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Biomedical subjects

M Horlitz

Publications and source records attributed to M Horlitz.

17 recordsLinked to original sources

[Curative treatment in a patient with exercise induced syncope].

HISTORY: A 38 year old man suffered from exercise-induced reproducible dizziness and syncopes. INVESTIGATIONS AND DIAGNOSIS: During exercise testing a ventricular tachycardia at a rate of 300 beats/min was identified as the cause of the symptoms. Because of the ventricular morphology with inferior axis, left bunde branch block and the typical monomorphic repetitive characteristics, idiopathic adenosine-sensitive ventricular tachycardia was diagnosed. TREATMENT AND CLINICAL COURSE: Curative catheter ablation of the arrhythmogenic focus in the right ventricular outflow tract was performed. The patient has now been free of symptoms for more than two years. The characteristics of idiopathic ventricular tachycardia and the electrophysiological techniques are described. CONCLUSION: Idiopathic ventricular tachycardia is a rare cause of syncope in young patients without underlying heart disease and can be cured by catheter ablation. Exclusion of cardiac diseases, especially arrhythmogenic right ventricular cardiomyopathy, is of prognostic value.

Adult↗

[Recurrent ventricular tachycardias following myocardial infarction: linear ablation strategy using an electroanatomical mapping system].

BACKGROUND AND AIM OF STUDY: The implantable cardioverter defibrillator (ICD) is the therapy of choice for patients with ventricular tachycardia (VT) after myocardial infarction. In some patients frequent ICD shocks occur, often resulting in clinical problems, if antiarrhythmic drugs insufficiently suppress them. Our aim was to describe electro-anatomical mapping and ablation techniques in patients with VTs, in which conventional strategy treatments have failed. PATIENTS AND METHODS: 17 patients (69.5 +/- 8 years, 12 male) were included. During 3 months before ablation the number of ICD shocks was 21 +/- 8 (mean +/- SD). Using an electro-anatomical mapping system (CARTO), activation mapping was performed in 12 patients during hemodynamically tolerable, stable VT. In 5 cases with "non-mappable" VT only voltage mapping during sinus rhythm was obtained. The aim was to characterize the underlying scar tissue precisely in order to modify the substrate with an individual strategic linear lesion, thus preventing re-induction of VT. RESULTS: Procedure time was 184 +/- 9 minutes, fluoroscopy time totalled 19 +/- 9 minutes. Lesion lines were established with 13 +/- 9 ablation pulses. In 15 patients (88 %) acute ablation of the VT was successful. During a follow-up of 8 +/- 7 months, 2 patients had a recurrence of the VT. Two patients developed a VT with a different morphology. In another case ventricular fibrillation occurred. No major complications were observed. CONCLUSION: Electro-anatomical mapping combined with an individual linear ablation strategy is a safe and effective method to prevent symptomatic VT in patients after myocardial infarction.

Aged↗

Plasma levels of NT-pro-BNP in patients with atrial fibrillation before and after electrical cardioversion.

OBJECTIVE: Plasma levels of brain natriuretic peptide (BNP) have been examined in studies on patients with persistent atrial fibrillation, both before and after electrical cardioversion. Studied patients often showed a comorbidity with congestive heart failure, which complicates interpretation of measured BNP values as a natriuretic peptide. The aim of this study was to examine plasma levels of N-terminal fragment pro-brain natriuretic peptide (NT-pro-BNP), which is the more stable but inactive cleavage product of pro-BNP in patients with atrial fibrillation, but normal left ventricular ejection fraction, before and after electrical cardioversion. PATIENTS AND METHODS: NT-pro-BNP plasma levels of 34 consecutive patients were measured before, shortly after and 11 days after electrical cardioversion. All patients showed a normal ejection fraction after echocardiographic or laevocardiographic criteria. RESULTS: At baseline, all patients showed elevated NT-pro-BNP compared to a healthy control group (1086 vs. 66.9 pg/ml, p<0.001). After a mean follow-up time of 11 days in patients with persistent restored sinusrhythm, NT-pro-BNP decreased from 1071 pg/ml at baseline to 300 pg/ml (p<0.001). In contrast, patients with recurrence of atrial fibrillation showed increased levels from 1570.5 pg/ml at baseline to 1991 pg/ml (p=0.13; n.s.). Recurrence of atrial fibrillation was independent from height of NT-pro-BNP levels at baseline (p=0.23). CONCLUSIONS: Atrial fibrillation in patients with a normal left ventricular ejection fraction is associated with elevated NT-pro-BNP plasma levels, which decrease when a persistent sinus-rhythm can be restored by electrical cardioversion. On the other hand, NT-pro-BNP seems to increase (n.s.) when recurrence of atrial fibrillation occurs. Finally, NT-pro-BNP is no valid predictor for long-term success of sinus-rhythm restoration by electrical cardioversion.

