-
[show abstract]
[hide abstract]
ABSTRACT: OPINION STATEMENT: Stroke is a dreaded complication of atrial fibrillation. In the past, preventive therapy included aspirin and oral anticoagulation. Selected patients who are not suitable for oral anticoagulation may benefit from the addition of clopidogrel with aspirin. This combination, when compared with aspirin, offers a reduced risk of stroke at a cost of more major bleeding. We use this therapy in patients with atrial fibrillation who have unstable coronary syndromes or in patients who receive coronary artery stents who are not good candidates for "triple therapy" with aspirin, clopidogrel, and warfarin. The duration of therapy is tempered by many variables. In the case of coronary stents, we ask the interventionalist to consider a bare metal stent to shorten the duration of need for clopidogrel plus aspirin. After several months of combination therapy, we stop this therapy and begin warfarin therapy. Dabigatran is commercially available in the United States. In patients who have difficult to control International Normalized Ratio (INR) values or who do not wish to have regular coagulation monitoring, dabigatran offers a huge advantage. The benefit seems less if the INR is consistently within range. We are impressed with the superior reduction in stroke and systemic embolism with 150 mg of dabigatran twice daily compared to warfarin and also its low risk of intracranial hemorrhage. The results of clinical trials involving factor Xa agents are now being presented. How these agents fit into the marketplace remains to be seen but they will offer clinicians additional therapy for stroke prevention in atrial fibrillation.
Current Treatment Options in Cardiovascular Medicine 07/2011; 13(5):361-9.
-
[show abstract]
[hide abstract]
ABSTRACT: INTRODUCTION: Atrial fibrillation is a common cardiac rhythm abnormality with a considerable cardiovascular disease burden worldwide. It is an independent major risk factor for stroke. Stroke prevention with anticoagulation or antiplatelet agents has been an important area of clinical research. Warfarin is the most widely used antithrombotic therapy for stroke prophylaxis for last several years, and now dabigatran (150 mg b.i.d.) is more effective than warfarin in stroke prevention in individuals at increased of stroke. In addition, several studies have evaluated the efficacy of clopidogrel for stroke prophylaxis either alone or in combination with aspirin. AREAS COVERED: This review summarizes the key findings of the trials looking at the efficacy of clopidogrel in stroke prevention. A literature search was performed using PubMed and Google Scholar. The trials that evaluated the efficacy of clopidogrel in preventing atherothrombotic events or stroke were also included. EXPERT OPINION: Clopidogrel prevents more vascular events, including stroke, in patients with a recent myocardial infarction, stroke or peripheral vascular disease than aspirin. Combination of clopidogrel and aspirin provides a greater reduction of stroke than aspirin or clopidogrel monotherapy, but at an increased risk of bleeding. Dual antiplatelet therapy (clopidogrel and aspirin) is inferior to warfarin in primary stroke prevention for patient with atrial fibrillation and thus should be considered for stroke prophylaxis only in patients ineligible for warfarin. However, with the advent of newer agents, like direct thrombin inhibitors and Factor Xa inhibitors, the role of antiplatelet therapy for stroke prevention in atrial fibrillation remains unclear.
Expert Opinion on Pharmacotherapy 06/2011; 12(11):1781-7. · 3.20 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The aims of this study are to evaluate the cardiac safety of the Stinger S-200 Conducted Energy Weapon Device (CED) (Stinger Systems, Tampa, Fla) on a human-sized pig model and to test the effect of various commercially available CEDs, specifically the Stinger S-200, TASER M26 (Taser International, Scottsdale, Ariz), and TASER X26 on pacemaker function.
Two groups of pigs, divided based on weight as group 1 (n = 3, 67.3 ± 4.7 kg) and group 2 (n = 3, 89.3 ± 1.2 kg), were used. In protocol 1, the Stinger S-200 was applied in multiple different orientations to simulate possible field scenarios across the heart. In protocol 2, a single-chamber bipolar lead connected to a pacemaker was placed in the right ventricle of the pig, and different CEDs were applied to test the pacemaker function during CED application.
