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Atrial Sensing (atrial + sensing)
Selected AbstractsInhibition of Bradycardia Pacing and Detection of Ventricular Fibrillation Due to Far-Field Atrial Sensing in a Triple Chamber ImplantablePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2002DIRK VOLLMANN VOLLMANN, D., et al.: Inhibition of Bradycardia Pacing and Detection of Ventricular Fibrillation Due to Far-Field Atrial Sensing in a Triple Chamber Implantable Cardioverter Defibrillator. Oversensing of intracardiac signals or myopotentials may cause inappropriate ICD therapy. Reports on far-field sensing of atrial signals are rare, and inappropriate ICD therapy due to oversensing of atrial fibrillation has not yet been described. This report presents a patient with a triple chamber ICD and a history of His-bundle ablation who experienced asystolic ventricular pauses and inappropriate detection of ventricular fibrillation due to far-field oversensing of atrial fibrillation. Several factors contributed to the complication, which resolved after reduction of the ventricular sensitivity. [source] Development of an Echocardiographic Method for Choosing the Best Fitting Single-Pass VDD LeadPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 5 2002WEI-HSIAN YIN YIN, W.-H., et al.: Development of an Echocardiographic Method for Choosing the Best Fitting Single-Pass VDD Lead. To achieve stable single-lead VDD pacing, a selection of the electrode with the optimal distance between the lead tip and the floating atrial dipole (AV distance [AVD]) is important. The authors hypothesized that the size of the right heart chambers may affect atrial sensing, and that measurement of their internal dimension at end-diastole (RHIDd) in the apical four chamber view by transthoracic echocardiography may aid in choosing the proper AVD. Twenty-six consecutive cases that had undergone VDD pacer implantation using the conventional chest X ray were examined retrospectively by the echocardiographic method. The chest x-ray method properly selected a lead with optimal atrial sensing, defined as minimum P wave amplitude , 1.0 mV, for only 20 (77%) of 26 patients. By comparing these results with their respective RHIDd, a cut-off point of 13 cm was obtained that indicated a criterion for choosing the proper AVD. The indication was that if the RHIDd was , 13 cm, a lead with an AVD of 15.5/16 cm should have been used; if the RHIDd was < 13 cm, a lead with an AVD of 13/13.5 cm should have been chosen. Using the echocardiographic method, all six patients who had suboptimal atrial sensing could be identified and classified as having missized (four undersized; two oversized) permanent leads. In conclusion, the described method provides a promising preoperative assessment of the best fitting electrode length in single lead VDD pacing. A prospective study is ongoing to verify its applicability. [source] Implantation of a Dual Chamber Pacing and Sensing Single Pass Defibrillation LeadPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 4 2001RAINER GRADAUS GRADAUS, R., et al.: Implantation of a Dual Chamber Pacing and Sensing Single Pass Defibrillation Lead. Dual-chamber ICDs are increasingly used to avoid inappropriate shocks due to supraventricular tachycardias. Additionally, many ICD patients will probably benefit from dual chamber pacing. The purpose of this pilot study was to evaluate the intraoperative performance and short-term follow-up of an innovative single pass right ventricular defibrillation lead capable of bipolar sensing and pacing in the right atrium and ventricle. Implantation of this single pass right ventricular defibrillation lead was successful in all 13 patients (age 63 ± 8 years; LVEF 0.44 ± 0.16; New York Heart Association [NYHA] 2.4 ± 0.4, previous open heart surgery in all patients). The operation time was 79 ± 29 minutes, the fluoroscopy time 4.7 ± 3.1 minutes. No perioperative complications occurred. The intraoperative atrial sensing was 1.7 ± 0.5 mV, the atrial pacing threshold product was 0.20 ± 0.14 V/ms (range 0.03,0.50 V/ms). The defibrillation threshold was 8.8 ± 2.7 J. At prehospital discharge and at 1-month and 3-month follow-up, atrial sensing was 1.9 ± 0.9, 2.1 ± 0.5, and 2.7 ± 0.6 mV, respectively, (P = NS, P < 0.05, P < 0.05 to implant, respectively), the