Transcoronary pacing in an animal model : Second coated guidewire versus cutaneous patch as indifferent electrodes.

BACKGROUND: Transcoronary pacing is a seldom used treatment option for unheralded bradycardias in the setting of percutaneous coronary interventions (PCI). In the present study we compared a coated guidewire inserted proximally into a coronary artery with a cutaneous patch electrode as indifferent electrodes for transcoronary pacing in a porcine model. METHODS: Transcoronary pacing was investigated in 7 adult pigs in an animal catheterization laboratory. A standard guidewire insulated by a monorail-balloon was advanced into the periphery of a coronary artery serving as the cathode. As the indifferent anode, a special guidewire with electrical insulated by a polytetrafluoroethylene (PTFE) coating was positioned into the proximal part of the same coronary vessel. Transcoronary pacing parameters (threshold and impedance data and the magnitude of the epicardial electrogram) were compared with unipolar transcoronary pacing using a cutaneous patch electrode. RESULTS: Transcoronary pacing was successful against both indifferent electrodes. Pacing thresholds obtained with the coated guidewire technique (1.8 ± 1.3 V) were similar to those obtained by standard unipolar transcoronary pacing with a cutaneous patch electrode (1.8 ± 1.5 V). The impedance with the additional coated guidewire was 419 ± 144 Ω and thereby slightly higher compared to 320 ± 103 Ω obtained by pacing against the patch electrode (p < 0.05). Both settings yielded comparable R­wave amplitudes (8.0 ± 5.1 mV vs. 7.1 ± 3.6 mV). CONCLUSIONS: A second coated guidewire is as effective as a cutaneous patch electrode when added as an indifferent electrode in transcoronary pacing. This transcoronary pacing technique could replace temporary transvenous pacing in emergency situations during PCI, especially when using the radial approach.

Wire- and needle potentials facilitating transseptal puncture.

BACKGROUND: Transseptal puncture for left heart interventions became a routine procedure guided by fluoroscopy and echocardiography. The use of intracardiac potentials derived from the sheath-transseptal-needle/guidewire-combination may provide helpful information to increase safety of this procedure. METHODS AND RESULTS: We recorded the intracardiac potentials from the sheath-transseptal-needle/guidewire-combination during the transseptal puncture procedure in 31 consecutive patients (mean age 67.2±8.2years; 21 in sinus rhythm, 10 in atrial fibrillation) designated for ablation of atrial fibrillation by the Cryo-balloon ® technique (Medtronic, Minnesota, USA). The EP-Navigator ® 3-D-image integration tool (Philips Healthcare, Hamburg, Germany) was used for visualization of the device position in relation to the cardiac structures. Typical and reproducible potentials could be derived in all patients for the different device localizations at transseptal puncture procedure. Especially the transition from the muscular interatrial septum into the fossa ovalis could be easily depicted by the changes of both morphology and magnitude of the atrial signal (6.1±2.3mV in sinus rhythm [SR]/3.5±0.9mV in atrial fibrillation [AF] at the muscular interatrial septum and 0.5±0.2mV in SR/0.5±0.1mV in AF in the fossa ovalis). CONCLUSIONS: The crucial steps of a transseptal procedure can be verified by typical changes (morphology and amplitude) of the intracardiac signals derived from the sheath-transseptal-needle/guidewire-combination in patients with sinus rhythm as well as in atrial fibrillation.

Transcoronary mapping of ventricular asynchrony due to left bundle branch block in a porcine model.

