Biomedical subjects

Sabine Ernst

Publications and source records attributed to Sabine Ernst.

32 records · Page 2Linked to original sources

PubMed2003

Catheter-induced linear lesions in the left atrium in patients with atrial fibrillation: an electroanatomic study.

OBJECTIVES: In this study using radiofrequency current and the electroanatomic mapping system CARTO, four line designs were tested in 84 patients suffering from drug-refractory atrial fibrillation (AFib). BACKGROUND: Prevention of AFib by trigger elimination within the pulmonary veins (PVs) has been recently reported, but the success may be lesser in patients with chronic AFib or large atria requiring linear lesion deployment. METHODS: Type A encircled the ostia of all four PVs with a connection to the mitral annulus (MA). In type B, three lines connected anatomic barriers. Type C encircled both septal and lateral PVs with connections between PVs and to the MA. Type D encircled PVs only. In the initial 12 patients (type D/1), line validation was performed without, and in 23 patients (type D/2) with, an additional catheter inside the encircled PVs. RESULTS: The ability to achieve completeness of all intended lines was 5% in type A, 21% in type B, 29% in C, 66% in type D/1, and 61% in type D/2. This resulted in stable sinus rhythm in 19% (4/21 patients) in type A, 32% (6/19 patients) in type B, 50% (7/14 patients) in type C, 58% (7/12 patients) in type D/1, and 65% (15/23 patients) in type D/2, respectively, over a mean follow-up of 620 +/- 376 days. Besides thromboembolic events (one stroke and one transient ischemic attack), total occlusion of a PV was a major complication in one patient, and acute tamponade in two patients. CONCLUSIONS: Complete lesions in the left atrium were difficult to achieve using conventional radiofrequency current technology, but were associated with sinus rhythm in 74% of patients during long-term follow-up, whereas incomplete lesions led mostly to recurrences of AFib or gap-related atrial tachycardia.

Atrial Fibrillation↗

PubMed2003

An underrecognized subepicardial reentrant ventricular tachycardia attributable to left ventricular aneurysm in patients with normal coronary arteriograms.

BACKGROUND: In patients with apparently normal hearts, ventricular tachycardia (VT) may only involve the subepicardial myocardium. METHODS AND RESULTS: Four patients with exercise-induced fast VT with right bundle branch block morphology were investigated. ECG showed a small q wave in leads II, III, and aVF during sinus rhythm (SR) in all 4 patients. Left ventricular angiography showed small inferolateral aneurysms in all patients. Coronary arteriograms were normal in all 4 patients. Six unstable VTs (cycle length, 200 to 305 ms) and 1 stable VT (cycle length 370 ms) were reproducibly induced in the 4 patients. During SR, endocardial mapping was normal in all 4 patients, and epicardial mapping showed fragmented and late potentials in the left inferolateral wall anatomically consistent with the left ventricle aneurysm. During tachycardia, epicardial mapping showed a macroreentrant VT with focal endocardial activation in the patient with stable VT, whereas in 2 patients with unstable VT, a diastolic potential was only recorded and coincided with the late potential in the same area. Epicardial ablation was performed in 3 patients and successfully abolished those VTs. No VT recurred in 2 patients during follow-up of 2 and 9 months. Clinical VT recurred 6 months after the ablation and was successfully ablated in a repeated epicardial ablation in 1 patient. In the remaining patient without epicardial ablation, an implantable cardiac defibrillator was implanted. There were multiple shocks during a follow-up of 31 months. CONCLUSIONS: In patients with normal coronary arteriograms and left ventricle aneurysm, exercise-induced VT with right bundle branch block morphology may have a subepicardial arrhythmogenic substrate, which may be amenable to epicardial ablation.

Adult↗

PubMed2003

Catheter ablation of subepicardial ventricular tachycardia using electroanatomic mapping.

