Appropriate Implantable Cardioverter-Defibrillator Therapies Delivered 5 Years After End of Service.

We present the case of a 57-year-old man with a primary prevention internal cardioverter-defibrillator for severe nonischemic cardiomyopathy. At the time of elective replacement indicator, systolic function had fully recovered, and his generator was not changed. Nearly 5 years post-elective replacement indicator he received appropriate internal cardioverter-defibrillator therapies during a myocardial infarction. (Level of Difficulty: Intermediate.).

Intracranial hemorrhage as a complication of dobutamine stress echocardiography: case report and review of the literature.

Dobutamine stress echocardiography is a generally well-tolerated study to evaluate patients with suspected coronary artery disease. Rare but life-threatening complications of this study have been well described. Severe hypertensive responses are a known but uncommon adverse reaction to dobutamine infusion. The authors report a case of intracranial hemorrhage in the setting of severe hypertension as a complication of dobutamine stress echocardiography. The patient was on systemic anticoagulation with warfarin for a prosthetic mitral valve and had an international normalized ratio (INR) of 3.8 that was slightly over the therapeutic goal INR of 2.5-3.5. He had no predisposing intracranial lesions such as tumor, vascular malformation, or aneurysm. He suffered an intraparenchymal hemorrhage in three distinct areas of his brain. Intracranial hemorrhage related to dobutamine infusion has not been reported previously, but given the known risk of hypertension, life-threatening sequelae including intracranial hemorrhage are possible.

Prospective randomized comparison between the conventional electroanatomical system and three-dimensional rotational angiography during catheter ablation for atrial fibrillation.

BACKGROUND: Theoretically, the use of electroanatomical mapping systems may reduce radiation exposure, while three-dimensional rotational atriography (3DATG) may increase exposure. Anatomical representation and image registration using 3DATG are likely to be superior, but the net clinical benefit of either system is unknown. OBJECTIVE: The purpose of this prospective randomized two-center study was to compare the procedural and clinical outcome of patients with atrial fibrillation (AF) treated by catheter ablation using either three-dimensional (3D) electroanatomical mapping (Carto) or 3DATG. METHODS: From November 2007 to November 2008, 91 consecutive patients with AF (mean age 58 +/- 10 years; 63% paroxysmal AF, 37% persistent AF) from two centers (Bordeaux and Boston) were randomized to ablation using either 3DATG (44 patients) or Carto (47 patients). RESULTS: Of the 47 left atrial shells acquired with 3DATG, one was uninterpretable. There was no difference in total radiofrequency applications (72 +/- 23 vs. 79 +/- 33 minutes, respectively, P = .296), procedural duration (232 +/- 65 vs. 218 +/- 67 minutes; P = .335), fluroroscopic duration (75 +/- 28 vs. 67 +/- 26 minutes; P = .151), or radiation exposure (71,810 +/- 42,954 vs. 68,009 +/- 38,345 mGy cm(2); P = .719) between procedures performed with 3DATG or Carto. After a mean follow-up of 10 +/- 4 months, there was no difference in clinical outcome using either Carto or 3DATG concerning total arrhythmia recurrence (34% versus 38%; P = .668) or AF recurrence (20% vs. 15%; P = .555). CONCLUSION: Three-dimensional ATG-guided AF ablation has similar radiation exposure and procedural and outcome characteristics compared with Carto-guided ablation. The ease of use and accurate 3D representation of the left atrium make 3DATG a reasonable alternative to conventional 3D electroanatomical mapping systems, however, without advanced mapping functions.

Segmentation and registration of three-dimensional rotational angiogram on live fluoroscopy to guide atrial fibrillation ablation: a new online imaging tool.

BACKGROUND: Three-dimensional rotational atriography (3DATG) was developed to supplement two-dimensional fluoroscopy with 3D volume reconstruction of the left atrium (LA), pulmonary veins (PV), and other structures. Until recently, 3DATG images could only be viewed separately and were not suitable to directly guide atrial fibrillation (AF) ablation. OBJECTIVE: The purpose of this study was to evaluate the feasibility and accuracy of intraprocedural 3DATG. METHODS: Three-dimensional rotational atriography with right atrial contrast injection was obtained using a Philips Allura Xper FD10 system in 30 patients with symptomatic AF who also underwent preprocedural computed tomographic (CT) scan. RESULTS: The majority (93%) of 3DATG image reconstructions were useful for guidance of catheter ablation. Nearly all PVs (94%), LA appendage (89%), and esophagus (100%) were successfully segmented. Measured PV ostial diameters compared using 3DATG and CT showed close concordance. Registration and re-registration of 3DATG overlay image was easily achieved with thoracic landmarks and validated by catheter placement demonstrating minimal discrepancy. Endoscopic views allowed for improved visualization of ostial position, dimensions, and navigation within the antrum. Lesion tagging on 3DATG overlay enhanced ablation guidance. Radiation exposure with 3DATG was significantly reduced compared with preprocedural CT scan (2.1 +/- 0.3 mSv vs 13.8 +/- 2.4 mSv, P <.001). CONCLUSION: Intraprocedural 3DATG imaging during AF ablation with online segmentation and superimposition on live fluoroscopy is feasible. Overlay provides valuable and accurate information on 3D surface outline and endoscopic PV location. Three-dimensional rotational atriography overlay is a new imaging method with reduced radiation exposure that may replace preprocedural CT scan for catheter navigation and ablation of AF.

