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1.
Circulation ; 141(21): 1727-1728, 2020 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-32453665
2.
Europace ; 22(5): 813-820, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32142121

RESUMO

AIMS: High premature ventricular contractions (PVCs) burden does not always predict the development of PVC-cardiomyopathy (CM). We sought to evaluate post-extrasystolic potentiation (PESP) of left ventricular ejection fraction (LVEF) to predict the severity of PVC-CM in an animal model. METHODS AND RESULTS: Right ventricular apical bigeminal PVCs were introduced for 12 weeks in 11 canines to induce PVC-CM. Echocardiograms were performed to obtain LVEF without ectopy (Echo-1) and during PVCs (200 and 350 ms coupling intervals, Echo-2, and Echo-3, respectively), and premature atrial contractions (PACs) (Echo-4) at baseline and after 12 weeks of bigeminal PVCs. PESP was calculated as delta-LVEF between the sinus beat post-ectopy LVEF (Echo-2, -3, and -4, respectively) and LVEF without PVC (Echo-1) at baseline and 12 weeks of high PVC burden. A hyperdynamic LV function (LVEF > 70%) was noted in all animals only with early-coupled PVCs (LVEF at 200 ms: 74.4 ± 6%) at baseline. While PVC PESP at 200 ms had a strong significant correlation with the final 12-week LVEF (R = 0.8, P = 0.003), PVC PESP at 350 ms and PAC PESP had a positive but non-significant correlation (R = 0.53, P = 0.09, and R = 0.29, P = 0.34, respectively). Premature ventricular contraction PESP at 350 ms was significantly higher after PVC-CM had developed (delta-LVEF baseline 2.7 ± 2.9% vs. 12 weeks 18.6 ± 12.3% P < 0.001). CONCLUSION: Bigeminal early-coupled PVCs cause hyperdynamic left ventricular function in the structurally normal canine heart due to PESP. The degree of PESP at baseline is inversely proportional to the PVC-CM severity at 12 weeks and maybe a predictor of PVC-CM as it may assess the myocardial adaptation reserve to PVCs.

3.
Heart Rhythm ; 2020 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-32142876

RESUMO

To date, multiple modes of research have been leveraged to study the optimal cryoballoon ablation parameters to safely, effectively, and efficiently isolate the pulmonary veins for the treatment of atrial fibrillation. Basic scientific investigation, preclinical studies, clinical observations, trials, and, more recently, computational modeling have helped to generate and test new hypotheses for the advancement of cryoballoon treatment in patients with atrial fibrillation. In this review, we examine the data and evidence that have contributed to the development of patient-tailored dosing strategies that are currently used for pulmonary vein isolation by using the Arctic Front series of cryoballoon ablation catheters.

5.
J Am Heart Assoc ; 9(3): e014213, 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-32013700

RESUMO

Background Catheter ablation is an effective treatment for atrial fibrillation (AF), but high levels of post-procedure inflammation predict adverse clinical events. Ascorbic acid (AA) has shown promise in reducing inflammation but is untested in this population. We sought to test the feasibility, safety, and preliminary effects on inflammatory biomarkers in the CITRIS-AF (Vitamin C Intravenous Treatment In the Setting of Atrial Fibrillation Ablation) pilot study. Methods and Results Patients scheduled to undergo AF ablation (N=20) were randomized 1:1 to double-blinded treatment with AA (200 mg/kg divided over 24 hours) or placebo. C-reactive protein and interleukin-6 levels were obtained before the first infusion and repeated at 24 hours and 30 days. Pain levels within 24 hours and early recurrence of AF within 90 days were recorded. Median and interquartile range were aged 63 (56-70) years, 13 (65%) men, and 18 (90%) white. Baseline data were similar between the 2 groups except ejection fraction. Baseline C-reactive protein levels were 2.56 (1.47-5.87) mg/L and similar between groups (P=0.48). Change in C-reactive protein from baseline to 24 hours was +10.79 (+6.56-23.19) mg/L in the placebo group and +3.01 (+0.40-5.43) mg/L in the AA group (P=0.02). Conversely, change in interleukin-6 was numerically higher in the AA group, though not statistically significant (P=0.32). One patient in each arm developed pericarditis; no adverse events related to the infusions were seen. There were no significant differences between aggregated post-procedure pain levels within 24 hours or early recurrence of AF (both P>0.05). Conclusions High-dose AA is safe and well tolerated at the time of AF ablation and may be associated with a blunted rise in C-reactive protein, although consistent findings were not seen in interleukin-6 levels. Further studies are needed to validate these findings and explore the potential benefit in improving clinically relevant outcomes. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT03148236.