BACKGROUND: In patients with left ventricular tachycardia (VT) and failed endocardial ablation, a subepicardial substrate may be considered. PATIENTS AND METHODS: Seven patients with drug-refractory VT of right bundle branch block morphology were investigated to identify the arrhythmogenic substrate using three-dimensional (3-D) electroanatomic endocardial and epicardial mapping. RESULTS: In three patients with repetitive monomorphic VT, endocardial and epicardial mapping during tachycardia showed a focal pattern with an earliest activation preceding the onset of the QRS complex by 20 and 28 ms in the lateral aspect of the epicardial outflow tract in two patients and by 24 ms near the posterolateral mitral annulus in one patient; in two patients with sustained VT, endocardial mapping during tachycardia displayed a focal pattern with a wide breakthrough, and epicardial mapping showed a macroreentrant VT with an isthmus located in the left anterior wall in one patient and in the left inferolateral wall in the other. In the remaining two patients, endocardial and epicardial mapping were performed during sinus rhythm. An area with fragmented and late potentials as well as low amplitude was only identified in the epicardial left inferolateral wall. During tachycardia, a diastolic potential was only recorded on the epicardium and coincided with the late potential during sinus rhythm in the same area. A focal or linear epicardial irrigated lesion terminated the VT and resulted in noninducibility in all seven patients. During a median follow-up of 16 months, VT recurred in two patients without antiarrhythmic drugs. The recurrent VT was successfully reablated in one patient and treated with oral amiodarone in the other. CONCLUSION: Subepicardial left focal and macroreentrant VT may present as focal origin on endocardial mapping and can only be abolished by radiofrequency (RF) applications in the epicardial space.

Adult↗

PubMed2003

[Three-dimensional reconstruction of pulmonary veins and left atrium. Implications for catheter ablation of atrial fibrillation].

BACKGROUND: Selective pulmonary vein (PV) isolation to eliminate triggers is commonly used for curative catheter ablation of atrial fibrillation guided by two-dimensional (2-D) PV angiography, which is somewhat limited to depict the complex morphology of the PVs. 3-D mapping systems are limited to reconstruct the complete "true" anatomy by the reach of the mapping electrode related to catheter properties (maximum deflection and curve). New 3-D imaging systems (spiral computed tomography [CT] or magnetic resonance imaging [MRI]) provide detailed knowledge of the individual left atrial and PV morphology. Especially with the tampering, funnel-shaped PV ostia, identification of the PV ostium in selective PV isolation procedures aiming at the interruption of myocardial fibers is rather challenging using the 2-D imaging technique of contrast angiography. PATIENTS AND METHODS: In a total of 16 patients (13 male, three female, mean age 57 +/- 8 years), cardiac 3-D magnetic resonance angiography (MRA; 1.5 T, ACS Intera Philips, Germany) using an ECG-gated technique (1.3-1.7 mm slices) was performed. Using the postprocessing software Leonardo (Siemens, Germany), all adjacent anatomic structures such as the pulmonary artery were cut off to focus on the left atrium (LA) and PV anatomy. RESULTS: Left-sided PVs always entered in close proximity into the LA (common ostium in two patients). The right PVs entered more separately into the LA with a predominance of oval shapes. CONCLUSION: MRA is a noninvasive tool providing knowledge of the individual 3-D anatomy in a photorealistic fashion. Ultimately, image fusion with 3-D mappings systems would allow for true 3-D electrophysiologic mapping and could facilitate further understanding of the underlying substrate of so far "unsolved" complex arrhythmias such as atrial fibrillation in the future.

Aged↗

PubMed2003

A model for in vivo validation of linear lesions in the right atrium.

UNLABELLED: Linear lesions have been proposed for treatment of complex atrial arrhythmias including atrial macroreentry tachycardia and compartmentalization in atrial fibrillation. AIM: To judge the effectiveness of a given lesion design, definite endpoints are necessary to ascertain the completeness of the line of block produced. METHODS AND RESULTS: We report validation criteria for long linear lesions in the right atrium in 42 pts, that combine both conventional and 3D mapping information (CARTO). Transferring from the validation of bi-directional block of the cavotricuspid isthmus line for atrial flutter, we validated 2 additional long linear lesions in the right atrium (anterior line and intercaval line). In addition to a complete isthmus line in all 42 pts, in 28 pts a complete anterior line was achieved and validated by both conventional and CARTO criteria. A complete intercaval line was deployed in 11 pts with complete anterior and isthmus lines (with a characteristic shift for the intercaval line) and in 5 pts without a complete anterior line (without characteristic shift). CONCLUSIONS: Conventional catheters placed at strategic locations on opposite sides of the intended ablation line, can depict a sudden characteristic change in the activation sequence. Using a combination of both techniques, deployment and validation of long linear lesion can be facilitated.

Action Potentials↗

PubMed2003

Ostial PV isolation: is there a role for three-dimensional mapping?

