Electroanatomic visualization of coronary arteries: a case series to elicit safety, feasibility, and diagnostic value in complex ablation procedures.

AIMS: The goal of this case series was to evaluate the feasibility, safety, and advantages of a wire-based approach for the live visualization of coronary arteries (CAs) in an electroanatomic mapping (EAM) system and to assess its diagnostic information. METHODS AND RESULTS: For this single-centre case series, we included procedures in which close proximity of a possible ablation site to any epicardial vessel was suspected. An uncoated-tip guidewire was introduced into the relevant CAs after exclusion of critical CA stenosis by coronary angiography. By connecting this wire to the EAM system using a clip and pin connection, mapping and live visualization of the wire tip is possible, as well as the assessment of the local electrograms within the respective CAs. Procedural wire insertion and intracoronary mapping was performed by EP specialists and was assisted to judge the relevance of CA disease by an interventional cardiologist. A total of nine procedures in nine patients were included in this case series, four ventricular tachycardia ablation procedures and five procedures for the ablation of premature ventricular contractions. The left CAs were mapped in eight cases and the right CA was mapped in one case. In two cases, epicardial mapping was combined with visualization of the right or left CAs. There were no complications attributed to coronary wiring and mapping in this case. CONCLUSION: We demonstrated the feasibility and safety of CA visualization and integration in an EAM. The live visualization of the CAs added valuable information without the need for preprocedural planning or the purchase of separate software. Electroanatomic visualization was achieved intraprocedurally in a safe and straightforward manner, adding critical diagnostic information without excessive costs or risks.

Baroreceptor stimulation in a patient with preexisting subcutaneous implantable cardioverter defibrillator.

BACKGROUND: Many patients with severe heart failure (HF) have an indication for baroreflex activation therapy (BAT) and an implantable cardioverter-defibrillator (ICD). Concerns about device-device interactions were addressed in a study with small sample size that concluded combined BAT and ICD therapy is safe. There are no published data, however, concerning device-device interactions between BAT and a subcutaneous ICD (S-ICD). Since BAT frequently interferes with surface electrocardiogram recordings, there are doubts about compatibility of BAT and S-ICD devices. CASE DESCRIPTION: A 54-year-old male patient with dilated cardiomyopathy and severely reduced left ventricular ejection fraction received an S-ICD after recurrent systemic infections due to a diabetic foot syndrome, ultimately associated with infective endocarditis. Since medical HF therapy could not be further optimized and the patient presented with persistent cardiac decompensations, he was evaluated for BAT. Preoperatively, the barostim was epicutaneously placed on the patient's thorax with conductive gel in order to evaluate a possible interference with the S-ICD. Positioning of the barostim in loco typico did not affect the S-ICD's sensing in any vector. Only positioning of the carotis sinus lead directly upon the S-ICD lead, which is beyond clinical relevance, lead to missensing. Subsequently, BAT was implanted with successful perioperative testing of the S-ICD: there was accurate detection of ventricular fibrillation and immediate termination via first shock delivery under maximum barostim output. CONCLUSIONS: To our knowledge, there are no other reports in which a barostim was safely implanted in a patient with a preexisting S-ICD. Until data with large patient numbers are available, individual perioperative testing is highly recommended.

Safety of the Wearable Cardioverter Defibrillator (WCD) in Patients with Implanted Pacemakers.

