Neil E. Bernstein

Protruding atheromas of the aortic arch in symptomatic patients with carotid artery disease

Protruding aortic arch atheromas are associated with otherwise unexplained strokes and transient ischemic attacks. Therefore aortic atheromas also may be important in patients with carotid artery disease. Forty-five patients with > or = 50% carotid stenosis and stroke or transient ischemic attack within 6 weeks underwent transesophageal echocardiographic examination (TEE). They were matched for age, sex, and hypertension with 45 control subjects who had also had a recent cerebral event but in whom significant carotid stenosis was absent. Protruding aortic arch atheromas were present in 17 (38%) of 45 patients with carotid disease and only 7 (16%) of 45 of control subjects (p = 0.02). Mobile atheromas (with the greatest embolic potential) were present almost exclusively in case patients, 6 (13%) of 45, versus 1 (2%) of 45 control subjects (p = 0.05). Case patients with mobile atheromas had the most severe carotid stenosis ( > or = 80%). Cerebral symptoms were discordant with the side of the carotid stenosis in 10 case patients, and 4 had atheromas. In conclusion, protruding atheromas of the aortic arch are present in significant numbers of symptomatic patients with carotid artery disease. These atheromas may represent an additional cause of symptoms in patients with carotid stenosis. TEE to look for protruding aortic atheromas may be considered in patients with neurologic events despite the presence of significant carotid stenosis, especially if the symptoms are discordant with the side of carotid stenosis.

Standardization and validation of an automated algorithm to identify fractionation as a guide for atrial fibrillation ablation

BACKGROUND Atrial fibrillation catheter ablation is frequently guided by identification of fractionated electrograms, which are thought to be critical for maintenance of the arrhythmia. Objective automated means for identifying fractionation independent of physician interpretation have not been standardized or validated. OBJECTIVE The purpose of this study was to standardize and validate an automated algorithm to rapidly identify fractionated electrograms for high-density atrial fibrillation fractionation mapping. METHODS Left and right atrial fractionation maps were generated by EnSite NavX 6.0 software, using standardized ablation catheters in eight patients with atrial fibrillation. Two blinded electrophysiologists interpreted all electrograms as either fractionated or not fractionated. A stepwise approach was used to optimize automated settings to accurately identify fractionation. High-density fractionation maps were generated with a 20-pole mapping catheter in eight other patients. Two blinded electrophysiologists interpreted all electrograms as near field or far field. The algorithm was refined to optimize settings to exclude far-field signals and retain near-field signals. The sampling segment length was adjusted to optimize recording time to ensure reproducibility. RESULTS Using 1,514 points, the automated software achieved sensitivity of 0.75 and specificity of 0.80 for identification of fractionated electrograms. Using 725 points collected via multipole catheters with optimal automated settings, 94% of near-field fractionated electrograms were accurately identified. A 6-second sampling length was needed for reproducible fractionation measurements. CONCLUSION Standardized settings of EnSite NavX 6.0 software with 6-second data collection per point can rapidly and accurately generate high-density fractionation maps independent of physician electrogram interpretation. This may allow for an automated, standardized approach to atrial fibrillation fractionated ablation.

Venous changes occurring during the valsalva maneuver: Evaluation by intravascular ultrasound

Abstract The Valsalva maneuver, originally described in 1704, is a widely used physiologic technique for the non-invasive evaluation of heart murmurs and ventricular function.1–3 The maneuver consists of forceful expiration against a closed glottis, resulting in an increase in intrathoracic pressure and a decrease in venous return to the heart. Although the hemodynamic changes occurring during the various stages of the maneuver have been well documented, the associated venous changes have not been precisely described. Intravascular ultrasound allows for the accurate evaluation of the dimensions of vascular structures.4,5 In this study, we assessed the changes in area and circumference that occurred in an intrathoracic vein, the superior vena cava, and an extrathoracic vein, the right internal jugular, during the strain phase (phase 2) of the Valsalva maneuver. From these measurements, we wished to determine whether the decrease in venous flow to the heart during the Valsalva maneuver was due to the elevated pressure in the right atrium secondary to the elevated intrathoracic pressure, or to direct external compression of the superior vena cava by the elevated intrathoracic pressure.