Adult↗

[Curative therapy in symptomatic atrial ectopy].

A female patient without underlying heart disease was highly symptomatic from short runs of atrial ectopy. Sustained atrial tachycardia or atrial fibrillation never occurred. Due to ineffective pharmacological therapy, catheter ablation combined with electroanatomic mapping (CARTO) was performed effectively. Characteristics of ectopic atrial tachycardia and the electrophysiological techniques are described.

Adult↗

Cardiogenic shock due to thrombotic thrombocytopenic purpura.

We report the case of a 49-year-old man with thrombotic thrombocytopenic purpura (TTP) leading to cardiogenic shock. Laboratory data were typical for TTP with thrombocytopenia and microangiopathic hemolytic anemia. The electrocardiogram recorded significant ST-segment elevations in the anterior and inferior leads. In addition' coronary angiography showed normal epicardial coronary arteries with slow flow. The patient died due to electromechanical dissociation six hours after admission. During autopsy typical features of thrombotic thrombocytopenic purpura were found. Histological preparation of the heart showed a diffuse myocardial necrosis due to microvascular thrombosis. Cardiac involvement is common in TTP but extended myocardial necrosis has been reported in only a few cases.

Diagnosis, Differential↗

Frequency and quantity of the parvovirus B19 genome in endomyocardial biopsies from patients with suspected myocarditis or idiopathic left ventricular dysfunction.

Parvovirus B19 (PB19) has been identified as a possible cause of myocarditis and heart failure in both children and adult patients. This study used real time PCR analysis, to determine the frequency and to quantify PB19 viral genomes in endomyocardial tissue samples from 80 adult patients with clinically suspected myocarditis or idiopathic left ventricular dysfunction and from 36 controls. Histological (Dallas classification) and immunohistological analyses were performed to detect myocardial inflammation in the endomyocardial biopsies.PB19 genomic DNA was found in nine of 80 patients (11.2%), 4 out of 31 (12.9%) patients with inflammatory infiltrates detected via immunohistological methods and 5 out of 49 (10.2%) patients with left ventricular dysfunction without myocardial inflammation. The copy numbers for PB19 DNA ranged between 30 and 3900 per microg of cellular DNA. Four patients with clinically suspected myocarditis had copy numbers for PB19 DNA of 70, 740, 3400 and 3900, respectively, per microg of cellular DNA in the endomyocardial biopsy. Five patients with idiopathic left ventricular dysfunction had copy numbers for PB19 DNA of 30, 38, 52, 58 and 90, respectively, per microg of cellular DNA in the endomyocardial biopsy. The amplicon of one of the nine positive PCR fragment was sequenced and was found to be fully identical in the highly conserved sequence of published Parvovirus B19 VP1/VP2 genes (NCBI gene bank). In all patients, acute myocarditis was excluded according to the Dallas classification. All biopsies of 36 controls with no history of myocarditis or recent viral infection were negative for myocardial inflammation and parvovirus B19 genomes. In summary, Parvovirus B19 DNA is present within the myocardium of patients with suspected myocarditis and idiopathic left ventricular dysfunction and can be detected and quantified in endomyocardial specimens via real time PCR.

Adult↗

Identification and ablation of atypical atrial flutter. Entrainment pacing combined with electroanatomic mapping.

