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Cardiovascular AND Tachycardia, ventricular, [keywords]
- Hemodynamic effects of Ivabradine in addition to dobutamine in patients with severe systolic dysfunction. [JOURNAL ARTICLE]
- Int J Cardiol 2014 Aug 1.
Dobutamine induced tachycardia increases myocardial oxygen consumption and impairs ventricular filling. We hypothesized that Ivabradine may be efficient to control dobutamine induced tachycardia.We assessed the effects of Ivabradine in addition to dobutamine in stable heart failure (HF) patients (LVEF<35%, n=22, test population) and validated its effects in refractory cardiogenic shock patients (n=9, validation population) with contraindication to cardiac assistance or transplant. In the test population (62±17years, LVEF=24±8%), systolic and diastolic function were assessed at rest and under dobutamine [10γ/min], before and after Ivabradine [5mg per os]. In the validation population (54±11years, LVEF=22±7%), Ivabradine [5mg twice a day] was added to the dobutamine infusion.In the test population, Ivabradine decreased heart rate [HR] at rest and during dobutamine echocardiography (-9±8bpm, P=0.0004). The decrease in HR was associated with a decrease in cardiac power output and an increase in diastolic duration at rest (+74±67ms, P=0.0002), and during dobutamine infusion (+75±67ms, P<0.0001). Change in LVEF during dobutamine was greater after Ivabradine treatment than before (+7.2±4.7% vs. +3.6±4.2%, P=0.002). In the validation population, Ivabradine decreased HR (-18±11bpm, P=0.008) and improved diastolic filling time (+67±42ms, P=0.012) without decreasing cardiac output. At 24h, Ivabradine improved systolic blood pressure (+9±5mmHg, P=0.007), daily urine output (+0.7±0.5L, P=0.008), oxygen balance (ΔScv02=+13±15%, P=0.010), and NT-pro BNP (-2270±1912pg/mL, P=0.017). Finally, only 2/9 (22%) patients died whereas expected mortality determined from a historical cohort was 78% (P=0.017).This pilot study demonstrates the safety and potential benefit of a HR lowering agent in cardiogenic shock.
- Morphological and Thermodynamic Comparison of the Lesions Created by Four Open-irrigated Catheters in Two Experimental Models. [JOURNAL ARTICLE]
- J Cardiovasc Electrophysiol 2014 Aug 14.
New generation open-irrigated catheters aim to improve irrigation efficiency. This may change lesion patterns, challenging operators. Indeed, safety issues have recently arisen. We aimed to experimentally assess 4 open-irrigated catheters, comparing lesion size, safety and heat transfer.The thigh lesion model was employed in 6 anesthetized pigs to assess the morphology of perpendicular and tangential lesions (n = 140) created by the newer catheters ThermoCool® SF, CoolFlex(™) and Blazer(™) Open-Irrigated, and the standard ThermoCool®, at a constant power of 30W (60s). To evaluate the propensity for deep-tissue overheating, a set of 120 applications were performed at 50W (180s) comparing pop rates. Thermal assessment of the lesion generation process (20W, 60s, n = 32) was performed with an infrared camera on bovine ventricular tissue.At 30W, the newer catheters showed lower temperature readings compared with the ThermoCool®. No major efficacy or safety differences were found at tangential applications; however, at perpendicular applications: 1) the SF at 17 mL/min better preserved the superficial layers and focused its maximum thermal effect deeper, but at recommended flow rates (8 mL/min) it generated the largest superficial lesions; 2) CoolFlex(™) created smaller lesions than SF and readily induced steam pops at 50W without temperature control; 3) no major differences were found comparing Blazer(™) Open-Irrigated and ThermoCool®.The lower temperature readings in the newer catheters make them more prone to deliver the maximum programmed power. Under experimental conditions, the SF catheter focuses its maximum effect deeper and the CoolFlex(™) can be more prone to induce steam pops at high power settings. This article is protected by copyright. All rights reserved.
- Cardiovascular Complications following Chronic Treatment with Cocaine and Testosterone in Adolescent Rats. [Journal Article]
- PLoS One 2014; 9(8):e105172.
