (25.2%) presented with late atrial arrhythmia. Male gender (P = 0.008), creatinine (P = 0.002), atrial arrhythmia before (P < 0.0001) and within 1 month after repair (P = 0.001) and a mean pulmonary artery pressure (mPAP) ≥ 25 mm Hg (P < 0.0001) correlated with late atrial arrhythmia in univariate Cox-regression analysis. Multivariate analysis showed that mPAP ≥ 25 mm Hg (HR 3.72; 95%CI 1.82-7.59; P < 0.0001) and the presence of atrial arrhythmia before (HR 3.22; 95%CI 1.56-6.66; P = 0.002) and within 1 month after repair (HR 2.08; 95%CI 2.08-15.92; P = 0.001) were predictive of late atrial arrhythmia. Kaplan-Meier analysis showed that patients with a mPAP ≥ 25 mm Hg had a higher risk at developing late atrial arrhythmia (P < 0.0001).

Conclusion

In patients with ASD type secundum, a mPAP ≥ 25 mm Hg is an independent predictor of late atrial arrhythmia. The presence of pulmonary hypertension before repair should raise awareness for atrial arrhythmias and may be used to guide therapy.     

The frequency of electrocardiographic errors due to electrode cable switches: a before and after study

Introduction

Electrocardiographic (ECG) errors due to electrode cable reversal confuse physicians and provoke unnecessary diagnostic tests. They occur in approximately 4% of ECGs performed in the intensive care unit (ICU). We aimed to investigate whether this frequency could be reduced by an appropriate intervention.

Methods

All ECGs from consecutive patients were collected at ICU discharge and analyzed by the investigators. Before collecting a second set of ECGs, we educated our ICU staff and performed technical improvements on the electrocardiographs (system approach). Electrocardiographic errors were identified applying previously published morphologic criteria.

Results

We collected and analyzed 1123 ECGs from 416 patients. Nine hundred ten ECGs (81%) were recorded in the ICU; and the frequencies of electrode cable misplacements before and after the intervention were 4.8% and 1.2%, respectively (P = .002).

Conclusions

Using a system approach, we were able to significantly reduce the frequency of ECG errors due to electrode cable switches by 75%.     

Racial Differences in Atrial Fibrillation Prevalence and Left Atrial Size

Background

Previous studies relying on clinical care data have suggested that atrial fibrillation is less common in African Americans than Caucasians, but the mechanism remains unknown. Clinical care may itself vary by race, potentially affecting the accuracy of atrial fibrillation ascertainment in studies relying on clinical data. We sought to examine racial differences in atrial fibrillation prevalence determined by protocol-driven electrocardiograms (ECGs) obtained in prospective cohort studies and to study racial differences in echocardiographic characteristics.

Methods

We pooled primary data from 3 cohort studies with atrial fibrillation adjudicated from study protocol ECGs and documentation of potentially important confounders: the Heart and Soul Study (n = 1014), the Heart and Estrogen-Progestin Replacement Study (n = 2673), and The Osteoporotic Fractures in Men Sleep Study (n = 2911). Left atrial anatomic dimensions were compared among races from sinus rhythm echocardiograms in the Heart and Soul Study.

Results

Of the 6611 participants, 268 (4%) had atrial fibrillation: Caucasians had the highest prevalence (5%), and African Americans had the lowest (1%; P <.001 for each compared with all other races). After adjustment for potential confounders, Caucasians had a 3.8-fold greater odds of having atrial fibrillation than African Americans (95% confidence interval, 1.6-8.8, P = .002). Although ventricular and atrial volumes and function were similar in Caucasians and African Americans, Caucasians had a 2 mm larger anterior-posterior left atrial diameter after adjusting for potential confounders (95% confidence interval, 1-3 mm, P <.001).

Conclusion

ECG confirmed atrial fibrillation is more common in Caucasians than in African Americans, which might be related to the larger left atrial diameter observed in Caucasians.     

Outcome of direct current cardioversion for atrial arrhythmias in adults with congenital heart disease

Objectives

We sought to evaluate safety, efficacy, and outcome of direct current cardioversion (DCCV) for atrial arrhythmias in adults with congenital heart disease (CHD).

