Analysis of Electrocardiographic Criteria of Right Ventricular Hypertrophy in Patients with Chronic Thromboembolic Pulmonary Hypertension before and after Balloon Pulmonary Angioplasty.

BACKGROUND: Chronic thromboembolic pulmonary hypertension (CTEPH) may lead to typical electrocardiographic changes that can be reversed by balloon pulmonary angioplasty (BPA). The aim of this study was to investigate the significance of rarely used electrocardiogram (ECG) parameters, possible electrocardiographic differences between residual and significantly improved CTEPH and the role of electrocardiographic parameters in low mPAP (mean pulmonary arterial pressure) ranges since the mPAP threshold for the definition of pulmonary hypertension has recently been adjusted (≥25 mmHg to >20 mmHg). MATERIAL AND METHODS: Between March 2014 and October 2020, 140 patients with CTEPH and 10 with CTEPD (chronic thromboembolic pulmonary disease) without pulmonary hypertension (PH) were retrospectively enrolled (12-lead ECG and right heart catheterization before and 6 months after BPA). The ECG parameters of right heart strain validated by studies and clinical experience were evaluated. Special attention was paid to six specific ECG parameters. After BPA, the cohort was divided into subgroups to investigate possible electrocardiographic differences with regard to the haemodynamic result. RESULTS: The present study confirmed that the typical electrocardiographic signs of CTEPH can be found on an ECG, can regress after BPA and partially correlate well with haemodynamic parameters. "R V1, V2 + S I, aVL - S V1" was a parameter of particular note. BPA reduced its frequency (47% vs. 29%) statistically significantly after Bonferroni correction (p < 0.001). Moreover, it showed a good correlation with mPAP and PVR (r-values: 0.372-0.519, p-values: < 0.001). Exceeding its cut-off value before therapy was associated with more severe CTEPH before therapy (higher mPAP, PVR, NT-pro-BNP and troponin and lower TAPSE) and an increased risk of death. Exceeding its cut-off value before and after therapy was associated with more severe CTEPH after therapy (higher RAP, mPAP, PVR, NT-pro-BNP and NYHA class) and an increased risk of death. Men tend to be affected more frequently. After subgrouping, it was observed that a higher median mPAP was associated with a higher right atrial pressure (RAP), a higher pulmonary vascular resistance (PVR) and a lower cardiac output (CO) before and after BPA. In addition, under these conditions, more and more severe electrocardiographic pathologies were detected before and after BPA. Some patients with low mPAP also continued to show mild ECG changes after BPA. In some cases, very few to no pathological ECG changes were detected, and the ECG could present as mostly normal in some patients (5% before BPA and 13% after BPA). CONCLUSION: "R V1, V2 + S I, aVL - S V1" seems to be able to support the diagnosis of CTEPH, indicate therapeutic improvement and estimate haemodynamics. It also seems capable of predicting a (persistent) severe disease with probably increased need for therapy and increased mortality. Mild PH has been observed to have either no or few mild ECG changes. This might complicate the (early) detection of PH.

Uninterrupted use of direct oral anticoagulants versus vitamin K antagonists for catheter ablation of atrial fibrillation with PVAC gold: incidence of silent cerebral microembolic events.

