Predictive Factors and Safety of Noninvasive Mechanical Ventilation in Combination With Propofol Deep Sedation in Left Atrial Ablation Procedures.

Catheter ablation is nowadays the core treatment of atrial fibrillation (AF). Propofol infusion sedation is an accepted safety strategy; however, respiratory depression with respiratory variations is frequent. Noninvasive mechanical ventilation (NIV) added to deep sedation could improve procedural safety and success. We sought to assess the predictive factors and safety of NIV in combination to propofol deep sedation in left atrial ablation procedures. Procedural data from 252 consecutive patients who underwent left atrial ablation (166 [66%] persistent, 86 [34%] for paroxysmal AF) were analyzed. Sedation with 1% propofol was used in all procedures and controlled by electrophysiologists. Arterial blood gas analysis was performed regularly during the procedure. NIV was indicated for respiratory depression with pH <7.25 and pCO2 >50 mm Hg or agitated patient with the need for more profound sedation. No patient needed endotracheal intubation, and no procedure was abandoned due to adverse effects of sedation. NIV was used in 25 patients (10%). Predictive factors for the use of NIV were high-dose propofol sedation (p = 0.010), persistent AF (p = 0.029), prolonged procedure time (p = 0.006), increased body mass index (p = 0.008) and presence of obstructive sleep apnea (OSA; p <0.001). In a Cox regression analysis, OSA was an independent factor for NIV use (p = 0.016). In conclusion, propofol deep sedation for patients who underwent left atrial ablation is safe. Adding NIV in high-risk patients (i.e., OSA, high body mass index, and lengthy procedure duration) provides better respiratory homeostasis and could impact long-term procedure results.

Lesion formation after pulmonary vein isolation using the advance cryoballoon and the standard cryoballoon: lessons learned from late gadolinium enhancement magnetic resonance imaging.

AIMS: To compare ablation lesion formation after pulmonary vein isolation (PVI) using the standard cryoballoon (CB-S) vs. the re-designed cryoballoon Arctic Front Advance (CB-A) using late gadolinium enhancement magnetic resonance imaging (LGE-MRI) 3 months post-ablation. METHODS AND RESULTS: Thirty-six consecutive patients with paroxysmal or short-lasting persistent atrial fibrillation (AF) were evaluated prospectively after PVI using the CB-S in the first 18 patients and the CB-A in the subsequent 18 patients. All patients underwent LGE-MRI and a 7-day Holter electrocardiogram monitoring 3 months after ablation. Fifty-six per cent of the patients were male (mean age 63.0 ± 9.1 years). Fifty-six per cent in the first group and 89% in the second group were free of AF recurrence 3 months after ablation (P = 0.025). Three months after ablation, LGE-MRI of the left atrium showed complete circular lesions in 35% of PVs in the first group and in 32% of PVs in the second group (n.s.). The left PVs showed a significantly higher proportion of PV segments with complete ablation lesions compared with the right PVs (83 vs. 34%; P < 0.001). CONCLUSION: Cardiac MRI is able to visualize induced ablation lesions after PVI and might be suitable to quantify ablation lesion amount. Ablation lesion formation did not differ significantly in patients treated with the CB-S vs. the CB-A, despite a significantly lower rate of AF recurrence after 3 months in the CB-A group. Left PVs showed a significantly higher amount of ablation lesions compared with the right PVs. Larger and randomized studies are needed to understand the relationship between representable tissue lesions and success rates.

[Use of cardiac MRI in the field of electrophysiology. Present status and future aspects]. / Einsatz der kardialen MRT in der Elektrophysiologie. Aktueller Stand und Ausblicke in die Zukunft.

In recent years, ablation therapy has become the first-line treatment of modern electrophysiology in patients with cardiac arrhythmias. Today, cardiac magnetic resonance imaging (cMRI) is an important supportive imaging technique in the implementation of complex electrophysiological investigations and ablation therapy. In clinical routine, cMRI is used not only to generate accurate three-dimensional (3D) models of cavities of the heart but also for visualization of complex anatomical structures. The development of cMRI makes it possible to detect the underlying substrate of complex arrhythmias such as myocardial scar in patients with ventricular tachycardia or the structural remodeling of the left atrium in patients with atrial fibrillation. The opportunity of fusion of the different imaging modalities (e.g., fluoroscopy, cMRI) has become essential for the planning and the implementation of a safe ablation therapy. The possibility of direct visualization of induced lesions using cMRI after and in the long term after ablation can predict the success of therapy and detects potential complications. The continuous research in the field of cMRI and the development of MRI-compatible pacing and ablation catheters provided the basics for performing electrophysiological treatment in humans directly inside the MRI. The implementation of ablation using exact visualization of the anatomical substrate, precise catheter navigation and real-time visualization of lesions in cMRI promises to improve success rates and the safety of complex ablation treatment and may revolutionize electrophysiology in the future.

