Atrial lead implantation in the Bachmann bundle.
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Cardiac Pacing, Artificial↗
Biomedical subjects
Steven J Bailin
Publications and source records attributed to Steven J Bailin.
Lack of a hypotensive effect with rapid administration of a new aqueous formulation of intravenous amiodarone.
Hypotension is the most frequent adverse event reported with intravenous amiodarone. Hypotension has been attributed to the vasoactive solvents of the standard formulation (Cordarone IV) and is not dose related, but related to the rate of infusion. Drug labeling calls for intravenous amiodarone to be administered over 10 minutes. A new aqueous formulation of amiodarone (Amio-Aqueous) does not contain vasoactive excipients and may be administered safely by rapid administration without hypotension. This hypothesis was tested using combined data of 4 clinical trials; each assessed the development of hypotension prospectively. Hypotension was defined as a 25% decrease in systolic blood pressure (BP), with the development of a systolic BP of <90 mm Hg or a systolic BP that decreased to <80 mm Hg. In all, 358 Amio-Aqueous and 225 lidocaine boluses were administered to 278 patients; 246 had ventricular tachycardia (VT) during drug administration. Hypotension developed in 11% of patients on Amio-Aqueous versus 19% on lidocaine (p = NS), all during VT; most resolved spontaneously with VT termination. With both drugs, hypotension persisted after VT termination in 1% of patients; the incidence of drug-related hypotension occurred in 2% of patients (1% had hypotension requiring treatment). The Amio-Aqueous was discontinued in 1% of patients, and lidocaine was discontinued in 2% of patients because of hypotension. We conclude that Amio-Aqueous is at least as safe as lidocaine in terms of causing hypotension when administered rapidly. This is a significant advantage over the standard amiodarone formulation, because Cordarone cannot be administered by rapid bolus owing to excipient-related hypotension.
Aged↗
Is Bachmann's Bundle the only right site for single-site pacing to prevent atrial fibrillation? Results of a multicenter randomized trial.
The site of atrial pacing influences atrial activation patterns. It is believed that disparities in atrial activation and repolarization are contributors to the development and recurrence of atrial arrhythmias. We hypothesized that pacing from Bachmann's Bundle would improve clinical outcomes in patients with paroxysmal atrial fibrillation compared to right atrial appendage pacing. Pacing from Bachmann's Bundle results in a significant reduction in P wave duration and improvement in biatrial activation symmetry compared to right atrial appendage pacing. Compared to right atrial appendage pacing, Bachmann's bundle pacing improves sinus rhythm (75% vs. 47% at two years, p < 0.01) in patients with a history of paroxysmal atrial fibrillation. Recent studies have confirmed the benefits of Bachmann's Bundle pacing on atrial activation and rhythm regulation. Thus, Bachman's Bundle should be considered the preferred site for atrial pacing in patients with a history of paroxysmal atrial fibrillation.
Animals↗
Bachmann's bundle versus right atrial appendage capture.
The tissue in the high intraatrial septum in the region of Bachmann's Bundle (BB) exhibits electrophysiological properties that differ from the right atrial appendage (RAA). As BB pacing emerges as an alternative to RAA pacing, the feasibility of using automatic capture recognition technology in this location should be examined. At implant, active-fixation leads were consecutively placed in the RAA, then the BB in 18 patients (55.5% men, mean age 77.1 +/- 9.1). There was no significant difference between BB and RAA in the average capture threshold (1.12 vs 1.77 V, P = 0.09), sensing threshold (3.85 vs 3.69 mV, P = 0.84), impedance (508 vs 529 Ohms, P = 0.64), evoked response (1.78 vs 1.67 mV, P = 0.83), and polarization (0.41 vs 0.46 mV, P = 0.84) between. The difference in tissue characteristics was not associated with a different evoked response measured by the ventricular capture recognition algorithm. Based on the analogous evoked response and polarization values, capture recognition technology designed for the atrium will most likely be applicable at both pacing sites.
Aged↗
Clinical investigation of a new dual-chamber implantable cardioverter defibrillator with improved rhythm discrimination capabilities.