Differentiation between typical and atypical atrial flutter solely based upon surface ECG pattern may be limited. However, successful ablation of atrial flutter depends on the exact identification of the responsible re-entrant circuit and its critical isthmus. Between August 2001 and June 2003, we performed conventional entrainment pacing within the cavotricuspid isthmus in 71 patients with sustained atrial flutter. In patients with positive entrainment we considered the arrhythmia as typical flutter and treated them with conventional ablation of the cavotricuspid isthmus. As a consequence of negative entrainment we performed 3D-electroanatomic activation mapping (CARTO trade mark ). Conventional ablation of the right atrial isthmus was successful in all patients (n = 54) with positive entrainment. We performed electroanatomic mapping in the remaining 17 patients (14 male; age 60.9 +/- 16 years) resulting in the identification of 6 cases with typical and 11 cases with atypical flutter. Therefore, entrainment pacing was able to predict the true presence of typical atrial flutter in 91.5%. Atypical flutter was right sided in 4 patients and left sided in 7 cases. Electrically silent ("low voltage") areas probably demonstrating atrial myopathy were identified in all cases with left sided and in 2 patients with right sided flutter. In these patients targets for ablation lines were located between silent areas and anatomic barriers (inferior pulmonary veins, mitral respectively tricuspid annulus, or vena cava inferior). In 1 patient, the investigation was stopped due to variable ECG pattern and atrial cycle lengths. In the remaining cases, ablation was acutely successful. One patient, after surgical closure of a ventricular septal defect, demonstrated a dual-loop intra-atrial reentry tachycardia dependent on two different isthmuses. This arrhythmia required ablation of those distinct isthmuses to be interrupted. After a mean follow-up of 8.8 +/- 3.4 months, there was one patient with a recurrence of left-sided atrial flutter. Another patient developed permanent atrial fibrillation shortly after the procedure. Mean duration time of the procedure was 235.6 +/- 56.4 min (right atrium: 196 +/- 17.3 min; left atrium: 267.2 +/- 59.5 min), and average fluoroscopy time was 21.8 +/- 11.7 min (right atrium: 9.5 +/- 6 min; left atrium: 28.9 +/- 7 min). There was no incidence of serious complications associated with these procedures. In conclusion, conventional pacing in the cavotricuspid isthmus combined with electroanatomic mapping was an effective method to differentiate between typical and atypical atrial flutter. Electroanatomic mapping was a powerful tool both for identification of different atrial re-entrant circuits including their critical isthmuses as well as for effective application of individual ablation line strategies.

Adolescent↗

[Clinical experiences with cooled radiofrequency ablation of ectopic atrial tachycardia employing an electroanatomic mapping system].

Due to its variable origin success for ablation of ectopic atrial tachycardia (EAT) has been difficult to achieve using conventional mapping and ablation strategies. In contrast, no information in the literature is available about the use of a nonfluoroscopic, 3-dimensional electroanatomic mapping system (CARTO) combined with the cooled ablation technology creating deeper lesions in experimental studies compared to standard catheters. In 20 consecutive patients (15 female; age 52.5 +/- 15.4 years), a single focus responsible for clinical EAT has been mapped. Twelve EATs were located in the right atrium, whereas 8 foci were left sided including 3 origins within a pulmonary vein (PV). Due to the reported development of PV stenosis in the ablative treatment of focal atrial fibrillation, direct ablation applied inside the PV was avoided. Instead, PV-disconnection achieved by the use of a Lasso trade mark catheter in 1 case and by circumferential ablation around the PV in 2 other patients was preferred. In 2 patients, ablation was not attempted because of an origin located directly in the area of the atrioventricular node. In another case, CARTO mapping was stopped due to persistent mechanical termination of the tachycardia with no possibility of reinduction. In the latter, ablation was performed in sinus rhythm at the earliest mapped site before terminating. Three weeks later another episode of EAT was noted in this patient. In the remaining 17 cases, ablation was associated with acute success and no recurrences of sustained tachycardia in all patients. Mean duration time was 192 +/- 53.3 min (right atrium 161 +/- 37.9 min; left atrium 229.6 +/- 46.2 min), and average fluoroscopic time was 22.8 +/- 9.7 min (right atrium 17.1 +/- 6.2 min; left atrium 29.8 +/- 8.9 min). There was no incidence of serious complications associated with this procedure. In conclusions, electroanatomical mapping including cooled ablation was a safe and feasible strategy in treating EATs. The benefit of this technique may imply the combination of both precise localization of the focus and effective applications of radiofrequency pulses, thereby minimizing acute failures or reablation. Due to the time consuming point by point data acquisition, the ability to generate precise maps demonstrating the earliest activation at their exact anatomical location can be limited by transient or persistent termination of the tachycardia.

Adult↗

[Catheter ablation of ectopic atrial tachycardia by electrical pulmonary vein disconnection].

We report a 25-year-old female patient with a long history of symptomatic paroxysmal supraventricular tachycardia. Electroanatomic activation mapping demonstrated a focal tachycardia originating in the right upper pulmonary vein, 3 cm distal to the ostium. Due to the recent experiences in the management of focal atrial fibrillation with catheter ablation, direct ablation applied inside the pulmonary vein was avoided. Instead, an electrical disconnection of the pulmonary musculature from the left atrium guided by a circumferential 10-electrode mapping catheter was performed. The patient has since been asymptomatic during follow-up.

