Michael Ulbrich

Usefulness of Short-Term Variability of QT Intervals as a Predictor for Electrical Remodeling and Proarrhythmia in Patients With Nonischemic Heart Failure

The high incidence of sudden cardiac death in heart failure (HF) reflects electrophysiologic changes in response to myocardial failure. We previously showed that short-term variability of QT intervals (STV(QT)) identifies latent repolarization disorders in patients with drug-induced or congenital long QT syndrome. This study sought to determine (1) if STV(QT) is increased in patients with dilated cardiomyopathy (DC) and moderate congestive HF and (2) if increased STV(QT) is associated with ventricular arrhythmia in patients with HF. Sixty patients (53 +/- 12 years of age, 14 women) with DC and moderate HF (New York Heart Association classes II to III) were compared to matched controls. Twenty patients had implantable cardiac defibrillators secondary to a history of ventricular tachycardia (VT). Two cardiologists blinded to diagnosis manually measured QT intervals. Beat-to-beat variability of repolarization was determined from Poincaré plots of 30 consecutive QT intervals as was STV(QT). QTc intervals were comparable in patients and controls (419 +/- 36 vs 415 +/- 32 ms, respectively, p >0.05), whereas STV(QT) was significantly higher in patients with HF (7.8 +/- 3 vs 4.1 +/- 2 ms, respectively, p <0.05). STV(QT) was more increased in patients with a history of VT compared to those without VT (10.1 +/- 2 vs 6.6 +/- 2 ms, respectively, p <0.05). Increased STV(QT) and decreased ejection fraction were associated with a history of VT; however, STV(QT) was the strongest indicator. In conclusion, the present study demonstrates for the first time that STV(QT) is increased in patients with DC with HF. Patients with DC and HF and implantable cardiac defibrillators for secondary prevention had the highest STV(QT). Thus, increased STV(QT) in the context of moderate HF may reflect a latent repolarization disorder and increased susceptibility to sudden death in patients with DC, which is not identified by a prolonged QT interval.

Electrocardiogram-Gated 18F-FDG PET/CT Hybrid Imaging in Patients with Unsatisfactory Response to Cardiac Resynchronization Therapy: Initial Clinical Results

The present study aimed to distinguish responders to cardiac resynchronization therapy (CRT) from nonresponders, using electrocardiogram-gated 18F-FDG PET/CT. Methods: Seven consecutive CRT nonresponders were included in the study, along with 7 age- and sex-matched CRT responders, serving as reference material. Therapy response was defined as clinical improvement (≥1 New York Heart Association class) and evidence of reverse remodeling. Besides PET/CT, we measured brain natriuretic peptide levels and assessed dyssynchrony using transthoracic echocardiography. Results: Compared with nonresponders, CRT responders showed significant differences in the declines of left-ventricular end-systolic volume and brain natriuretic peptide and in left-ventricular dyssynchrony (global left-ventricular entropy), extent of the myocardial scar burden, and biventricular pacemaker leads positioned within viable myocardial regions. Among the nonresponders, further therapy management was guided by the PET/CT results in 4 of 7 patients. Conclusion: Cardiac hybrid imaging using gated 18F-FDG PET/CT enabled the identification of potential reasons for nonresponse to CRT therapy, which can guide subsequent therapy.

Different forms of ventricular tachycardia involving the left anterior fascicle in nonischemic cardiomyopathy: critical sites of the reentrant circuit in low-voltage areas.

Introduction: The purpose of this study was to examine the reentrant circuit of ventricular tachycardias (VTs) involving the left anterior fascicle (LAF) in nonischemic cardiomyopathy.

Reinitiation of Ventricular Macroreentry within the His‐Purkinje System by Back‐Up Ventricular Pacing—A Mechanism of Ventricular Tachycardia Storm

Background: We describe immediate reinitiation of macroreentry ventricular tachycardia (VT) involving the His‐Purkinje system by ventricular pacing from the electrode of an implantable cardioverter defibrillator (ICD) as a mechanism of VT storm refractory to ICD therapy.

Recording of low-amplitude diastolic electrograms through the coronary veins: a guide for epicardial ventricular tachycardia ablation

AIMS The purpose of the study was to evaluate the role of coronary venous mapping to identify epicardial ventricular tachycardia (VT) in patients with structural heart disease. METHODS AND RESULTS Epicardial mapping of the electrophysiological substrate through the coronary vein branches using a 2.2F, 16-pole microelectrode catheter was performed in 33 consecutive patients undergoing VT ablation. Twenty-six patients had a history of myocardial infarction and seven had a non-ischaemic cardiomyopathy. Endocardial ablation was successful in 19 of the 33 patients (58%). Low-amplitude fractionated diastolic electrograms with an electrogram-QRS interval amounting to 30-70% of the VT cycle length were recorded during the VT in the coronary vein branches in eight patients (24%). Endocardial ablation failed in seven of the eight patients with diastolic electrograms in the coronary veins, suggesting an epicardial involvement of the VT re-entry circuit. Among the patients with a suspected epicardial VT origin, four patients underwent epicardial ablation using a pericardial access after unsuccessful endocardial ablation which eliminated mappable VTs in all. CONCLUSION Recording of low-amplitude fractionated diastolic electrograms through the coronary veins facilitates the identification of VTs with an epicardial origin requiring mapping and ablation through a pericardial access.

