Daniel L. Lustgarten

Coronary Sinus-Ventricular Accessory Connections Producing Posteroseptal and Left Posterior Accessory Pathways Incidence and Electrophysiological Identification

Background—The coronary sinus (CS) has a myocardial coat (CSMC) with extensive connections to the left and right atria. We postulated that some posteroseptal and left posterior accessory pathways (CSAPs) result from connections between a cuff of CSMC extending along the middle cardiac vein (MCV) or posterior coronary vein (PCV) and the ventricle. The purpose of the present study was to use CS angiography and mapping to define and determine the incidence of CSAPs and determine the relationship to CS anatomy. Methods and Results—CSAP was defined by accessory pathway (AP) potential or earliest activation in the MCV or PCV and late activation at anular endocardial sites. A CSAP was identified in 171 of 480 patients undergoing ablation of a posteroseptal or left posterior AP. CS angiography revealed a CS diverticulum in 36 (21%) and fusiform or bulbous enlargement of the small cardiac vein, MCV, or CS in 15 (9%) patients. The remaining 120 (70%) patients had an angiographically normal CS. A CSMC extension potential (CSE), like an AP potential, was recorded in the MCV in 98 (82%), in the PCV in 13 (11%), in both the MCV and PCV in 6 (5%), and in the CS in 3 (2%) of 120 patients. CSMC potentials were recorded between the timing of atrial and CSE potentials. Conclusions—CSAPs result from a connection between a CSMC extension (along the MCV or PCV) and the ventricle. The CS is angiographically normal in most patients.

His-bundle pacing versus biventricular pacing in cardiac resynchronization therapy patients: A crossover design comparison

BACKGROUND Cardiac resynchronization therapy (CRT) typically is attempted with biventricular pacing (BiVP). One-third of patients are nonresponders. His-bundle pacing (HBP) has been evaluated as an alternative means of effecting CRT because it generates truly physiologic ventricular activation, as evidenced in part by the morphologic identity between normally conducted and paced QRS complexes. OBJECTIVE The purpose of this study was to assess the feasibility of, and clinical response to, permanent HBP as an alternative to BiVP in CRT-indicated patients. METHODS Patients were implanted with a right atrial pacing lead, defibrillation lead, left ventricular (LV) lead via the coronary sinus, and HBP lead. His and LV leads were plugged into the LV port via a Y-adapter. After successful implant, patients were randomized in single patient-blinded fashion to either HBP or BiVP. After 6 months, patients were crossed over to the other pacing modality and followed for another 6 months. Quality-of-life assessments, echocardiographic measurements, New York Heart Association classification, and 6-minute hall walk test were obtained at baseline and at each 6-month follow-up. RESULTS Twenty-nine patients were enrolled; 21 (72%) demonstrated electrical resynchronization (QRS narrowing) at implant. Twelve patients completed the crossover analysis at 1 year. Clinical outcomes (quality of life, New York Heart Association functional class, 6-minute hall walk test, LV ejection fraction) were significantly improved for both pacing modes compared with baseline measures. CONCLUSION In this crossover comparison between HBP and BiVP, HBP was found to effect an equivalent CRT response. QRS narrowing was observed in 21 of 29 patients, suggesting this approach may be feasible in more patients with left bundle branch block than previously assumed.

The temporal variability of dominant frequency and complex fractionated atrial electrograms constrains the validity of sequential mapping in human atrial fibrillation