In protocol 1, the S-200 was applied a total of 216 times in the 6 pigs, and neither episodes of ventricular fibrillation nor episodes of sustained ventricular tachycardia were noted. In protocol 2, the CED discharges (1) were recognized by the pulse generator and sensed as either high-rate atrial or ventricular activity, (2) did not affect the native rhythm, (3) did not conduct down the lead systems to cause any extra systoles, and (4) had no effect on paced rhythm.
In this model, the application of the S-200 in various orientations across the heart did not result in any sustained abnormal cardiac rhythms. None of the tested CEDs adversely affected the functioning of the tested pacemaker. Stinger Systems has now replaced the S-200 with the S-200T with a different output.
The American journal of emergency medicine 10/2010; 29(9):1089-96. · 1.54 Impact Factor
-
Journal of Cardiovascular Electrophysiology 11/2008; 20(3):249-50. · 3.06 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The 2006 American Heart Association guidelines for management of patients with atrial fibrillation state "For patients with no identifiable thrombus in the left atrium (LA) or left atrial appendage (LAA), cardioversion (CV) is reasonable immediately after anticoagulation with unfractionated heparin. Thereafter, continuation of oral anticoagulation is reasonable for an anticoagulation period of at least 4 weeks". For patients with thrombus identified by transesophageal echocardiography, guidelines recommend therapeutic oral anticoagulation for 3 weeks prior to and 4 weeks after elective cardioversion. Patients with spontaneous echo contrast (SEC) identified by TEE have a high risk of thromboembolic events,1-8 however, the guidelines do not address whether patients with SEC without thrombus can be safely cardioverted. This paper reviews the literature describing the pathogenesis of SEC, how it is detected, and whether elective cardioversion is safe. On the basis of our review, we believe that the risk of cardioembolic stroke after cardioversion of a patient with SEC is low, regardless of anticoagulation. The safe conclusion is that patients with SEC on TEE should receive therapeutic anticoagulation prior to cardioversion if possible and early cardioversion is not contraindicated.
Clinical Cardiology 05/2008; 31(4):148-52. · 2.15 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Evaluation of: Macias A, Garcia-Bolao I, Diaz-Infante E et al. Cardiac resynchronization therapy: predictive factors of unsuccessful left ventricular lead implant. Eur. Heart J. 28, 450-456 (2007).Congestive heart failure (CHF) is a leading cause of morbidity, mortality and hospitalization in the elderly of industrialized nations. In CHF patients with moderate-to-severe left ventricular systolic dysfunction and significant dyssynchrony, cardiac resynchronization therapy (CRT) has been shown to improve functional status and decrease heart failure mortality and hospitalizations. Inability to transvenously implant a lead within a desired branch of the coronary sinus for CRT occurs in 5-10% of cases. The article under evaluation identifies two independent predictors of failed transvenous left ventricular lead implantation - the presence of permanent atrial fibrillation and an increased anteroposterior left atrial diameter.
Expert Review of Cardiovascular Therapy 06/2007; 5(4):625-628.
-
Journal of Cardiovascular Electrophysiology 04/2007; 18(3):296-7. · 3.06 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Radio frequency (RF) energy is capable of interrupting the reentrant circuit of atrial flutter and curing the arrhythmia. The development of 8-mm tip catheter provides more tissue damage and has offered the promise of improved success. The purpose of our study was to determine if the acute and long-term success with the 8-mm tips were superior to the 4- or 5-mm tips.
The outcomes of the first 20 patients in whom an 8-mm tip catheter was used were compared with the previous 20 patients in whom a 4-or 5-mm tip catheter was used. Procedural (acute) ablation success was defined by creation of bi-directional isthmus block. Long-term success was defined as the prevention of clinically evident atrial flutter (AFl) as determined by the absence of symptoms or maintenance of sinus rhythm on electrocardiogram, six months to one year after the procedure.
