Bahman Esmailzadeh

Individualized selection of pacing algorithms for the prevention of recurrent atrial fibrillation: Results from the VIP registry.

Objectives: The VIP registry investigated the efficacy of preventive pacing algorithm selection in reducing atrial fibrillation (AF) burden.

Clinical Experience with Implantable Atrial and Combined Atrioventricular Defibrillators

The high prevalence of atrial fibrillation (AF) and its clinical complications, the poor efficacy of medical therapy for preventing recurrences, and dissatisfaction with alternative modes of therapy stimulated interest in implantable atrial and combined atrioventricular defibrillators.In a multicenter study, the safety and efficacy of a stand alone implantable atrial defibrillator, the Metrix system, were evaluated. The device was implanted in 51 patients with highly symptomatic episodes of AF refractory to pharmacological treatment. During a follow-up of 9 months, 96% of 227 spontaneous AF episodes were successfully converted to sinus rhythm in 41 patients. In 62 episodes (27%), several shocks and/or additional drug treatment were required to maintain stable sinus rhythm because of early recurrences of AF. A total of 3719 shocks were delivered and no induction of ventricular proarrhythmia or inaccurately synchronized shocks occurred. The AF detection algorithm exhibited a 100% specificity for the recognition of sinus rhythm and a 92.3% sensitivity for the detection of AF.The combined atrioventricular defibrillator, Jewel AF 7250, was evaluated in a multicenter, randomized, cross-over trial. The primary study objectives included: overall safety as determined by complications-free survival at 6 months, efficacy of tiered atrial pacing and defibrillation therapies for termination of spontaneous atrial tachycardias (AT) and AF, and relative sensitivity of a new dual-chamber detection algorithm. The device was implanted in 211 patients with either a history of ventricular tachyarrhythmias (VT/VF) alone or with a history of both AT/AF and VT/VF. During a mean follow-up of 4.5 months, it has been shown that the Jewel AF is safe and effective in treating atrial and ventricular tachyarrhythmias. Pace termination of 85% of AT episodes were achieved with painless delivery of antitachycardia pacing; additional 35% of AT episodes were terminated by high frequency burst pacing.Conclusions: The stand alone implantable atrial defibrillator may be safe and clinically useful in selected patients for the treatment of highly symptomatic, drug resistant recurrences of AF. The combined atrioventricular defibrillator may be particularly indicated in patients presenting with both a history of atrial and ventricular tachyarrhythmias.

Transit time flow measurement in on-pump and off-pump coronary artery surgery

OBJECTIVE Transit time flow measurement is frequently used during coronary artery bypass with and without cardiopulmonary bypass to detect graft dysfunction resulting from technical errors. METHODS Intraoperative transit time flow measurement measurements of 896 patients requiring surgery for double- or triple-vessel disease were reviewed retrospectively. Six-hundred and ninety-five patients were operated on-pump (Group A: coronary artery bypass with cardiopulmonary bypass), and 201 patients off-pump (Group B: coronary artery bypass without cardiopulmonary bypass). Transit time flow measurement measurements were analyzed for mean flow (mL/min). In total, measurements of 2247 grafts were analyzed. RESULTS Transit time flow measurement flows were lower in coronary artery bypass without cardiopulmonary bypass patients (left internal thoracic artery to left anterior descending artery: Group A, 37 [31, 40] mL/min vs Group B, 24 [20, 26] mL/min; saphenous vein graft to left anterior descending artery: Group A, 46.5 [40, 56] mL/min vs Group B, 21 [14, 57] mL/min. Troponin I release was reduced in the coronary artery bypass without cardiopulmonary bypass patients, with median values of 7.8 [7.0, 8.3] microg/L in Group A and 1.2 [0.9, 2.3] microg/L in Group B. CONCLUSION Evaluation of transit time flow measurement is valuable in determining coronary graft patency after coronary artery bypass with cardiopulmonary bypass and coronary artery bypass without cardiopulmonary bypass. Decreased troponin I release suggests a myocardial benefit of coronary artery bypass without cardiopulmonary bypass compared to coronary artery bypass with cardiopulmonary bypass, although the intraoperative transit time flow measurement flow measurements are markedly lower.

