2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society (HRS), the Asia Pacific HRS, and the Latin American HRS.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society .

Chronic Total Occlusion Techniques to Recanalize an Occluded Pulmonary Vein After Atrial Fibrillation Ablation

Cardiac computed tomography (CT) scan was performed in a 69-year-old male with atrial fibrillation radiofrequency ablation who was admitted for transcatheter angioplasty of left inferior pulmonary vein (LIPV) stenosis due to recurrent hemoptysis. CT showed complete ostial occlusion in the area of the LIPV. Occlusion of the pulmonary vein ostium is a rare complication. We describe the successful use of chronic occlusion techniques in the treatment of this patient.

Quantifying the variability of bipolar voltage amplitude with sensing angle in residual conduction isthmuses in atrial scar

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Abbott

Background

The angle between the activation wavefront and bipole may conceal the conduction isthmus in conventional bipolar voltage mapping, but the extent of variability of electrogram (EGM) voltage amplitude with directional changes has not been quantified.

Purpose

Using a well-defined model of discrete atrial conduction, we sought to use Omnipolar Technology (OT) to assess variability of voltage amplitude as a function of sensing angle, in sites of residual conduction and scar tissue.

Methods

During redo pulmonary vein isolation (PVI) procedures, baseline voltage maps were acquired during coronary sinus pacing (500 ms) using a rectangular 16-pole catheter (HD Grid). During retrospective analysis with OT research software, all EGM’s ≤1 cm radius from the site of PVI were classified as GAP (vs No-GAP; Panel A) The variability of voltage amplitude (OT-ΔV) with sensing angle (θ) was computed as the difference between the maximum and minimum voltages (OT-Vmax - OT-Vmin), in both GAP and No-GAP subregions (Panels A & B).

Results

23 GAP sites were identified in 12 of 15 consecutive patients studied. 3464 EGM’s (1386 GAP vs 2078 No-GAP) were analyzed. Global mean OT-ΔV was 0.46±0.80 mV. GAP regions showed significantly (P<0.0001) higher OT-ΔV as compared with No-GAP regions (0.80±1.03 mV vs 0.24±0.47 mV respectively; Panel C) The mean Δθ angle for OT-ΔV was similar in both GAP and No-GAP regions (88.6±11.3° vs 88.0±13.6°, P=0.1; Panel D).

Conclusion

The variability of voltage amplitude as a function of bipole orientation can be significant, especially in GAP regions (0.80±1.03 mV). (2) OT-ΔV holds promise for identification of residual conduction within atrial scar tissue.

Influence of atrial cycle length and site of origin on the peak frequency of bipolar electrograms to discriminate isthmus conduction in atrial scar

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Abbott

Background

Peak frequency (PF) of conventional bipolar electrograms is a novel parameter which may distinguish between near-field (NF) and far-field (FF) signals. However, the influence of activation rate and the direction of the activation front on it is unknown.

Purpose

1. To study the influence of atrial cycle length and wavefront origin on PF to detect residual conduction in a well-defined model of narrow isthmus of conduction such as subacute pulmonary vein (PV) reconnection following atrial fibrillation ablation. 2. To compare this influence with that found for Bipolar voltage (BiV).

Methods

Baseline maps were acquired in redo PV isolation (PVI) procedures with a 16-pole grid catheter (HD-Grid) during low rate sinus rhythm (SR), low rate coronary sinus pacing at 500 ms cycle length (CSLR) and high rate coronary sinus pacing at 300 ms cycle length (CSHR). PFs were retrospectively computed. PVI sites requiring ≤3 radiofrequency applications were included, with EGMʼs ≤1cm from the PVI site classified as GAP (vs >1cm, No-GAP).

Results

28 GAPs were found in 12 of 14 consecutive patients in the study. 3976 EGMʼs (1547 GAP vs 2429 No-GAP) were analyzed. In both GAP and No-GAP, PF was similar in SR vs CSLR (GAP: 363±132 Hz -SR vs 345±135 Hz -CSLR, P=NS ; No-GAP: 196±110 Hz -SR vs 181±116 Hz -CSLR, P=NS). PF was slightly higher for CSLR vs CSHR. (GAP: 345±135 Hz -CSLR vs 317±154 Hz -CSHR, P<0.001; No-GAP 181±116 mV -CSLR vs 162±129 mV -CSHR, P<0.01). (Panel A). BiV was significantly higher in SR vs CS pacing but similar between CSLR and CSHR (GAP: 1.86±2.11 mV -SR vs 0.87±1.19 mV -CSLR vs 0.74±0.92 mV -CSHR, P= NS, No-GAP: 0.62±1.22 mV -SR vs 0.33±0.68 mV - CSLR vs 0.27±0.48 mV - CSHR, P=NS. (Panel B). ROC GAP discrimination for PF was similar between SR and CSLR (AUCʼs: 0.86-SR, 0.84-CSLR) and slightly lower for CSHR (AUC: 0.81) with optimal cutoffs of 260, 240 and 220 Hz, respectively. ROC GAP discrimination for BiV was lower vs PF in all rhythm modes (AUCʼs: 0.77-SR, 0.74-CSLR, 0.75-CSHR), with optimal cutoffs of 0.3, 0.2 and 0.15 mV, respectively.

Conclusion

ROC gap discrimination was significantly higher for all rhythm modes with PF vs BiV. PF showed slightly decreasing cutoff values for SR, CSLR and CSHR respectively, whereas BiV showed a greater relative decrease in cutoffs for SR, CSLR and CSHR.

Atrial imaging and cardiac rhythm in cryptogenic embolic stroke: a preliminary analysis of the ARIES study

Funding Acknowledgements

Type of funding sources: None.

Background

Cryptogenic stroke is frequently related to cardioembolic source previously unknown. We aim to analyze atrial fibrillation (AF), parafibrilatory status (para-AF) and echocardiographic signs of atrial dysfunction in patients (p) with cryptogenic stroke.