BACKGROUND: Silent cerebral microembolic events (SCE) after duty-cycled ablation of atrial fibrillation using PVAC have been detected by cerebral magnet resonance imaging (MRI) in a substantial number of patients. The purpose of this study was to investigate if uninterrupted oral anticoagulation with non-vitamin K antagonists (NOACs) compared with vitamin K antagonists (VKA) affects the incidence of SCE after pulmonary vein isolation (PVI) using PVAC Gold. METHODS: Eighty-four consecutive patients (62 ± 15 years, 58% male) undergoing a first PVI were prospectively enrolled. Of these, 42 were on VKA and 42 on uninterrupted NOAC treatment. An activated clotting time (ACT) ≥ 350 s was targeted for ablation. RESULTS: Cerebral MRI the day after PVI revealed acute diffusion-weighted positive lesions in 11/42 (26%) VKA compared with 14/42 (33%) in NOAC patients (p = 0.634). No differences were found for lesion size, number of lesions/patient, and number of lesions indicating cerebral infarction (2.4% for VKA and 4.8% for NOAC patients). Seventy-five percent of NOAC patients with sporadic ACT levels < 300 s during PVI developed SCE compared with 22% of corresponding VKA patients (p = 0.030). VKA and NOAC subgroups with ACT ≥ 350 s had no reduced incidence of SCE compared with ACT 300-350 s. CONCLUSIONS: A significant, but comparable, number of patients under uninterrupted anticoagulation with VKA or NOACs still experience SCE after PVAC Gold PVI. NOAC patients with sporadic subtherapeutic ACT levels during PVI are at the highest risk for SCE while permanent ACT levels ≥ 350 s did not further reduce the incidence of SCE in both groups.

Is the time of atrial fibrillation recurrence after cryoballoon ablation of paroxysmal atrial fibrillation influenced by the pattern of PV reconnections?

BACKGROUND: Pulmonary vein isolation (PVI) with 2nd-generation cryoballoon (CB) has been shown to be effective in the treatment of paroxysmal atrial fibrillation (AF). We describe pulmonary vein (PV) reconnection at repeat ablation in patients with AF recurrence after CB PVI and analyze the correlation between the time of AF recurrence and the observed PV reconnection patterns. METHODS: Sixty-six patients undergoing a redo PVI for recurrent AF were enrolled 9.1 ± 2.6 months after the initial CB PVI procedure. RESULTS: Ninety-two percent had PV reconnections with a mean of 1.97 ± 0.8 reconnected PVs/patient, and 52% of formerly isolated PVs were found reconnected. The highest reconnected rates were observed for left superior PVs (67%). Fifty-three percent of the patients had 2 reconnected PVs, no patient had all PVs reconnected, and 8% were without PV reconnection. There was a significant negative correlation between the time of AF recurrences and the extent of PV reconnections at redo PVI for patients with proven PV reconnection in more than one PV (R = 0.52, p < 0.001), while all patients without PV reconnection had AF recurrences within the first 9 months after PVI. CONCLUSIONS: At redo ablation, most patients with recurrence of AF after CB PVI had PV reconnection(s). Patients with PV reconnection(s) showed a negative correlation between the number of reconnected PVs and the time of AF recurrence with more extensive PV reconnections resulting in earlier PV recurrences after the blanking period. Patients without PV reconnection experienced early AF recurrences, indicating non-PV triggers contributing for paroxysmal AF recurrences in these patients.

Correlation of pulmonary vein reconnection patterns after cryoballoon and duty-cycled ablation of atrial fibrillation with the time of arrhythmia recurrence.

BACKGROUND: Pulmonary vein isolation (PVI) is safe and effective in the treatment of atrial fibrillation (AF). We compare and correlate pulmonary vein (PV) reconnection patterns at repeat ablation in patients with recurrent AF after PVI using duty-cycled radiofrequency (RF) technology (PVAC) or second-generation cryoballoon (CB) with the time of AF recurrence. METHODS AND RESULTS: In total, 85 PVAC and 66 CB patients undergoing a second ablation were enrolled 9.7 ± 3.4 months after initial PVI. PV reconnections were comparably high between both groups (93% PVAC and 92% CB patients). A mean of 2.79 ± 1.2 PVs/patient were reconnected after PVAC PVI compared with 1.97 ± 0.8 in CB patients, P < .0001. 33% PVAC patients, but no CB patient had 4 reconnected PVs (P < .0001). Early AF recurrences were more frequently observed in PVAC patients with ≥2 reconnected PVs, in CB patients with ≥3 reconnected PVs (both P < .01) and patients without PV reconnection, irrespective of the ablation technique. One reconnected PV was associated with late AF recurrence only in CB patients. The correlation between number of reconnected PVs and time of AF recurrence was -0.32 for PVAC and -0.52 for CB. CONCLUSIONS: CB PVI was associated with greater durability and lesser PV reconnections/patient. There were negative correlations for both devices between extent of PV reconnections and time of AF recurrence. CB patients with early AF recurrences- although less frequently observed compared with PVAC patients had more reconnected PVs than PVAC patients, suggesting additional effects for AF prevention after CB PVI.