Hybrid procedures can reduce the risk of congenital cardiovascular surgery

BACKGROUND Minimally invasive operations and percutaneous interventions are well-accepted options in the treatment of congenital heart defects. However, percutaneous interventions may be associated with an increased risk due to limited vascular access or a very tortuous catheter course. In these cases, combining operative and interventional approaches with direct puncture of the heart or the great vessels may facilitate implantation of even large devices. Furthermore, in some situations, cardiopulmonary bypass or circulatory arrest can be omitted when doing a hybrid procedure. PATIENTS Between January 2000 and April 2007 17 patients were operated in a hybrid fashion. Age ranged from 14 days to 45 years. Operative procedures consisted of implantation of an atrial septal defect occluder via direct puncture of the right atrium (n=4), closure of a ventricular septal defect via direct puncture of the right ventricle (n=1), implantation of isthmus stents via the ascending aorta (n=5), redilation of an isthmus stent (n=1), redilation of a ductal stent (n=1), angioplasty of a pulmonary artery stenosis (n=1), interventional occlusion of an intrahepatic porto-caval shunt (n=1), stent implantation into the right pulmonary artery (n=1) and into the right ventricular outflow tract (n=1) under direct vision as well as atrioseptoplasty combined with a bilateral pulmonary artery banding in one newborn with a single ventricle and very low birth weight (n=1). RESULTS The planned intervention could be performed in all cases under the assistance of intraoperative fluoroscopy, transesophageal or epicardial echocardiography, or under direct vision. In all cases, the primary hemodynamic objectives were achieved. CONCLUSION In selected patients, the combination of a surgical procedure and a percutaneous intervention may help to reduce both operative and interventional risks. This concept may enable new treatment options, especially in patients with complex congenital heart defects or complex vascular situations.

Potential device interaction of a dual chamber implantable cardioverter defibrillator in a patient with continuous spinal cord stimulation

Spinal cord or thalamic deep brain stimulation with a pacemaker is becoming more important in the treatment of drug refractory pain due to peripheral vascular disease, angina pectoris and intractable tremor in patients with neurologic disorders such as Parkinsons disease. An additional indication for a cardiac pacemaker or implantable cardioverter defibrillator raises concerns about possible interactions between the implanted electrical devices. We report on a patient with existing spinal cord stimulation who survived sudden cardiac death and received a dual chamber cardioverter defibrillator capable of delivering tiered therapies in both the atrium and ventricle.

Inappropriate Implantable Defibrillator Discharge Caused by a Retained Pacemaker Lead Fragment

Introduction: Inappropriate discharge is still a major issue of implantable cardioverter defibrillator therapy. The diagnostic options of modern devices facilitate classification of the underlying abnormality.Methods and Results: A 65-year-old woman with depressed left ventricular performance received spurious shocks from an ICD, implanted for ventricular tachycardia. A lead fragment of an explanted VVI pacemaker system could be identified as cause of erroneous ventricular fibrillation detection by the ICD. The electrical noise caused by interaction between the lead remnant and the ICD lead was detectable even on the surface ECG.Conclusion: Based on our findings, removal of fragmented lead material should be considered prior to ICD implantation, to avoid potentially adverse and harmful interactions with ICD systems.

Myocardial hypertrophy is associated with inflammation and activation of endocannabinoid system in patients with aortic valve stenosis

AIMS Endocannabinoids and their receptors have been associated with cardiac adaptation to injury, inflammation and fibrosis. Experimental studies suggested a role for inflammatory reaction and active remodeling in myocardial hypertrophy, but they have not been shown in human hypertrophy. We investigated the association of the endocannabinoid system with myocardial hypertrophy in patients with aortic stenosis. MAIN METHODS Myocardial biopsies were collected from patients with aortic stenosis (AS) and atrial myxoma as controls during surgery. Histological and molecular analysis of endocannabinoids and their receptors, inflammatory and remodeling-related cells and mediators was performed. KEY FINDINGS Myocardial hypertrophy was confirmed with significantly higher cardiomyocyte diameter in AS than in myxoma patients, which had normal cell size. AS patients presented compensated myocardial adaptation to pressure overload. AS patients had significantly higher: concentration of endocannabinoid anandamide, expression of its degrading enzyme FAAH, and of cannabinoid receptor CB2, being predominantly located on cardiomyocytes. Cell density of macrophages and newly recruited leukocytes were higher in AS group, which together with increased expression of chemokines CCL2, CCL4 and CXCL8, and suppression of anti-inflammatory IL-10 indicates persistent inflammatory reaction. We found higher myofibroblast density and stronger tenascin C staining along with mRNA induction of tenascin C and CTGF in AS patients showing active myocardial remodeling. SIGNIFICANCE Our study shows for the first time activation of the endocannabinoid system and predominant expression of its receptor CB2 on cardiomyocytes being associated with persistent inflammation and active remodeling in hypertrophic myocardium of patients with aortic stenosis.