Correlates of spontaneous echo contrast in patients with mitral stenosis and normal sinus rhythm.

The purpose of this study was to evaluate the correlates of spontaneous echo contrast in mitral stenosis and normal sinus rhythm. Spontaneous echo contrast is associated with clot formation and embolic phenomena. It has been noted in conditions involving blood stasis, especially mitral stenosis and atrial fibrillation, but the correlates of spontaneous echo contrast in patients with mitral stenosis and normal sinus rhythm have not been extensively evaluated. The transthoracic and transesophageal echocardiograms and clinical findings of 47 patients with mitral stenosis and normal sinus rhythm were reviewed. Left atrial size, mean transmitral gradient, and valve area were measured, and the presence or absence of spontaneous echo contrast in the left atrium was noted. Spontaneous echo contrast was found in the echocardiograms of 21 (45%, group 1) of 47 patients. There was no contrast in those of the other 26 patients (group 2). Mean transmitral gradient was significantly higher in group 1 (13.6 +/- 5.2 mm Hg) than in group 2 (10.5 +/- 4.9 mm Hg) (p < 0.05). Mitral valve area was significantly smaller in group 1 than in group 2 (1.0 +/- 0.5 vs 1.4 +/- 0.5 cm2; p < 0.02). There was a trend toward a higher prevalence of significant mitral regurgitation in group 2. There was no significant difference with respect to age, left atrial size, history of embolism, or warfarin therapy. We conclude that spontaneous echo contrast in the left atrium of patients with mitral stenosis and normal sinus rhythm is common and is associated with a significantly smaller mitral valve area and higher mitral gradient.(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiographic evaluation of the coronary sinus.

The purpose of this study was to compare transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) in the evaluation of the coronary sinus and its blood flow. Forty patients were studied by TTE and TEE. The distal coronary sinus and its right atrial communication could be identified in 21 of 40 by TTE, and in all patients by TEE. Coronary sinus diameter measurement at the right atrial communication was possible by TTE in 16 of 40, and in all patients by TEE (maximal diameter 6 to 14 mm, mean 9 +/- 2). Flow velocity measurement by pulsed Doppler was possible in 25 of 40 patients (63%) by TEE, and in none by TTE. The flow velocity pattern was similar to central vein flow velocity, with systolic and diastolic antegrade waves, and a small retrograde end diastolic wave. The coronary sinus cross-sectional area was measured in 5 patients by intravascular ultrasound. It varied in size and shape during the cardiac cycle, reaching a maximum (0.3 to 1.5 cm2) at end diastole, and decreasing by 40% to 70% at end systole. TEE is superior to TTE in the evaluation of the coronary sinus and its blood flow velocity. However, because of the variability in cross-sectional area size and shape, measurement of coronary sinus blood flow may be inaccurate.

Mapping Reentry Around Atriotomy Scars Using Double Potentials

Supraventricular arrhythmias, often seen in patients after cardiac surgery, may be associated with scars produced in the atria at the time of surgery. Double potentials, found in the presence of functional or anatomical block, can define the limits and critical regions of a reentrant circuit associated with the atriotomy scars. We describe six patients with seven distinct atrial tachycardias in whom atriotomy scars were successfully mapped during intraatrial reentry utilizing the presence and interelectrogram relationship of observed double potentials. The reentrant circuit was mapped in all patients by following the relationship between double potentials along the surgical scar, assuming that they would be widely split in the middle of the scar and merge into a single continuous fractionated potential at the apex of the scar. At this site, atrial pacing was performed to entrain the tachycardia and confirm the participation of the atriotomy scar in the clinically relevant atrial tachycardia. Radiofrequency ablation was performed from the site of electrogram fusion to the nearest anatomical obstacle. Five of seven atrial tachycardias were successfully ablated utilizing this technique over a mean follow‐up of 10 months. We proposed that these double potentials and their interelectrogram relationship are an effective means of mapping atriotomy scars and guiding successful radiofrequency ablation.

