[Acute bradycardia]. / Akute Bradykardien.

Clinical relevance of acute bradycardia is driven by symptoms and not primarily by the reported decreased heart rate. Bradycardias may remain asymptomatic especially due to compensatory mechanisms (in particular increase of left ventricular ejection fraction). Nearly half of acute bradycardias have a reversible cause. Detection of potential reversible bradycardia causes is therefore regarded as the cornerstone of bradycardia treatment in the emergency setting. Effective therapies for the treatment of acute bradycardia are available, including intravenous chronotropic drugs and pacemaker implantation.

Application of the Bogossian formula for evaluation of the QT interval in pacemaker patients with stimulated left bundle branch block.

BACKGROUND: The presence of left bundle branch block (LBBB) represents a particular challenge in properly measuring the QT interval. Here we demonstrate the applicability of the "Bogossian formula" in pacemaker patients with LBBB due to apical or nonapical right ventricular (RV) pacing and preserved left ventricular function. METHODS: A total of 163 patients with a cardiac one- or two-chamber pacemaker were included in this prospective, multicentre observational study. Twelve-lead ECG recordings were obtained during both intrinsic rhythm and RV pacing with induced LBBB. The QT interval measured during LBBB was corrected using the Bogossian formula to obtain the "modified QT" (QTm). The QTmc interval was calculated with the Bazett formula, and this was compared with the QTc interval during intrinsic rhythm. RESULTS: Eighty-three patients (78 ± 9 years; male n = 83) with apical and eighty patients (71 ± 13 years; male n = 80) with non-apical RV pacing were included in this study. In the apical group the QTmc was determined to be 444 ± 39 ms in paced rhythm and the QTc interval 413 ± 36 ms in intrinsic rhythm. In the non-apical group these values were 430 ± 34 ms in paced and 416 ± 32 ms in intrinsic rhythm. CONCLUSION: The Bogossian formula is a reliable tool for QTc interval evaluation in pacemaker patients with LBBB due to apical or non-apical RV pacing. However, an overestimation of 30 ms should be included in the calculation.

Predictors of sustained ventricular arrhythmia episodes in patients with primary ICD indication: male gender and AF in primary ICD prophylaxis.

AIMS: Implantable cardioverter-defibrillators (ICD) reduce mortality in patients with severely impaired left ventricular function. In randomized studies, female patients are underrepresented and data on ICD therapy is limited. Atrial fibrillation (AF) is a determinant of poor prognosis but has not been consistently evaluated. We evaluated the risk factors for the occurrence of ventricular arrhythmia episodes in patients with primary ICD prophylaxis. METHODS: Consecutive patients after ICD implantation for primary prophylaxis were followed. During follow-up, detected sustained episodes of ventricular arrhythmia were documented. Multivariate analysis controlled for propensity score was used to evaluate the correlation between gender, history of AF, and the occurrence of ventricular arrhythmia episodes. RESULTS: A total of 400 patients (19.8% female; n = 79) were included. During follow-up, 64 patients (16%) had appropriate ICD therapy episodes. Men (18%) had significantly more often episodes than women (8%; p = 0.025). Patients with a history of AF (102, 25.5%) had significantly more often episodes (30%) compared to patients without a history of AF (11%; p < 0.001). In a multivariate model, only gender (p = 0.02) and history of AF (p < 0.001) were significantly associated predictors of the occurrence of appropriate ICD therapies during follow-up. Based on the propensity score model, the adjusted hazard ratio for male gender was 2.7 (p = 0.02) and 2.6 (p = 0.0004) for history of AF. CONCLUSION: Male gender and history of AF are independent predictors for the occurrence of sustained ventricular arrhythmia in primary ICD prophylaxis. Further studies need to evaluate whether history of AF in female patients might be an indicator for higher risk of sudden cardiac arrhythmic death.

Do induced tachycardias within the scope of electrophysiological studies lead to elevated plasma troponin I levels?