BACKGROUND: Optimal positioning of the left ventricular (LV) lead at the latest activated part of the left ventricle is one of the major challenges in implantation of cardiac resynchronization therapy (CRT) devices with respect to ascertaining an optimal resynchronization effect resulting in a high responder rate. In the present study, we evaluated the feasibility of transcoronary measurement of LV electrical activation by a coated guidewire in a porcine model. METHODS AND RESULTS: Transcoronary measurement of ventricular activation was performed in 16 pigs under general anesthesia. Left bundle branch block (LBBB) was induced by transvenous pacing in the right ventricular apex (RVA). A specially coated guidewire (Vision Wire; Biotronik) serving as the different electrode was positioned subsequently in the proximal and distal part of each coronary main vessel. A cutaneous skin patch electrode was placed at the back of the thorax of the animal to act as the indifferent electrode. Both electrodes were connected to a portable electrophysiology lab system (EP Tracer 38; CardioTek). Mean QRS width during transvenous right ventricular pacing was 83 ± 5 ms with a typical LBBB pattern. The measured time interval between the beginning of the QRS complex in the surface electrocardiogram (ECG) and the local signal derived from the tip of the guidewire (QRS-EGM) was 32 ± 9 ms in the distal ramus circumflex (RCX) coronary artery and 51 ± 6 ms in the proximal RCX, yielding a mean delay of 18 ± 8 ms within this vessel. In the left anterior descending (LAD) coronary artery, the local signal was 23 ± 10 ms in the distal part and 41 ± 10 ms in the proximal part of the vessel, with an identical mean delay of 18 ± 8 ms. The QRS-EGM interval within the right coronary artery (RCA) was 14 ± 8 ms in the distal part and 40 ± 9 ms in the proximal part of the vessel, resulting in a mean delay of 25 ± 7 ms. The delay between the activation of the distal RCA and the activation of the distal LAD and RCX was statistically significant (P<.001). Within the proximal guidewire positions, the latest electrical activation of the left ventricle during pacing-induced LBBB could be observed in the RCX with 51.4 ± 6.3 ms (P<.01). CONCLUSION: Transcoronary measurement of LV excitation by a specially coated guidewire is feasible and could confirm the electrical asynchrony induced by LBBB. Since coronary angiography is a mandatory part of the evaluation of patients for CRT implantation, a "transcoronary mapping procedure" can be easily performed, thereby evaluating the latest activated part of the left ventricle in advance of the implantation procedure, aiming to improve the responder rate in CRT therapy.

A novel approach for transcoronary pacing in a porcine model.

BACKGROUND: Transcoronary pacing for the treatment of bradycardias during percutaneous coronary intervention (PCI) is a useful technique in interventional cardiology. The standard technique is unipolar pacing with the guidewire in the coronary artery against a cutaneous patch electrode. We developed a novel approach for transcoronary pacing by using intravascular electrodes in different positions in the aorta in a porcine model. METHODS AND RESULTS: Unipolar transcoronary pacing was applied in 8 pigs under general anesthesia using a standard floppy guidewire in a coronary artery as the cathode with additional insulation of the guidewire by a monorail angioplasty balloon. Intravascular electrodes positioned in the aorta thoracalis and the aorta abdominalis served as indifferent anodes. The efficacy of transcoronary pacing with intravascular anodal electrodes was assessed by measurement of threshold and impedance data and the magnitude of the epicardial electrogram in comparison to unipolar transvenous pacing using the same indifferent anodal electrodes. Transcoronary pacing with the guidewire-balloon combination using indifferent intravascular electrodes was effective in all cases. Transcoronary pacing thresholds obtained against the indifferent coil electrodes in the aorta thoracalis (0.8 ± 0.5 V) and in the aorta abdominalis (0.8 ± 0.5 V) were similar to those obtained with unipolar transvenous pacing (0.7 ± 0.3 V and 0.6 ± 0.2 V, respectively), whereas the tip-electrode in the aorta thoracalis serving as indifferent anode produced significantly higher pacing thresholds (guidewire, 2.8 ± 2.6 V; transvenous lead, 1.5 ± 0.8 V). The lower pacing threshold of the coil-electrodes was associated with significantly lower impedance values (aorta thoracalis, 285 ± 63 ohm; aorta abdominalis, 294 ± 61 ohm) as compared to the tip-electrode in the aorta thoracalis (718 ± 254 ohm). The amplitude of the epicardial electrogram acquired by the intracoronary guidewire was without significant differences between the indifferent electrodes. CONCLUSIONS: Transcoronary pacing in the animal model using a standard guidewire with balloon insulation and intravascular indifferent electrodes is depending on the optimal configuration of the anodal electrode. The use of intravascular coil electrodes with a sufficient surface area can produce 100% capture at thresholds comparable to transvenous pacing. Therefore, technical integration of these coil electrodes into the access sheath or the guiding catheter with respect to handling these tools in daily clinical practice in the catheterization laboratory could further facilitate the transcoronary pacing approach.