Background

Atrial arrhythmias are increasingly noted in adults with CHD. The outcome of DCCV for atrial arrhythmias in this population is unknown.

Methods

Our study was a retrospective review of patients 18 years or older with CHD who underwent DCCV between June 2000 and July 2003. This constituted the CHD group. Patient characteristics reviewed included the specific cardiac diagnosis and arrhythmia history. A subset of patients had transesophageal echocardiography (TEE) before DCCV; this subset was reviewed to evaluate spontaneous echocardiographic contrast. The outcome data evaluated included success of DCCV, complications, recurrence of arrhythmia, antiarrhythmic medication use, electrophysiology or pacemaker procedure in follow-up, and all-cause mortality. The recurrence rate of the arrhythmia was compared to a control group consisting of an age, gender, and rhythm matched group of patients who have no CHD and who underwent DCCV for atrial arrhythmias.

Results

Sixty-three patients in the CHD group underwent 80 DCCVs, 59 of which were TEE-guided. Atrial flutter was more common in the CHD group (37 of 80 DCCV, 46%) than in the control group (13 of 56, 23%) (p < 0.001). DCCV was successful in 75 (94%). Mean follow-up was 387 days. No thromboembolic events were noted. All-cause mortality on follow-up was 11%. There was no death related to DCCV. Twenty-five patients in the CHD group (40%) remained in sinus rhythm throughout follow-up. This was similar to that observed in the control group (30/56, 54%, p = 0.13). Recurrent arrhythmia in the CHD group was predicted by the presence of atrial fibrillation (p = 0.009) and less so spontaneous echo contrast in the left atrium (p = 0.05).

Conclusions

DCCV with appropriate anticoagulation is safe and effective for patients with CHD, even in the presence of an intracardiac shunt and spontaneous contrast on TEE. However, the recurrence rate is substantial. Spontaneous echo contrast in the left atrium along with atrial fibrillation predicts arrhythmia recurrence following DCCV in patients with CHD.     

Warfarin Use and Outcomes in Patients with Atrial Fibrillation Complicating Acute Coronary Syndromes

Background

We examined warfarin use at discharge (according to Congestive heart failure, Hypertension, Age > 75 years, Diabetes, Prior Stroke/transient ischemic attack score and bleeding risk) and its association with 6-month death or myocardial infarction in patients with post-acute coronary syndrome atrial fibrillation.

Methods

Of the 23,208 patients enrolled in the Platelet IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy, Platelet IIb/IIIa Antagonist for the Reduction of Acute Coronary Syndrome Events in a Global Organization Network A, and Superior Yield of the New Strategy of Enoxaparin, Revascularization and Glycoprotein IIb/IIIa Inhibitors trials, 4.0% (917 patients) had atrial fibrillation as an in-hospital complication and were discharged alive. Cox proportional hazards models were performed to assess 6-month outcomes after discharge.

Results

Overall, 13.5% of patients with an acute coronary syndrome complicated by atrial fibrillation received warfarin at discharge. Warfarin use among patients with atrial fibrillation had no relation with estimated stroke risk; similar rates were observed across Congestive heart failure, Hypertension, Age > 75 years, Diabetes, Prior Stroke/transient ischemic attack (CHADS₂) scores (0, 13%; 1, 14%; ≥ 2, 13%) and across different bleeding risk categories (low risk, 11.9%; intermediate risk, 13.3%; high risk, 11.1%). Among patients with in-hospital atrial fibrillation, warfarin use at discharge was independently associated with a lower risk of death or myocardial infarction within 6 months of discharge (hazard ratio 0.39; 95% confidence interval, 0.15-0.98).

Conclusion

Warfarin is associated with better 6-month outcomes among patients with atrial fibrillation complicating an acute coronary syndrome, but its use is not related to CHADS₂ score or bleeding risk.     

Diagnostic accuracy of a new detection algorithm for atrial fibrillation in cardiac telemonitoring with portable electrocardiogram devices

Background

Telemedical approaches targeting cardiac outpatients try to include electrocardiogram (ECG) analysis. Increasing numbers of monitored patients require automated preanalysis of the ECG to prioritize the evaluation for the clinical professional to enable an efficient intervention.