Methods

Consecutive p with cryptogenic stroke were prospectively enrolled in the on-going study ARIES (Atrial Imaging and cardiac Rhythm In Embolic Stroke). Cardiologic work-up includes external wearable 2-lead ECG monitoring system for 30 days (non-AF, AF, para-AF defined as >3000 atrial ectopic beats/day or >2 "micro-AF" episodes (fibrillatory burst <30 s)/day) and advanced left atrial echocardiography (signs of atrial dysfunction as strain during three phases -reservoir, conduit, and contractile-). The first monitoring was started before hospital discharge, p without AF in the first monitoring and without extremely disabling neurologic sequelae underwent a further 30 days monitoring. We describe stroke recurrence at 90 days follow-up, and we compare echocardiographic signs of atrial dysfunction according to rhythm study.

Results

78 p completed follow-up (72±12 yo, 53% females). AF was diagnosed in 27 (34%) p: 22/78 (28%) in the first monitoring and 5/43 (12%) in the second one. para-AF was diagnosed in 22/51 (43%) non-AF p. Other arrhythmias: sustained (>30 s) focal atrial tachycardia documented in 4/51 (8%) non-AF p, AVNRT in 1/51 (2%) non-AF p, advanced AV block in 1/78 (1%) p. Worse left atrial mechanical properties were demonstrated in p with para-AF compared to non-AF p (reservoir strain 22.2±9.8 vs 32.8±12, p=0.004; conduit strain -9.6±4.8 vs -14.4±9, p=0.008; contractile strain 12.6±4.8 vs 17.9±7.8, p=0.025), without significative differences compared to AF p. There were three stroke recurrences (3.8%), 2/3 in para-AF p.

Conclusion

In this preliminary analysis, patients with cryptogenic stroke presented AF in 34% and para-AF in 28%. Para-AF patients show significative atrial dysfunction in echocardiography and more stroke recurrences. A longer follow-up is required to confirm these findings.

Validation of the peak frequency of bipolar electrograms for detection of residual conduction in atrial scar tissue

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Abbott

Background

Activation and voltage (Bi-V) maps (Panel A) based on conventional bipolar electrograms (EGMs) are influenced by both near-field (NF) and far-field (FF) EGM components. This represents a limitation in the accurate detection of residual conduction within regions of scar. Peak frequency (PF) EGM analysis may better distinguish NF from FF activation vs conventional detection methods. (Panels B & C)

Purpose

1. To validate the use of PF to detect residual conduction in a well-defined model of narrow isthmus of conduction such as subacute pulmonary vein (PV) reconnection following atrial fibrillation ablation. 2. To compare discrimination value of PF and conventional Bi-V to detect such isthmuses.

Methods

Bi-V and activation maps were acquired during redo PV isolation (PVI) procedures using a rectangular 16-pole catheter (HD-Grid). LA-PV conduction was assessed during coronary sinus (CS) pacing (500ms cycle length). Any conduction gap (GAP) site at which PVI was established using ≤3 focal radiofrequency applications was analyzed. (Panel A) EGMʼs ≤1cm from the site of PVI were classified as GAP (vs EGMʼs ≥1cm - No-Gap). (Panel B)

Results

28 GAPs were found in 12 of 14 consecutive patients in the study. 3,976 EGMʼs (1,547 GAP vs 2,429 No-GAP) were analyzed. GAP regions showed significantly higher PF than No-GAP regions (345 ±135 vs 181±116 Hz, P<0.0001) (Panel E). GAP regions also showed significantly higher BiV than No-GAP regions

(1.86±2.11 mV vs 0.62±1.22 mV, P<0.0001) (Panel D). ROC curves for GAP vs No-GAP discrimination were better for PF (AUC 0.84) than for Bi-V (AUC 0.74) with optimal cutoffs of 240 Hz and 0.2 mV, respectively. (Panel F)

Conclusion

PF better detects residual conduction within an atrial scar region than conventional Bi-V. The PF cutoff value for gap discrimination in the PV antra is 240 Hz.

Systematic identification of low voltage-high frequency electrogram zones at sites of left atrial reentrant tachycardia termination

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Abbott

Background

Localization of the narrow isthmus of conduction of left atrial local and macro reentrant tachycardia (LAMRT) circuits within scar tissue is challenging. (Panel A). Near-field (NF) electrograms are often obscured by and difficult to distinguish from far-field (FF) activation. The peak frequency (PF) associated with bipolar electrograms is a novel parameter which may distinguish between NF and FF signals. (Panel B). However, the potential value of PF for LAMRT ablation has never been evaluated.

Purpose

1) To quantify the percentage of LA surface with low voltage (LV) and NF signals. 2) To study the proportion of LAMRT ablation sites which were located within a LV-NF region or in the vicinity of it (<10 mm away).

Methods

LART bipolar voltage and activation maps were generated with a 16-pole grid catheter (HD-Grid) during tachycardia. (Panels A,B). PF maps were retrospectively computed (Panels C,D). LV zones were defined according to a cutoff <0.3mV. Four different PF cut-off values (>250, >300, >350 and >400 Hz) were assessed in the delineation of overlapping LV-NF regions. (Panel E)

Results

16 consecutive patients with 24 LAMRT’s targeted for ablation were prospectively enrolled. 21/24 LAMRT’s were terminated by radiofrequency application. (Panel F). The LV area represented 47.7±14% of the LA surface. The LV-NF area represented 8.2±6.2%, 5.2±5.4%, 3.4±7.4% and 3.3±4.1% of the LA surface by using 250, 300, 350, and 400 Hz PF cutoffs respectively. There were 2.1±1 (range 0-3), 0.9±0.8(range 0-3), 0.5±0.6 (range 0-2) and 0.5±0.6 (range 0-2) LV-NF areas per patient using 250, 300, 350 and 400 Hz PF cutoffs respectively. At the optimal PF cutoff > 250Hz and voltage < 0.3mV, the site of tachycardia termination by radiofrequency application was found inside of a LV-NF region in 13/21 LAMRTs (sensitivity 68.4%), and within 1cm of a LV-NF region in 19/21 LAMRTs (sensitivity 89.5%) respectively.

Conclusion

1. Left atrial reentry termination sites by radiofrequency application are often within or nearby LV-NF areas as identified by the PF and voltage analysis of bipolar electrograms. 2. Beyond conventional substrate mapping, the systematic identification of high frequency activity within the low voltage zone holds promise for rapid identification of isthmus conduction critical to LAMRTs.