Pulmonary vein (PV) isolation by elimination of spike potentials has been reported to cure drug refractory atrial fibrillation. Because of the heterogenous morphology of the PVs, sequential electroanatomic reconstruction of the PVs was performed in 39 patients (group A), who underwent subsequent PV isolation by interruption of all conductive myocardial fibers by distinct RF current applications using a "lasso" approach. In group B (157 patients), only biplane two-dimensional fluoroscopy was performed to guide the diagnostic and the ablation catheters. After reprocedures (in 7% of patients in group A and 22% of group B), which depicted a recurrence of a spike potential inside or at the ostium of >1 previously isolated PV in all restudied patients, stable sinus rhythm was documented in 69% of patients in group A and 60% of patients in group B. Reasons for the relapse of the previously eliminated spike potentials include a temporary ablation effect and a too distal interruption of the conducting myocardial fiber. Detailed knowledge of the individual three-dimensional morphology enhanced the clinical success rate of PV isolation but is time-consuming using CARTO (8.0 +/- 1.7 vs 5.0 +/- 1.6, P < 0.001). Further technical improvement to fuse the individual three-dimensional anatomy and the electrophysiological markers to a composed "electroanatomic" map may overcome this limitation in the future.

Action Potentials↗

PubMed2003

Total pulmonary vein occlusion as a consequence of catheter ablation for atrial fibrillation mimicking primary lung disease.

INTRODUCTION: Catheter ablation has recently been used for curative treatment of atrial fibrillation. METHODS AND RESULTS: Three of 239 patients who underwent ablation close to the pulmonary vein (PV) ostia at our institute developed severe hemoptysis, dyspnea, and pneumonia as early as 1 week and as late as 6 months after the ablation. Because the patients were arrhythmia-free, the treating physician initially attributed the symptoms to new-onset pulmonary disease (e.g., bronchopulmonary neoplasm). After absent PV flow was confirmed by transesophageal echocardiography, transseptal contrast injection depicted a totally occluded PV in all three patients. Successful recanalization, even in chronically occluded Pvs, was performed in all patients. During follow-up, Doppler flow measurements by transesophageal echocardiography demonstrated restenosis in all primarily dilated PV, which led to stent implantation. CONCLUSION: PV stenosis/occlusion after catheter ablation of atrial fibrillation occurs in a subset of patients. However, because in-stent restenosis occurred in two patients after 6 to 10 weeks, final interventional strategy for PV stenosis or occlusion remains unclear. To prevent future PV stenosis or occlusion, a decrease in target temperature and energy of radiofrequency current or the use of new energy sources (ultrasound, cryothermia, microwave) seems necessary.

Angiography↗

PubMed2002

Electroanatomic mapping and catheter ablation of breakthroughs from the right atrium to the superior vena cava in patients with atrial fibrillation.

BACKGROUND: The superior vena cava (SVC) is one of the sources of ectopies that can initiate atrial fibrillation (AF). We investigated by radiofrequency ablation the electrophysiological characteristics of the junction of the right atrium (RA) and the SVC and the feasibility of electrical disconnection of the SVC from the RA. METHODS AND RESULTS: Sixteen patients with paroxysmal AF after pulmonary vein isolation underwent electroanatomic mapping at the RA-SVC junction during sinus rhythm. Mapping showed sharp potentials (SVC potentials) inside the SVC. Activation spread from the earliest SVC potential (breakthrough) to the rest of the SVC. SVC potentials were found over a large amount of the circumference, suggesting widespread muscle coverage of the SVC. Breakthroughs from the RA to SVC were located anteriorly, laterally, posteriorly, and septally in 3, 4, 10, and 6 patients, respectively. The number of breakthroughs was 1.4+/-0.5 per patient. Radiofrequency energy was applied with the end point of electrical disconnection. All breakthroughs were eliminated with 3.1+/-1.7 applications per breakthrough without complications. CONCLUSIONS: SVC potentials can be recorded inside the SVC. There are specific breakthroughs from the RA to the SVC that can be identified by electroanatomic mapping. The electrical disconnection of the SVC from the RA is feasible.

Atrial Fibrillation↗

PubMed2002

Characterization of reentrant circuits in left atrial macroreentrant tachycardia: critical isthmus block can prevent atrial tachycardia recurrence.