6.
J Am Coll Cardiol ; 75(1): 1-13, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31918815

RESUMO

BACKGROUND: The presence and significance of neural remodeling in premature ventricular contraction-induced cardiomyopathy (PVC-CM) remain unknown. OBJECTIVES: This study aimed to characterize cardiac sympathovagal balance and proarrhythmia in a canine model of PVC-CM. METHODS: In 12 canines, the investigators implanted epicardial pacemakers and radiotelemetry units to record cardiac rhythm and nerve activity (NA) from the left stellate ganglion (SNA), left cardiac vagus (VNA), and arterial blood pressure. Bigeminal PVCs (200 ms coupling) were applied for 12 weeks to induce PVC-CM in 7 animals then disabled for 4 weeks to allow complete recovery of left ventricular ejection fraction (LVEF), versus 5 sham controls. RESULTS: After 12 weeks of PVCs, LVEF (p = 0.006) and dP/dT (p = 0.007) decreased. Resting SNA (p = 0.002) and VNA (p = 0.04), exercise SNA (p = 0.01), SNA response to evoked PVCs (p = 0.005), heart rate (HR) at rest (p = 0.003), and exercise (p < 0.04) increased, whereas HR variability (HRV) decreased (p = 0.009). There was increased spontaneous atrial (p = 0.02) and ventricular arrhythmias (p = 0.03) in PVC-CM. Increased SNA preceded both atrial (p = 0.0003) and ventricular (p = 0.009) arrhythmia onset. Clonidine suppressed SNA and abolished all arrhythmias. After disabling PVC for 4 weeks, LVEF (p = 0.01), dP/dT (p = 0.047), and resting VNA (p = 0.03) recovered to baseline levels. However, SNA, resting HR, HRV, and atrial (p = 0.03) and ventricular (p = 0.03) proarrhythmia persisted. There was sympathetic hyperinnervation in stellate ganglia (p = 0.02) but not ventricles (p = 0.2) of PVC-CM and recovered animals versus sham controls. CONCLUSIONS: Neural remodeling in PVC-CM is characterized by extracardiac sympathetic hyperinnervation and sympathetic neural hyperactivity that persists despite normalization of LVEF. The altered cardiac sympathovagal balance is an important trigger and substrate for atrial and ventricular proarrhythmia.

7.
Circ Arrhythm Electrophysiol ; 13(2): e008092, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31985260

RESUMO

Impedance is the ratio of voltage to current in an electrical circuit. Cardiovascular implantable electronic devices measure impedance to assess the structural integrity electrical performance of leads, typically using subthreshold pulses. We review determinants of impedance, how it is measured, variation in clinically measured pacing and high-voltage impedance and impedance trends as a diagnostic for lead failure and lead-device connection problems. We consider the differential diagnosis of abnormal impedance and the approach to the challenging problem of a single, abnormal impedance measurement. Present impedance provides a specific but insensitive diagnostic. For pacing circuits, we review the complementary roles of impedance and more sensitive oversensing diagnostics. Shock circuits lack a sensitive diagnostic. This deficiency is particularly important for insulation breaches, which may go undetected and present with short circuits during therapeutic shocks. We consider new methods for measuring impedance that may increase sensitivity for insulation breaches.

9.
Nat Rev Cardiol ; 17(1): 22-36, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31249403

RESUMO

Conventional right ventricular (RV) pacing, particularly RV apical pacing, can have deleterious effects on cardiac function. Long-term RV apical pacing has been associated with increased risk of atrial fibrillation, hospitalization for heart failure, pacing-induced cardiomyopathy and associated death. His bundle pacing (HBP) results in physiological ventricular activation and has generated tremendous research interest and enthusiasm. By stimulating the His-Purkinje network directly, HBP results in synchronized ventricular activation, which might translate into improved clinical outcomes compared with dyssynchronous ventricular activation with RV apical pacing. HBP can also overcome bundle branch block patterns, and data are accumulating on the benefit of HBP for cardiac resynchronization therapy. In this Review, we summarize the anatomy of the His bundle and early clinical observations, implantation techniques and available outcome data associated with permanent HBP. We also highlight the challenges with HBP and the need for additional tools and more randomized data before widespread application of permanent HBP.


Assuntos
Arritmias Cardíacas/terapia , Fascículo Atrioventricular/fisiopatologia , Estimulação Cardíaca Artificial/tendências , Insuficiência Cardíaca/terapia , Potenciais de Ação , Animais , Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/mortalidade , Arritmias Cardíacas/fisiopatologia , Estimulação Cardíaca Artificial/efeitos adversos , Estimulação Cardíaca Artificial/mortalidade , Difusão de Inovações , Previsões , Insuficiência Cardíaca/diagnóstico por imagem , Insuficiência Cardíaca/mortalidade , Insuficiência Cardíaca/fisiopatologia , Frequência Cardíaca , Humanos , Fatores de Risco , Resultado do Tratamento
10.
J Cardiovasc Electrophysiol ; 30(12): 2877-2884, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31646695