BACKGROUND: The wearable cardioverter defibrillator (WCD) is an important approach for better risk stratification, applied to patients considered to be at high risk of sudden arrhythmic death. Patients with implanted pacemakers may also become candidates for use of the WCD. However, there is a potential risk that pacemaker signals may mislead the WCD detection algorithm and cause inappropriate WCD shock delivery. The aim of the study was to test the impact of different types of pacing, various right ventricular (RV) lead positions, and pacing modes for potential misleading of the WCD detection algorithm. METHODS: Sixty patients with implanted pacemakers received the WCD for a short time and each pacing mode (AAI, VVI, and DDD) was tested for at least 30 seconds in unipolar and bipolar pacing configuration. In case of triggering the WCD detection algorithm and starting the sequence of arrhythmia alarms, shock delivery was prevented by pushing of the response buttons. RESULTS: In six of 60 patients (10%), continuous unipolar pacing in DDD mode triggered the WCD detection algorithm. In no patient, triggering occurred with bipolar DDD pacing, unipolar and bipolar AAI, and VVI pacing. Triggering was independent of pacing amplitude, RV pacing lead position, and pulse generator implantation site. CONCLUSION: Unipolar DDD pacing bears a high risk of false triggering of the WCD detection algorithm. Other types of unipolar pacing and all bipolar pacing modes do not seem to mislead the WCD detection algorithm. Therefore, patients with no reprogrammable unipolar DDD pacing should not become candidates for the WCD.

Applicability of a Novel Formula (Bogossian formula) for Evaluation of the QT-Interval in Heart Failure and Left Bundle Branch Block Due to Right Ventricular Pacing.

BACKGROUND: The presence of left bundle branch block (LBBB) due to right ventricular pacing represents a particular challenge in properly measuring the QTc interval. In 2014, a new formula for the evaluation of QT interval in patients with LBBB was reported. METHODS: 145 patients with implantable cardioverter defibrillator were included in this prospective multicenter observational study. Inclusion criteria were: no permanent right ventricular stimulation, an intrinsic QRS interval of <120 ms, and reduced left ventricular function. 12-lead electrocardiogram recordings during intrinsic rhythm and during right ventricular threshold testing were performed. After LBBB correction using the reported Bogossian formula, the QTc interval was evaluated with Bazett's formula. The corrected QTc interval was compared in each patient with the QTc interval during intrinsic rhythm. All measurements were performed by an experienced electrophysiologist and a trainee who worked independently and in a blinded manner. RESULTS: 74 patients (65 ± 13 years; male n = 42) with apical and 71 patients (68 ± 11 years; male n = 42) with nonapical right ventricular pacing were included in this study. The mean left ventricular ejection fraction was 40 ± 13%. The QTc interval was determined to be 461 ± 34 ms (modified by Bogossian's formula) in paced and 436 ± 34 ms in intrinsic rhythm. The QTc interval was overestimated by ΔQTc of 25 ± 21 ms (mean deviation 5.7%) when using the Bogossian formula. CONCLUSION: The novel Bogossian formula seems to be a reliable tool for QTc interval evaluation in patients with heart failure and right ventricular pacing. However, a slight overestimation of the QT-interval must be respected.

Safety and Performance of the Subcutaneous Implantable Cardioverter Defibrillator Detection Algorithm INSIGHTTM in Pacemaker Patients.

BACKGROUND: The use of the S-ICD is limited by its inability to provide backup pacing. Combined use of the S-ICD with a pacemaker may be a good choice in certain situations, yet current experience concerning the compatibility is limited. The goal of this study was to determine the safety and efficacy of the S-ICD in patients with a pacemaker. METHODS: A total of 74 consecutive patients with a bipolar pacemaker were prospectively enrolled. First, surface rhythm strips were recorded in all possible pacemaker stimulation modes, to screen for T-wave oversensing (TWOS). Second, a S-ICD functional dummy was placed epicutaneously on the patient in the typical implant position. The same standardized pacing protocol was used as mentioned above, and every stimulation mode was recorded via S-ECG in all vectors. RESULTS: In 16 patients (21.6%), programmed stimulation would have led to VT/VF detection. Triggered episodes were due to counting of the pacing spike(s), QRS complex, premature ventricular contractions, and/or additional TWOS. Three cases triggered in the bipolar stimulation mode. Oversensing was associated with lung emphysema and a reduced QRS amplitude in the S-ECG. CONCLUSION: The combination of an S-ICD and a pacemaker may lead to inadequate shock delivery due to oversensing, even under programmed bipolar stimulation. Oversensing cannot be sufficiently predicted by the screening tool in pacemaker patients. Testing with an epicutaneous S-ICD dummy in all vectors and stimulation settings is recommended in patients with pre-existing pacemakers.