Invasive Elektrophysiologie: Komplikationen, Alpträume und deren Management

Most minor side effects of ablation in the right atrium and right ventricle relate to femoral venous catheterization but there is a small risk of severe complications including atrioventricular (AV) block, damage of surrounding structures and thromboembolic events. Impairment of AV conduction can occur during ablation of atrioventricular re-entrant tachycardia, ablation of anteroseptal, mid-septal and parahisian accessory pathways, ablation of ectopic atrial tachycardia originating from the vicinity of the atrioventricular node and when ablating the septal isthmus for typical atrial flutter. Damage of the right coronary artery is a very rare complication after inferior isthmus ablation with high energy. The thromboembolic risk during and after cardioversion and ablation of atrial flutter is higher than previously recognized and anticoagulation therapy decreases this risk. The risk of perforation and tamponade during ablation in the right atrium and right ventricle is very low but particular caution is necessary in thin-walled structures such as the coronary sinus and the upper right ventricular outflow tract. Phrenic nerve injury can be avoided by pacing from the mapping electrode before application of radiofrequency energy at the right atrial free wall. Limitation of power output depending on the site of ablation and titration of energy application with continuous control of temperature and impedance should be considered to minimize the risk of complications.ZusammenfassungDie meisten nicht-lebensbedrohlichen Nebenwirkungen der Ablation im rechten Vorhof und rechten Ventrikel sind lokale Folgen der Katheterisierung der Vena femoralis, aber es besteht auch ein geringes Risiko schwerwiegender kardialer Komplikationen, welche im wesentlichen einen atrioventrikulären (AV) Block, eine Schädigung benachbarter anatomischer Strukturen und thromboembolische Ereignisse beeinhaltet. Eine Beeinträchtigung der AV-Überleitung kann während der Ablation einer AV-Knoten-Reentrytachykardie, der Ablation anteroseptaler, mittseptaler und parahisärer akzessorischer Leitungsbahnen, der Ablation ektoper atrialer Tachykardien mit Ursprung in der Umgebung des AV-Knotens und bei septaler Isthmusablation von typischem Vorhofflattern entstehen. Die Schädigung der rechten Koronararterie ist eine sehr seltene Komplikation nach inferiorer Isthmusablation mit hoher Energie. Das Thromboembolierisiko während und nach der Kardioversion und Ablation von Vorhofflattern ist höher als früher angenommen und wird durch Antikoagulation reduziert. Das Risiko einer Perforation und Tamponade während der Ablation im rechten Vorhof und rechten Ventrikel ist sehr niedrig, aber in dünnwandigen Strukturen wie dem Koronarsinus oder dem oberen rechtsventrikulären Ausflusstrakt ist besondere Vorsicht notwendig. Eine Schädigung des Nervus phrenicus kann durch Stimulationsmanöver von der Ablationselektrode vor der Applikation von Radiofrequenzenergie an der freien Wand des rechten Vorhofes vermieden werden. Eine Begrenzung der Ablationsenergie in Abhängigkeit von der Ablationsposition sowie eine Titration der Ablationsleistung mit kontinuierlicher Kontrolle von Temperatur und Impedanz sollten zur Minimierung des Komplikationsrisikos Berücksichtigung finden.

[Invasive electrophysiology: complications, nightmares and their management].