BACKGROUND: Left atrial macroreentrant tachycardia (LAMRT) has not been characterized in detail. METHODS AND RESULTS: Twenty-eight patients with LAMRT, including 4 patients with ablated typical atrial flutter (AFL), underwent electroanatomic mapping of the left atrium (LA) between February 1999 and October 2001. LA maps were performed during LAMRT in 26 patients and during sinus rhythm in 2 patients. Electrically silent areas or continuous lines of double potentials were identified as acquired anatomic barriers in all patients. In 23 of 26 patients with LAMRT mapping, 42 reentry circuits with a protected isthmus were identified. The isthmus was 11.8+/-5.9 mm wide, with the maximal amplitude of 0.07 to 3.61 mV. Radiofrequency pulses terminated all LAMRTs in 23 patients and resulted in conduction block across the isthmus in 20 patients. In 2 patients with sinus mapping, all identified isthmuses were ablated. Additionally, AFL was induced and ablated in 6 patients. Atrial tachycardia recurred in 4 patients: 3 patients without validated block across the isthmus presented with recurrence of the same LAMRT, and 1 patient without ablated cavotricuspid isthmus presented with AFL. All tachycardias were abolished during a second procedure. Of 25 patients with identified isthmuses, 20 patients were without atrial arrhythmia and 5 had only atrial fibrillation during a median follow-up of 14 months. CONCLUSION: The reentry circuit with a protected isthmus can be identified in 89% patients with LAMRT by electroanatomic mapping. The isthmuses were amenable to radiofrequency applications in most patients. No atrial tachycardia recurred in any patients with isthmus block.

Adolescent↗

PubMed2002

Repetitive monomorphic ventricular tachycardia originating from the aortic sinus cusp: electrocardiographic characterization for guiding catheter ablation.

OBJECTIVES: We sought to investigate the electrocardiographic (ECG) characteristics for guiding catheter ablation in patients with repetitive monomorphic ventricular tachycardia (RMVT) originating from the aortic sinus cusp (ASC). BACKGROUND: Repetitive monomorphic ventricular tachycardia can originate from the right ventricular outflow tract (RVOT) and ASC in patients with a left bundle branch block (LBBB) morphology and an inferior axis. METHODS: Activation mapping and ECG analysis was performed in 15 patients with RMVT or ventricular premature contractions. The left main coronary artery (LMCA) was cannulated as a marker and for protection during radiofrequency delivery if RMVT originated from the left coronary ASC. RESULTS: During arrhythmia, the earliest ventricular activation was recorded from the superior septal RVOT in eight patients (group 1) and from the ASC in the remaining seven patients (group 2). The indexes of R-wave duration and R/S-wave amplitude were significantly lower in group 1 than in group 2 (31.8+/-13.5% vs. 58.3+/-12.1% and 14.9+/-9.9% vs. 56.7+/-29.5%, respectively; p < 0.01), despite similar QRS morphology. In five patients from group 2, RMVT originated from the left ASC, with a mean distance of 12.2+/-3.2 mm (range 7.3 to 16.1) below the ostium of the LMCA. In the remaining two patients, the RMVT origin was in the right ASC. All arrhythmias were successfully abolished. None of the patients had recurrence or complications during 9+/-3 months of follow-up. CONCLUSIONS: On the surface ECG, RMVT from the ASC has a QRS morphology similar to that of RVOT arrhythmias. The indexes of R-wave duration and R/S-wave amplitude can be used to differentiate between the two origins. Radiofrequency ablation can be safely performed within the left ASC with a catheter cannulating the LMCA.

Adolescent↗

PubMed2002

Electroanatomic substrate of idiopathic left ventricular tachycardia: unidirectional block and macroreentry within the purkinje network.

BACKGROUND: An abnormal potential (retroPP) from the left posterior Purkinje network has been demonstrated during sinus rhythm (SR) in some patients with idiopathic left ventricular tachycardia (ILVT). We hypothesized that this potential can specifically be identified and be a critical substrate for ILVT. METHODS AND RESULTS: In 9 patients with ILVT and 6 control patients who underwent mapping of the left ventricle during SR using 3-dimensional electroanatomic mapping, an area with retroPP was found within the posterior Purkinje fiber network only in patients with ILVT. The earliest and latest retroPP was 185.4+/-57.4 and 465.2+/-37.3 ms after Purkinje potential; in the other patient with ILVT, an entire left ventricle mapping demonstrated a slow conduction area and passive retrograde activation along the posterior fascicle during ILVT. ILVT was noninducible in 3 patients after SR mapping. Diastolic potentials critical for ILVT during ILVT coincided with the earliest retroPP during SR in 7 patients. Mechanical termination of ILVT occurred in 5 patients. A single radiofrequency pulse was applied at the site with mechanical translation in 5 patients and the site with diastolic potential in 2 patients, and 3 radiofrequency pulses were delivered to the site with the earliest retroPP in the other 3 patients without inducible ILVT after SR mapping. No ILVT was inducible during control stimulation, and none recurred during follow-up of 9.1+/-5.1 months. CONCLUSION: In patients with ILVT, abnormal retroPP within the posterior Purkinje fiber network is a common finding. The earliest retroPP critical for ILVT substrate can be used for guiding successful ablation.