[Three-dimensional mapping systems]. / Dreidimensionale Mappingsysteme.

Three-dimensional (3-D) mapping systems are of great value for the diagnosis and ablation of cardiac arrhythmias. If applied appropriately, 3-D mapping systems (3DM) can reduce fluoroscopy and procedural time. In general, two advanced mapping systems are currently in use: the Carto™ system (Biosense Webster) uses ultralow-intensity magnetic fields to locate specially designed catheters in the heart chamber. Both, the activation sequence (activation map) and the local potential amplitude (voltage map) can be displayed. Additional applications are available: the SmartTouch™ Catheter offers contact force registration, while CartoMerge™ enables integration of other imaging modalities into the map. The other commonly used mapping system is EnSite NavX™(Endocardial Solutions, St. Jude), which uses electrical current delivered across different pairs of patches on the body surface, and thereby creating voltage gradients. Thus, catheter tips and shafts in a 3-D field can be localized. Special applications of this system are the automated registration of complex fractionated atrial electrograms (CFAE) and a non-contact mapping function using the EnSite Array™ Mapping system. The EnSite-NavX™ system is not limited to the use of special sensor-equipped catheters. Basically, both systems are compatible with the remote navigation systems "Niobe™" and "Sensei®.

Criteria for patient selection in cardiac resynchronization therapy.

Since the implementation of cardiac resynchronization therapy (CRT) the prognosis of patients with severe heart failure has been improved owing to a reduction in morbidity and mortality rates, as several multicenter trials have shown. However, several patients treated by CRT still lack improvement or even deteriorate during therapy. In some of them, this might be due to the severity and progression of chronic heart failure. In others, the criteria for the indication of CRT and/or optimized device programming might have not been met. Thus, one important option to improve CRT outcome is to improve CRT patient selection. A lot of publications describing various methods identifying a positive or negative prediction of CRT have been released. In summary, decision making based on all these partly contradictory publications indicate a strong need for guidelines for the use of such expensive therapy. The purpose of this article is to give an overview of CRT and summarize the different methods and the limitations of CRT patient selection parameters. With the focus of the different guidelines, this article tries to give an appropriate overview and aid decision making in CRT patients, including a short view of possible new indications.

Intracardiac echocardiography improves procedural efficiency during cryoballoon ablation for atrial fibrillation: a pilot study.

UNLABELLED: Intracardiac Echocardiography Guided Cryoballoon Ablation. BACKGROUND: Cryoballoon ablation is increasingly used for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). This new technique aims to perform PVI safer and faster. However, procedure and fluoroscopy times were similar to conventional RF approaches. We compared ICE plus fluoroscopy versus fluoroscopy alone for anatomical guidance of PVI. METHODS: Forty-three consecutive patients with paroxysmal AF were randomly assigned to ICE plus fluoroscopy (n = 22) versus fluoroscopy alone (n = 21) for guidance of cryoballoon PVI. A "single big balloon" procedure using a 28 mm cryoballoon was performed. The optimal ICE-guided position of the cryoballoon was assessed by full ostial occlusion and loss of Doppler coded reflow to the left atrium (LA). Any further freezes were ICE-guided only without use of fluoroscopy or contrast media injection. RESULTS: A total of 171 pulmonary veins could be visualized with ICE. 80% of ICE-guided freezes were performed with excellent ICE quality. Acute procedural success and AF recurrence rate at 6 months were similar in both groups (AF recurrence: ICE-guided = 27% vs Fluoroscopy = 33%; P = ns). Patients without ICE guidance had significantly longer procedure (143 ± 27 minutes vs 130 ± 19 minutes; P = 0.05) and fluoroscopy times (42 ± 13 minutes vs 26 ± 10, P = 0.01). The total amount of contrast used during the procedure was significantly lower in patients with ICE guidance (88 ± 31 mL vs 169 ± 38 mL, P < 0.001). CONCLUSION: Additional ICE guidance appears to be associated with lower fluoroscopy, contrast, and procedure times, with similar efficacy rates. Specifically, ICE allows for better identification of the PV LA junction and more precise anatomically guided cryoballoon ablations.