Adult↗

[Therapy options for Prinzmetal angina induced ventricular vulnerability].

We report about a 46 year old male, who survived sudden cardiac death caused by recurrent ventricular tachycardia as the clinical manifestation of a vasospastic right coronary artery. After implantation of an implantable cardioverter defibrillator, the patient did not respond to conservative treatment despite of different drug therapies. Therefore, the vasospastic right coronary artery was treated by a percutaneous transluminal coronary angioplasty and stenting, which could not reduce the occurrence of further tachycardias. Finally, the patient underwent an operative myocardial revascularization combined with sympathectomy. During the whole follow-up of six months no new episodes of ventricular tachyarrhythmias have occurred.

Angina Pectoris, Variant↗

[Atrial lead placement in cases of intraoperative atrial fibrillation].

AIM: Evaluating the efficiency of a prescribed concept for atrial lead placement in cases of intraoperative atrial fibrillation (AF). METHODS: Over the period from 11/1998 to 5/2000, we carried out a prospective study on 40 patients with AF. After implantation of the screw electrode into the lateral wall of the atrium, an amplitude of the intracardial ECG of > or = 1.4 mV was arbitrarily defined as tolerable. At amplitudes of < 1.4 mV, atrial overdrive-stimulation occurred at 400 to 800 ppm in order to convert the AF to sinus rhythm (SR). Following successful overdrive-stimulation, the atrial electrode was positioned according to standard values (P-wave > 3 mV, pacing threshold < 0.5 V at 0.5 ms). In the case of unsuccessful intraoperative atrial stimulation, the electrode was repositioned until an amplitude of > or = 1.4 mV was reached. In all cases bipolar atrial screw electrodes (Model 4068, Medtronic Inc., Minneapolis, MN, USA) were implanted. The intraoperative measurements were carried out via the atrial channel of a 5311 PSA (Medtronic Inc., Minneapolis, MN, USA). In follow-up after 6 weeks, the atrial stimulation threshold was measured in [V] at 0.5 ms and the signal amplitude of the P-wave in [mV], or in the case of AF detection with successful mode switch activation. RESULTS: In 31/40 patients (77.5 %) with intraoperative persistent AF, fibrillation amplitudes of 1.4 to 3.1 mV (mean value 1.9 +/- 0.4 mV) were measured. In 9/40 patients (22.5 %) with intraoperative AF, 4 cases of conversion to SR using burst stimulation were documented. Atrial lead placement was performed using standard values. After 6 weeks, 33/40 patients (82.5 %) had SR, while intermittent AF episodes with successful mode switch activation were documented in 21 patients (52.5 %). The P-wave amplitude was 3.63 +/- 0.69 mV (range 1.8 to 4.9 mV), the atrial stimulation threshold was 1.3 +/- 0.4 mV (range 0.4 to 1.9 mV). Atrial lead adjustment due to sensing defects was not required for any patients. CONCLUSION: The results show that all atrial leads implanted in accordance with this concept demonstrate proper sensing at SR as well as under AF, with successful mode switch episodes and acceptable stimulation thresholds.

Aged↗

[Statins do not prevent restenosis after coronary angioplasty: where to go from here?].

BACKGROUND: Despite the use of intracoronary stents, approximately 15-20% of patients who undergo percutaneous transluminal coronary angioplasty (PTCA) experience symptomatic restenosis. Known mechanisms of restenotic lesion formation are smooth muscle cell proliferation, extracellular matrix production, remodeling and decreased programmed cell death (apoptosis). RESULTS AND STUDIES: Experimental observations suggest that HMG-CoA reductase inhibitors ("statins") reduce the risk of restenosis. The activity of statins limits the rate of synthesis, not only of cholesterol, but also of a range of other molecules involved in cellular function. Their benefits in primary and secondary prevention of atherosclerosis have been widely recognized. Clinical trials using different types of statins were designed to evaluate their ability to influence the incidence of restenosis after successful conventional PTCA. The results clearly demonstrated that statins reduce lipid levels but do not prevent restenosis. Experimental evidence has failed to translate into clinical effect. The underlying pathological reasons for this shortcoming as well as promising alternative approaches including vascular gene therapy and brachytherapy will be discussed in this review.

Angioplasty, Balloon, Coronary↗

Morphological differences of the internal thoracic artery in patients with and without coronary artery disease--evaluation by duplex-scanning.