A modified fluoroscopy protocol to minimize radiation exposure during pulmonary vein isolation with second-generation cryoballoon.

BACKGROUND: Pulmonary vein isolation (PVI) using second-generation cryoballoon (CB2) is considered to be safe and effective in the treatment of atrial fibrillation (AF). Reported radiation exposure during PVI with CB2 is higher if compared with other technologies. We investigated acute and mid-term effects of a modified fluoroscopy protocol to minimize radiation exposure during CB2 PVI with regard to safety and efficacy. METHODS: The study comprised 180 consecutive patients undergoing CB2 PVI. In the first 100 patients, PVI was performed using conventional fluoroscopy settings (group 1), while the following 80 patients (group 2) received PVI with a modified protocol. The protocol consisted of (a) general reduction of fluoroscopy frame rate to 3/s, (b) avoidance of cine runs and selective PV angiograms, and (c) enhanced radiation awareness. Retrospective data analysis was performed in respect to dose area product (DAP), fluoroscopy time, and freedom from AF during a 12-month follow-up. RESULTS: Group 2 patients had lower DAP (426 ± 433 vs 3334 ± 2271 cGycm2 ), fluoroscopy time (13.8 ± 6.3 vs 16.7 ± 5.6 minutes), LA dwell time (49.3 ± 15.5 vs 61.6 ± 16.2 minutes), and procedure time (85.5 ± 22.9 vs 94.9 ± 23.6 minutes); P < .01 for all. One-year freedom from AF was comparable between both groups (71% group 1 vs 73% group 2, ns). CONCLUSION: Radiation exposure and procedure time during CB2 PVI can be significantly reduced by using a modified fluoroscopy protocol and increased radiation awareness without compromising acute and 1-year freedom from AF if performed by experienced operators.

Is the Time of Atrial Fibrillation Recurrence After Duty-Cycled Radiofrequency Ablation Affected by the Pattern of Pulmonary Vein Reconnections?

BACKGROUND: Pulmonary vein isolation (PVI) with multielectrode duty-cycled radiofrequency (PVAC) has been shown to be effective in the treatment of atrial fibrillation (AF). We describe pulmonary vein (PV) reconnection at repeat ablation in patients with AF recurrence after PVAC PVI and analyze the correlation between the time of AF recurrence and the observed PV reconnection patterns. METHODS: Eighty-five patients undergoing a redo PVI for recurrent AF 9.2 ± 3.8 months after an initial PVAC PVI procedure was retrospectively enrolled. RESULTS: A total of 93% had PV reconnections with a mean of 2.97 ± 1.2 reconnected PVs/patients and 75% of formerly isolated PVs were found reconnected. The highest reconnection rates (94%) were observed for left common trunks (CTs). A total of 33% patients had three and four reconnected PVs, respectively, while 7% were without PV reconnection. There was a moderate but significant negative correlation between the time of AF recurrences and the extending of PV reconnections at redo PVI for patients with proven PV reconnection (r = -0.32, P = 0.005), whereas five out of six patients without PV reconnection had recurrences within the first 9 months after PVI. CONCLUSIONS: At redo ablation most patients with recurrence of AF after PVAC PVI had PV reconnection(s). Patients with PV reconnection(s) showed a moderate negative correlation between the number of reconnected PVs and the time of AF recurrence with more extensive PV reconnections resulting in earlier PV recurrences after the blanking period. Patients without PV reconnection experienced early AF recurrences, indicating non-PV triggers contribute to AF recurrences in these patients.

Comparison of pulmonary vein reconnection patterns after multielectrode phased radiofrequency- and cryoballoon ablation of atrial fibrillation.