Diagnostic value of dynamic contrast-enhanced magnetic resonance imaging in the evaluation of the biliary obstruction.

PURPOSE: In this study, our purpose was to investigate the diagnostic efficacy of the dynamic contrast-enhanced magnetic resonance imaging (MRI) method in the patients with bile duct obstruction. MATERIALS AND METHODS: 108 consecutive patients (53 men, 55 women, mean age; 55.77 ± 14.62, range 18-86 years) were included in this study. All the patients underwent conventional upper abdomen MRI using intravenous contrast material (Gd-DTPA) and MRCP in 1.5 Tesla MRI scanner. MRCP images were evaluated together with the T1 and T2w images, and both biliary ducts and surrounding tissues were examined for possible pathologies that may cause obstruction. RESULTS: MRI/MRCP findings compared with final diagnoses, MRI/MRCP in the demonstration of bile duct obstruction sensitivity 96%, the specificity 100%, and accuracy 96.3%, in the detection of presence and level of obstruction, the sensitivity 96.7%, specificity 100%, and accuracy 97.2%, in the diagnosis of choledocholithiasis, the sensitivity 82.3%, specificity 96%, and accuracy 91.7%, and in the determination of the character of the stenosis, sensitivity 95.6%, specificity 91.3%, and accuracy 94.5% were found. CONCLUSION: The combination of dynamic contrast-enhanced MRI and MRCP techniques in patients with suspected biliary obstruction gives the detailed information about the presence of obstruction, location, and causes and is a highly specific and sensitive method.

Cardiac arrhythmias in patients with SARS-CoV­2 infection and effects of the lockdown on invasive rhythmological therapy.

BACKGROUND: Since the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, various strategies have been taken worldwide to reduce the risk of infection. As part of the amendment to the Infection Protection Act, elective medical interventions were restricted, leading to a change in patient care. However, the consequences of the lockdown on the treatment of rhythmological patients in Germany remains unclear. OBJECTIVES: The aim of this study was to analyze the reduction in rhythmological interventions and the patient care situation using a nationwide survey during the first lockdown period. METHODS: A survey was sent to all electrophysiological centers certified by the German Society of Cardiology. Here, the treatment volume of tachycardia and bradycardia and their invasive therapy were surveyed before and during the lockdown period. Furthermore, the number of patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) treated at these centers and the incidence of cardiac arrhythmias was also recorded. RESULTS: Participating centers performed a total of 24,648 ablation procedures/year and represent approximately 34% (24,648/72,548) of the estimated German ablation treatments. The majority of these centers (33/40; 82.5%) were so-called primary COVID-19 hospitals (level-1). Overall, the number of ablations and pacemaker implantations were reduced by 41% and 18% respectively. Due to postponed ablation procedures and pacemaker implantations, 22/40 (55%) centers reported a worsening of clinical symptoms or early re-hospitalization of their patients. CONCLUSION: These results demonstrate a significant decline in elective rhythmological procedures during the lockdown, as required by the German Federal Government. At the same time, however, more than half of the participating centers reported an increase in patient re-hospitalizations due to postponed procedures.

Left Atrial Fibrosis after Single Shot Guided Pulmonary Vein Isolation.

Cryoballoon (CB)-based pulmonary vein isolation (PVI) is an effective treatment modality for patients with atrial fibrillation (AF) with encouraging acute and long-term outcome data. However, the size of collaterally created lesion sets adjacent to the pulmonary veins (PVs) remains unclear, especially when CB ablation is performed with individualized time-to-isolation (TTI) protocols. This study seeks to investigate the extension of lesions at the posterior wall and the roof of the left atrium (LA). Thirty patients with paroxysmal or persistent AF underwent ablation with a fourth-generation CB. The individual freeze-cycle duration was set at TTI + 120 s. A total of 120 PVs were identified, and all were successfully isolated. A three-dimensional electroanatomical high-density (HD) mapping of the LA was performed in every patient before and after PVI. The surface areas of the posterior wall and LA roof were measured and compared with lesion extension after PVI. After CB ablation, 65.6 ± 16.9% of the posterior wall and 75.4 ± 18.4% of the LA roof remained unablated. In addition, non-antral lesion formation was observed in every patient in at least one PV. After CB ablation, anterior antral parts of the superior PVs showed the greatest unablated areas compared with the other antral areas. HD re-mapping after CB-based PVI demonstrated that major regions of the posterior wall and roof remained electrically normal and unaffected. Unablated antral areas were localized predominantly in the anterior segments of the superior PVs and may be partly responsible for AF recurrence.