Thrombolytic efficacy of recombinant human microplasmin in a canine model of copper coil-induced coronary artery thrombosis.

We investigated the in vitro fibrinolytic properties of microplasmin, the isolated proteinase domain of plasmin, and its thrombolytic efficacy in a coronary artery thrombosis model in dogs. The amidolytic and fibrinolytic activity of recombinant microplasmin was compared with natural human plasmin. The thrombolytic efficacy of microplasmin was studied in a canine model of copper coil induced coronary artery thrombosis. Animals were randomly assigned to one of six treatment regimens, each with five animals per cohort. Four treatment groups received an intravenous bolus of microplasmin followed by an intravenous infusion of microplasmin for 1 h (1 mg/kg + 1.5 mg/kg/h with or without abciximab or 2 mg/kg + 3 mg/kg/h). In two treatment groups, microplasmin was administered intracoronary. Bolus administration was followed by a 1-h infusion if coronary flow was incompletely restored after the initial bolus administration (1 mg/kg + 1.5 mg/kg/h or 2 mg/kg + 3 mg/kg/h, respectively). The thrombolytic efficacy was documented by repeated angiographies and the coronary perfusion was assessed with the Thrombolysis in Myocardial Infarction (TIMI) grading. No significant differences between plasmin and microplasmin were observed with respect to the catalytic efficiencies towards the synthetic chromogenic substrates S-2403 or S-2444. The concentration required for 50% lysis of purified fibrin clots in 3 h, was approximately 100 nM for microplasmin compared to 20 nM for natural plasmin. Intravenous bolus administration of microplasmin restored TIMI 3 coronary flow in 0/5, 0/5, 1/5 and 2/5, respectively, whereas intracoronary bolus administration restored TIMI 3 coronary flow in 1/5 and 4/5 (1 mg/kg and 2 mg/kg, respectively) (ANOVA P < 0.05). TIMI 3 coronary flow was obtained in 0/5, 2/5, 2/5 and 3/5, respectively, during subsequent intravenous administration and in 5/5 and 4/5 in case of intracoronary administration (ANOVA P < 0.05). When compared to natural plasmin, the catalytic efficiency of microplasmin towards chromogenic substrates was similar, but the fibrinolytic potency of microplasmin towards fibrin clots was lower. Intracoronay administration of microplasmin effectively lysed coronary thrombosis.

The sequential changes in myocardial thickness and thickening which occur during acute transmural infarction, infarct reperfusion and the resultant expression of reperfusion injury.

AIM: Successful primary PTCA (with TIMI 3 reflow) in patients with acute transmural infarction has been observed to result in an immediate abnormal increase in wall thickness associated with persisting abnormal post-systolic thickening. To understand the sequential changes in regional deformation during: (i) the development of acute transmural infarction, (ii) upon TIMI grade 3 infarct reperfusion and (iii) during the subsequent expression of reperfusion injury the following correlative experimental study was performed in a pure animal model in which there was no distal dispersion of thrombotic material causing either no reflow or secondary microvascular obstruction. METHODS: In 10 closed-chest pigs, a 90 min PTCA circumflex occlusion was used to induce a transmural infarction. This was followed by 60 min of TIMI 3 infarct reperfusion. M-mode ultrasound data from the "at risk" posterior wall infarct segment and from a control remote non-ischemic septal segment were acquired at standardized time intervals. Changes in regional deformation (end-diastolic (EDWT), end-systolic (ESWT) and post-systolic (PSWT) wall thickness, end-systolic strain (epsilonES) and post-systolic strain (epsilonps)) were measured. RESULTS: In this pure animal model of acute transmural infarction/infarct reperfusion (with no pre-existing intra-luminal thrombus), the induced changes in wall thickness and thickening were complex. During prolonged occlusion, after an initial acute fall in ESWT, there was no further change in systolic deformation to indicate the progression of ischaemia to infarction. Both transmurally infarcted and reperfused-infarcted myocardium retained post-systolic thickening indicating that this parameter, taken in isolation, is not a consistent marker of segmental viability and, in this regard, should be interpreted only in combination with other indices of segmental function. The most striking abnormality induced by reperfusion was an immediate increase in EDWT which then increased logarithmically over a 60 min period as reperfusion injury was further expressed. PS did not change significantly during reperfusion. Histology confirmed the wall thickness changes on reperfusion to be due to massive extra-cellular oedema. CONCLUSIONS: The identification of an acute increase in regional wall thickness in a reperfused infarct zone by cardiac ultrasound following primary PTCA might be used in patients to both identify successful infarct reperfusion and to monitor the presence, extent and resolution of the oedema associated with reperfusion injury.