RESUMO

BACKGROUND: Contemporary implantable cardioverter-defibrillator (ICD) programming involving delayed high-rate detection and use of supraventricular tachycardia (SVT) discriminators has significantly reduced the rate of inappropriate shocks. The extent to which SVT algorithms alone reduce inappropriate therapies is poorly understood. METHODS AND RESULTS: PainFree SST enrolled 2770 patients with a single- or dual-chamber ICD or cardiac resynchronization defibrillator. Patients were followed for 22 ± 9 months with SVT discriminators on in 96% of patients. Sustained ventricular tachyarrhythmias and SVT episodes were adjudicated by an independent physician committee. For this analysis, all episodes were subjected to postprocessing computer simulation with SVT discriminators off with and without delayed high-rate detection criteria (ventricular fibrillation zone only, 30/40 at 320 ms). There were 3282 adjudicated SVT episodes of which 115 resulted in an ICD shock and 113 received only ATP (2-year inappropriate shock and therapy rates of 3.1% and 4.1%). Therapy was appropriately withheld for the remaining 3054 SVT episodes. With both SVT discriminators and delayed high-rate detection simulated off, the 2-year inappropriate therapy rate would have been 22.9% (hazard ratio [HR] = 6.24; 95% confidence interval [CI]: 5.20-7.49). With SVT discriminators simulated off and delayed high-rate detection simulated on in all patients, the 2-year rate would have been 6.4% (HR = 1.63; CI: 1.44-1.85). CONCLUSIONS: The use of SVT discriminators has a significant role in reducing the rate of inappropriate ICD therapy even in the setting of delayed high-rate detection settings. Deactivating SVT discriminators would have resulted in an overall increase in the inappropriate ICD therapy rate by 63% and 524% with and without delayed high-rate detection programming, respectively.

11.
J Cardiovasc Electrophysiol ; 30(11): 2561-2563, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31502305
13.
J Cardiovasc Electrophysiol ; 30(10): 2027-2033, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31392815

RESUMO

BACKGROUND AND OBJECTIVES: The use of nonfluoroscopic three-dimensional electroanatomic mapping (3DM) systems reduces radiation exposure during ablation procedures. In this study, we sought to determine the value of 3DM during routine device implant procedures. METHODS: Seventy nonselected patients underwent implantation of a single chamber, dual chamber, or biventricular device guided by Ensite (Abbott Laboratories) to limit fluoroscopy use and compared with 70 consecutive patients, who underwent matching procedures with standard fluoroscopy use (FL) in the period immediately preceding the use of 3DM. The venous anatomy, right atrium, and ventricle and coronary sinus were mapped with 0.035 inch J-wire, quadripolar catheter, and/or angioplasty wire. The leads were advanced under real-time visualization in Ensite. RESULTS: 3DM reduced both fluoroscopy time and dose. Median fluoroscopy time for FL vs 3DM was 5.5 minutes (interquartile range [IQR]: 3.8-8.1) vs 0.9 minutes (IQR: 0.6-1.9) (P < .001) for single chamber devices, 6.3 minutes (IQR: 5.1-7.9) vs 3.3 minutes (IQR: 1.9-4) (P < .001) for dual-chamber devices, and 28.6 minutes (IQR: 19.6-36.2) to 14.7 minutes (IQR: 10.4-22.3) (P = .009) for biventricular devices, respectively. The median air kerma for FL vs 3DM was 15.4 mGy (IQR: 8.1-30.2) vs 4 mGy (IQR: 1.8-8) (P < .001) for single chamber devices, 16 mGy (IQR: 12-18.5) to 9.4 mGy (IQR: 7.5-11.3) (P = .001) for dual-chamber devices, and 324 mGy (IQR: 143-668.7) to 115 mGy (IQR:77-204) (P = .014) for biventricular devices, respectively. There were no procedural complications. At 3-month follow-up, there was no difference in voltage threshold measurements between the groups. CONCLUSION: The use of 3DM leads to significantly reduced fluoroscopy time and fluoroscopy dose during routine device implantation.

14.
Can J Cardiol ; 35(8): 1069-1077, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31376908

RESUMO

BACKGROUND: Compelling evidence showing a link between atrial fibrillation (AF) and cognitive decline and dementia is accumulating. METHODS: Blinded Randomized Trial of Anticoagulation to Prevent Ischemic Stroke and Neurocognitive Impairment in Atrial Fibrillation (BRAIN-AF) is a prospective, multicentric, double-blind, randomized-controlled trial, recruiting patients with nonvalvular AF and a low risk of stroke. Patients with a high risk of bleeding will be excluded from the study. Participants will be randomized to receive either rivaroxaban (15 mg daily) or standard of care (placebo in patients without vascular disease or acetylsalicylic acid 100 mg daily in patients with vascular disease). RESULTS: The primary outcome is the composite of stroke, transient ischemic attack, and cognitive decline (defined by a decrease in the Montreal Cognitive Assessment score ≥ 3 at any follow-up visit after baseline). Approximately 3250 patients will be enrolled in approximately 130 clinical sites until 609 adjudicated primary outcome events have occurred. CONCLUSIONS: BRAIN-AF determines whether oral anticoagulation therapy with rivaroxaban compared with standard of care reduces the risk of stroke, transient ischemic attack, or cognitive decline in patients with nonvalvular AF and a low risk of stroke.