AIMS: Troponin I (TNI) is an established marker for the diagnosis of acute coronary syndrome (ACS). The study evaluated if (induced) tachycardiac arrhyhthmias within the scope of the electrophysiological studies (EPS) led to elevation of TNI serum levels. METHOD: TNI was measured in the serum of 28 patients before and after the EPS. The left ventricular ejection fraction (LV-EF) was investigated by two-dimensional echocardiography. Left ventricle hypertrophy (LVH) was measured according to the recommendations of the American Society of Echocardiography. All patients underwent coronary angiography prior to the EPS, and significant coronary heart disease was defined as stenosis > 50%. The EPS revealed supraventricular and ventricular tachycardias using the 18-step protocol with one, two, and three extrastimuli. RESULTS: Indications for the EPS were syncope (n = 15), atrioventricular tachycardia (n = 4), non-sustained VT (n = 6), and sustained VT (n = 3). Coronary heart disease (CHD) was detected in 8 patients (1-vessel: n = 3; 2-vessel: n = 4; 3-vessel: n = 1), and 2 patients underwent percutaneous coronary intervention before EPS. Echocardiography revealed normal LV-EF in 18 patients and a reduction in the others (low n = 3, middle n = 5, high n = 2). Thirteen patients suffered from LVH. In 2 patients, external cardioversion was required during the EPS. TNI was elevated over 0.1 ng/ml (risk stratification cut-off for ACS) in 4 patients before and in 12 patients after EPS. There was no relationship between LV-EF, CHD, and the elevation of TNI after the EPS. CONCLUSION: TNI can be elevated by (induced) tachycardias within the scope of electrophysiological studies without a relationship to LV-EF, LVH, and CHD.

[Scientific results of the pacemaker register: possibilities and limits]. / Wissenschaftliche Ergebnisse des Herzschrittmacherregisters: Möglichkeiten und Grenzen.

The German obligatory external quality assurance for pacemaker implantation generates a large database giving an almost complete review of in-patient pacemaker interventions since 2001. Publications on lead fixation, age and gender dependency of pacemaker indications, choice of pacing mode and complication rates as well as investigations into the causes of lead dysfunction prove that the database is basically suitable for health service research. In contrast to pacemaker registries of other European countries the focus on in-patient operations, missing product specifications and the absence of patient follow-up largely limits the scientific potential of the database. It is greatly hoped that these limitations will be overcome by cross-sectional and longitudinal quality assurance within the next years.

[Stored electrograms in pacemakers and ICDs from Medtronic]. / Gespeicherte Elektrogramme in Schrittmachern und ICDs der Firma Medtronic.

Modern pacemakers and implantable defibrillators provide a multitude of technical algorithms and parameters, which can be programmed individually and can treat different forms of arrhythmias. Stored electrograms offer the possibility to obtain valuable information during follow-up (but also in real-time) about arrhythmias and device function or malfunction. This results in improved treatment of cardiac arrhythmias and heart disease. Due to constant innovation and development of these systems, it requires, however, profound biomedical and technical knowledge, since stored electrograms may display complex arrhythmias and device reactions that are not easy to interpret. Understanding of stored device information improves follow-up and facilitates individual care for the patient.

Gender differences in onset of symptoms in AV nodal re-entrant and accessory pathway-mediated re-entrant tachycardia.

PURPOSE: Is onset of symptoms in AV nodal re-entrant tachycardia (AVNRT) and accessory pathway-mediated re-entrant tachycardia (AVRT) patients gender-specific? METHODS: Intra- and inter-gender differences in onset of symptoms and mechanism of supraventricular tachycardia in adult patients undergoing catheter ablation for AVNRT or AVRT (N=230) were documented. RESULTS: Women with AVNRT were significantly younger at onset of symptoms compared to men (38+/-18, 51+/-18 years, p=0.01). Male AVNRT patients were significantly older at onset of symptoms compared to male AVRT patients (51+/-18, 25+/-11 years, p=0.04) but there was no difference in women. Symptoms beginning <30 years in men predicted AVRT in 73%, and beginning >or=30 years the predominant mechanism was AVNRT (85%). In women AVNRT was the most likely mechanism independent of symptom onset (>75%). CONCLUSIONS: Symptoms beginning in patients with AVNRT and AVRT prior to age 30 correlates with a 70% incidence of AVRT in men and a 80% incidence of AVNRT in women. Onset of palpitations >or= age 30 relates to AVNRT in 85% of patients.

[Optimized programming during cardiac resynchronization therapy]. / Optimierte Programmierung der atrio-ventrikulären und ventrikulo-ventrikulären Verzögerungszeiten bei Patienten unter biventrikulärer Stimulation - ein pragmatischer Ansatz.