Improvement of cardiac function during enzyme replacement therapy in patients with Fabry disease: a prospective strain rate imaging study.

BACKGROUND: Enzyme replacement therapy (ERT) has been shown to enhance microvascular endothelial globotriaosylceramide clearance in the hearts of patients with Fabry disease. Whether these results can be translated into an improvement of myocardial function has yet to be demonstrated. METHODS AND RESULTS: Sixteen patients with Fabry disease who were treated in an open-label study with 1.0 mg/kg body weight of recombinant alpha-Gal A (agalsidase beta, Fabrazyme) were followed up for 12 months. Myocardial function was quantified by ultrasonic strain rate imaging to assess radial and longitudinal myocardial deformation. End-diastolic thickness of the left ventricular posterior wall and myocardial mass (assessed by magnetic resonance imaging, n=10) was measured at baseline and after 12 months of ERT. Data were compared with 16 age-matched healthy controls. At baseline, both peak systolic strain rate and systolic strain were significantly reduced in the radial and longitudinal direction in patients compared with controls. Peak systolic strain rate increased significantly in the posterior wall (radial function) after one year of treatment (baseline, 2.8+/-0.2 s(-1); 12 months, 3.7+/-0.3 s(-1); P<0.05). In addition, end-systolic strain of the posterior wall increased significantly (baseline, 34+/-3%; 12 months, 45+/-4%; P<0.05). This enhancement in radial function was accompanied by an improvement in longitudinal function. End-diastolic thickness of the posterior wall decreased significantly after 12 months of treatment (baseline, 13.8+/-0.6 mm; 12 months, 11.8+/-0.6 mm; P<0.05). In parallel, myocardial mass decreased significantly from 201+/-18 to 180+/-21 g (P<0.05). CONCLUSIONS: These results suggest that ERT can decrease left ventricular hypertrophy and improve regional myocardial function.

Effect of additional temporary glycoprotein IIb/IIIa receptor inhibition on troponin release in elective percutaneous coronary interventions after pretreatment with aspirin and clopidogrel (TOPSTAR trial).

OBJECTIVES: The Troponin in Planned PTCA/Stent Implantation With or Without Administration of the Glycoprotein IIb/IIIa Receptor Antagonist Tirofiban (TOPSTAR) trial investigated: 1) the amount of troponin T (TnT) release after nonacute, elective percutaneous coronary intervention (PCI) in patients pretreated with aspirin and clopidogrel; and 2) the effect of additional glycoprotein (GP) IIb/IIIa receptor inhibiton on postinterventional TnT release. BACKGROUND: No data are available yet as to whether additional administration of a GP IIb/IIIa receptor antagonist might be beneficial in patients undergoing elective PCI already pretreated with aspirin and clopidogrel. METHODS: After bolus application of the study medication (tirofiban [T] or placebo [P]), PCI was performed followed by an 18-h continuous infusion of T/P. Primary end point of the study was incidence and amount of TnT release after elective PCI after 24 h. RESULTS: A total of 12 h after PCI troponin release was detected in 63% of the patients receiving P and in 40% of the patients receiving T (p < 0.05), after 24 h in 69% (P) and 48% (T) (p < 0.05) and after 48 h in 74% (P) versus 58% (T) (p < 0.08) of the patients. No differences were observed regarding major bleeding, intracranial bleeding or nonhemorrhagic strokes. After nine months a reduction of combined death/myocardial infarction/target vessel revascularization could be observed in the tirofiban group ([T] 2.3% vs. [P] 13.04%, p < 0.05). CONCLUSIONS: Troponin T release occurs after successful intervention in 74% of the patients undergoing elective PCI after 48 h even after pretreatment with aspirin and clopidogrel. The GP IIb/IIIa receptor antagonist tirofiban is able to decrease the incidence of troponin release significantly in this patient population.