BACKGROUND: Pulmonary vein isolation (PVI) using phased radiofrequency (RF) energy has been shown to be effective in the treatment of atrial fibrillation (AF). METHODS: We characterize and compare pulmonary vein (PV) reconnection at repeat ablation in patients with AF after initially successful PVI using phased RF technology (PVAC) or 2nd generation cryoballoon (CB). Eighty five patients undergoing redo PVI using multielectrode PVAC phased RF catheter and 66 patients after CB PVI were enrolled 9.7 ± 3.4 months after the initial ablation procedure. RESULTS: The percentage of patients with PV reconnection(s) was comparably high between both groups (93% PVAC and 92% CB). However, 75% of all PVs and left common trunks (CTs) isolated with PVAC were reconnected, compared with 52% reconnections after CB PVI (p < 0.001). A mean of 2.79 ± 1.2 PVs and CTs/patient were reconnected after PVAC PVI compared with 1.97 ± 0.8 in CB patients, p < 0.0001. No patients in the CB group had 4 reconnected PVs, while this pattern of reconnection was observed in 33% in the PVAC group (p < 0.0001). The percentage of patients in the PVAC group with ≥3 reconnected PVs was significantly higher compared with CB patients (56 patients (66%) vs. 17 patients (26%), p < 0.0001), while the percentage of patients with no PV reconnection was comparably low in PVAC and CB patients (7 and 8%, respectively). CTs were most frequently reconnected after PVAC PVI (94%) and left superior PVs after CB ablation (67%), respectively. CONCLUSIONS: The number of patients with recurrent AF and PV reconnection(s) at redo PVI was comparably high between both groups. However, the extent and distribution of PV reconnections was different in many aspects, indicating more stable atrial lesions after CB PVI compared with PVAC technology.

A subvalvular catheter approach for radiofrequency ablation of right-sided accessory pathways.

BACKGROUND: Conventional catheter ablation of right-sided accessory pathways (RAPs) can be challenging. OBJECTIVE: To determine if a subvalvular catheter approach for RAPs targeting the ventricular insertion site, as on the left side, can improve catheter stability and tissue contact and thus increase acute and chronic ablation success rates. METHODS AND RESULTS: We retrospectively compared 22 patients (pts) with conventional catheter ablation of RAPs (group 1) with 9 consecutive pts (group 2) undergoing catheter ablation of a RAP using a subvalvular catheter approach targeting the ventricular site of AP. Ablation failed in 2/22 group 1 vs 0/9 group 2 pts (ns) and recurrences of AP conduction were registered in 4/19 group 1 vs 1/9 group 2 pts (ns) during follow-up. Significant shorter values were found in group 2 pts compared with group 1 for number of RF applications (3.6 ± 1.6 vs 8.2 ± 4.3), AP block time (6.2 ± 2.4 vs 9.2 ± 3.9 min), fluoroscopy time (17.2 ± 6.9 vs 25.6 ± 10.3 min), and procedure time (70.8 ± 23.9 vs 138 ± 44.4 min). There were no procedure related complications. CONCLUSION: Catheter ablation of RAPs using a subvalvular approach seems as effective and safe compared with conventional ablation but with reduced procedure time and radiation exposure and might be at least considered an alternative after failed conventional catheter ablation of RAPs.

Incidence of early pulmonary vein reconnections using different energy sources for pulmonary vein isolation: Multielectrode phased radiofrequency vs second-generation cryoballoon.