Interleukin-6, -7, -8 and -10 predict outcome in acute myocardial infarction complicated by cardiogenic shock.

BACKGROUND: The IABP-SHOCK-trial was a morbidity-based randomized controlled trial in patients with infarction-related cardiogenic shock (CS), which used the change of the quantified degree of multiorgan failure as determined by APACHE II score over a 4-day period as primary outcome measure. The prospective hypothesis was that adding IABP therapy to "standard care" would improve CS-triggered multi organ dysfunction syndrome (MODS). The primary endpoint showed no difference between conventionally managed cardiogenic shock patients and those with IABP support. In an inflammatory marker substudy, we analysed the prognostic value of interleukin (IL)-1ß, -6, -7, -8, and -10 in patients with acute myocardial infarction complicated by cardiogenic shock. DESIGN: Inflammatory marker substudy of the prospective, randomized, controlled, open label IABP-SHOCK-trial (ClinicalTrials.gov ID-NCT00469248). SETTING AND METHODS: A single-center study was performed in a 12-bed Intensive-Care-Unit in an university hospital in which 40 consecutive patients were enrolled with an observational period of 96 h. RESULTS: The pro- and anti-inflammatory markers IL-6, -7, -8 and -10 showed a predictive power for mortality of infarct-related CS patients, while IL-1ß did not discriminate. The maximal values during the observational period, in case of IL-7 the minimal value, showed the best power to predict mortality. Both, ROC and multivariate analyses confirmed these suggestions (area under the curve: IL-8, 0.80 ± 0.08; IL-6, 0.79 ± 0.08; IL-10, 0.76 ± 0.08; IL-7, 0.69 ± 0.08). Inflammatory markers were not affected by the presence of IABP support. CONCLUSION: The inflammatory response in patients with myocardial infarction complicated by cardiogenic shock, as reflected by the inflammatory markers IL-6, IL-7, IL-8 and IL-10, demonstrates a clinically relevant prognostic contribution to clinical outcome.

Transcoronary pacing in a porcine model--impact of guidewire insulation.

BACKGROUND: Bradycardia complicating percutaneous coronary intervention (PCI) can require temporary pacing. A transcoronary approach using the guidewire in the coronary artery may be a useful alternative to transvenous pacing. The purpose of the present study was to compare the efficacy of two different coronary guidewires in transcoronary pacing: a novel guidewire (VisionWire®, Biotronik, Germany) which has a coating to electrically insulate the shaft, thereby maximizing current delivery through the intracoronary section compared to a standard guidewire (without insulation) and a standard guidewire/balloon combination. METHODS AND RESULTS: Unipolar transcoronary pacing was performed in 15 pigs under general anesthesia. In each animal, the new VisionWire was compared to a standard floppy guidewire and to a standard floppy guidewire loaded with a standard angioplasty balloon (which provides additional shaft insulation). The coronary guidewire was the cathode and a skin patch electrode (on the anterior or posterior chest wall) was the anode. We examined the effect of different electrode combinations on transcoronary pacing as assessed by threshold and impedance data and the magnitude of the epicardial electrocardiogram. Transcoronary pacing with the bare standard guidewire was effective in 77% of cases using an anterior skin patch electrode and in 87% with a posterior patch at pacing thresholds of 6.7 ± 2.9 V and 4.1 ± 3.0 V, respectively. Loading the same guidewire with an angioplasty balloon increased the pacing efficacy to 100% with significantly lower pacing thresholds of 2.4 ± 1.6 V with an anterior patch and 1.6 ± 1.3 V with a posterior patch (p < 0.001). The bare VisionWire yielded 100% pacing efficacy, with the lowest pacing thresholds of 1.6 ± 0.7 V and 1.0 ± 0.6 V anterior and posterior patch positions, respectively (p < 0.001). In all studies the pacing efficacy was higher and thresholds lower with the skin patch electrode on the posterior chest wall than on the anterior chest wall. CONCLUSIONS: Transcoronary pacing in the animal model is an effective technique. The VisionWire, (even without the additional insulation of a balloon in place) performed better than a standard guidewire (with or without balloon use), and enabled 100% pacing efficacy at acceptable thresholds. Thus, transcoronary pacing, particularly with specific coronary guidewires may be a useful alternative to transvenous pacing during PCI, particularly in the emergency situation when unexpected bradycardias arise during transradial angioplasty when no central venous access is immediately available for transvenous pacing.

