Multistep approach to electrical stimulation after cardiomyoplasty.

Unlabelled: Still a controversial procedure, cardiomyoplasty (CMP) improves the failing heart's ability to contract by using a latissimus dorsi muscle (LDM), but to date, hemodynamic results correlate poorly with clinical improvement. The following two causes for apprehension bar attempting to change the conventional electrical stimulation (ES) protocol to improve CMP results: (1) fear of beginning ES for LDM-assisted contraction immediately postmobilization and CMP and (2) fear of stopping or slowing ES during sleep periods.

Methods: In ten different experimental series, I used animal models of CMP to determine how to apply ES to newly mobilized LDM, how to begin partial cardiac assist immediately post-CMP, and how to suspend ES for 12 hours daily.

Transseptal Catheterization with Transesophageal Guidance in High Risk Patients.

Atrial transseptal catheterization is usually performed with fluoroscopic guidance of the needle. We report our experience with both fluoroscopic and transesophageal guidance in patients who would otherwise have been at risk by using only fluoroscopy. A total of eleven procedures were performed during a 4 year period.

Effects of electrical stimulation postcardiomyoplasty in a model of chronic heart failure: hemodynamic results after daily 12-hour cessation versus a nonstop regimen.

The hemodynamic effects of cardiomyoplasty (CMP) have been investigated in many centers, but the question of whether it is necessary to stimulate the latissimus dorsi muscle (LDM) 24 hours a day has not been answered. The main goal of our investigation was to determine whether hemodynamic results after CMP were impaired when continuous electrical stimulation (ES) was off for 12 hours a day. A model of chronic heart failure was created in 12 sheep by performing an arteriovenous anastamosis and administering doxorubicin.

Carotid stenting in patients older than 65 years with inoperable carotid artery disease: a single-center experience.

Carotid angioplasty and stenting to treat extracranial carotid stenosis is an alternative (as yet not widely accepted) to high-risk surgery, but its safety and efficacy are little known, especially in elderly patients. We reviewed our 3-year experience of treating 100 elderly patients (> 65 years old) considered to be inoperable (76 men, 24 women, mean age 76+/-10 years, mean follow-up 18+/-9.2 months) and present two case histories.

Evaluation and treatment strategies in patients at high risk of sudden death post myocardial infarction.

Over 50 percent of deaths in patients who survive an acute myocardial infarction are due to fatal ventricular tachyarrhythmias. Patients who survive an episode of sustained ventricular arrhythmia are at highest risk of recurrent cardiac arrest. Electrophysiologic studies have been found to be useful in guiding therapy and reducing mortality in these patients and in patients with syncope due to arrhythmic etiology.

The effect of biphasic waveform tilt in transvenous atrial defibrillation.

Atrial defibrillation can be accomplished using low energy shocks and transvenous catheters. The biphasic waveform tilt required to achieve optimal atrial defibrillation thresholds (ADFTs) is, however, not known. The effect of single capacitor biphasic waveform tilt modification on ADFT was assessed in 20 patients.

Efficacy of the implantable cardioverter-defibrillator in the elderly.

Objectives: We sought to assess the effect of advanced age on the outcome of patients with an implantable cardioverter-defibrillator (ICD).

Background: ICDs are effective in preventing sudden cardiac death in susceptible patients, but their beneficial effect on survival is attenuated by the high rate of nonsudden cardiac death in those treated. Although advanced age is an important variable in determining cardiovascular mortality, its impact on the outcome of patients with an ICD has been inadequately studied.

The effect of polarity of the initial phase of a biphasic shock waveform on the defibrillation threshold of pectorally implanted defibrillators.

The effect of initial phase polarity on the DFT of two pectorally implanted biphasic ICDs was tested in a randomized, prospective manner at the time of implantation. Twenty-two consecutive patients with VT-VF who received either the Medtronic PCD 7219C Jewel device (10 patients) or PCD 7219D Jewel device (12 patients) were studied. DFT testing was performed in a standard step-down manner.

Therapy of ventricular tachycardia in patients with nonischemic cardiomyopathies.

In patients with IDCM and sustained VT, every effort should be made to exclude bundle branch reentrant tachycardia. We strongly believe that this mechanism of VT remains underdiagnosed despite electrophysiologic evaluation. In appropriate candidates with cardiomyopathies and "nonbundle branch reentrant VT," ICD implantation is frequently the treatment of choice, especially if the clinical presentation is that of hemodynamic collapse, or there is significant left ventricular systolic dysfunction.