BACKGROUND It has been proposed that sequential mapping of dominant frequency (DF) and complex fractionated atrial electrograms (CFAE) can identify target sites for ablation of atrial fibrillation (AF). These mapping strategies are valid only if DF and CFAE are temporally stable on the timescale of the mapping procedure. We postulate that DF and CFAE are temporally variable; consequently, sequential mapping can be misleading. OBJECTIVE To make prolonged spatially stable multielectrode recordings to assess the temporal stability of DF and CFAE. METHODS We recorded electrical activity for 5 minutes with the use of a 64-electrode basket catheter placed in the left atrium of 18 patients presenting for AF ablation. DF and CFAE were determined off-line, and their temporal variability was quantified. Maps created from simultaneous versus sequentially acquired data were compared. RESULTS DF was temporally variable: the average temporal coefficient of variation was 22.7% +/- 5.4%. DF sites were transient, meeting criteria for only 22.1 seconds out of 5 minutes. Similarly, CFAEs were transient (average duration of CFAE 8.8 +/- 11.3 seconds). DF and CFAE sequential maps failed to identify 93.0% +/- 12.4% and 35.9% +/- 14.9% of DF and CFAE sites, respectively. CONCLUSION Because of temporal variability, sequential DF and CFAE maps do not accurately reflect the spatial distribution of excitation frequency during any given sampling interval. The spatial distribution of DF and CFAE sites on maps created with sequential point acquisition depends upon the time at which each site is sampled.

Electrical resynchronization induced by direct His-bundle pacing

BACKGROUND Biventricular pacing (BiV) to effect cardiac resynchronization therapy can be technically difficult and fails to elicit a clinical response in 30% to 40% of patients. Direct His-bundle pacing (DHBP) theoretically could obviate some of these problems. Although DHBP is capable of narrowing the QRS in some patients, the consistency with which this can be achieved has not been characterized. OBJECTIVE The purpose of this study was to restore His-Purkinje functionality in consecutive patients undergoing de novo clinically mandated cardiac resynchronization therapy. METHODS DHBP was temporarily implemented at the time of implantation of a permanent BiV system in patients referred for cardiac resynchronization therapy. Native conduction, DHBP, and BiV QRS duration were compared. All patients presenting for BiV cardiac resynchronization therapy were eligible for the study. Ten patients were studied. RESULTS DHBP was successfully implemented in all 10 patients. In 7 of 10 patients, DHBP narrowed the QRS significantly compared with native conduction and BiV (mean QRS duration: native 171 +/- 13 ms, DHBP 148 +/- 11 ms, BiV 158 +/- 21, P <.0001). QRS narrowing with DHBP was specifically attributable to capture of latent His-Purkinje tissue. DHBP lead implantation time (16 minutes) was shorter than standard left ventricular lead implantation time (42 minutes). CONCLUSION DHBP was readily implemented in patients with standard indications for BiV cardiac resynchronization therapy. In most patients studied, DHBP resulted in a significantly narrower QRS compared with native conduction. DHBP may offer a physiologic alternative to BiV for cardiac resynchronization therapy.

Relation Between Pulmonary Vein Firing and Extent of Left Atrial–Pulmonary Vein Connection in Patients With Atrial Fibrillation

Background—The purpose of this study was to measure the extent of left atrial–pulmonary vein (LA-PV) connections and determine the relation to PV firing in patients with atrial fibrillation (AF). Methods and Results—Ten close-bipolar (1 mm-spacing) Lasso electrograms were recorded circumferentially around 210 PVs (excluding 2 right middle PVs and 4 left common trunks) in 62 patients with AF. PV firing was provoked by isoproterenol (4 &mgr;g/min) and cardioversion of pacing-induced AF. The width of each LA-PV connection was measured in tenths of PV circumference, based on number of continuous close-bipolar Lasso electrode sites required for ablation (10% for each close-bipolar electrode site). One, 2, or 3 to 4 discrete LA-PV connections (discrete connection defined by ablation along 10% to 30% of PV circumference) were present in 18 (9%), 31 (14%), and 32 (15%) of 210 PVs, respectively: 1 broad connection (ablation along continuous 40% to 80% circumference) in 46 (22%) PVs; 1 broad plus other broad or discrete connections in 54 (26%) PVs; and a circumferential connection (ablation along 90% to 100%) in 29 (14%) PVs. Circumferential LA-PV connections were more common in superior than in inferior PVs (20% versus 7%, P <0.01). There was no major difference in distribution of the other types of LA-PV connections between the four PVs. PV firing occurred in 27%, 47%, and 72% of PVs with discrete only, broad and circumferential connections, respectively (P <0.01). Dissociated PV potentials after isolation were more common in arrhythmogenic (firing) PVs (32% versus 8%, P <0.01). Conclusions—The extent of LA-PV connections corresponds with arrhythmognesis. The incidence of PV firing increases with progressively wider LA-PV connections (discrete versus broad versus circumferential).