Tilt testing and what you should know about it - Experience with 835 consecutive patients with syncope of unknown origin.

BACKGROUND: Numerous tilt testing protocols with and without a preceding passive phase or the administration of nitrates have already been investigated. However, a truely standardized method for the investigation does not yet exist. METHODS AND RESULTS: A total of 835 consecutive patients who underwent tilt testing between January 2005 and March 2015 were included in this study. Results of a passive tilt test (PTT), a nitrate-stimulated tilt test (NSTT) with a preceding passive phase of 20 min, or an early nitrate-stimulated tilt test (ENSTT) without a preceding passive phase were compared and analyzed retrospectively in 735 patients. In addition, a further 100 consecutive patients were prospectively randomized 1:1 to compare NSTT and ENSTT. In the retrospective analysis, 38% of the patients in the ENSTT group had a positive test response compared with 45% in the NSTT group and only 27% in the PTT group (p = 0.0002). In the prospective study, 34% of the patients had a positive test response in the ENSTT group compared with 42% in the NSTT group (p = 0.537). The mean duration to a positive test response was significantly shorter in the ENSTT group (retrospective and prospective p < 0.001). The nitrate-stimulated groups did not differ significantly with respect to the hemodynamic characteristics of a positive test response (retrospective: p = 0.773; prospective: p = 0.086). CONCLUSION: Due to the rate of positive test response being comparable to other protocols and its significantly shorter test duration, nitrate-stimulated tilt testing without a preceding passive tilt test may be favored for use in a busy clinical practice.

Effects of parathyroid hormone-related peptide on the large conductance calcium-activated potassium channel and calcium homeostasis in vascular smooth muscle cells.

AIM: To demonstrate the impact of the parathyroid hormone-related peptide (PTHrP) on the large conductance calcium-activated potassium (BKCa) channels in vascular smooth muscle cells (VSMC) and hyperpolarization of the cell membrane and its dependence on calcium. MATERIALS AND METHODS: VSMC were isolated from rat aorta and further subcultured. Four experiments were conducted in calcium-release measurements and each of them consisted of a control group, PTHrP, chemical substance, and PTHrP + chemical substance. Chemical substances used were: iberiotoxin, xestospongin C, xestospongin D, and thapsigargin, respectively. Fura-2 imaging was used to determine changes in calcium release of VSMC. In membrane-potential experiments, groups were designed similarly to the Fura-2 imaging experiments: iberiotoxin, BAPTA, and xestospongin D were added, in respective order. Changes in the membrane potential were examined using the fluorescence dye (DiBAC). RESULTS: Given in a dose between 0.01 and 1.0 µmol/L, PTHrP caused a concentration-dependent decrease in fluorescence intensity, with a maximum effect at 0.5 µmol/L. The decrease, therefore, demonstrated a PTHrP-induced hyperpolarization of the VSMC. The effect was blocked by use of iberiotoxin (100 nmol/L), a highly selective inhibitor of BKCa. Furthermore, when the calcium chelator BAPTA (10 µmol/L) was added, there was a significant reduction in PTHrP-induced hyperpolarization. Use of PTHrP (0.5 µmol/L) also decreased the fluorescence intensity of the indicator for intracellular calcium, Fura-2AM (a membrane-permeable derivative of Fura 2). This effect was re-blocked by use of iberiotoxin. Xestospongin C (3 µmol/L) and xestospongin D (6 µmol/L), both inhibitors of the inositol 1,4,5 trisphosphate-triggered calcium release, inhibited the effects of PTHrP. Additionally, thapsigargin (1 µmol/L), a sarcoplasmic/endoplasmic reticulum Ca2+-ATPase inhibitor, inhibited the effect of PTHrP. CONCLUSION: The results of our study show that PTHrP induces hyperpolarization and activates BKCa in VSMC. The activation of BKCa channels is calcium dependent; activation is linked to the inositol 1,4,5 trisphosphate-triggered calcium release and is also dependent on the endo/sarcoplasmic reticulum calcium pump.