Time-efficient three-dimensional transmural scar assessment provides relevant substrate characterization for ventricular tachycardia features and long-term recurrences in ischemic cardiomyopathy

Delayed gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) imaging requires novel and time-efficient approaches to characterize the myocardial substrate associated with ventricular arrhythmia in patients with ischemic cardiomyopathy. Using a translational approach in pigs and patients with established myocardial infarction, we tested and validated a novel 3D methodology to assess ventricular scar using custom transmural criteria and a semiautomatic approach to obtain transmural scar maps in ventricular models reconstructed from both 3D-acquired and 3D-upsampled-2D-acquired LGE-CMR images. The results showed that 3D-upsampled models from 2D LGE-CMR images provided a time-efficient alternative to 3D-acquired sequences to assess the myocardial substrate associated with ischemic cardiomyopathy. Scar assessment from 2D-LGE-CMR sequences using 3D-upsampled models was superior to conventional 2D assessment to identify scar sizes associated with the cycle length of spontaneous ventricular tachycardia episodes and long-term ventricular tachycardia recurrences after catheter ablation. This novel methodology may represent an efficient approach in clinical practice after manual or automatic segmentation of myocardial borders in a small number of conventional 2D LGE-CMR slices and automatic scar detection.

Cardiac arrhythmias in COVID-19: Mechanisms, outcomes and the potential role of proarrhythmia

Funding Acknowledgements

Type of funding sources: None.

Cardiac arrhythmia seems to be a risk factor for mortality in coronavirus disease 2019 (COVID-19). However, the mechanisms, risk factors and outcomes of new arrhythmic events (NAEs) in this disease are unclear.

Methods

All patients with confirmed COVID-19 were retrospectively included in this single centre study. Patients who were alive and admitted <30 days before the database lock were excluded.

Results

3416 consecutive patients were reviewed and 1476 finally enrolled (65.9 ± 20.9 years, 57.3% male). 76 (5.1%) patients had NAEs. Most of them were new atrial fibrillation episodes (48 patients, 3.2%), mostly seen in patients with no previous arrhythmia (38 patients, 79.2%). Atrial flutter (AFL) accounted for 20% of all NAEs. Ventricular arrhythmias were seen in 9 (0.6%) patients. Multivariable analysis showed that prior AFL, heart failure, dyslipidaemia, lopinavir/ritonavir, and combined hydroxychloroquine and azithromycin were independently associated with NAEs. 66 (86.8%) patients with NAEs died. The Kaplan-Meier analysis showed a lower survival of patients with NAEs (P < 0.001). Eight out of 9 (88.9%) and 41 out of 48 (85.4%) patients with ventricular arrhythmias and atrial fibrillation respectively died. Older age, male gender and NAEs were independently associated with death. NAEs and other outcomes, such as heart failure, thromboembolism, and bleeding independently predicted death.

Conclusions

NAEs are relatively uncommon in COVID-19 patients and mainly have an atrial mechanism. AFL is particularly frequent in this disease. The use of hydroxychloroquine, azithromycin and lopinavir/ritonavir, is associated with them, especially when used in combination. NAEs are independently and strongly associated with death.

Characterization of conduction gaps at the pulmonary vein antra by omnipolar voltage mapping

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Abbott provided some software to perform special maps

Introduction

Voltage mapping of atrial tissue may be influenced by the direction of the activation front. Omnipolar electrograms may result in better characterization of the atrial tissue. However, little is known about characterization of the pulmonary vein (PV) antra with omnipolar mapping in patients with recurrent atrial fibrillation (AF) following PV isolation (PVI). 

Purpose

To study differences in voltage between regions with (Gap) and without (No-Gap) conduction recurrence at the PV antra by both omnipolar and conventional bipolar mapping in redo PVI procedures.

Methods

Single centre prospective study  of consecutive patients who underwent a redo PVI procedure for AF ablation. Activation and voltage bipolar maps were developed on a electroanatomical system (Ensite Precision) by a steerable catheter with a 16 grid-patterned electrode configuration (HD-Grid) during coronary sinus pacing at both 500 and 300 ms.  Precise location of conduction gaps in the PV antra was attempted by atrial and PV pacing. Only conduction gaps that were ablated by ≤3 focal radiofrequency applications were included in the analysis. Electrograms recorded within 1 cm at both sides of the RF application site were considered related to the gap region. Off-line omnipolar voltage maps were developed with a dedicated experimental software after the procedure .

Results

11 patients were included in the study and 18 gaps were found in 9 patients. 6762 (2688 Gap and 4074 No-Gap)  electrograms were analyzed. Compared with No-Gap PV regions, Gap regions showed significantly (P &lt; 0.0001) higher voltages by omnipolar mapping (0.3 ± 0.6 mV vs 1.1 ± 1.4 mV)  and by absolute (0.2 ± 0.5 mV vs 0.8 ± 1.2 mV),  grid-along (0.3 ± 0.5 mV vs 0.8 ± 1.2 mV) and grid-across  (0.3 ± 0.5 mV vs 0.8 ± 1.1 mV) bipolar mapping.  Omnipolar mapping resulted in higher voltage electrograms when compared with absolute bipole, longitudinal and horizontal bipolar electrograms (P &lt; 0.0001). ROC curves (figure) to differentiate between Gap and No-Gap regions were slightly better for omnipolar electrograms (AUC 0.79) than for conventional grid -along or grid-across bipolar mapping (AUC 0.76 and 0.77) with the best discrimination value of 0.3 and 0.2 mV respectively.  Conclusion: There are significant differences in voltage between conduction Gap and No-Gap regions at the PV antra which are more apparent with omnipolar than with conventional bipolar mapping. 0.3 mV and 0.2 mV values are the best to differentiate between PV conduction Gap and No-Gap regions with ominpolar and conventional mapping respectively

Incidence and type of arrhythmias recorded by one-month continuous ECG monitoring in stroke patients

Funding Acknowledgements

Type of funding sources: None.

BACKGROUND

The incidence of atrial fibrillation (AF) following stroke has been studied with implantable loop recorders.  However, these devices do not record short lasting AF episodes (&lt;30-120 seconds [s]). In addition, the incidence and type of other clinically relevant arrhythmias is poorly understood in this clinical setting.

PURPOSE

To evaluate the incidence, type and clinical relevance of arrhythmias detected by one-month continuous ECG monitoring in patients after cryptogenic stroke.