Permanent His bundle pacing: Recommendations from a Multicenter His Bundle Pacing Collaborative Working Group for standardization of definitions, implant measurements, and follow-up

His bundle pacing (HBP) prevents ventricular dyssynchrony and its long-term consequences by preserving normal electrical activation of the ventricles. Since the original description of permanent HBP in 2000, the adoption of HBP has increased over the past several years. However, the reporting of procedural and clinical outcomes to date is not uniform. This article is a collaboration between several implanters with significant experience in HBP to establish a uniform set of definitions encompassing the different forms of HBP as well as define a standardized approach to gathering data end points to ensure consistency in reported outcomes.

Autopsy Analysis of the Implantation Site of a Permanent Selective Direct His Bundle Pacing Lead

To date, there has not been direct visualization of the anatomic location of direct His bundle pacing (DHBP) leads in the human heart. The absence of such data has contributed to disagreement about the location of DHBP leads with respect to the plane of the tricuspid valve.1,2 We present an autopsy study of a patient who had previously had a DHBP lead implanted, showing unequivocally that the lead is implanted on the atrial side of the tricuspid annulus. An 81-year-old man with diabetes died of sepsis secondary to a lower-extremity infection. Two years prior, the patient presented with symptoms of congestive heart failure and presyncope. He had a history of coronary artery bypass graft and myocardial infarction with mild to moderate left ventricular dysfunction (ejection fraction, 40%–45%). β-blockade therapy was limited by sinus bradycardia and frequent Wenckebach block. The patient was noninducible for ventricular arrhythmias, and a pacemaker was recommended for chronotropic incompetence and AV block. To prevent pacemaker-induced electric dyssynchrony, we implanted a DHBP lead. DHBP lead implantation was performed as previously described.3 Briefly, an octapolar mapping catheter was used to map the His bundle. A pacing lead was actively fixed adjacent to bipolar electrodes recording a His potential (SelectSecure lead, model 3830, delivered …

Ablation using irrigated radiofrequency: A hands-on guide

t t e p e e ntroduction he advent of irrigated radiofrequency (RF) catheters has ed to the common misconception that irrigation somehow akes ablation both safer and more effective. In fact, this is ot true. Irrigation (or any other means of cooling the atheter tip) results in the ability to deliver greater energy nd as such can lead to steam pops, collateral damage, and hrombus formation. It is important to recognize that irrigaion allows greater energy delivery; it does not mandate it. he operator must determine the appropriate power settings, rrigant flow rates, and lesion duration for each ablation site. his requires balancing the competing demands of efficacy transmural tissue destruction) against those of safety avoidance of catheter or tissue overheating and/or collatral tissue heating). Current technological limitations reuire that these decisions be based on incomplete informaion about the tissue effects of ablation. We will review the iophysics of RF ablation and the role of irrigation to rovide a context for making rational decisions about the se of irrigated RF catheters.

The Impact of Pharmacologic Sympathetic and Parasympathetic Blockade on Atrial Electrogram Characteristics in Patients with Atrial Fibrillation

Background:  Ablation of atrial autonomic inputs exerts antifibrillatory effects. However, because ablation destroys both myocardium and nerve cells, the effect of autonomic withdrawal alone remains unclear. We therefore examined the effects of pharmacologic autonomic blockade (PAB) on frequency and fractionation in patients with atrial fibrillation (AF).

Permanent His bundle pacing: Electrophysiological and echocardiographic observations from long-term follow-up: VIJAYARAMAN et al.

Permanent His bundle pacing (HBP) is a physiological alternative to right ventricular pacing. It is not known whether HBP can cause His‐Purkinje conduction (HPC) disease. The aim of our study is to assess His bundle capture and its effect on left ventricular (LV) function in long‐term follow‐up and to determine HPC at the time of pulse generator change (GC) in patients with chronic HBP.