Compared to the 4- or 5-mm tip, the 8-mm catheter tip was associated with a reduced ablation duration {22.3 +/- 16 versus 11.5 +/- 5 min (p = 0.0078)}, a lower mean number of ablations {13.5 +/- 9.9 versus 6.8 +/- 2.9 (p = 0.0065)} and a reduced procedure time {1.8 +/- 0.7 versus 1.1 +/- 0.5 h (p = 0.0032)}. Acute success was 95% in the 4- or 5-mm group versus 80% in the 8-mm group (p = NS), but long-term success was higher in the 8-mm group than the 4- or 5-mm group (87.5 versus 63.2%, p = 0.0436).
Eight-millimeter tip catheters for AFl shorten procedure time, reduce the duration and number of ablations and accomplish bi-directional block when compared with smaller tipped catheters. The long-term success rate is better with the 8-mm tips and should be the preferred catheter for RF ablation of AFl.
Journal of Interventional Cardiac Electrophysiology 10/2006; 16(3):183-6. · 1.17 Impact Factor
-
Journal of the CardioMetabolic Syndrome 02/2006; 1(2):153-5.
-
[show abstract]
[hide abstract]
ABSTRACT: Anomalous origin of coronary arteries is discovered incidentally during coronary arteriography or at autopsy, and awareness among angiographers is required. We describe a case with a rare combination of a single coronary artery originating from the right sinus of Valsalva associated with an absent left anterior descending artery and a secundum-type atrial septal defect.
The Journal of invasive cardiology 12/2005; 17(11):E20-3. · 1.84 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Cardiac anatomists have known the presence of a group of specialized fibers connecting the right and left atrium for years. However, only recently have clinical cardiologists come to recognize the potential importance of this specialized conduction system. Anatomical and microscopic studies have shown that the Bachmann's bundle (BB) represents a distinct structure similar to the atrio-ventricular node and the His-Purkinje conduction system but without any insulating tissue.
BB cells have specialized electrophysiological properties like supernormal excitability and faster longitudinal conduction that can facilitate more rapid impulse transmission compared to the normal atrial tissue. Experimental blockage of this pathway causes prolongation and widening of the P wave, which is associated with an increased incidence of atrial fibrillation. Atrial pacing is effective in reducing the incidence of atrial fibrillation by preventing bradycardia, synchronizing the atria, limiting anisotropy and reducing the dispersion of refractoriness. Various animal and human studies have shown pacing near the right atrial insertion of BB to have a beneficial effect in patients with interatrial conduction delay and atrial tachyarrhythmias. This mode of atrial septal pacing is convenient, safe, reliable, and clinically as effective as multisite pacing.
This article is an effort to define the special properties of BB and its possible role in prevention of atrial fibrillation by permanent pacemakers.
Pacing and Clinical Electrophysiology 09/2005; 28(8):855-63. · 1.35 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Although more than one million patients in the United States have permanent pacemakers, little is known about their cause of death. We evaluated the cause of death in 404 patients who died in the Mode Selection Trial (MOST).
In MOST, patients received a dual-chamber pacemaker randomly programmed to either dual-chamber or ventricular pacing. The circumstances surrounding each death were reviewed by a clinical events committee, which used prospectively defined criteria to adjudicate the cause of death.
A total of 2010 patients with a median age of 74 years were included. After a median follow-up of 33 months, 404 (20%) patients died, including 198 (49%) of noncardiac causes and 143 (35.4%) of cardiac causes. In 63 patients, the cause of death was unknown. Independent predictors of death through the use of a multivariable analysis were (1) demographic factors including age, male sex, and weight; (2) clinical factors including prior myocardial infarction, cardiomyopathy, New York Heart Association class III/IV, and the Charlson Comorbidity Index; and (3) scores from two measures of functional status, the Karnofsky Score and the Mini-Mental State Examination. Independent predictors of cardiovascular death were similar.