MATERIAL AND METHODS

Consecutive patients (p) with stroke and no previous AF or other cardioembolic or atheroembolic causes were prospectively enrolled in the study. An external wearable 2-lead ECG monitoring system (NUUBO) was used for 30 days (d) in all of them after the acute phase of the stroke. In the absence of documented AF, a parafibrillatory status was defined as &gt;3000 atrial ectopic beats/d or &gt;2 "micro AF" episodes (fibrillatory burst &lt;30 s)/d or ≥1 episode of "micro AF" &gt;14 s.

RESULTS

130 p. were included in the study (age 73 ± 12, 57% males, 19% previous stroke, 7% ischemic cardiopathy, CHA2DSVA2Sc pre-stroke 3.1 ± 1.7).  3 were withdrawn from the study due to inadequate use (recording time &lt;14 d) and 1 due to stroke during SARS-CoV2 infection. Total recording time was 28 ± 3 d, total analyzable ECG time was 23 ± 5 d. ECG monitoring was repeated in 12 (9.5%) p due to poor ECG quality in 6 p or high suspicion of AF despite an initial negative result in 6 p.  AF &gt;30 s was detected in a total of 27 (21.4%) p, average AF duration was 52 hours (range 30 s-22 d). AF &gt;30s was detected in 2 (17%) p with repeated monitoring. All these patients were placed on anticoagulation. Sustained paroxysmal supraventricular tachycardia (SVT) was documented in 4 (4.4%) p without AF. All episodes of AF and SVT were asymptomatic. Mobitz I second degree AV block in 4 (3.2%) p. 3 (2.4%) p had a pacemaker implanted: 2 for severe sinus dysfunction and 1 for AV block. High-density ventricular ectopy (&gt;3000/d) was present in 7 (6%) p and ≥1 episode of non-sustained ventricular tachycardia was detected in 26 (21%) p. A parafibrillatory status was identified in 27 (21%) p with no AF &gt;30 s. At 1-year follow up 4/22 (18%) of patients with parafibrillatory status and 3/59 (5%) without parafibrillatory status suffered a new stroke (p = 0.08).

CONCLUSIONS

AF and other potentially relevant arrhythmias are frequent after stroke and easily detectable with one-month non-invasive continuous ECG monitoring. Patients with a parafibrillatory status could benefit from longer monitoring time to detect AF.

Antiarrhythmic Medication for Atrial Fibrillation (AIM-AF) study: A physician survey of antiarrhythmic drug (AAD) treatment practices and guideline adherence in the EU and USA

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Sanofi

Introduction

The 2020 European Society of Cardiology and the 2019 USA (AHA/ACC/HRS) guidelines recommend the use of AADs for rhythm control in patients with symptomatic AF. This study sought to understand AAD treatment practices and adherence to guidelines across the EU and the USA.

Method

An online physician survey of cardiologists, cardiac electrophysiologists and interventional electrophysiologists (N = 569) was conducted in the USA, Germany, Italy and the UK. All respondents were actively treating ≥10 AF patients who received drug therapy and/or who had received or were referred for ablation. This extensively detailed survey explored questions on physician demographics, AF types, and drug treatment and ablation practices.

Results: Of the responses obtained

(1) Amiodarone was used frequently across co-morbidity categories (highest use in those with heart failure with reduced left ventricular ejection fraction [LVEF] [80%]), including in those in which it is not indicated for initial therapy (minimal or no structural heart disease: 26%). Other deviations from guideline recommendations, include: class 1C drugs were used with structural heart disease, including coronary artery disease (CAD) (average class 1C use in CAD-related comorbidities: 6%); sotalol was used with renal dysfunction (22%); and drugs such as sotalol and dofetilide were initiated out of hospital (56% and 17% of respondents, respectively). (2) Nonetheless, a majority of respondents (53%) considered guidelines as the most important non-patient factor in influencing their choice of AF management. (3) Rhythm control was selected more frequently as primary therapy for paroxysmal AF (PAF) (59% of patients) while rate control was used more often for persistent AF (53%). (4) For PAF, AADs were preferred as 1st line more often than ablation, especially if PAF was infrequent and mildly symptomatic (59% of respondents) while ablation was preferred more if frequent symptomatic PAF and for recurrent persistent AF. (5) Rhythm control (AAD or ablation) was chosen in notable numbers for asymptomatic AF and subclinical AF (AADs: 36% and 37%, respectively; ablation: 9% and 14%, respectively). (6) AAD use for those with a first or recurrent episodes of symptomatic AF was 60% or 47%, respectively. (7) Efficacy and safety were chosen as the most important considerations for choice of specific rhythm control therapy (49% and 33%, respectively), and reduction of mortality and cardiovascular hospitalisation (23%) were as important as maintaining sinus rhythm (26%) for rhythm therapy goals.

Conclusions

Although surveyed clinicians consider guidelines important, deviations in patient types and treatments chosen that compromise safety or were not indicated were common. Findings suggest a lack of understanding of the pharmacology and safe use of AADs, highlighting an important need for further education. Abstract Figure.

Differences in Thromboembolic Complications Between Paroxysmal and Persistent Atrial Fibrillation Patients Following Electrical Cardioversion (From the ENSURE-AF Study)

It is unclear if patients with paroxysmal atrial fibrillation (AF) and persistent AF have different outcomes following electrical cardioversion (ECV). ENSURE-AF-a multicenter, prospective, randomized, open-label, blinded-endpoint evaluation trial-compared once-daily edoxaban 60 mg with enoxaparin-warfarin in 2,199 subjects undergoing ECV of nonvalvular AF (NCT02072434). Patients received ≥3 weeks of proper anticoagulation or transesophageal echocardiogram before ECV paroxysmal AF was defined as AF with spontaneous conversion of duration of <7 days; persistent AF was defined as AF lasting ≥7 days without spontaneous conversion. Clinical characteristics and outcomes were compared between subjects based on type of AF present at baseline. In total, 415 subjects had paroxysmal AF; 1,777 had persistent AF. Patients with paroxysmal AF were older (65.8 ± 10.3 vs 63.9 ± 10.5, p = 0.001) with more hypertension (82.7% vs 77.2%, p = 0.01) versus persistent AF patients. Congestive heart failure was more common in persistent AF (46.7%) versus paroxysmal AF (31.3%, p <0.0001). CHA₂DS₂-VASc (score >2: 52.0% vs 49.5%, p = 0.4375) and prior myocardial infarction (6.5% vs 6.8%, p = 0.91) did not significantly differ between groups. After ECV, primary endpoint events were numerically higher in paroxysmal AF versus persistent AF (1.5% vs 0.6%, p = 0.0571), approaching statistical significance. Of note, myocardial infarction was observed in paroxysmal AF (n = 4 vs 0), whereas persistent AF was accompanied by stroke (n = 0 vs 5; p <0.05). In conclusion, patients with paroxysmal AF had more frequent major cardiovascular events than patients with persistent AF. Composite event rates were driven mainly by myocardial infarction in patients with paroxysmal AF and by stroke in those with persistent AF. Overall, the absolute number of events was low after ECV under anticoagulation.