Concomitant use of anabolic androgenic steroids and cocaine has increased in the last years. However, the effects of chronic exposure to these substances during adolescence on cardiovascular function are unknown. Here, we investigated the effects of treatment for 10 consecutive days with testosterone and cocaine alone or in combination on basal cardiovascular parameters, baroreflex activity, hemodynamic responses to vasoactive agents, and cardiac morphology in adolescent rats. Administration of testosterone alone increased arterial pressure, reduced heart rate (HR), and exacerbated the tachycardiac baroreflex response. Cocaine-treated animals showed resting bradycardia without changes in arterial pressure and baroreflex activity. Combined treatment with testosterone and cocaine did not affect baseline arterial pressure and HR, but reduced baroreflex-mediated tachycardia. None of the treatments affected arterial pressure response to either vasoconstrictor or vasodilator agents. Also, heart to body ratio and left and right ventricular wall thickness were not modified by drug treatments. However, histological analysis of left ventricular sections of animals subjected to treatment with testosterone and cocaine alone and combined showed a greater spacing between cardiac muscle fibers, dilated blood vessels, and fibrosis. These data show important cardiovascular changes following treatment with testosterone in adolescent rats. However, the results suggest that exposure to cocaine alone or combined with testosterone during adolescence minimally affect cardiovascular function.
- Longitudinal hemodynamic measurements in Swine heart failure using a fully implantable telemetry system. [Journal Article]
- PLoS One 2014; 9(8):e103331.
Chronic monitoring of heart rate, blood pressure, and flow in conscious free-roaming large animals can offer considerable opportunity to understand the progression of cardiovascular diseases and can test new diagnostics and therapeutics. The objective of this study was to demonstrate the feasibility of chronic, simultaneous measurement of several hemodynamic parameters (left ventricular pressure, systemic pressure, blood flow velocity, and heart rate) using a totally implantable multichannel telemetry system in swine heart failure models. Two solid-state blood pressure sensors were inserted in the left ventricle and the descending aorta for pressure measurements. Two Doppler probes were placed around the left anterior descending (LAD) and the brachiocephalic arteries for blood flow velocity measurements. Electrocardiographic (ECG) electrodes were attached to the surface of the left ventricle to monitor heart rate. The telemeter body was implanted in the right side of the abdomen under the skin for approximately 4 to 6 weeks. The animals were subjected to various heart failure models, including volume overload (A-V fistula, n = 3), pressure overload (aortic banding, n = 2) and dilated cardiomyopathy (pacing-induced tachycardia, n = 3). Longitudinal changes in hemodynamics were monitored during the progression of the disease. In the pacing-induced tachycardia animals, the systemic blood pressure progressively decreased within the first 2 weeks and returned to baseline levels thereafter. In the aortic banding animals, the pressure progressively increased during the development of the disease. The pressure in the A-V fistula animals only showed a small increase during the first week and remained stable thereafter. The results demonstrated the ability of this telemetry system of long-term, simultaneous monitoring of blood flow, pressure and heart rate in heart failure models, which may offer significant utility for understanding cardiovascular disease progression and treatment.
- Impact of Pre-Procedural Cardiopulmonary Instability in Patients With Acute Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention (from the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction Trial). [JOURNAL ARTICLE]
- Am J Cardiol 2014 Jul 16.
Rapid reperfusion with primary percutaneous coronary intervention improves survival in patients with ST-segment elevation myocardial infarction. Preprocedural cardiopulmonary instability and adverse events (IAE) may delay reperfusion time and worsen prognosis. The aim of this study was to evaluate the relation between preprocedural cardiopulmonary IAE, door-to-balloon time (DBT), and outcomes in the Harmonizing Outcomes With Revascularization and Stents in AMI (HORIZONS-AMI) trial. Preprocedural cardiopulmonary IAE included sustained ventricular or supraventricular tachycardia or fibrillation requiring cardioversion or defibrillation, heart block or bradycardia requiring pacemaker implantation, severe hypotension requiring vasopressors or intra-aortic balloon counterpulsation, respiratory failure requiring mechanical ventilation, and cardiopulmonary resuscitation. Three-year outcomes of patients with and without IAE according to DBT were compared. Among 3,602 patients, 159 (4.4%) had ≥1 IAE. DBT did not differ significantly in patients with and without IAE; however, patients with IAE were less likely to have Thrombolysis In Myocardial Infarction (TIMI) grade 3 flow after percutaneous coronary intervention. Mortality at 3 years was significantly higher in patients with versus those without IAE (17.0% vs 6.3%, p <0.0001), and IAE was an independent predictor of mortality, whereas DBT was not. However, a significant interaction was present such that 3-year mortality was reduced in patients with DBT <99 minutes (the median) versus ≥99 minutes to a greater extent in patients with IAE (9.9% vs 20.7%, hazard ratio 0.43, 95% confidence interval 0.16 to 1.16) compared with those without IAE (5.0% vs 7.2%, hazard ratio 0.69, 95% confidence interval 0.50 to 0.95) (p for interaction = 0.004). In conclusion, IAE before PCI is an independent predictor of death and identifies a high-risk group in whom faster reperfusion may be particularly important to improve survival.