Meta-analysis to assess the appropriate endpoint for slow pathway ablation of atrioventricular nodal reentrant tachycardia.

Background:  There are little data on the appropriate endpoint for slow pathway ablation that balances acceptable procedural times, recurrence rates, and complication rates. This study compared recurrence rates of three commonly utilized endpoints of slow pathway ablation for atrioventricular nodal reentrant tachycardia (AVNRT).

Cardiac Vein Angioplasty for Biventricular Pacing

SANDLER, D.A., et al.; Cardiac Vein Angioplasty for Biventricular Pacing. Biventricular pacing for the treatment of congestive heart failure has consistently demonstrated improvement in quality‐of‐life and reduction in heart failure symptoms. Though the over‐the‐wire systems will be helpful in overcoming many existing obstacles to optimal lead placement, anatomic variability will still limit overall success. Cardiac vein angioplasty may be required for deployment of leads into tortuous or obstructed cardiac veins. This case report describes the angioplasty of a focal cardiac vein stenosis allowing for successful implantation of a left ventricular pacing lead. The safety of this procedure is unknown, though the risks may be acceptable in certain patients.

Cosmic radiation induced software electrical resets in ICDs during air travel

C T c r . ntroduction osmic radiation is a well-known cause of single-event psets (SEU) on disruption to electrical circuits in electronic evices. It most commonly occurs and is reported for deices such as laptop computers, cell phones, and personal igital assistants. We report 3 patients with implantable ardioverter-defibrillators (ICDs) who experienced SEUs uring air travel that may be attributed to exposure to osmic radiation while on commercial airline flights. These ases highlight the significant impact of SEUs on ICDs and atient clinical outcomes and the need for further recogniion and study of this problem. Cosmic radiation was discovered by the Nobel Laureate ictor Hess in 1912. While studying radioactivity, he disovered the source of radioactive particles showering down hrough the earth’s atmosphere as cosmic radiation. Cosmic adiation originates from the sun, other stars, and catalysms in outer space, some having occurred millions of ears ago, and is made up of protons, electrons, and neurons. At sea level, cosmic radiation contributes 13% of the atural background radiation. There are 4 predominant factors contributing to cosmic adiation. (1) Altitude: the earth’s atmosphere shields osmic radiation. At higher altitude the shield decreases, herefore the density of cosmic radiation increases. At flying ltitude, cosmic radiation is 100 times greater than at sea evel (Figure 1). (2) Latitude: the earth’s magnetic field eflects cosmic radiation. Shielding cosmic rays is greatest t the equator and decreases at the outer poles. Cosmic adiation at either the north or the south pole is twice as reat as at the equator. (3) Solar activity: the sun’s activity ycles every 11 years, with periods of high and low activity. uring a quiet solar year (2007), large amounts of cosmic adiation shower down through the atmosphere. (4) Solar roton events: these are large, explosive ejections of harged particles. This increased ejection of solar energy

Percutaneous treatment of the superior vena cava syndrome via an excimer laser sheath in a patient with a single chamber atrial pacemaker

A 21-year-old woman presented with a pacemaker-associated superior vena cava (SVC) syndrome refractory to medical therapy. In the past, treatment of this condition has involved surgical exploration which is invasive. With the evolution of percutaneous techniques, treatment has included venoplasty and stenting over the pacemaker lead. There is limited experience with a more advanced percutaneous technique in which the lead is extracted by an excimer laser sheath. The extraction is immediately followed by venoplasty and stenting at the site of stenosis with subsequent implantation of a new permanent pacemaker at the previously occluded access site. The patient underwent this procedure which proved to be safe, minimally invasive, and an efficient method of treating SVC syndrome secondary to a single chamber atrial pacemaker.