1246High-power and short-duration radiofrequency ablation for atrial fibrillation: feasibility, safety and one-year results

Funding Acknowledgements

SEC-Bayer research project 2018, Spanish Society of Cardiology. Research project 2018, FIS, Insituto de Salud Carlos III.

OnBehalf

none

Pulmonary vein (PV) isolation (PVI) by point-by-point radiofrequency application (PPRF) results in longer procedures than cryoablation. In addition, it is associated with more oesophageal lesions. The aim of this study was to evaluate the feasibility, safety and 1-year efficacy of PVI by high power short duration (HPSD) PPRF in patients with atrial fibrillation (AF).

METHODS

PPRF around the PV was performed in 125 patients (P) distributed in two groups. Conventional PPRF with 30W/≤30 s under luminal oesophageal temperature monitoring was performed in the first 47 P (Group 1). 68 P were enrolled in the HPSD (Group 2). Power was set to 50 W and delivered to reach a predefined lesion index value (LSI≥5 or AI≥350) in the first 18 P (Group 2A). 30 P underwent PPRF with 60 W for 7-10 s (Group 2B) and the last 30 P underwent PPRF with 70W for 9 s (Group 2C). Oesophageal endoscopy was performed after ablation in all P.

RESULTS

17 (36%) P in Group 1 and 30 (38%) in Group 2 had persistent AF. PVI of all targeted veins was achieved in 96% and 100% of P in both groups (p = 0,6).  Total RF time was 30 [27-42], 25[ 20-29], 16 [14-20] and 13 [11-16] in Groups 1, 2A, 2B and 2C respectively (p &lt; 0.01). RF duration per target lesions was 12[9-17], 9[8-9] and 9[9-9] s in Groups 2A, 2B and 2C respectively (p &lt; 0.001). First-pass PVI was achieved in 35% 56%, 57% and 85% of left PV circles (p &lt; 0.001) and in 46%, 56%, 60% and 82% of right PV circles (p = 0.04) in groups 30W, 50W, 60W and 70W respectively. Reconnections occurred in 8% of PV circles in Group 1 and in 6.5% of PV circles in Group 2 (p = 0.8).  Dormant conduction was tested with adenosine in Groups 2B and 2C and the incidence was 30% and 25% of PV circles respectively (p = 0.31). The carina was the most frequent location of conduction gaps, reconnections and dormant conduction in all groups. The incidence of oesophageal lesions was 28% in Group 1, 22% in Group 2A and 0% in groups 2B and 2C (p &lt; 0.002). The 1-year efficacy (freedom from any atrial tachycardia recurrences &gt;30 s) was 59% in Group 1, 88% in group 2A, 77% in group 2B and 87% in group 2C (p = 0.019).

CONCLUSIONS

PVI by HPSD PPRF is feasible and results in high 1-year efficacy in P with AF. This approach appears safe and associated with low incidence of oesophageal damage especially when short application time and 60 or 70W are used. However, this latter power setting is associated with slightly better 1-year efficacy than HPSD PPRF using 60W.

Abstract Figure. Recurrences of atrial arrhythmias (&gt;30 s

Initiating renal replacement therapy through incremental haemodialysis: Protocol for a randomized multicentre clinical trial

Background

Thrice-weekly haemodialysis is the usual dose when starting renal replacement therapy; however, this schedule is no longer appropriate since it does not consider residual renal function. Several reports have suggested the potential benefit of beginning haemodialysis less frequently and incrementally increasing the dose as the residual renal function decreases. However, all the data published so far are from observational studies. Thus, this clinical trial avoids any potential selection bias and will assess the possible benefits that have been observed in observational studies.

Methods/design

This report describes the study protocol of a randomized prospective multi-centre open-label clinical trial to evaluate whether starting renal replacement therapy with twice-weekly haemodialysis sessions preserves residual renal function better than the standard thrice-weekly regimen. We also explore other clinical parameters, such as concentrations of uremic toxins, dialysis doses, control of anaemia, removal of medium-weight uremic toxins, nutritional status, quality of life, hospital admissions and mortality. Only incident haemodialysis patients who can maintain a urea clearance rate KrU ≥ 2.5 mL/min/1.73 m² are eligible. Patient recruitment began on 1 January 2017 and will last for 2 years or until the required sample size has been recruited to ensure the established statistical power has been reached. The minimum follow-up period will be 1 year. Anuric patients with acute renal failure and patients who return to haemodialysis after a kidney transplant failure are excluded. It has been calculated that 44 patients should be recruited into each group to achieve a power of 80% in a two-sided comparison of means with a usual significance level of 0.05. A time-to-event analysis will estimate the probability of kidney function survival in both groups using the Kaplan–Meier method. Survival curves will be compared with log-rank tests. This survival analysis will be complemented with a proportional hazard model to estimate the hazard ratio of kidney function survival adjusted for any confounding factors. Analyses will be carried out in accordance with the intention-to-treat principle.

Discussion

The incremental initiation of dialysis may preserve residual renal function better than the conventional treatment, with similar or higher survival rates, as reported by observational studies. To our knowledge, this is the first clinical trial to evaluate whether initiating renal replacement therapy with twice-weekly haemodialysis sessions preserves residual renal function better than beginning with the standard thrice-weekly regimen.

Trial registration

ClinicalTrials.gov, NCT03302546. Registered on 5 October 2017.

P1013Biannular atrial flutter: clinical and electrophysiological characterization by activation and entrainment

Introduction

re-entry mechanisms around mitral and tricuspid annuli are frequent causes of left and right atrial flutter (AFt) respectively in patients with ipsilateral atrial pathology. However, clinical and electrophysiological characteristics of other types of atrial re-entries that could involve both AV annuli are less known.