Methods

ECGs were recorded from 60 patients, both with a standard 12-lead ECG and with a new handheld ECG device having dry electrodes for direct skin contact. Recordings of the handheld device were automatically analyzed by a new algorithm. The 12-lead recordings were evaluated by a blinded cardiologist and then compared to the automated analysis of the handheld ECG. Sensitivity and specificity of the algorithm for the detection of atrial fibrillation (AF) were calculated.

Results

A total of 60 ECG strips having 122 ± 36 beats were registered. One hundred percent of the ECG strips were sufficient for automated heart rate count; 96.6%, for automated AF analysis; and 80%, for PQ, QRS, and QTc time measurements. AF detection had a sensitivity of 92.9% and a specificity of 90.9%. There was no difference in heart rate count between automated and manual analysis (median, 71 vs 70 beats per minute; P = .51). Automated measurements of a summary complex showed no difference for PQ time (165 vs 161 milliseconds, P = .50) but overestimated QRS (119 vs 90 milliseconds, P = .001) and QTc (489 vs 417 milliseconds, P < .001) times as compared to the 12-lead recordings analyzed manually.

Conclusion

The new algorithm is suitable for automated preanalysis of the ECG data with regard to AF. It could be used for rapid selection of ECGs with relevant rhythm abnormalities from a large pool. Electrocardiographic data remain to be evaluated by health care professionals for exact diagnosis.     

Influence of coffee and caffeine consumption on atrial fibrillation in hypertensive patients

Background and aims

Coffee and caffeine are widely consumed in Western countries. Little information is available on the influence of coffee and caffeine consumption on atrial fibrillation (AF) in hypertensive patients. We sought to investigate the relationship between coffee consumption and atrial fibrillation with regard to spontaneous conversion of arrhythmia.

Methods and results

A group of 600 patients presenting with a first known episode of AF was investigated, and we identified 247 hypertensive patients. The prevalence of nutritional parameters was assessed with a food frequency questionnaire. Coffee and caffeine intake were specifically estimated. Left ventricular hypertrophy was evaluated by electrocardiogram (ECG) and echocardiogram. Coffee consumption was higher in normotensive patients. High coffee consumers were more frequent in normotensive patients compared with hypertensive patients. On the other hand, the intake of caffeine was similar in hypertensive and normotensive patients, owing to a higher intake in hypertensive patients from sources other than coffee. Within normotensive patients, we report that non-habitual and low coffee consumers showed the highest probability of spontaneous conversion (OR 1.93 95%CI 0.88-3.23; p = 0.001), whereas, within hypertensive patients, moderate but not high coffee consumers had the lowest probability of spontaneous conversion (OR 1.13 95%CI 0.67-1.99; p = 0.05).

Conclusion

Coffee and caffeine consumption influence spontaneous conversion of atrial fibrillation. Normotensive non-habitual coffee consumers are more likely to convert arrhythmia within 48 h from the onset of symptoms. Hypertensive patients showed a U-shaped relationship between coffee consumption and spontaneous conversion of AF, moderate coffee consumers were less likely to show spontaneous conversion of arrhythmia. Patients with left ventricular hypertrophy showed a reduced rate of spontaneous conversion of arrhythmia.     

Clinical impact of screening for sleep related breathing disorders in atrial fibrillation

Objective

The aim of this study was to quantify daytime symptoms in atrial fibrillation (AF) patients with and without sleep related breathing disorders (SRBD).

Background

SRBD are common in patients with AF but little is known about daytime symptoms among those with SRBD.

Methods

Patients with AF admitted to clinics of two tertiary referral hospitals for a variety of different cardiovascular diseases were screened with a trans-nasal airflow measurement device allowing measurement of the apnea-hypopnea-index. Data on cardiac risk factors, left ventricular ejection fraction (LVEF) and cardiac medication were collected. Presence of SRBD was defined as an AHI ≥ 15/h. The Epworth sleepiness scale (ESS) was used to quantify daytime symptoms.