OBJECTIVE: To determine and compare the incidence of early recurrence of conduction after pulmonary vein isolation (PVI) using two different ablation technologies: phased radiofrequency by a multipolar ablation catheter (PVAC) and cryo-ablation by a second-generation cryoballoon (CB). METHODS AND RESULTS: Two hundred patients (pts) with atrial fibrillation underwent PVI with PVAC (Group 1) or CB (Group 2), with 100 pts in each group. The incidence of PV reconnection (PVR) for each vein was examined in both groups at least 30 minutes after successful PVI. There were no significant clinical differences between both groups. Total procedure-, fluoroscopy-, and left atrial (LA) dwell time were significantly shorter in Group 2 pts (P < .0001). Early PVR was recorded in 69/388 (18%) isolated PVs or left common trunks (CTs) in Group 1 compared with 25/386 (7%) in Group 2 (P < .0001). Forty-three pts in Group1 were found to have PVR compared with 22 pts in Group 2 (P = .0015). Group 1 pts with CTs showed significantly more PVR than pts of Group 2 (P = .047). In both groups, CTs and CT branches were found to reconnect significantly more frequent compared with all other veins. CONCLUSION: Both PVAC and CB are effective to achieve PVI. Early PVR is observed with the significantly lower frequency with second-generation CB compared with PVAC, contributing to shorter procedure-, fluoroscopy, and LA dwell times. CTs and CT branches exhibit the highest incidence of PVR for both devices.

Follow-Up (Measurement) of Corrected QT Interval in Adult Patients before and after Lung Transplantation.

BACKGROUND: Prolongation of the corrected QT (QTc) interval is well known for many drugs, some of which are an integral part of the therapeutic regimen after lung transplantation (LTX). Therefore, we investigated the QTc interval after LTX in the present study. PATIENTS AND METHODS: The medical records of patients after LTX were studied for demographic data, indication of LTX, medication, and baseline and follow-up ECGs. The QT interval was corrected for the patient's heart rate using the different formulae of Bazett, Fridericia, Hodges, and Framingham. RESULTS: Fifty-nine patients were included. The mean age ± SD was 55.6 ± 7.8 years (median 58 years). After LTX, QTc intervals showed no (relevant) changes during follow-up, even though all patients were treated with drugs (in combination) known to bear a risk of prolonged QTc interval and cortisone. The longest QTc intervals were obtained using Bazett's formula. CONCLUSION: The QTc interval did not increase under immunosuppressive medication after LTX in our cohort of patients. We speculate that the concurrent use of cortisone may shorten the QT(c) intervals or cancel out drug-induced prolongation of the QTc interval.

Is there a prognostic relevance of electrophysiological studies in bundle branch block patients?

BACKGROUND: The present European guidelines suggest a diagnostic electrophysiological (EP) study to determine indication for cardiac pacing in patients with bundle branch block and unexplained syncope. We evaluated the prognostic relevance of an EP study for mortality and the development of permanent complete atrioventricular (AV) block in patients with symptomatic bifascicular block and first-degree AV block. HYPOTHESIS: The HV interval is a poor prognostic marker to predict the development of permanent AV block in patients with symptomatic bifascicular block (BFB) and AV block I°. METHODS: Thirty consecutive patients (mean age, 74.8 ± 8.6 years; 25 males) with symptomatic BFB and first-degree AV block underwent an EP study before device implantation, according to current guidelines. For 53 ± 31 months, patients underwent yearly follow-up screening for syncope or higher-degree AV block. RESULTS: Thirty patients presented with prolonged HV interval during the EP study (mean, 82.2 ± 20.1 ms; range, 57-142 ms), classified into 3 groups: group 1, <70 ms (mean, 62 ± 4 ms; range, 57-67 ms; n = 7), group 2, >70 to ≤100 ms (mean, 80 ± 8 ms; range, 70-97 ms; n = 18), and group 3, >100 ms (mean, 119 ± 14 ms; range, 107-142 ms; n = 5). According to the guidelines, patients in groups 2 and 3 received a pacemaker. The length of the HV interval was not associated with the later development of third-degree AV block or with increased mortality. CONCLUSIONS: Our present study suggests that an indication for pacemaker implantation based solely on a diagnostic EP study with prolongation of the HV interval is not justified.

Contraindications for video capsule endoscopy.