Purpose

characterize biannular atrial flutters.

Methods

4 patients with AFt were submitted for ablation (aged 30, 31, 58 and 61 yo; 2 females). All had a cardiac congenital disease with a prior surgical procedure: 3 atrial septal defects (ASD) with surgical repair and 1 with transposition of the great arteries (TGA) with Senning repair. The AFt had a cycle length (CL) of 290, 315, 330 y 340 ms respectively and 1:1 AV conduction in 3 of them. For the electrophysiological study, a multipolar catheter (20 or 24 poles) was placed in the right atrium (RA) in every patient, showing counterclockwise and clockwise activation in 1 and 3 patients, respectively. Coronary sinus (CS) activation was proximal to distal in one patient and distal to proximal in the other 2. No CS activation could be obtained in the patient with Senning repair.

Results

each AFt was mapped by entrainment from different sites of the RA, showing post-pacing intervals (PPI) similar to the CL of the AFt around the tricuspid annulus in all of them and also from proximal and distal CS in the 3 patients with ASD. Access to the native left atrium (LA) was achieved in the patient with Senning repair, showing PPIs around the mitral annulus that were similar to the LC of the tachycardia. In 2 patients the attempt to get to the LA through the interatrial septum (IAS) could not be achieved and was unattempted in the other one. Recordings and PPIs of the LA roof were obtained from the right branch of the pulmonary artery in 2 patients. Counterclockwise AFt and clockwise AFt by single biannular perimitrotricuspid rotation in 1 and 3 patients respectively. The AFt was ended and no reinduction was possible after radiofrequency application that achieved cavotricuspid isthmus block in all of the patients.

Conclusions

reentry around both AV annuli is possible as a single loop, counterclockwise or clockwise, of simultaneous rotation as a clinical mechanism of Aft. This type of AFt seems to be associated to absence or severe damage in the IAS.

6122Pulmonary vein isolation by different setting of high-power short-duration radiofrequency application: feasibility, short term efficacy and safety in patients with atrial fibrillation

Aims

Pulmonary vein (PV) isolation (PVI) by point-by-point radiofrequency application (PPRF) results in longer procedures than cryoballoon ablation. In addition, it is associated with more esophageal lesions. The aim of this study was to evaluate the feasibility and safety of PVI by high power short duration (HPSD) PPRF in patients with atrial fibrillation.

Methods

PPRF around the PVs was done in 125 consecutive patients distributed in two chronologically successive groups. Conventional PPRF with 30W for ≤30 s under luminal esophageal temperature monitoring was performed in the first 47 patients (Group 1). 68 patients were enrolled in the HPSD (Group 2). Power was set to 50 W and delivered to reach a predefined lesion index value (LSI ≥5 or Abl-I ≥350) in the first 18 patients (Group 2A). 30 patients underwent PPRF with 60W for 7–10 s (Group 2B) and the last 30 patients underwent PPRF with 70W for 9 s (Group 2C). Esophageal endoscopy was performed after ablation in all patients.

Results

PVI of all targeted veins was achieved in 96% and 100% of patients of groups 1 and 2 respectively (p=0.6). Total RF time was 30 [27–43], 25 [20–29], 16 [14–20] and 14 [11–16] min in groups 1, 2A and 2B and 2C respectively (p<0.001). RF was delivered for 12 [9–17] s vs 9 [8–9]s vs 9 [8–9] per application in groups 2 A, 2B and 2C respectively (p<0.001). Total number of RFa to completely isolate all PV was 105 [90–126] in group 2A, 113 [90–135] in group 2B and 94 [79–112] in group 2C (p=0.12).

First-pass PVI was achieved in 56%, 57% and 85% of left PV (p=0.038) and in 56%, 60% and 82% of right PV (p=0.13) in groups 50W, 60W and 70W respectively. The carina was the most frequent location of persistent conduction when first-pass failed. Reconnections occurred in 6%, 3% and 11% of left PV (p=0.6) and in 6%, 7% and 4% (p=0.63) of right PV in groups 50W, 60W and 70W respectively. Adenosine test was systematically used in groups 60W and 70W: the incidence of dormant conduction was 23% and 22% (p=0.9) in left PV and 20% and 22% (p=0.8) in right PV respectively.

The incidence of esophageal lesions was 28% in Group 1, 2% in Group 2A, and 0% in groups 2B and 2C (p<0.001). No other intraprocedural complications occurred in the high-power group.

Total RF time

Conclusions

PVI is feasible with HPSD PPRF in most patients using shorter total RF times. This approach appears associated with very low incidence esophageal damage than the conventional one, especially when 60W/70W and shorter application time are used.

Acknowledgement/Funding

Grant of the Spanish Society of Cardiology

EHRA White Paper: knowledge gaps in arrhythmia management—status 2019

Clinicians accept that there are many unknowns when we make diagnostic and therapeutic decisions. Acceptance of uncertainty is essential for the pursuit of the profession: bedside decisions must often be made on the basis of incomplete evidence. Over the years, physicians sometimes even do not realize anymore which the fundamental gaps in our knowledge are. As clinical scientists, however, we have to halt and consider what we do not know yet, and how we can move forward addressing those unknowns. The European Heart Rhythm Association (EHRA) believes that scanning the field of arrhythmia / cardiac electrophysiology to identify knowledge gaps which are not yet the subject of organized research, should be undertaken on a regular basis. Such a review (White Paper) should concentrate on research which is feasible, realistic, and clinically relevant, and should not deal with futuristic aspirations. It fits with the EHRA mission that these White Papers should be shared on a global basis in order to foster collaborative and needed research which will ultimately lead to better care for our patients. The present EHRA White Paper summarizes knowledge gaps in the management of atrial fibrillation, ventricular tachycardia/sudden death and heart failure.

Using the Electronic Nose to Identify Airway Infection during COPD Exacerbations

BACKGROUND

The electronic nose (e-nose) detects volatile organic compounds (VOCs) in exhaled air. We hypothesized that the exhaled VOCs print is different in stable vs. exacerbated patients with chronic obstructive pulmonary disease (COPD), particularly if the latter is associated with airway bacterial infection, and that the e-nose can distinguish them.