Results

Of 102 screened patients 8 were excluded due to device malfunction (n = 1), dislocation of nasal cannula (n = 6), or hyperthyroidism (n = 1). Among the remaining 94 patients, 40 (43%) were diagnosed with SRBD. Patients with and without SRBD had similar age, body mass index, LVEF and cardiac medication. The prevalence of coronary artery disease was higher in patients with SRBD than in those without (50 vs. 17%; p = 0.0007). ESS score was low and similar in both groups (no SRBD: median 4, interquartile range (IQR) 2-4 vs. SRBD: 5, IQR 3-8; p = 0.14). Only 6/40 (5%) of the patients underwent overnight polysomnography and 2 (5%) started CPAP ventilation during follow-up.

Conclusions

Even though SRBD are common in patients with AF, the prevalence of daytime symptoms is rare. Consequently, most patients will not initiate CPAP ventilation after positive SRBD screening.     

Ablation of left atrial tachycardia with cycle length alternans after atrial fibrillation ablation: significance of fractionated electrogram mapping

Introduction

Atrial tachycardia (AT) with cycle length alternans occurring after atrial fibrillation ablation has not been previously described.

Methods

Among 66 patients with left AT, stable AT with 2 alternating cycles was registered in 5 cases. Activation mapping of both alternating cycles was performed in all 5 patients. Entrainment and fractionated electrogram mappings were also carried out.

Results

Among 10 AT cycles, activation maps suggested underlying mechanism of 5 cycles (50%) in 3 patients. Entrainment pacing was helpful in 2 patients (confirmed mechanism of 2 AT cycles). Catheter ablation successfully terminated AT in all 5 patients: ablation of sites with fractionated potentials in 4 patients and mitral isthmus ablation in 1 patient.

Conclusion

Consecutive activation mapping of both AT cycles is feasible for mechanism determination in some patients. The results of our small study suggest that fractionated electrogram-guided ablation might be a reasonable approach for termination of this type of AT.     

Time course of markers of tissue repair after ablation of atrial fibrillation and their relation to left atrial structural changes and clinical ablation outcome

Background

Radiofrequency ablation of atrial fibrillation (AF) creates left atrial (LA) tissue damage with a subsequent healing process. We sought to prospectively assess the time course of biomarkers of tissue repair after ablation and to evaluate their association with clinical variables.

Methods

30 consecutive patients (57.9 ± 1.7 yrs, 63% males) with paroxysmal AF underwent a CARTO-guided LA circumferential ablation, Lasso-guided segmental pulmonary vein isolation and ablation of complex fractionated atrial electrograms. Matrix metalloproteinase-9 (MMP-9) and transforming growth factor-β1 (TGF-β1), both key regulators of tissue repair, and the aminoterminal propeptide of type III procollagen (PIIINP), reflecting collagen synthesis, were determined in blood samples before and 6 h, 1, 2, 7, 30, 90 and 180 days post-ablation.

Results

All markers showed a significant ablation-induced up-regulation (MMP-9: 1.8 ± 0.1-fold, TGF-β1: 2.4 ± 0.4-fold, PIIINP: 1.3 ± 0.1-fold). MMP-9 was significantly up-regulated until day 90, TGF-β1 only on day 2. PIIINP increased from day 2 to 7. The area under the curve (AUC) of MMP-9 and TGF-β1 correlated with the ablation-induced reduction of LA volume (both p < 0.05). The AUC of MMP-9 was additionally associated with the amount of radiofrequency energy delivered during ablation (p < 0.05). At 12 months of follow-up 57% of patients were free of AF off antiarrhythmic drugs. The AUC of PIIINP independently predicted recurrent AF (p < 0.05).

Conclusions

Markers of healing showed a significant up-regulation after AF ablation detectable for up to 90 days. A more pronounced up-regulation of MMP-9 or TGF-β1 is associated with a greater reduction of LA size. High PIIINP levels after ablation predict a poor ablation outcome.     

Atrial flutter and fibrillation in patients with pulmonary hypertension

Background

Atrial flutter and fibrillation are being increasingly reported in patients with pulmonary hypertension but little is known about their clinical implications. We sought to determine the incidence and clinical impact of these arrhythmias in patients with pulmonary hypertension.