Unmasking the trifascicular left intraventricular conduction system by ablation of the right bundle branch.

Twenty-five patients underwent transcatheter right bundle ablation either for bundle branch reentrant tachycardias or inadvertent or deliberate right bundle ablation during atrioventricular junctional ablation for rate control. Electrophysiologic data and 12-lead electrocardiograms before and after right bundle ablation were available in all patients. Eleven of the patients had no significant intraventricular conduction abnormalities by surface electrocardiograms (group I), whereas 14 patients had underlying intraventricular conduction delays (group II).

Effects of initial polarity on defibrillation threshold with biphasic pulses.

Background: Previous studies have shown that the polarity of epicardial patches significantly affects the defibrillation efficacy of monophasic shocks. However, whether this improvement can be extended to different pulsing methods and lead systems, such as biphasic shocks using endocardial defibrillating electrodes, is unknown.

Methods: Twenty consecutive patients undergoing testing and permanent implant using an Endotak lead system with a biphasic device were included in the study.

Cardiac pacing during neurocardiogenic (vasovagal) syncope.

Head-up tilt testing is increasingly being used as a diagnostic modality in patients with unexplained syncope who are thought to have neurocardiogenic (vasovagal) mechanisms of syncope. Although large-scale placebo-controlled trials are still awaited, pharmacologic therapy is usually effective in preventing syncope or presyncope in this patient population. However, the role of permanent pacemaker therapy remains controversial.

Provocation of hypotension during head-up tilt testing in subjects with no history of syncope or presyncope.

Background: Head-up tilt test is increasingly being used to evaluate patients with syncope. This study was designed to evaluate the specificity of head-up tilt testing using different tilt angles and isoproterenol infusion doses in normal volunteers with no prior history of syncope or presyncope.

Methods And Results: One hundred fifty volunteers were randomized to two groups of 75 each.

Comparison of biphasic and monophasic pulses: does the advantage of biphasic shocks depend on the waveshape?

With present implantable defibrillators, the ability to vary the defibrillation technique has been shown to increase the number of patients suitable for transvenous system. As newer waveforms become available, the need for a flexible device may change. In addition, although it has been shown that the option of biphasic waveform may increase the defibrillation efficacy, this may depend upon the shape of the biphasic waveform used.

Transesophageal echocardiographically guided atrial transseptal catheterization in patients with normal-sized atria: incidence of complications.

The incidence of cardiac complications from atrial transseptal catheterization has never been quantified in patients with normal-sized atria. Series defining the complication rate are derived from diseased hearts with structural changes that may alter the complication rate of the procedure. The generation of a standardized incidence of perforation in a population of structurally normal atria has important implications.

Efficacy of different treatment strategies for neurocardiogenic syncope.

Objectives: The purpose of this study was to evaluate the efficacy of different therapeutic approaches for patients with a history of syncope and positive head-up tilt testing.

Background: Head-up tilt testing has gained broad acceptance as a reliable diagnostic method for the assessment of patients with recurrent unexplained syncope. However, once the diagnosis is established, there is no consensus on the most appropriate treatment.

Management strategies in patients at high risk of sudden cardiac death following myocardial infarction.

Over 50 percent of deaths in patients who survive an acute myocardial infarction (MI) are due to fatal ventricular tachyarrhythmias. Patients who survive an episode of sustained ventricular arrhythmia are at highest risk of recurrent cardiac arrest. Electrophysiological studies have been found to be useful in guiding therapy and reducing mortality in these patients.

Fee-for-service versus capitation-based reimbursement: how the payment method affects utilization of echocardiographic services by referring physicians.

Historically, health insurance carriers (HIC) have reimbursed physicians on a fee-for-service basis for echocardiographic studies. With the emergence of managed care, the HIC now may have the option of paying on a capitation basis. To determine whether the method of reimbursement had any bearing on the types of patients referred for echocardiographic services, we conducted a two-phase (retrospective) study.

Posteroseptal accessory pathways: an overview of anatomical characteristics, electrocardiographic patterns, electrophysiological features, and ablative therapy.

First, the posteroseptal region of the heart is probably the most complex area among those that harbor AV accessory fibers and a firm grasp of the anatomical characteristics of this region may facilitate achieving a successful AP ablation. Second, there is no sharp demarcation between the posteroseptal area and its surrounding regions including mid-septal, left posterior paraseptal, and right posterior paraseptal locations. Therefore, there are some inevitable overlaps between the electrocardiographic and electrophysiological features of APs located in the posteroseptal region and those areas immediately adjacent to it.