Cardiac resynchronization (CRT) has evolved as a therapeutic add-on tool in patients with refractory heart failure. Additional pacing of the left ventricle leads to relevant clinical and hemodynamic improvement. Optimized programming of these pacing systems may modulate therapeutic efficacy. Optimal atrio-ventricular (AV) and ventriculo-ventricular (VV) delay programming is documented to increase invasively and non-invasively determined parameters of cardiac hemodynamics. In this manuscript different options for determining optimal AV and VV delay are discussed and a pragmatic approach to optimize CRT programming is detailed. VV delay needs to be optimized as a first step of programming. Different techniques may estimate the individual need for sequential ventricular pacing. Especially electrocardiographic criteria during right and left ventricular pacing may approximate the time-delay for pre-excitation. Delay between aortic and pulmonic valve ejection can be determined using Doppler echocardiography may identify patients who benefit from sequential pacing. Optimizing AV delay is a domain of Doppler echocardiography where using a simple formula the AV delay that produces the best diastolic resynchronization of left atrial contraction and left ventricular ejection can be calculated.Using the above mentioned techniques a pragmatic, easy and fast method for increasing CRT performance can be established. In cases of worsening heart failure or relevant changes of left ventricular dimensions adaptions (re-optimization) of VV and AV delay may be needed.

[New technologies in the optimization of CRT programming]. / Neue Technologien zur Optimierung in der CRT-Programmierung.

After implanting a CRT device, consistent and scheduled patient follow-up is mandatory. Besides determining electrode parameters and reviewing arrhythmic episodes, these follow-ups focus on monitoring and optimizing congestive heart failure therapy. Therefore new CRT devices present methods for heart failure surveillance and telemetric transmission of the acquired data, which allows the physician to respond immediately to the varying needs of the respective heart failure patient. In addition to cardiac resynchronization, optimization of atrioventricular (AV) and interventricular (VV) delay provide major hemodynamic benefits. As echocardiographic optimization of AV and VV delay is time consuming it is often not feasible during daily clinical practice. Therefore implemented algorithms that automatically determine and adapt AV and VV delays with respect to the fluctuating needs of the patients are essential. This article presents the current state of monitoring and optimization methods in CRT devices.

Surgical treatment of atrial fibrillation : a systematic review.

BACKGROUND: The recently published overwhelming number of publications on the surgical treatment of AF, using a wide variety of techniques, blurred any precise appreciation of the nowadays surgical treatment of AF. As a consequence, the "state of the art" of the surgical technique of AF is ill-defined. OBJECTIVES: In this review the efficacy of the alternative sources of energy (radiofrequency-microwave and cryoablation; (group I) and the classical "cut and sew" Cox-Maze III (group II), which claims a 97-99% sinus rhythm (SR) success rate, were evaluated in the surgical treatment of atrial fibrillation (AF). METHODS: A computerized search in the PubMed and Medline database was conducted. Only original, English written, clinical manuscripts on the surgical treatment of atrial fibrillation citing the clinical outcome, including the postoperative sinus rhythm, were included. The following data were registered: the absolute numbers and percentages of treated patients, gender (male versus female) distribution, the type of arrhythmia (permanent or paroxysmal AF), type of surgery (mitral or non-mitral valve or a lone AF surgical procedure), postoperative morbidity (bleeding, the use of an intra-aortic balloon pump, cerebral vascular accident), postoperative pacemaker implantations, 30-day mortality, survival and sinus rhythm conversion. The mean values for age (years), left atrial diameter (mm), preoperative duration of AF (years) and left ventricular ejection fraction (%) were also recorded. RESULTS: Forty-eight studies were included comprising 3832 patients: 2279 in group I and 1553 in group II. The mean duration of AF, left atrial diameter and LVEF were 5.4 versus 5.5 years (p=0.90), 55.5 versus 57.8 mm (p=0.23) and 57 versus 58% (p=0.63). The postoperative SR rates for group I and II were 78.3 versus 84.9% (p=0.03). However, the "cut and sew" Cox-Maze III was conducted in younger patients (55.0 versus 61.2 years; p=0.005), more often to treat paroxysmal (22.9 versus 8.0%) and lone AF (19.3 versus 1.6%). Alternative sources of energy were predominantly used to treat permanent AF (92.0%), almost always as a concomitant surgical procedure (98.4%) and increasingly in combination with non-mitral valve surgery (18.5%). After correction for these variations, the postoperative SR conversion rates for group I and II did not differ significantly anymore. CONCLUSIONS: We could not identify any significant difference in the postoperative SR conversion rates between the classical 'cut and sew' and the alternative sources of energy, which were used to treat atrial fibrillation.

Substrate-modification using electroanatomical mapping in sinus rhythm to treat ventricular tachycardia in patients with ischemic cardiomyopathy.