- Ventricular Arrhythmias near the Distal Great Cardiac Vein: A Challenging Arrhythmia for Ablation. [JOURNAL ARTICLE]
- Circ Arrhythm Electrophysiol 2014 Aug 10.
-Catheter ablation (CA) for ventricular arrhythmia (VA) near the distal great cardiac vein (GCV) is often challenging and data are limited.-Analysis was performed of 30 patients (19 male; age 52.8±15.5 years) who underwent CA for focal VA (11 ventricular tachycardia, 19 premature contractions) with early activation in the GCV (36.7±8.0 ms pre-QRS). Angiography in 27 patients showed earliest GCV site within 5 mm of a coronary artery in 20 (74%). Ablation was performed in the GCV in 15 patients and abolished VA in 8. Ablation was attempted at adjacent non-GCV sites in 19 patients and abolished VA in 5 patients (4 from the left ventricular endocardium and 1 from the left coronary cusp); all success had VA with an initial r wave in lead I and activation ≤7 ms after the GCV (GCV-nonGCV interval). In 13 patients percutaneous epicardial mapping was performed, but due to adjacent coronaries only 2 received radiofrequency application with VA elimination in 1. Surgical cryoablation was performed in 3 patients and abolished VA in 2. Overall acute success was achieved in 16 (53%) patients. After a median of 2.8 months, 13 patients remained free of VA. Major complications occurred in 4 patients including coronary injury requiring stenting.-Ablation for this arrhythmia is challenging and often limited by the adjacent coronary vessels. Success of anatomically guided endocardial ablation may be identified by a short GCV-nonGCV interval and r wave in lead I.
- Utility of Intracardiac Echocardiography for Catheter Ablation of Complex Cardiac Arrhythmias in a Medium-Volume Training Center. [JOURNAL ARTICLE]
- Echocardiography 2014 Aug 11.
New electrophysiology tools like intracardiac echocardiography (ICE) might help to minimize and early detect complications during cardiac ablation procedures. The aim of the study was to assess the utility and vascular safety of ICE during catheter ablation of complex cardiac arrhythmias in a medium-volume training center.Prospective, observational study consisted of consecutive patients who underwent catheter-based ablation of complex cardiac arrhythmias. All procedures were performed using three-dimensional electro-anatomical mapping and routine cannulation of right and left femoral veins. The ICE probe was initially positioned at the mid-level of the right atrium and properly moved to monitor different steps of the procedure and identify complications. All procedure-related vascular complications were registered.One hundred two patients (age 61.4 ± 13.1 years, 69 male) underwent 110 ablation procedures. Pulmonary vein isolation was the most common ablation substrate (55.4%). Ventricular tachycardia (17.2%) and left atrial flutter procedures (16.4%) were also common. The use of ICE enabled us to early initiate anticoagulation and to optimize the transseptal puncture. It also provided the capability to early detect life-threatening complications such as tamponade (3.6%), along with important information during the procedure such as exact catheter location, lesion formation, and stability during radiofrequency delivery. Such benefits were not associated with a higher number of vascular complications.The use of ICE during catheter-based ablation of complex cardiac substrates provides technical features that may decrease complications and increase accuracy while applying radiofrequency, especially in training centers where fellows start to perform complex procedures.
- Evaluation of long-term pituitary functions in patients with severe ventricular arrhythmia: a pilot study. [JOURNAL ARTICLE]
- J Endocrinol Invest 2014 Aug 9.