METHODS

Smell-prints of the bacteria most commonly involved in exacerbations of COPD (ECOPD) were identified in vitro. Subsequently, we tested our hypothesis in 93 patients with ECOPD, 19 of them with pneumonia, 50 with stable COPD and 30 healthy controls in a cross-sectional case-controlled study. Secondly, ECOPD patients were re-studied after 2 months if clinically stable. Exhaled air was collected within a Tedlar bag and processed by a Cynarose 320 e-nose. Breath-prints were analyzed by Linear Discriminant Analysis (LDA) with "One Out" technique and Sensor logic Relations (SLR). Sputum samples were collected for culture.

RESULTS

ECOPD with evidence of infection were significantly distinguishable from non-infected ECOPD (p = 0.018), with better accuracy when ECOPD was associated to pneumonia. The same patients with ECOPD were significantly distinguishable from stable COPD during follow-up (p = 0.018), unless the patient was colonized. Additionally, breath-prints from COPD patients were significantly distinguished from healthy controls. Various bacteria species were identified in culture but the e-nose was unable to identify accurately the bacteria smell-print in infected patients.

CONCLUSION

E-nose can identify ECOPD, especially if associated with airway bacterial infection or pneumonia.

Inflammatory Asthma Phenotype Discrimination Using an Electronic Nose Breath Analyzer

BACKGROUND AND OBJECTIVE

Patients with persistent asthma have different inflammatory phenotypes. The electronic nose is a new technology capable of distinguishing volatile organic compound (VOC) breath-prints in exhaled breath. The aim of the study was to investigate the capacity of electronic nose breath-print analysis to discriminate between different inflammatory asthma phenotypes (eosinophilic, neutrophilic, paucigranulocytic) determined by induced sputum in patients with persistent asthma.

METHODS

Fifty-two patients with persistent asthma were consecutively included in a cross-sectional proof-of-concept study. Inflammatory asthma phenotypes (eosinophilic, neutrophilic and paucigranulocytic) were recognized by inflammatory cell counts in induced sputum. VOC breath-prints were analyzed using the electronic nose Cyranose 320 and assessed by discriminant analysis on principal component reduction, resulting in cross-validated accuracy values. Receiver operating characteristic (ROC) curves were calculated.

RESULTS

VOC breath-prints were different in eosinophilic asthmatics compared with both neutrophilic asthmatics (accuracy 73%; P=.008; area under ROC, 0.92) and paucigranulocytic asthmatics (accuracy 74%; P=.004; area under ROC, 0.79). Likewise, neutrophilic and paucigranulocytic breath-prints were also different (accuracy 89%; P=.001; area under ROC, 0.88).

CONCLUSION

An electronic nose can discriminate inflammatory phenotypes in patients with persistent asthma in a regular clinical setting. ClinicalTrials.gov identifier: NCT02026336.

[Recurrence of p-ANCA positive vasculitis with lung hemorrhage in a patient on hemodialysis]

Relapses of p-ANCA vasculitis during chronic dialysis treatment are infrequent. We report a patient with a pulmonary-renal syndrome and p-ANCA vasculitis who relapsed one year after starting hemodialysis treatment. Treatment with steroids and cyclosphosphamide successfully controlled the relapse, though cyclophosphamide had to be discontinued because of leucopenia. Clinical features of renal vasculitis, relapse after dialysis, the usefulness of ANCA titles as possible predictors and therapeutic options are discussed.

Catheter ablation of multiple, surgically created, atrioventricular connections following Fontan Bjork procedure

An increased incidence of Wolff-Parkinson-White (WPW) syndrome with tricuspid atresia has been reported. Although atrioventricular accessory pathways may develop across suture lines after the Fontan-Björk procedure, the presence of multiple acquired accessory pathways has only been described rarely. We report on a case of a female with tricuspid atresia who underwent the Fontan operation at 5 years of age. One year later, she developed a WPW pattern. Narrow complex tachycardias started at the age of 18. An electrophysiological study revealed the presence of three accessory pathway connections at the surgical anastomosis level. All of them were successfully ablated and there were no recurrences.

[The figure of Chief of Residents in the Residencing training: establishment and development in a Spanish hospital]

Training qualified medical specialists is one of the great supports of the Spanish health care system. The teaching structure of the hospital is essential for the correct development of this training. The figure of the chief resident (CR) is widely developed in the USA and Canada, but not in our country. Including this figure in the teaching organigram of our hospital has meant one more advance in the search for improving our teaching capacity. In the following, we explain our experience during the introduction and later development of the figure of CR, stressing its theoretical functions, the notification mechanism, constitution of the Residents' Committee and later development of activities and tasks conducted. After three years, our experience is favorable, subject to modifications, but adaptable to the idiosyncrasy of each site.

[Control of the dialysis dose by ionic dialysance and bioimpedance]

INTRODUCTION

The ionic dialysance monitor allows an automated measure of Kt in each dialysis session. Bioelectrical impedance analysis (BIA) determines the total body water which it is equivalent to the urea volume of distribution (V). If the Kt, determined by ionic dialysance, is divided by the V, estimated by bioelectrical impedance, a Kt/V at the end of dialysis session (Kt/VDiBi) is obtained.

AIM OF THE STUDY

To evaluate the agreement between the Kt/VDiBi and the Kt/V obtained by two simplified formulas: the monocompartimental (Kt/Vm) and the equilibrated (Kt/Ve) Daugirdas equations.

METHODS

The Kt/VDiBi, the Kt/Vm and the Kt/Ve were determined in 38 hemodialysis patients (27 males and 11 females) in the same hemodialysis session. The patients were on dialysis three times a week for 3.5 to 4 hours. The V was determined by monofrequency bioelectrical impedance (50 kHz) at the end of the dialysis session.

RESULTS

The Kt/VDiBi, Kt/Vm and Kt/Ve were 1.29+/-0.26, 1.54+/-0.29 and 1.36+/-0.25, respectively (p<0.001 between the Kt/VDiBi and the KtVm, and p<0.001 between the KtV/DiBi and the Kt/Ve). The intraclass correlation coefficient showed better concordance between the KtV/DiBi and the Kt/Ve (coefficient 0.88) than between the Kt/VDiBi and the KtVm (coefficient 0.65). The relative difference of the Kt/VDiBi was 8.3+/-6.4% with respect to the Kt/Ve and 18.4+/-7.8 % with respect to the Kt/Vm (p<0.001). The relative difference between the Kt/VDiBi and the Kt/Ve was lower than 15% in the 84% of the patients and lower than 10% in the 64% of the patients.