Most minor side effects of ablation in the right atrium and right ventricle relate to femoral venous catheterization but there is a small risk of severe complications including atrioventricular (AV) block, damage of surrounding structures and thromboembolic events. Impairment of AV conduction can occur during ablation of atrioventricular re-entrant tachycardia, ablation of anteroseptal, mid-septal and parahisian accessory pathways, ablation of ectopic atrial tachycardia originating from the vicinity of the atrioventricular node and when ablating the septal isthmus for typical atrial flutter. Damage of the right coronary artery is a very rare complication after inferior isthmus ablation with high energy. The thromboembolic risk during and after cardioversion and ablation of atrial flutter is higher than previously recognized and anticoagulation therapy decreases this risk. The risk of perforation and tamponade during ablation in the right atrium and right ventricle is very low but particular caution is necessary in thin-walled structures such as the coronary sinus and the upper right ventricular outflow tract. Phrenic nerve injury can be avoided by pacing from the mapping electrode before application of radiofrequency energy at the right atrial free wall. Limitation of power output depending on the site of ablation and titration of energy application with continuous control of temperature and impedance should be considered to minimize the risk of complications.ZusammenfassungDie meisten nicht-lebensbedrohlichen Nebenwirkungen der Ablation im rechten Vorhof und rechten Ventrikel sind lokale Folgen der Katheterisierung der Vena femoralis, aber es besteht auch ein geringes Risiko schwerwiegender kardialer Komplikationen, welche im wesentlichen einen atrioventrikulären (AV) Block, eine Schädigung benachbarter anatomischer Strukturen und thromboembolische Ereignisse beeinhaltet. Eine Beeinträchtigung der AV-Überleitung kann während der Ablation einer AV-Knoten-Reentrytachykardie, der Ablation anteroseptaler, mittseptaler und parahisärer akzessorischer Leitungsbahnen, der Ablation ektoper atrialer Tachykardien mit Ursprung in der Umgebung des AV-Knotens und bei septaler Isthmusablation von typischem Vorhofflattern entstehen. Die Schädigung der rechten Koronararterie ist eine sehr seltene Komplikation nach inferiorer Isthmusablation mit hoher Energie. Das Thromboembolierisiko während und nach der Kardioversion und Ablation von Vorhofflattern ist höher als früher angenommen und wird durch Antikoagulation reduziert. Das Risiko einer Perforation und Tamponade während der Ablation im rechten Vorhof und rechten Ventrikel ist sehr niedrig, aber in dünnwandigen Strukturen wie dem Koronarsinus oder dem oberen rechtsventrikulären Ausflusstrakt ist besondere Vorsicht notwendig. Eine Schädigung des Nervus phrenicus kann durch Stimulationsmanöver von der Ablationselektrode vor der Applikation von Radiofrequenzenergie an der freien Wand des rechten Vorhofes vermieden werden. Eine Begrenzung der Ablationsenergie in Abhängigkeit von der Ablationsposition sowie eine Titration der Ablationsleistung mit kontinuierlicher Kontrolle von Temperatur und Impedanz sollten zur Minimierung des Komplikationsrisikos Berücksichtigung finden.

Analysis during Sinus Rhythm and Ventricular Pacing of Reentry Circuit Isthmus Sites in Right Ventricular Cardiomyopathy

Background: The entrainment mapping algorithm is used for ablation of ventricular tachycardia (VT) in right ventricular (RV) cardiomyopathy, but ablation at endocardial isthmus sites has only a moderate success rate. This study was performed to identify additional local electrogram characteristics associated with successful ablation.

Successful use of transvenous coil electrodes as single element subcutaneous array leads

For implantable cardioverter defibrillator a 10 J safety margin between the defibrillation threshold (DFT) and the maximum output of the device is intended. In complex cases, the additional placement of a subcutaneous array lead is a common strategy for lowering the DFT. We report the successful use of transvenous coil electrodes as single element subcutaneous array leads in order to lower the DFT.

Long-term outcomes after event-free cardioverter defibrillator implantation: comparison between patients discharged within 24 h and routinely hospitalized patients in the German DEVICE registry

Aims To analyse the long-term safety of implantable cardioverter defibrillators (ICDs) in patients discharged within 24 h or after 2- 5-day hospitalization, respectively, after complication-free implantation, in circumstances of actual care. Methods and results Patients in the multicentre, nationwide German DEVICE registry were contacted 12-15 months after their first ICD implantation or device replacement. Data were collected on complications, potential arrhythmic events, syncope, resuscitation, ablation procedures, cardiac events, hospitalizations, heart failure status, change of medication, and quality of life. Of 2356 patients from 43 centres, 527 patients were discharged within 24 h and 1829 were hospitalized routinely for >24 h after complication-free implantations. The disease profiles and rates of co-morbidities were similar at baseline for both cohorts. During between 384 and 543 days of follow-up, there were no significant differences between the groups in terms of complications, hospitalizations, or quality of life. One-year rates of death were 4.5% in patients discharged early compared with 7.2% in hospitalized patients (hazard ratio 0.65; 95% confidence interval 0.42-1.02; P = 0.052). Rates of major adverse cardiovascular events or defibrillator events were not higher in patients discharged after 24 h. In both groups, a high rate of patients declared that they would opt for the procedure again in the same situation. Conclusion Data from a large-scale registry reflecting current day-to-day practice in Germany suggest that most patients can be discharged safely within 24 h of successful ICD implantation if there are no procedure-related events. Follow-up data up to 1.5 years after implantation did not raise long-term safety concerns.