Video capsule endoscopy (VCE) has been applied in the last 15 years in an increasing field of applications. Although many contraindications have been put into perspective, some precautions still have to be considered. Known stenosis of the gastrointestinal tract is a clear contraindication for VCE unless surgery is already scheduled or at least has been considered as an optional treatment modality. In patients with a higher incidence of stenosis, as in an established diagnosis of Crohn's disease, clinical signs of obstruction, prior radiation or surgical small bowel resection, a preceding test with the self-dissolving patency capsule can override this contraindication. Endoscopic placement of the capsule should be considered in patients with swallowing disorders to avoid aspiration. Esophageal or gastric motility disorders may require endoscopic capsule transport or application of prokinetics if the real-time viewer proofs delayed transit. In pregnant women, VCE should be restricted to urgent cases where diagnosis cannot be postponed after delivery, as data on safety are missing. There is theoretical and clinical evidence that patients with implanted cardiac devices such as a pacemaker, cardioverters or left heart assist devices, can safely undergo VCE in spite of still existing contraindication by manufacturers. Children from the age of 2 years have safely undergone VCE. Although video capsules are not proven safe with magnetic resonance imaging (MRI), first single cases of patients incidentally undergoing MRI with an incorporated capsule have been reported, showing susceptibility artifacts but no signs of clinical harm.

Evaluation of the prognostic value of electrocardiography parameters and heart rhythm in patients with pulmonary hypertension.

BACKGROUND: Several studies have analyzed arrhythmias in patients with pulmonary hypertension (PH) and increased P-wave duration was identified as a risk factor for development of atrial fibrillation (AF). METHODS: We retrospectively analyzed the incidence of arrhythmias in patients with an initial diagnosis of PH during long-term follow-up and assessed the prognostic value of electrocardiography (ECG) data. Data from 167 patients were analyzed (Dana Point Classification: Group 1: 59 patients, Group 2: 28 patients, Group 3: 39 patients, Group 4: 41 patients). Clinical, 6-min-ute walk distance test, echocardiography and right heart catheterization data were collected, and baseline/follow-up ECGs were analyzed. RESULTS: Baseline ECGs revealed sinus rhythm in 137 patients. Thirteen patients had newly onset AF during follow-up. In 30 patients, baseline ECG showed AF. Patients with baseline AF showed higher atrial diameters and higher right atrial pressure. Patients with P-wave du-ration > 0.11 s had shorter survival. Other ECG parameters (PQ-interval, QRS-width, QT-/ /QTc-interval) were not associated with survival. Mean survival times were 79.4 ± 5.4 months (sinus rhythm), 64.4 ± 12.9 months (baseline AF) and 58.8 ± 8.9 months (newly onset AF during follow-up) (p = 0.565). CONCLUSIONS: Atrial fibrillation predict adverse prognosis in patients with PH and a longer P-wave (> 0.11 s) is associated with shorter survival time.

Transient Elimination of Posterior Right Ventricular Outflow Tract Ectopy by Sternal Pressure.

BACKGROUND: Ventricular ectopy (VE) originating in the right ventricular outflow tract (RVOT) is a common arrhythmia. Mechanisms triggering or eliminating VE from RVOT are not entirely understood. METHODS AND RESULTS: A patient with frequent, symptomatic VE underwent an electrophysiologic study: VE origin was mapped by NavX 3D navigation (St. Jude Medical, Inc., St. Paul, MN, USA). Incidental pressure applied manually to the sternum reproducibly eliminated VE for the time of exposure. Radiofrequency-ablation was successfully performed in the posterior RVOT. CONCLUSION: The mechanism resulting in VE suppression remains speculative, since a mechanical alteration of the substrate for VE in the posterior RVOT by sternal pressure seems unlikely. "Mechano-electrical feedback" might have been the mechanism operative in this case.

Prognostic Relevance of Nonsustained Ventricular Tachycardia in Patients with Pulmonary Hypertension.