Patients treated with permanent pacemakers for sinus node dysfunction are elderly and have a substantial mortality rate, with more than half the classifiable deaths being noncardiac. Baseline demographic variables and scores from quality-of-life measures can identify patients with the highest risk of death.
American heart journal 12/2003; 146(5):887-93. · 4.65 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Atrial flutter is relatively uncommon, especially among athletic populations. The case of a 19-year-old college football player who spontaneously developed atrial flutter illustrates recent advances in treatment, including electrical cardioversion and radiofrequency catheter ablation. Return-to-play decisions center around the risk of recurrence and the degree of symptoms during recurrences. Clinicians should be aware that the most current return-to-play guidelines do not take into consideration the newer treatment techniques that have greatly changed definitive management of atrial flutter.
The Physician and sportsmedicine 10/2003; 31(10):21-35. · 1.02 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Implantable cardioverter defibrillator (ICD) lead infection is a rare condition with reported incidence of 0.2% to 16%. It usually presents with persistent bacteremia or fever of unknown origin and requires high clinical suspicion for diagnosis. Whenever ICD lead infection is suspected, transesophageal echocardiography is the diagnostic technique of choice for detection and characterization of the lesions. Lead infections are extremely difficult to manage conservatively and surgical removal of the entire defibrillator system is recommended along with antimicrobial therapy. We describe a case of recurrent staphylococci bacteremia due to an ICD lead infection in a patient with arrhythmogenic right ventricular dysplasia.
Echocardiography 05/2003; 20(3):289-90. · 1.24 Impact Factor
-
Gervasio A Lamas,
Kerry L Lee,
Michael O Sweeney,
Russell Silverman,
Angel Leon,
Raymond Yee,
Roger A Marinchak, Greg Flaker,
Eleanor Schron,
E John Orav,
Anne S Hellkamp,
Stephen Greer,
John McAnulty,
Kenneth Ellenbogen,
Frederick Ehlert,
Roger A Freedman,
N A Mark Estes,
Arnold Greenspon,
Lee Goldman
[show abstract]
[hide abstract]
ABSTRACT: Dual-chamber (atrioventricular) and single-chamber (ventricular) pacing are alternative treatment approaches for sinus-node dysfunction that causes clinically significant bradycardia. However, it is unknown which type of pacing results in the better outcome.
We randomly assigned a total of 2010 patients with sinus-node dysfunction to dual-chamber pacing (1014 patients) or ventricular pacing (996 patients) and followed them for a median of 33.1 months. The primary end point was death from any cause or nonfatal stroke. Secondary end points included the composite of death, stroke, or hospitalization for heart failure; atrial fibrillation; heart-failure score; the pacemaker syndrome; and the quality of life.
The incidence of the primary end point did not differ significantly between the dual-chamber group (21.5 percent) and the ventricular-paced group (23.0 percent, P=0.48). In patients assigned to dual-chamber pacing, the risk of atrial fibrillation was lower (hazard ratio, 0.79; 95 percent confidence interval, 0.66 to 0.94; P=0.008), and heart-failure scores were better (P<0.001). The differences in the rates of hospitalization for heart failure and of death, stroke, or hospitalization for heart failure were not significant in unadjusted analyses but became marginally significant in adjusted analyses. Dual-chamber pacing resulted in a small but measurable increase in the quality of life, as compared with ventricular pacing.
In sinus-node dysfunction, dual-chamber pacing does not improve stroke-free survival, as compared with ventricular pacing. However, dual-chamber pacing reduces the risk of atrial fibrillation, reduces signs and symptoms of heart failure, and slightly improves the quality of life. Overall, dual-chamber pacing offers significant improvement as compared with ventricular pacing.
New England Journal of Medicine 06/2002; 346(24):1854-62. · 53.30 Impact Factor