CONCLUSIONS

If the V obtained by bioelectrical impedance analysis is included in the ionic dialysance monitor, we can obtain a Kt/V for each patient in real time, which is similar to the equilibrated Kt/V obtained from the Daugirdas equation.

[The Cockcroft-Gault equation is better than MDRD equation to estimate the glomerular filtration rate in patients with advanced chronic renal failure]

ABSTRACT The aim of this study was to compare the accuracy of three kidney function estimating equations: classic Cockcroft-Gault (classic CG), corrected Cockcroft-Gault (corrected CG) and simplified Modification of Diet in Renal Disease (MDRD), in patients with advanced chronic renal failure. The study was made in 84 nondialyzed patients with chronic renal disease in stage 4 or 5. The glomerular filtration rate was measured on a 24-hour urine collection as the arithmetic mean of the urea and creatinine clearances (CUrCr). In each patient, the difference between each estimating equation and the measured glomerular filtration rate was calculated. The absolute difference expressed as a percentage of the measured glomerular filtration rate indicates the intermethod variability. In the total group the glomerular filtration rate measured as the CUrCr was de 13,5+/-5,1 ml/min/1.73 m(2); and the results of the estimating equations were: classic CG 14,2+/-5 (p<0,05); corrected CG 12+/-4,2 (p<0,01) and MDRD : 12,1+/-4,8 ml/min/1.73 m(2) (p<0,01). The variability of the estimating equations was 15,2+/-12,2%, 17,1+/-13,4 % and 19,3+/-13,3% (p<0,05), for classic CG, corrected CG and MDRD respectively. The percent of estimates falling within 30% above o below the measured glomerular filtration rate was 90% for CG classic, 87% for corrected CG and 79% for MDRD. The intraclass correlation coefficients respect to CUrCr were 0,86 for classic CG, 0,81 for corrected CG and 0,77 for MDRD. The MDRD variability, but not classic CG variability or corrected CG variability, showed a positive correlation with the glomerular filtration rate (r=0,25, p<0,05). In patients with chronic renal disease in stage 5, the variability of the different estimating equations was similar. We conclude that in our population with advanced chronic renal failure the classic CG equation is more accurate than the MDRD equation. Corrected CG equation has not any advantage respect to classic CG equation.

[Temperature dialysate and hemodialysis tolerance]

In this study, the effect of dialysate temperature on hemodynamic stability, patients' perception of dialysis discomfort and postdialysis fatigue were assessed. Thirty-one patients of the morning shift were eligible to participate in the study. Three patients refused. Patients were assessed during 6 dialysis sessions: in three sessions the dialysate temperature was normal (37 degrees C) and in other three sessions the dialysate temperature was low (35.5 degrees C). To evaluate the symptoms along the dialysis procedure and the postdialysis fatigue, specific scale questionnaires were administered in each dialysis session and respective scores were elaborated. Low temperature dialysate was associated with higher postdialysis systolic blood pressure (122 +/- 24 vs. 126 +/- 27 mmHg, p < 0.05), and lower postdialysis heart rate (82 +/- 13 vs. 78 +/- 9 beats/min, p < 0.05) with the same ultrafiltration rate. Dialysis symptoms score and postdialysis fatigue score were better with the low dialysate temperature (0.7 +/- 0.9 vs. 0.4 +/- 1 vs. p < 0.05, and 1.3 +/- 1 vs. 1 +/- 0.9 p < 0.05, respectively). Furthermore, low temperature dialysate shortened the post-dialysis fatigue period (5.4 +/- 6.3 vs. 3.1 +/- 3.3 vs. hours, p < 0.05). The clinical improvement experimented with the low temperature dialysate was not universal. A beneficial effect was exclusively observed in the patients with higher dialysis symptoms and postdialysis fatigue scores or having more than one episode of hypotension in a week. The patients were asked about their temperature preference, 7 patients (23%) request a dialysate at 37 degrees C, 19 patients (61%) prefered to be dialysed with the low temperature dialysate, and 5 patients (16%) were indifferent. The later two groups of the patients continued with the low temperature dialysate during other 4 weeks. At the end of that period, the clinical improvement remained unchanged. In summary, low temperature dialysate is particularly beneficial for highly symptomatic patients.

[Urea distribution volume calculated by ionic dialysance]

BACKGROUND

Direct dialysis quantification is considered the gold standard for determining urea distribution volume, but it is impractical for routine use. So, urea distribution volume in hemodialysis patients is usually estimated from anthropometric equations. Ionic dialysance allows to calculate the urea distribution volume dividing the Kt obtained by ionic dialysance by the Kt/V obtained by a simplified formula. The aim of the present work was to analyse the concordance between the ionic dialysance and the direct dialysis quantification methods to estimate de urea distribution volume.

MATERIAL AND METHODS

In 15 hemodialysis patients (10 males and 5 females), we have estimated the urea distribution volume by the direct dialysis quantification (Vurea), by the anthropometrics equations of Watson (VWatson) and Chertow (VChertow) and by the ionic dialysance method (VDI). To obtain VDI we have used two simplified Kt/V formulas: the monocompartimental and the equilibrated Daugirdas equations (VDIm and VDIe respectively). The intermethod variability was assessed by the relative difference (absolute difference between VUrea and the other methods, divided by the mean).

RESULTS

VUrea (26,2 L) was statistically different from theVDIe (30,6 L, p < 0.01), VWatson 35.2 L (p < 0.001) and VChertow (38 L, p < 0.001). VDIm was 26.3 L (p = ns). VUrea represents the 42% of the body weight for the males (range 36 to 49%) and the 33% of the body weight for the female (range 28 to 38%). The intermethod variability was high for the VDIe (21.6%), VWatson (37.4%) and VChertow (48. 1%), but it was low for the VDIm (9.9%).

CONCLUSIONS

Urea distribution volume calculated by the ionic dialysance method using the monocompartimental Daugirdas Kt/V equation has an acceptable agreement with the urea distribution volume calculated by the direct dialysis quantification. Anthropometry-based equations overestimate the urea distribution volume in hemodialysis patients.