The impact of statins on FGF-2-stimulated human umbilical vein endothelial cells.

AIM: To determine the effects of different types of statins on proliferative and migrative behaviors of basic fibroblastic growth factor (FGF)-2-stimulated endothelial cells. MATERIALS AND METHODS: Human umbilical vein endothelial cells (HUVECs) were isolated and cultured. Groups were arranged in order to observe the impact of each individual substance alone, or under stimulation with statin on FGF-2-stimulated endothelial cells. Endothelial cells were stimulated with human growth factor (HGF), statins, methyl-ß-cyclodextrin (ß-MCD), and either farnesyl pyrophosphate (FPP) ammonium salt, or geranylgeranyl-pyrophosphate (GGPP), respectively. Cell proliferation analyses were performed 48 hours after stimulation and gaps between migration borders were used in migration analyses. RESULTS: The statins showed significant antiproliferative and anti-migrative effects and inhibited the proliferative behavior of FGF-2. However, endothelial cell proliferation and migration were significantly increased after mevalonate co-incubation. Experiments with ß-MCD indicated that the destruction of lipid rafts had a negative impact on the action of FGF-2. Stimulation of statin-incubated cells with FPP had no additional effect on proliferation or migration. Notably, although FGF-2 exerted a pro-migrative effect, the effect was not shown in the FPP + FGF-2 group. The anti-migrative actions of statins along with disruption of membrane integrity were reversed by the addition of GGPP. CONCLUSION: The angiogenic effect of FGF-2 is suppressed through inhibition of the intracellular cholesterol biosynthesis via statins. Inhibitory effects of statins on FGF-2-stimulated HUVECs were observed to result from both the inhibition of isoprenylation and the destruction of lipid rafts on the cell membrane.

Transcatheter aortic valve implantation: our experience and review of the literature.

Transcatheter Aortic Valve Implantation [TAVI] is widespread worldwide as an alternative therapy procedure to the patients suffering from severe aortic valve stenosis. However, we shouldn't forget that the conventional surgical aortic valve replacement is still the gold standard therapy for severe aortic valve stenosis. For the patients who cannot be treated conventionally because of high risk comorbid diseases and older age, TAVI is an effective alternative therapy method. The indications should be limited, concerning the high mortality rate, 10% within 30 days of intervention. Long term efficacy data are still inadequate. Although the indications are restricted to older patients with a STS score >10 or log-Euro Score >20, age is not a definite indication for this treatment. The patients should be assessed by a heart team including a non-interventional cardiologist, interventional cardiologist, cardiac anesthesiologist and cardiac surgeon according to their general status, frailty and STS- Euro score. In other words, assessment and treatment of the patient by a heart team is the main factor besides the limited power of the scoring systems. The treatment should be applied to the patients with an aortic annulus diameter between 18-27 mm and a life expectancy of at least over 1 year. The currently ongoing investigations are focused on parameters like safety, efficiency and long term reliability of TAVI. The scientific and technical developments lead to new definitions and parameters regarding the treatment indications of severe aortic valve stenosis. In this review, we present the actual data about TAVI and also our own experiences.

Quadripolar Left Ventricular Lead in a Patient with CRT-D Does Not Overcome Phrenic Nerve Stimulation.

Effective cardiac resynchronization therapy (CRT) requires an accurate atrio-biventricular pacing system. The innovative Quartet lead is a quadripolar, over-the-wire left ventricular lead with four electrodes and has recently been designed to provide more options and greater control in pacing vector selection. A lead with multiple pacing electrodes is a potential alternative to physical adjustment of the lead and may help to overcome high thresholds and phrenic nerve stimulation (PNS).