UNLABELLED: The treatment especially of frequent ischemic VT remains a challenge for medical and catheter ablation procedures. We evaluated the efficacy of a substrate-based procedure to eliminate clinical VTs in this patient collective. METHODS: In 25 consecutive patients (ejection fraction 37+/-12%) with frequent symptomatic medically refractory ischemic VT (with recurrent ICD-shocks), left ventricular anatomic scar mapping (Biosense Webster CARTO) was performed in order to modify the underlying myocardial substrate. Scar tissue was identified as having bipolar voltages <0.5 mV. Prior to the procedure an electrophysiological study (EPS) to determine number and morphology of inducible VTs was performed. Linear ablation procedures (8 mm tip, 70 Watts, 70 degrees C) were based on the findings of scar areas and proximity to anatomic obstacles. Correct location of ablation was documented by similarity of the morphology during pace-mapping. Follow-up included clinical evaluation, ICD holter interrogation plus holter ECG recording. RESULTS: The clinical VT was eliminated by linear catheter ablation in 23/25 patients (92%) (failure due to unstable catheter position during transaortic approach in 1 and epicardial origin of VT in 1). In 16/23 patients (70%) complete success could be produced with no VT inducible after substrate modification (1.7+/-1.0 lines per patient). In 7 patients (30%) only partial success was documented with further VTs inducible after ablation. No procedure-related complications occurred. During follow- up (10+/-4 months) 4 patients (16%) had occurrences of new VTs documented on ICD holter (3 patients with initially partial success and 1 with initial complete success) differing in cycle length and morphology from the clinical VT. Comparing patients with complete to those with partial success, there was a statistically significant difference of 93 vs. 48% freedom of arrhythmia (p=0.03). No difference in regard to baseline characteristics existed in these two patient subgroups. CONCLUSIONS: Ablation of frequent VTs in patients with ischemic cardiomyopathy can be safely performed using electro-anatomic scar mapping with a high procedural success of 90%. Based on the morphological findings, linear ablation can suppress inducibility of all VTs in 70% of patients with high mid-term efficacy. In patients with only partial ablation success, non-clinical VTs often occur early during follow-up (50%).

[Current guidelines]. / Aktuelle Leitlinien.

Cardiac resynchronisation therapy (CRT) has been adopted fast into clinical practice and current guidelines as a new therapy for some patients with severe systolic heart failure. Current American guidelines have accepted cardiac resynchronisation therapy with the highest level of evidence (A) and have classified the indication in the second highest range (II a). Recommendations in a consensus statement of the German Cardiac Society have been more moderate and have considered contemporarily unsolved questions. After completion of the COMPANION study, which showed a significant benefit for cardiac-resynchronization therapy in the primary end point (mortality and hospitalisation), there were claims for a new evaluation of the cardiac resynchronisation therapy in the German guidelines for cardiac pacing. Contrarily to the American guidelines a risk stratification has been performed into class I (therapy should be performed), class IIa (therapy is reasonable) and class II b (therapy is not unreasonable).

Normal angiogram in acute coronary syndrome-preangiographic risk stratification, angiographic findings and follow-up.

BACKGROUND: Coronary angiographies performed during acute coronary syndrome show different coronary morphologies-vessel occlusions, thrombi and various types of stenoses. In a few cases of acute coronary syndrome, angiography reveals normal coronary arteries. It is the purpose of this study to analyze this specific subset of patients who presented with an acute coronary syndrome but had a normal coronary angiogram with respect to the preangiographic diagnostics, risk stratification and clinical follow-up. METHODS AND RESULTS: A total of 897 coronary angiographies were performed as an emergency procedure in our institution. The majority of patients (n = 821) presented with coronary artery disease and the majority was treated by mechanical revascularization (86.3%). In 76 patients (8.5%), no coronary artery stenosis was documented. However, according to the preangiographic risk stratification, coronary artery disease was expected in these patients. Observations documented angiographically included coronary spasms (6.6%) and muscle bridges (5.3%). During a mean follow-up of 11.2 +/- 6.4 months, one patient developed an acute myocardial infarction requiring coronary intervention. All other patients were free of any cardiac event. CONCLUSIONS: In summary, we have to consider that coronary angiography may not always detect the cause of myocardial ischemia in every patient. There is a small group of patients with normal coronary angiograms during acute coronary syndrome. Additional diagnostic procedures like intravascular ultrasound (IVUS) or the assessment of intracoronary physiological parameters may increase the diagnostic value of angiography.