Background. Increased pulmonary vascular resistance in patients with pulmonary hypertension (PH) leads to an increased afterload of right heart and cardiac remodeling which could provide the substrate or trigger for arrhythmias. Supraventricular arrhythmias were associated with clinical deterioration but were not associated with sudden cardiac death (SCD). SCD has been reported to account for approximately 30% of deaths in patients with pulmonary arterial hypertension (PAH). Objective. The role of nonsustained ventricular tachycardia (nsVT) and its prognostic relevance in patients with PH remains unclear. This study evaluated the prognostic relevance of nsVT in patients with PAH and chronic thromboembolic pulmonary hypertension (CTEPH). Methods. Retrospectively, patients with PAH and CTEPH who underwent Holter ECG monitoring and available data of survival were investigated. Results. Seventy-eight (PAH: 55, CTEPH: 23) patients were evaluated. Holter ECG revealed nsVT in 12 patients. Twenty-one patients died during follow-up. In patients with nsVT, tricuspid annular plane systolic excursion was lower (p = 0.001), and systolic pulmonary arterial pressure was higher (p = 0.163). Mean survival of patients without/with nsVT was 155.2 ± 8.5/146.4 ± 21.4 months (p = 0.690). The association between arrhythmias and survival was not confounded by age (p = 0.681), gender (p = 0.752), 6-MW distance (p = 0.196), or arterial hypertension (p = 0.238). Conclusions. In patients with PH, nsVT occurs more often than previously reported, and patients with PH group 1 seem to be more at risk.

Usefulness of N-acetylcysteine or ascorbic acid versus placebo to prevent contrast-induced acute kidney injury in patients undergoing elective cardiac catheterization: a single-center, prospective, randomized, double-blind, placebo-controlled trial.

BACKGROUND: Contrast-induced acute kidney injury (CI-AKI) is a serious complication of procedures requiring contrast media associated with rising costs, prolonged hospitalization, and increased mortality. The aim of this study was to assess whether prophylactic administration of standard dosages of intravenous N-acetylcysteine or ascorbic acid reduce the incidence of CI-AKI in patients with chronic renal insufficiency undergoing elective cardiac catheterization. METHODS: In a single-center, prospective, randomized, double-blind, placebo-controlled trial, the preventive effects of N-acetylcysteine and ascorbic acid were evaluated in 520 patients with chronically impaired renal function (serum creatinine ≥1.3 mg/dL) undergoing elective cardiac catheterization. The study drugs (600 mg N-acetylcysteine, 500 mg ascorbic acid, placebo) were administered intravenously twice (at 24 hours and 1 hour before the procedure). Serum creatinine, estimated glomerular filtration rate (eGFR) and serum urea were assessed at baseline and at 24 hours and 72 hours after contrast media exposure. CI-AKI was defined as a postangiographical increase in serum creatinine ≥0.5 mg/dL. Results. The incidence of CI-AKI was 27.6% in the N-acetylcysteine group (P=.20 vs placebo group) and in 24.5% in the ascorbic acid group (P=.11 vs placebo group). CI-AKI occurred in 32.1% of the placebo group. CONCLUSIONS: Standard doses of N-acetylcysteine and ascorbic acid did not prevent CI-AKI in patients at high risk undergoing cardiac catheterization with non-ionic, low-osmolality contrast agent.

Right atrial tachycardias related to regions of low-voltage myocardium in patients without prior cardiac surgery: catheter ablation and follow-up results.

AIMS: There are only few descriptions of patients without prior cardiac surgery in whom a large low-voltage zone (LVZ) or scar is the electrophysiological substrate for various atrial tachycardias. We describe the electrophysiological and electroanatomic characteristics of unusual macroreentrant atrial tachycardias (MRATs) in seven patients with spontaneous right atrial (RA) scarring and present long-term follow-up results. METHODS AND RESULTS: In 7 of 326 patients with MRAT treated with radiofrequency ablation we detected regions of RA spontaneous LVZ or scarring during conventional mapping of the arrhythmia. They underwent electroanatomic mapping and catheter ablation of the spontaneous and further induced arrhythmias with a long-term follow-up. A total of 17 different atrial tachycardias were observed with typical atrial flutter in four patients. In five patients a LVZ was found in the RA free wall and two patients had a septal scar. Stable circuits were around the scar or LVZ in four patients and through a 'channel' within the scar in two. Radiofrequency ablation sites included the cavotricuspid isthmus for typical atrial flutter, between the inferior vena cava and scar, a channel in the scar or the left atrial (LA) mitral isthmus. During follow-up of 34 ± 5 months, four patients were free from atrial tachycardias. Both patients with a septal RA scar developed LA tachycardias, requiring further catheter ablation. One patient presented with a novel type of atypical scar-related RA flutter. CONCLUSION: Mapping and ablation of scar-related RA tachycardias is an effective treatment but does not preclude the development of further tachycardias, some of them arising from the LA during long-term follow-up.