Methods

In a 5-year, prospective study, we assessed the incidence of new-onset atrial flutter and fibrillation as well as risk factors, clinical consequences, management, and impact on survival in patients with pulmonary arterial hypertension (PAH, n = 157) or inoperable chronic thromboembolic pulmonary hypertension (CTEPH, n = 82).

Results

The cumulative 5-year incidence of new-onset atrial flutter and fibrillation was 25.1% (95% confidence interval, 13.8–35.4%). The development of these arrhythmias was frequently accompanied by clinical worsening (80%) and signs of right heart failure (30%). Stable sinus rhythm was successfully re-established in 21/24 (88%) of patients initially presenting with atrial flutter and in 16/24 (67%) of patients initially presenting with atrial fibrillation. New-onset atrial flutter and fibrillation were an independent risk factor of death (p = 0.04, simple Cox regression analysis) with a higher mortality in patients with persistent atrial fibrillation when compared to patients in whom sinus rhythm was restored (estimated survival at 1, 2 and 3 years 64%, 55%, and 27% versus 97%, 80%, and 57%, respectively; p = 0.01, log rank analysis).

Conclusions

Atrial flutter and fibrillation develop in a sizable number of patients with PAH or inoperable CTEPH and often lead to clinical deterioration and right heart failure. Mortality is high when sinus rhythm cannot be restored.     

Contribution of first trimester fasting plasma insulin levels to the incidence of glucose intolerance in later pregnancy: Tanaka women's clinic study

Aims

To clarify risk factors predictive of glucose intolerance in later pregnancy.

Methods

We prospectively studied 509 pregnant women who visited the obstetrics clinic in Tokyo prior to week 13 of gestation, between September 2008 and January 2010. Biochemical parameters were measured in fasting plasma samples collected at week 8.0 ± 2.0 of gestation. A 50 g glucose challenge test (GCT) was performed between weeks 26 and 29: plasma glucose levels ≥7.8 mmol/l 1 h after ingestion indicated a positive GCT. Logistic regression was performed, adjusting for relevant covariates.

Results

We identified 114 patients with positive GCTs, including 8 with gestational diabetes mellitus (GDM). After correcting for baseline body mass index, only the homeostasis model assessment of insulin resistance value remained a significant predictor of GCT positivity (OR 2.07; 1.21-3.55). We identified threshold values of fasting plasma glucose (FPG) ≥3.66 mmol/l and fasting plasma insulin (FPI) ≥36.69 pmol/l as indicative of a higher risk of positive GCT (OR 2.38; 1.49-3.80).

Conclusions

First trimester FPI levels improve the predictive ability of FPG level on subsequent GCT positivity.     

Interpretation of electrocardiograms by first-year residents: the need for change

Background

Prior studies have shown that misinterpretation of the electrocardiogram (ECG) can lead to inappropriate diagnoses and clinical decisions. This may be particularly true during the first month of postgraduate training. This study was designed to assess proficiency in ECG interpretation among residents at the start of their internal medicine (IM) residency.

Methods

Ten ECGs were selected from IM department teaching files. All were representative of conditions that a starting IM resident should be able to identify. The ECGs had 1 correct primary diagnosis and a short list of secondary findings as determined by 2 cardiologists who reviewed them independently. Fifty-two first-year IM residents were given copies and asked to record their interpretations and an assessment of their certainty in each interpretation. Certainty was scored on a scale of 0 to 4 (0 representing a guess and 4 representing 100% certainty). Two blinded, independent graders scored each interpretation on a scale of 0 to 2 (0 = incorrect, 1 = partially correct, 2 = correct).

Results

Overall, only half of all ECGs were read correctly. For the most critical diagnoses, the mean scores were as follows: 1.73/2.0 for acute myocardial infarction, 1.5/2.0 for atrial flutter, 1.11/2.0 for ventricular tachycardia, and 0.23/2.0 for complete heart block. The average level of certainty recorded by all participants was low at 18.5 of a maximum of 40.

Conclusions

Internal medicine residents at the beginning of their residency training demonstrated low overall proficiency in interpreting ECGs and self-perceived confidence. Nearly all residents felt that their training was insufficient. These findings emphasize the need for improved and more effective training in ECG interpretation for physicians starting residency.