Traumatic brain injury (TBI), subarachnoid hemorrhage (SAH), stroke and cerebrovascular disease (CVD) are identified as risk factors for hypopituitarism. Pituitary dysfunction after TBI, SAH, and CVD may present in the acute phase or later in the course of the event. Chronic hypopituitarism, particularly growth hormone (GH) deficiency is related to the increased cardiovascular morbidity and mortality. In patients with serious ventricular arrhythmias, who need cardiopulmonary resuscitation, brain tissue is exposed to short-term severe ischemia and hypoxia. However, there are no data in the literature regarding pituitary dysfunction after ventricular arrhythmias.Forty-four patients with ventricular arrhythmias [ventricular tachycardia (VT), ventricular fibrillation (VF)] (mean age, 55.6 ± 1.8 years; 37 men, 7 women) were included in the study. The patients were evaluated after mean period of 21.2 ± 0.8 months from VT-VF. Basal hormone levels, including serum free triiodothyronine (fT3), free thyroxine (fT4), TSH, ACTH, prolactin, FSH, LH, total testosterone, estradiol, IGF-1, and cortisol levels were measured in all patients. To assess (GH)-insulin like growth factor-1 (IGF-1) axis, glucagon stimulation test was performed and 1 µg ACTH stimulation test was used for assessing hypothalamic-pituitary-adrenal (HPA) axis.The frequencies of GH, gonadotropin and TSH deficiency were 27.2, 9.0, 2.2 %, respectively. Mean IGF-1 levels were lower in GH deficiency group, but it was not statistically significant.The present preliminary study showed that ventricular arrhythmias may result in hypopituitarism, particularly in growth hormone deficiency. Unrecognized hypopituitarism may be responsible for some of the cardiovascular problems at least in some patients.
- Left ventricular assist device in the management of refractory electrical storm. [JOURNAL ARTICLE]
- Perfusion 2014 Aug 8.
Electrical storm refers to a state of cardiac electrical instability characterized by multiple episodes of ventricular tachycardia (VT) or ventricular fibrillation (VF) within a relatively short period of time and is associated with increased mortality and morbidity. The management of electrical storm involves a variety of strategies, including sedation, anti-arrhythmic and electrolyte replacement as well as revascularization and electrical ablation. However, the management strategy in patients with refractory storm is less clear and may require more invasive approaches. We present a case of severe ventricular tachycardia storm refractory to conservative management that was managed with a HeartMate II left ventricular assist device.
- Outcomes in patients with sustained ventricular tachyarrhythmias occurring within 48 h of acute myocardial infarction: when is ICD appropriate? [JOURNAL ARTICLE]
- Europace 2014 Aug 6.
Recent guidelines for implantable cardioverter-defibrillator (ICD) use in patients with early ventricular arrhythmia (VA) after acute myocardial infarction (MI) are based on systolic function and revascularization status, yet decision to implant an ICD remains highly subjective. We aimed to determine characteristics, utilization of ICDs, and long-term outcomes of survivors of early VA (<48 h) after acute MI.We retrospectively analyzed clinical characteristics, ICD therapies, and survival in 128 patients with early VA after acute MI from 2002-12. Patients were classified for appropriateness of ICD implantation, per 2013 Appropriate Use Criteria (AUC). In 128 early VA survivors after MI, older age, female gender, history of coronary artery bypass graft surgery (CABG) or MI, non-ST-elevation MI or ventricular tachycardia (VT) at presentation predicted worse overall survival (all P < 0.05). While left ventricular ejection fraction (LVEF) did not predict mortality (HR = 1; P = 0.86), post-MI ventricular fibrillation (VF) portended a better long-term prognosis than VT (HR = 0.37; P = 0.001). Twenty-six (20%) early VA survivors received ICD, corresponding well with AUC. Implantable cardioverter-defibrillator recipients had lower post-MI LVEF (P = 0.02) and more frequently presented with non-ST-elevation MI (P = 0.007). Over 2.4 years of median follow-up, ICD recipients had a greater mortality rate than non-ICD recipients (42 vs. 17%; P = 0.02). Appropriate and inappropriate ICD discharges were high in ICD recipients.Early VA survivors after MI receiving ICD due to suspected non-reversible arrhythmogenic substrate have high rates of appropriate ICD therapy and mortality. Our ICD implantation practice corresponds well with the AUC. Sustained monomorphic VT and non-ST-elevation MI at presentation predict increased risk for death. Larger prospective studies are necessary to confirm our findings, such as to provide evidence for future ICD guidelines.