15.
J Am Coll Cardiol ; 74(8): 1086-1106, 2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31439219

RESUMO

Despite major improvements in transcatheter aortic valve replacement (TAVR) periprocedural complications in recent years, the occurrence of conduction disturbances has not decreased over time and remains the most frequent complication of the procedure. Additionally, there has been an important lack of consensus on the management of these complications, which has indeed translated into a high degree of uncertainty regarding the most appropriate treatment of a large proportion of such patients along with major differences between centers and studies in pacemaker rates post-TAVR. There is therefore an urgent need for a uniform strategy regarding the management of conduction disturbances after TAVR. The present expert consensus scientific panel document has been formulated by a multidisciplinary group of interventional cardiologists, electrophysiologists, and cardiac surgeons as an initial attempt to provide a guide for the management of conduction disturbances after TAVR based on the best available data and group expertise.

16.
J Cardiovasc Electrophysiol ; 30(11): 2618-2626, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31432581

RESUMO

INTRODUCTION: Loperamide, an antidiarrheal agent, is a µ-opioid receptor agonist increasingly abused to prevent opioid withdrawal or to produce euphoric effects. At supra-therapeutic doses, loperamide can cause cardiac toxicity due to blockade of Na and IKr channels, resulting in wide QRS rhythms, severe bradycardia, prolonged QTc, polymorphic ventricular tachycardia, cardiac arrest, and death. There are limited data on the cardiotoxic effects of high dose loperamide. METHODS AND RESULTS: A case report of loperamide toxicity is presented and then added to a contemporary review of the literature. In total, the presentation and management of 36 cases of loperamide cardiotoxicity are summarized. The overall median daily dose (interquartile range) of loperamide was 200 (134-400) mg. The median QRS duration was 160 (125-170) ms. The median QTc duration was 620 (565-701) ms. Ventricular tachycardia was experienced by 24/36 (67%) of patients, 20 of which were specified to be polymorphic. Treatment was supportive, providing advanced cardiopulmonary life support and aggressive electrolyte repletion. Isoproterenol infusion or overdrive pacing was employed in 19/36 (53%) of cases. The median time to electrocardiogram normalization or hospital discharge, whichever came first, was 5 (3.5-10) days. CONCLUSION: Loperamide overdose is a toxidrome that remains underrecognized, and in patients with unexplained cardiac arrhythmias, loperamide toxicity should be suspected. Prompt recognition is critical due to the delayed recovery and high risk for life-threatening arrhythmias.

17.
J Cardiovasc Electrophysiol ; 30(10): 1952-1959, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31310360

RESUMO

INTRODUCTION: Frequent premature ventricular contractions (PVCs) can cause cardiomyopathy (CM). Postextrasystolic potentiation (PESP) and irregularity have been in implicated as triggers of PVC-CM. Because both phenomena can also be found in premature atrial contractions (PACs), it is speculated that frequent PACs have similar consequences. METHODS AND RESULTS: A single-center, retrospective study included all consecutive patients undergoing a 14-day Holter monitors (November 2014 to October 2016). Patients were divided into four groups by ectopy burden group 1 (<1%) and remaining by tertiles (group 2-4). Echocardiographic and arrhythmic data were compared between PAC and PVC burdens. In addition, a translational PAC animal model was used to assess the chronic effects of frequent PACs. A total 846 patients were reviewed. In contrast to PVCs, we found no difference in left ventricular ejection fraction (LVEF), end-systolic and end-diastolic dimensions and presence of CM (LVEF <50%) between different PAC groups. Multivariate regression analysis demonstrated that only PVC burden predicted low EF (odds ratio, 1.1; confidence interval, 1.03-1.13; P = .001). While there was a weak correlation between PAC burden and supraventricular tachycardia (SVT) episodes and atrial fibrillation (AF) burden (r = 0.19; P < .001), there was no correlation between PAC burden and LVEF or CM. Finally, atrial bigeminy in our animal model did not significantly decrease LVEF after 3 months. CONCLUSION: PAC burden is associated with increased AF and SVT episodes. In contrast to a high PVC burden, a high PAC burden is not associated with CM. Our findings suggest that heart rate irregularity and/or PESP may play a minimal role in the pathophysiology of PVC-CM.

18.
Nat Rev Cardiol ; 16(12): 760, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31296944

RESUMO

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

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