Adolescent↗

PubMed2002

[Secondary catheter ablation of atrial fibrillation].

BACKGROUND: In patients with drug-refractory atrial fibrillation there are some non-pharmacologic therapeutic options for heart rate control or recurrence prophylaxis that do not primarily aim at the induction or maintenance of atrial fibrillation itself. AV NODE ABLATION AND MODULATION: Using radiofrequency ablation AV nodal conduction can be completely interrupted (AV node ablation) or partly impaired (AV node modulation), which allows subsequent control of the effective ventricular rate (if necessary by pacer maker implantation). Atrial fibrillation, however, does continue undisturbed in the atria, with its associated risk of thromboembolic complications. SECONDARY CATHETER ABLATION: The other option of a secondary catheter ablation approach to atrial fibrillation consists of a combination of antiarrhythmic medication using Class Ic or III antiarrhythmics and its conversion of atrial fibrillation to isthmus-dependent atrial flutter, which can subsequently be treated by curative bi-directional isthmus blockade. Termination of the antiarrhythmic medication may lead to reoccurrence of atrial fibrillation. OBJECTIVES: The review discusses the mentioned options for secondary catheter ablation of atrial fibrillation together with possible indications, success rates and potential complications.

Anti-Arrhythmia Agents↗

PubMed2002

[Primary catheter ablation in atrial fibrillation].

BACKGROUND: Primary catheter ablation of atrial fibrillation is a new and curative option for the treatment of patients with drug-refractory atrial fibrillation. It is aiming at a long-term restoration of sinus rhythm and thereby causing a coordinated atrial contraction. ABLATION METHODS: Two different ablation strategies have been established: The "trigger elimination" tries to identify triggering atrial extrasystoles (mostly within the pulmonary veins), followed by focal ablation or isolation within the pulmonary veins. The "substrate modification" changes by long linear radiofrequency-induced lesions the ability of the atrial myocardium to sustain atrial fibrillation. VALUATION: Both treatment options still have to prove their effectiveness in carefully monitored follow-up, before they can be offered to the general patient population with atrial fibrillation.

Atrial Fibrillation↗

PubMed2002

Risk of sudden death after successful accessory atrioventricular pathway ablation in resuscitated patients with Wolff-Parkinson-White syndrome.

INTRODUCTION: Cardiac arrest in patients with Wolff-Parkinson-White (WPW) syndrome can be due to ventricular fibrillation mediated by fast conduction over the accessory pathway during atrial fibrillation. However, if primary ventricular fibrillation is the reason for resuscitation, placement of an implantable cardioverter defibrillator (ICD) would be indicated. The aim of this study was to test the hypothesis that in resuscitated patients with WPW syndrome, recurrences can be prevented by sole ablation of their accessory pathways. METHODS AND RESULTS: We performed a long-term follow-up study of 48 resuscitated patients with WPW syndrome who underwent successful accessory pathway ablation as their sole primary treatment. Cardiac arrest had occurred either spontaneously in 32 patients (group A) or after intravenous administration of antiarrhythmic drugs in 16 patients (group B) and was never associated with an acute myocardial infarction or other concomitant factors. All patients had normal left ventricular function at echocardiography. A total of 56 accessory AV pathways were ablated successfully with radiofrequency current (n = 55) or during surgery (n = 1) and were located at the left free wall (n = 35), right free wall (n = 8), or septal-paraseptal region (n = 13). Follow-up 5.0+/-1.9 years after ablation (range 0.2 to 7.9) was obtained in all 48 patients. All of the patients were alive, and none had a life-threatening arrhythmia or syncope after successful ablation of their accessory pathways. CONCLUSION: In resuscitated patients with WPW syndrome who have normal left ventricular function at echocardiography and no ECG abnormalities suggesting additional electrical disease, ablation of their overt accessory pathways prevented cardiac arrest recurrences; therefore, ICD placement is generally not indicated.

Adolescent↗