Baseline myocardial perfusion predicts response to cardiac resynchronization therapy: a prospective observational study.

PURPOSE: We prospectively determined whether preimplant myocardial perfusion imaging (MPI) predicts outcome with biventricular pacing (BiVP). METHODS: Single-photon emission computed tomography (SPECT) MPI, left ventricular (LV) volumes, ejection fraction (EF), 6-min hall walk (6MW) were assessed at baseline and at 4 months in 19 patients with ischemic cardiomyopathy undergoing BiVP. Clinical and hemodynamic responses were correlated with MPI. RESULTS: Lower global myocardial scar burden predicted hemodynamic response to BiVP, while higher burden was associated with poor response. Clinical improvement with BiVP occurred in 12 (63%) of the patients. Clinical BiVP responders had lower rest/stress MPI score difference. There was a close negative correlation between MPI reversibility and increased 6MW distance. CONCLUSIONS: Baseline MPI is associated with clinical and hemodynamic response to BiVP: greater myocardial scar burden is predictive of poor hemodynamic response, while higher ischemic burden is predictive of poor clinical response. There is a differential response to BiVP by clinical and hemodynamic criteria.

Remote magnetic navigation system provides a superior catheter stability in acquisition of His bundle electrogram.

INTRODUCTION: Catheter stability is a key prerequisite for a successful EP procedure. Remote magnetic navigation system (RMNS) was recently introduced for the manipulation of EP catheters. It may provide an improved catheter stability but this has not been tested prospectively. We performed a prospective cross-over study which compares the amplitude and stability of the His-electrogram obtained by catheters using RMNS vs conventional manual catheter placement. METHODS: His-electrograms were continuously recorded for 3 min with a conventional His mapping catheter and magnetically tipped catheter capable of alignment in the direction of an externally controlled magnetic field (0.08-0.1 Tesla) in the same patient. First 100 beats of each recording were used for data analysis. The amplitudes of each set of His-electrograms were measured and compared in microvolts. Coefficient of variation of the measured His-signal amplitude was calculated for each beat. Miller's test for the equality of the coefficients of variation and Levene's test of homogeneity of variance were used for statistical analysis. RESULTS: Fourteen patients (6 males; aged 48+/-25 years) were included in the study. His-electrograms were more stable and homogenous with RMNS than manual method in 10/14 patients. Pooled variance of all RMNS recordings was significantly less than pooled variance of manual recordings (p=0.01). CONCLUSION: His-electrogram recording using RMNS is more stable and homogeneous than traditional manual method in most patients. These data indicate a superior catheter stability with RMNS.

Evaluation of left atrial and posterior mediastinal anatomy by multidetector helical computed tomography imaging: relevance to ablation.

INTRODUCTION: Increasing use of catheter ablation in the left atrium (LA) requires understanding of substrate anatomy, especially with regard to potential damage to adjacent structures. METHODS AND RESULTS: We reviewed multidetector helical computed tomography (MDCT) imaging on 42 subjects, 26 imaged before planned LA ablation for atrial fibrillation (AF), and 16 without AF. LA volume and dimensions were larger in patients with AF (p < 0.05) and the spine and aorta (Ao) impressed the LA more frequently in the AF group. The esophagus (Eo) was the predominant feature on the posterior LA wall, contacting it in all patients. The Ao was in contact with the LA body or the left inferior pulmonary vein (PV) in 32 (76%) of 42 cases, and in 10 it ran along an indentation on the posterior aspect of the LA. The coronary sinus was adjacent to LA ablation sites, the azygos vein was rarely adjacent to those sites, and the left bronchus abutted the PV ostium but not the LA. Two patients had findings that directly impacted the ablation procedure: one patient had a dilated fluid filled Eo with esophageal stricture and underwent nasogastric decompression before ablation, and one was discovered to have an anomalous PV and underwent surgical repair. CONCLUSIONS: MDCT imaging identifies structures adjacent to the LA, which could be affected by ablation. Posterior LA topography can be influenced by the position of the Ao or by the proximity of the spine. Preprocedural imaging can characterize anatomic structures that could be vulnerable during ablation, and detect unusual pathology that can affect the treatment plan.

Three-dimensional rotational angiography of the left atrium and esophagus--A virtual computed tomography scan in the electrophysiology lab?