Optimizing of transcoronary pacing in a porcine model.

BACKGROUND: Transcoronary pacing for the treatment of bradycardia during percutaneous coronary intervention (PCI) is not well established, but may be a useful technique in interventional cardiology. We developed a porcine model to examine the feasibility and efficacy of transcoronary pacing during PCI. METHODS AND RESULTS: Eight pigs under general anesthesia underwent unipolar transcoronary pacing with a standard floppy guidewire in a coronary artery (as the cathode) and a skin patch electrode (as the anode). We examined the effect of skin-patch position (groin vs. anterior or posterior chest wall), the presence of an angioplasty balloon on the guidewire and also which coronary artery was "wired" on the efficacy of pacing as assessed by capture and threshold data. Pacing with the bare guidewire and a maximum output of 10 V was successful in 54% of the animals with a groin patch and the anterior chestwall patch, but in 100% with a posterior chest-wall patch. The pacing thresholds were 8.3 +/- 2.2 V, 7.6 +/- 2.8 V and 3.4 +/- 2.4 V with the patch in these sites, respectively. With an angioplasty balloon over the guidewire, pacing efficacy increased to 100% (irrespective of the target vessel or patch location) and pacing thresholds were significantly reduced (p < 0.05) to 2.7 +/- 1.5 (with a groin patch) and 1.0 +/- 0.7 V (with a posterior chestwall patch). With optimal pacing set-up (posterior chest-wall patch and angioplasty-balloon insulation), pacing thresholds were similar to those obtained with standard bipolar transvenous pacing at 1.2 +/- 0.8 V. We did not observe any adverse effects of coronary pacing. Skeletal muscle contraction was only generated at high-output levels. CONCLUSIONS: This pig model examines the practicalities of transcoronary pacing and shows that this technique can produce 100% capture at thresholds comparable to the transvenous approach. This technique may have a role during PCI, particularly in an emergency situation.

Impedance cardiography: a useful and reliable tool in optimization of cardiac resynchronization devices.

AIMS: Optimizing cardiac resynchronization therapy (CRT) devices has become more complex since modification of both atrioventricular (AV) and interventricular (VV) stimulation intervals has become possible. The current paper presents data from the routine use of impedance cardiography (IC)-based cardiac output (CO) measurements to guide the optimization of AV- and VV-interval timing of CRT devices. METHODS AND RESULTS: Forty-six patients with heart failure (left ventricular ejection fraction <35%, New York Heart Association (NYHA) III-IV) and left bundle branch block (>130 ms) in sinus rhythm were evaluated 3-5 days after implantation of a CRT device by means of IC. CO was measured without pacing and with biventricular pacing using a standard protocol of VV- and AV-interval modification from -60 to +60 ms and 80 to 140 ms, respectively, in 20 ms steps. Mean CO without pacing was 3.66 +/- 0.85 L/min and significantly increased to 4.40 +/- 1.1 L/min (P<0.05) with simultaneous biventricular pacing and an AV interval of 120 ms. 'Optimizing' both VV and AV intervals further increased CO to 4.86 +/- 1.1 L/min (P<0.05). Maximum CO was measured in most patients with left ventricular pre-excitation. The proportion of 'non-responders' to CRT was reduced by 56% following AV- and VV-interval modification using IC guidance. CONCLUSION: Modification of both AV and VV intervals in patients with a CRT device significantly improves CO compared with standard simultaneous biventricular pacing and no pacing. IC is a useful non-invasive technique for guiding this modification. Marked variability of optimal AV and VV intervals between patients requires optimization of these intervals for each patient individually.