INTRODUCTION: Despite continuing advances, inappropriate implantable cardioverter defibrillator (ICD) therapies in response to nonventricular tachyarrhythmias continue to cause patient discomfort and increased follow-up demands. METHODS AND RESULTS: We investigated the performance of a new dual-chamber ICD (Photon DR, St. Jude Medical), with specific attention to its arrhythmia discrimination and detection capabilities. The system uses a hierarchical approach to tachyarrhythmia classification utilizing a new AV Rate Branch feature and subsequently utilizing morphology analysis, onset, and stability criteria. The arrhythmia discrimination results from this study group were compared to historical control group data from a recent clinical investigation of single-chamber Contour MD (Morphology Discrimination) and Angstrom MD ICDs without the Rate Branch feature. Rhythm discrimination was evaluated by comparing ventricular tachycardia diagnosis sensitivity and specificity between the two groups. To determine whether the new discrimination scheme affected detection speed, median ventricular fibrillation (VF) detection and redetection times also were compared. The study group consisted of 107 patients, and the control group consisted of 161 patients. Use of the AV Rate Branch feature was associated with significant improvements in both sensitivity (100% vs 97.9%, P < 0.0001) and specificity (84% vs 55.7%, P = 0.0002) of ventricular tachycardia diagnosis. Use of the new scheme slightly but significantly accelerated VF detection times (2.8 vs 3.0 sec, P < 0.0001) and redetection times (1.3 vs 1.4 sec, P < 0.0001). Adverse events were typical for this patient population. CONCLUSION: Compared with earlier St. Jude Medical ICDs, the Photon DR ICD offers improved rhythm discrimination without compromising VF detection time.
Adult↗
Intravenous lidocaine versus intravenous amiodarone (in a new aqueous formulation) for incessant ventricular tachycardia.
The effectiveness of intravenous amiodarone for the treatment of incessant (shock resistant) ventricular tachycardia (VT) has not been established. This study evaluated the efficacy of a water-soluble amiodarone preparation or lidocaine for the treatment of shock-resistant VT. The trial was a double-blinded parallel design. Patients were randomized to receive up to 2 boluses of either 150 mg intravenous amiodarone or 2 boluses of 100 mg lidocaine followed by a 24-hour infusion. If the first assigned medication failed to terminate VT, the patient was crossed over to the alternative therapy. Twenty-nine patients were randomized to the study (18 received amiodarone and 11 received lidocaine). There were no significant differences between groups with regard to baseline characteristics. Immediate VT termination was achieved in 14 patients (78%) with amiodarone versus 3 patients (27%) on lidocaine (p <0.05). After 1 hour, 12 patients (67%) on amiodarone and 1 patient (9%) on lidocaine were alive and free of VT (p <0.01). Amiodarone had a 33% drug failure rate, whereas there was a 91% drug failure rate for lidocaine. The 24-hour survival was 39% on amiodarone and 9% on lidocaine (p <0.01). Drug-related hypotension with aqueous amiodarone was less frequent than with lidocaine. This study found that amiodarone is more effective than lidocaine in the treatment of shock-resistant VT.
Aged↗
To map or not to map.
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Atrial Fibrillation↗
Determinants of first-shock success for atrial implantable cardioverter defibrillators.
INTRODUCTION: The aim of this study was to identify determinants of first-shock success for defibrillation of spontaneous atrial fibrillation (AF) in ambulatory patients with an atrial implantable cardioverter defibrillator (ICD). The determinants of first-shock success in ambulatory patients with atrial ICDs are unknown. METHODS AND RESULTS: We used the generalized estimating equation method to analyze determinants of first-shock success in 50 consecutive atrial ICD recipients in whom DFT+ (weakest shock that defibrillates on two consecutive trials) was determined at implant and spontaneous AF was shocked with shock strength > or = 2 x DFT+. DFT+ was 6.2 +/- 3.1 J. Of 470 first shocks, 407 were successful (generalized estimating equation 85%, confidence interval 79% to 90%). Determinants of first-shock success were use of coronary sinus electrode (univariate P = 0.02; multivariate P < 0.001, relative risk 5.0), absence of a Class III antiarrhythmic drug (univariate P = 0.06; multivariate P < 0.001, relative risk 3.2), absence of early recurrence of atrial fibrillation (ERAF; univariate P = 0.06; multivariate P = 0.02, relative risk 2.9), and longer duration of AF prior to shock > or = 3 hours (univariate: P = 0.02; multivariate P = NS). Sinus rhythm >1 minute persisted after 93% of first shocks in patients without documented ERAF but after only 58% of shocks in patients with documented ERAF (P < 0.001). CONCLUSION: Reducing ERAF is critical to achieving a clinically acceptable rate of persistent sinus rhythm after first shocks. For first shocks > or = 2 x DFT +, success is not increased by programming stronger shocks. Early cardioversion does not increase first-shock success.
Ambulatory Care↗