OBJECTIVE: The internal thoracic artery is an established arterial graft for myocardial revascularisation, especially of the left anterior descending artery because of a higher patency rate compared to venous grafts. It has never been investigated, whether there are morphological differences in this vessel between patients with or without coronary artery disease or if they are comparable to morphological changes in the common carotid artery. METHODS: We investigated the internal thoracic artery and the common carotid artery of 24 patients (12 with coronary artery disease, 12 without coronary artery disease) with an ultrasonic system on both sides. The intima-media thickness and the diameter of both vessels were estimated. RESULTS: The intima-media-thickness of the internal thoracic artery was comparable in all patients, independent of the presence of a coronary artery disease (0.51+/-0.11 mm with coronary artery disease, 0.50+/-0.17 mm without coronary artery disease, P>0.05). Compared with this the intima-media-thickness of the common carotid artery was thicker in patients with coronary artery disease (0.84+/-0.13 mm with coronary artery disease, 0.73+/-0.07 mm without coronary artery disease, P< or or =0.014). There was no correlation between the thickness of the internal thoracic artery and the common carotid artery (r=0.018, P>0.05). CONCLUSIONS: It could be demonstrated for the first with non-invasive ultrasound, that the intima-media-complex of the internal thoracic artery is protected of the influence of arteriosclerosis. There are no morphological differences like the intima-media-thickness of the common carotid artery. The proven protective mechanism underlines the widespread use of the internal thoracic artery as a coronary artery bypass graft.

Aged↗

Gene-specific trans-regulatory functions of magnesium for chloroplast mRNA stability in higher plants.

In higher plant chloroplasts the accumulation of plastid-encoded mRNAs during leaf maturation is regulated via gene-specific mRNA stabilization. The half-lives of chloroplast RNAs are specifically affected by magnesium ions. psbA mRNA (D1 protein of photosystem II), rbcL mRNA (large subunit of ribulose-1,5-bisphosphate carboxylase), 16 S rRNA, and tRNA(His) gain stability at specific magnesium concentrations in an in vitro degradation system from spinach chloroplasts. Each RNA exhibits a typical magnesium concentration-dependent stabilization profile. It shows a cooperative response of the stability-regulated psbA mRNA and a saturation curve for the other RNAs. The concentration of free Mg(2+) rises during chloroplast development within a range sufficient to mediate gene-specific mRNA stabilization in vivo as observed in vitro. We suggest that magnesium ions are a trans-acting factor mediating differential mRNA stability.

5' Untranslated Regions↗

[Successful high frequency current catheter ablation of an accessory conduction pathway in the "neck region" of a coronary sinus aneurysm. A case report].

In this case report the electrophysiological findings in a 24 year old female patient are demonstrated. For about 12 years she suffered from recurrent atrioventricular reentrant tachycardia with a rate of 230 beats per minute. Electrophysiological study resulted in diagnosis of a posteroseptal accessory pathway. Ablation was attempted primarily from a left ventricular access, but the pathway could not be reached from this position. After contrasting the coronary sinus a large coronary sinus aneurysm could be diagnosed. The accessory pathway was located in the "neck"-region of the aneurysm. By application of radiofrequency current in this location the bypass tract could be ablated. This case report shows that accessory pathways in coronary sinus aneurysms can be ablated without complications in this location.

Adult↗

[Ventricular bigeminy with fixed with fixed coupling at rest and during exercise as the cause of recurrent dizziness and syncope--successful anti-arrhythmic therapy by high frequency current catheter ablation of a right ventricular arrhythmogenic focus. A case report].

In a 52-year-old patient with beginning dilatative cardiomyopathy dizziness and syncopes could be observed due to a ventricular bigeminy at rest and under exercise conditions. The patient also showed a marked reduction of exercise capacity and was handicapped in his profession as electrician and unable to work for more than 10 months. Antiarrhythmic drug therapy including the subsequent use of all available antiarrhythmic agents failed in suppressing this arrhythmia. In an electrophysiological study the arrhythmogenic focus could be localized in the right ventricular outflow tract. Application of radiofrequency current resulted in instantaneous termination of the extrasystoly; this result could be documented in repeat Holter monitorings over 12 weeks to present. This case report shows that radiofrequency catheter ablation can in special cases be applied for therapy of extrasystolic phenomena when clinical symptoms necessitate treatment and antiarrhythmic drug therapy fails.

Cardiac Complexes, Premature↗