BACKGROUND: Three-dimensional (3D) reconstruction of the heart and surrounding structures has been supplementing traditional two-dimensional imaging to guide diagnostic and therapeutic electrophysiologic procedures. Current methods using computed tomography (CT)/magnetic resonance imaging (MRI) reconstruction have certain limitations. OBJECTIVE: We investigated the feasibility of rotational angiography (RA) combined with simultaneous esophagogram to create an intraprocedural 3D reconstruction of the left atrium (LA) and the esophagus. METHODS: Rotational angiography was performed. Contrast was injected via a pigtail catheter positioned in the left or right pulmonary artery to achieve a levophase venous cycle opacification of the ipsilateral pulmonary veins and adjacent LA. Simultaneous administration of oral contrast allowed a 3D reconstruction of the esophagus in the same image. Qualitative and quantitative comparison between the intraprocedural 3D RA and a remote CT scan was performed in 11 consecutive patients undergoing ablation for atrial fibrillation. RESULTS: Adequate visualization of the pulmonary veins, adjacent posterior LA, and esophagus was achieved in 10 patients. Determination of pulmonary transit time to guide the initiation of RA resulted in better-quality imaging. A close correlation between 3D RA and CT was found. Based on close proximity between the LA and esophagus, the ablation procedure was modified in three patients. CONCLUSIONS: Three-dimensional RA of the LA and esophagus is a promising new method allowing intraprocedural 3D reconstruction of these structures comparable in quality to a CT scan. Further studies refining the method are justified because it could eliminate the need for CT/MRI scans before ablation.

Sheathless implantation of permanent coronary sinus-LV pacing leads.

BACKGROUND: Implantation of CS-LV pacing leads is usually accomplished through specialized sheaths with additional use of contrast venography and other steps. Direct implantation at a target pacing site could provide a simplified procedure with appropriate leads. METHODS: A progressive CS-LV lead implant protocol was used, with initial attempts made to place the lead directly using only fluoroscopy and lead stylet or wire manipulation. Coronary sinus (CS) sheaths were only used later if direct lead placement failed. RESULTS: There were 105 attempted implants with 96% (101/105) success. Leads were implanted sheathlessly in 69% (70/101) cases. Pacing parameters and final lead position did not differ significantly between implants that did or did not require sheaths for implants. Three peri-procedural complications occurred in implants where sheaths were used. In 33% (33/101) of implants, the leads were placed without the use of sheaths or contrast venography in 20 minutes or less. CONCLUSIONS: Direct placement of the CS-LV pacing lead without sheaths can be accomplished successfully in a majority of implants and in < or =20 minutes in a third, without inferior pacing parameters. This may provide for shorter or less technically difficult or expensive procedures with low risk.

Potential proarrhythmic effect of biventricular pacing: fact or myth?

BACKGROUND: Hemodynamic improvement from biventricular pacing is well documented; however, its electrophysiologic effects have not been systematically studied. Sporadic case reports suggest a proarrhythmic effect of biventricular pacing resulting primarily in polymorphic ventricular tachycardia/ventricular fibrillation (VT/VF). OBJECTIVES: The purpose of this study was to report a series of patients in whom implantation of a biventricular system resulted in VT/VF storm with predominance of monomorphic VT. METHODS: In a retrospective analysis of all biventricular implants over a 4-year period at a single medical center, we identified 5 of 145 patients (3.4%) who developed VT/VF after they were upgraded to a biventricular system. All patients were male, age 71 +/- 8 years, with ejection fraction of 0.25 +/- 0.1. Four of five patients had ischemic cardiomyopathy. RESULTS: All patients developed incessant VT/VF within 1 week of implantation. Monomorphic VT of single morphology was noted in 3 of 5 patients, monomorphic VT of multiple morphologies in 1, and polymorphic VT/VF in 1. VT was managed by temporary discontinuation of biventricular pacing in all patients, amiodarone in 3 of 5, sotalol in 1, and beta-blocker in 1. During 11 +/- 7 months of follow-up, 4 of 5 patients remain alive and are arrhythmia-free. CONCLUSION: Biventricular pacing may result in precipitation of VT/VF storm in a minority of patients with prior history of VT/VF. This may be the first case series reporting both monomorphic and polymorphic VT after an upgrade to a system with biventricular pacing capabilities. The arrhythmias can be managed by conventional therapy and may require temporary discontinuation of left ventricular pacing. This observation is relevant to patients receiving a biventricular pacemaker without an implantable cardioverter-defibrillator backup.

Algorithms useful in the treatment of atrial fibrillation.

Atrial fibrillation (AF) is a heterogeneous disorder; its management must be individualized depending upon the mode of presentation, underlying substrate, and need for either rate or rhythm control. In hemodynamically unstable patients with new onset AF, conversion by electrical cardioversion is the preferred approach; however, in stable patients pharmacological options may be considered. Recurrence rate after conversion is high in the majority of patients, necessitating the use of antiarrhythmic agents. Because of modest efficacy and potential for untoward effects, various nonpharmacologic approaches are being explored. Some of these modalities are considered curative in the short-term but techniques are still being refined.