Does the number of simultaneously activated electrodes during phased RF multielectrode ablation of atrial fibrillation influence the incidence of silent cerebral microembolism?

BACKGROUND: Asymptomatic cerebral embolus (ACE) detected by diffusion-weighted magnetic resonance imaging (DW-MRI) following atrial fibrillation (AF) ablation has been reported at varying rates with different ablation techniques. OBJECTIVE: To evaluate the incidence of ACE after phased radiofrequency ablation for AF with procedural modifications that potentially reduce the embolic load. METHODS: One hundred twenty consecutive patients with AF underwent MRI before ablation, 24 hours after ablation, and at 4-6 weeks. In all patients, simultaneous activation of pulmonary vein ablation catheter electrode pairs 1 and 5 was forbidden. While in 60 group 1 patients, a maximum of 4 electrode pairs could be activated at a time, and in 60 group 2 patients, ablation was limited to a maximum of 2 pairs. All patients were on uninterrupted phenprocoumon, with an attempted activated clotting time of >300 seconds during ablation. RESULTS: Both patient groups were comparable. A total of 28 DW-positive lesions were detected in 24 of 120 patients (20%). Seventeen group 1 patients (28.3%) were positive for new asymptomatic DW cerebral lesions compared with 7 group 2 patients (11.7%) (P = .039). During MRI follow-up, 3 patients (2.5%) were diagnosed with a small T2-positive asymptomatic glial scar. Procedure time was longer in group 2 patients than in group 1 patients (159 ± 39 vs 121 ± 15; P < .001). CONCLUSIONS: Limiting the number of simultaneously activated electrode pairs to 2 significantly reduces the rate of ACE in patients treated with a multielectrode duty-cycled phased radiofrequency catheter system for AF. This reduction corresponds with a significant prolongation of the total procedure time.

Pulmonary vein re-isolation for atrial fibrillation using duty-cycled phased radiofrequency ablation: safety and efficacy of a primary 2:1 bipolar/unipolar ablation mode.

PURPOSE: Pulmonary vein isolation (PVI) using phased radiofrequency (RF) energy has been shown to be effective in the treatment of paroxysmal atrial fibrillation (AF). We characterize pulmonary vein (PV) conduction at repeat ablation in patients with AF after an initial successful PVI using phased RF technology and analyze the effects of a primary 2:1 ablation mode. METHODS AND RESULTS: A primary 4:1 bipolar/unipolar mode in group A patients (n = 22) was compared with a primary 2:1 mode in group B (n = 22) acutely and during follow-up. Of all PVs, 81 % showed reconnection(s); 52 % of them had reconnected in all PVs. PVI was achieved in all patients without complications. Procedure and fluoroscopy times were shorter in group B (108 ± 15 vs. 126 ± 24 min and 17 ± 5 vs. 23 ± 7 min, respectively). This was attributed to a significant decrease of early PV reconnections within the first 30 min in 17 % of group B patients vs. 45 % of group A patients (p < 0.001). After 9.5 ± 4 months, recurrence of AF was detected in 5 of 22 patients (22.7 %) in group A vs. 3 of 22 patients (13.6 %) in group B (p = 0.722). CONCLUSIONS: Phased RF energy applied by a 2:1 bipolar/unipolar mode seems safe and effective in redo-PVI procedures, resulting in a mid-term freedom from AF in 86.4%. Significant shorter procedure and fluoroscopy times compared with a primary 4:1 ablation mode during repeat PVI are mainly attributed to a lower incidence of acutely reconnected PVs within the first 30 min.