Temporary trans-coronary pacing by coated guidewires: a safe and reliable method during percutaneous coronary intervention.

Relevant bradycardias during percutaneous coronary intervention (PCI) are a rare event, but they require immediate therapy by temporary pacing. However, transvenous pacing is associated with frequent and severe complications. Therefore, we wanted to evaluate the safety and reliability of trans-coronary pacing by means of a PCI guidewire. Coronary pacing was applied to 70 consecutive patients undergoing PCI. Pacing was performed before and after PCI in a unipolar setting using standard guidewires as a cathode and a skin electrode as an anode. Both were connected to an external pacemaker. Coronary pacing (maximum output at 10 V, impulse duration 2.5 ms) was effective in 60 of 70 patients (85.7%). Successful pacing was achieved in the LAD and diagonal branches in 90% (27 of 30 Pts.), in the LCX and marginal branches 84.2% (16 of 19 Pts.) and in the RCA in 81% (17 of 21 Pts.). Pacing thresholds were comparable in all vessels within a range of 1-10 V averaging 6.6 +/- 2.3 V before and 6.6 +/- 2.2 V after PCI. The impedance ranged from 190-544 Omega with mean pacing impedance for coronary pacing of 424 Omega before and 416 Omega after PCI, respectively. Significant bradycardias during PCI occurred in 7 cases (10%). In three cases (4.3%) temporary coronary pacing became necessary at a maximum pacing duration of 3 min. There were no severe side effects. Coronary spasm occurred in 3 cases (4.3%) after pacing and was promptly reversible after intracoronary application of nitroglycerine. It is concluded that coronary pacing is a safe and feasible method for the treatment of bradycardias during PCI. It avoids additional venous puncture under hemodynamically unstable conditions and subsequent transvenous pacing, which is accompanied by potentially severe complications and additional costs.

Septic cardiomyopathy - A not yet discovered cardiomyopathy?

Myocardial depression in human sepsis was only unequivocally proven in the 1980s by the group of Parrillo, who used nuclear imaging techniques to measure heart volumes and function in intensive care patients. Heart failure in sepsis is frequently masked by a seemingly normal cardiac output. However, relative to the lowered systemic vascular resistance - resulting in a reduced afterload - cardiac outputs and ventricular ejection fractions are often not adequately enhanced. This septic cardiomyopathy (impairment of the heart within the scope of systemic sepsis) involves both the right and the left ventricles, and is potentially reversible. In response to volume substitution, the heart can be considerably enlarged. The cardiomyopathy is not primarily hypoxic in nature, but may be aggravated by ischemia. Autonomic dysfunction, documented by a reduced heart rate variability and impaired baroreflex and chemoreflex sensitivities, forms part of the disease entity. The severity of myocardial depression correlates with a poor prognosis. Noninfectious systemic inflammatory response syndrome can give rise to an analogous disease entity, namely, systemic inflammatory response syndrome cardiomyopathy.The etiology of septic cardiomyopathy is multifactorial. Several candidates with a potential pathogenetic impact on the heart were identified: bacterial toxins; cytokines and mediators including tumour necrosis factor-alpha, interleukin-1 and nitric oxide; cardiodepressant factors; oxygen reactive species; and catecholamines. Symptomatic treatment consists of volume substitution and catecholamine support; causal therapeutic approaches aiming at an interruption of the proinflammatory mediator cascades are being tested.