Emergent antegrade endovascular stent placement in a patient with perforated Stanford B dissection via right axillary artery

We present a case of a ruptured chronic Stanford B dissection of the aorta which was successfully treated with a tapered endoprosthesis using the right axillary artery for access. Challenges to endovascular strategies for thoracic aortic pathology include relatively restricted endoprosthesis configurations and problems associated with endovascular access. Especially in younger patients the right axillary artery should be considered as a possible and safe access for antegrade stent placement.

Advanced Pacemaker Diagnostic Features in the Characterization of Atrial Fibrillation: Impact on Preventive Pacing Algorithms

YANG, A., et al.: Advanced Pacemaker Diagnostic Features in the Characterization of Atrial Fibrillation: Impact on Preventive Pacing Algorithms. Pacing algorithms to prevent PAF are mainly based on the suppression of premature atrial complexes (PACs), which play an important role in its initiation. In contrast to 24‐hour ambulatory electrocardiograms, advanced pacemaker (PM) diagnostic features are capable of recording AF episodes during long follow‐up periods and of characterizing AF in a detailed fashion. For the specific use of these algorithms, a detailed characterization of AF was performed in 91 dual chamber PM recipients with histories of AF. Fifteen patients with episodes of oversensing due to far‐field signals or frequent episodes of “2:1‐undersensing” of atrial flutter were excluded. The remaining 76 patients had high recurrence rates of AF (median 0.8 episodes/day), however, the majority of episodes lasted <7 minutes. Despite frequent PACs (median 10.8/hour) during sinus rhythm, a median of 66.4% of the AF episodes were preceded by <2 PACs/min before onset. In conclusion, frequent, short‐lived AF episodes seem best suited for AF preventive pacing therapies. However, the small number of PACs preceding many AF episodes may limit the efficacy of PAC suppressing algorithms. (PACE 2003; 26[Pt. II]:310–313)

Incidence and Rate Characteristics of Atrial Tachyarrhythmias in Patients with a Dual Chamber Defibrillator

Atrial tachyarrhythmias play an important role in the treatment of patients with malignant ventricular tachyarrhythmias not only with respect to inappropriate discharges but also to left ventricular function and stroke risk. A combined dual chamber defibrillator provides separate therapies for atrial and ventricular tachyarrhythmias. To assess the incidence of atrial tachyarrhythmias in patients with this dual chamber implantable defibrillator, 40 patients with ventricular tachyarrhythmias and concomitant atrial tachyarrhythmias and/or AV conduction disturbances were included in a prospective study. During a mean follow‐up of 25 ± 11 months , 26 of 40 patients had a total of 1,430 recurrences of atrial tachyarrhythmias. The vast majority of the atrial tachyarrhythmias with regular atrial cycles had a mean median atrial cycle length of 235 ± 37 ms and a mean duration of 34 ± 144 minutes . Atrial tachyarrhythmias with irregular atrial cycles exhibited a median atrial cycle length of 198 ± 31 ms and had a mean duration of 246 ± 1,264 minutes . In addition, 67% of 375 tachyarrhythmias, in which the median ventricular cycle length during the ongoing episode could be documented, had a ventricular rate <100 beats/min. Continuous atrial arrhythmia detection with a dual chamber ICD reveals a high incidence of atrial tachyarrhythmias with a predominantly short duration of paroxysmal recurrences <1 hour in the vast majority of episodes. (PACE 2003; 26:1691–1698)