mean atrial threshold product 0.79, 1.65, and 1.29 V/ms, respectively. In two patients, an intermittent exit block occurred in different body postures. All spontaneous and induced ventricular arrhythmias were detected and terminated appropriately. Thus, in a highly selected patient group, atrial and ventricular sensing and pacing with a single lead is possible under consideration of an atrial pacing dysfunction in 17% of patients. [source] Efficacy of Single Lead VDD Pacing in Patients with Impaired and Normal Left Ventricular FunctionPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 8 2000ANDREAS SCHUCHERT Atrial synchronous ventricular pacing seems to be the best pacing mode for patients with advanced AV block and impaired LV function. The long-term follow-up of single lead VDD pacing was studied in 33 patients with impaired LV function and compared to 42 patients with normal LV function. All patients received the same VDD lead and VDDR pacemaker. The lead model with 13-cm AV spacing between the atrial and ventricular electrode was implanted in 89% of the patients. Follow-ups were 1, 3, 6, and 12 months after implantation. The percentage of atrial sensing and the P wave amplitude were determined at each follow-up. Minimal P wave amplitude at implantation was 2.0 ± 1.4 mV in patients with impaired and 1.7 ± 0.9 mV with normal LV function (not significant). At the 12-month follow-up, 33 patients with normal and 23 patients with depressed LV function remained paced in the VDD mode. The remaining patients died in five (impaired LV function) and seven cases (normal LV function) or their pacemakers were programmed to the VVI/VVIR pacing mode in four (impaired LV function) and three cases (normal LV function). P wave amplitude did not differ in the two groups (e.g., at month 12: impaired: 1.17 ± 0.42 mV; normal: 1.09 ± 0.49 mV). The atrial sensitivity was programmed in most patients to sensitive settings with no differences between the two groups (e.g., at month 12: impaired: 0.13 ± 0.06 mV; normal: 0.13 ± 0.05 m V). The diagnostic counters indicated nearly permanent atrial sensing (e.g., at month 12: impaired: 99.3 ± 2.2%; normal: 99.0 ± 1.0 mV). In conclusions, single lead VDD pacing restored AV synchronous ventricular pacing in patients with normal and with impaired LV function indicating that it could be an alternative to DDD pacemakers, but not to dual-chamber pacing. [source] Atrial Lead Placement During Atrial Fibrillation.PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 7 2000Is Restitution of Sinus Rhythm Required for Proper Lead Function? Unexpected atrial fibrillation (AF) during implantation of an atrial pacemaker lead is sometimes encountered. Infra-operative cardioversion may lengthen and complicate the implantation process. This study prospectively investigates the performance of atrial leads implanted during AF (group A) and compares atrial sensing and pacing properties to an age- and sex-matched control group in which sinus rhythm had been restored before atrial lead placement (group B). Patient groups consisted of 32 patients each. All patients received DDDE pacemakers and bipolar, steroid-elating, active fixation atrial leads. In patients with AF at the time of implantation (group A), a minimal intracardiac fibrillatory amplitude of at least 1.0 mV was required for acceptable atrial lead placement. In patients with restored sinus rhythm (group B). a voltage threshold < 1.5 V at 0.5 ms and a minimal atrial potential amplitude > 1.5 mV was required. Patients of group A in whom spontaneous conversion to sinus rhythm did not occur within 4 weeks after implantation underwent electrical cardioversion to sinus rhythm. Pacemaker interrogations were performed 3, 6, and 12 months after implantation. In group A, implantation time was significantly shorter as compared to group B (58.7 ± 8.6 minutes vs 73.0 ± 17.3 minutes, P < 0.001). Mean atrial potential amplitude during AF was correlated with the telemetered atrial potential during sinus rhythm (r = 0.49, P < 0.001), but not with the atrial stimulation threshold. Twelve months after implantation, sensing thresholds (1.74 ± 0.52 mV vs 1.78 ± 0.69 mV, P = 0.98) and stimulation thresholds (1.09 ± 0.42 V vs 1.01 ± 0.31 V.P = 0.66) did not differ between groups A and B. However, in three, patients of group A, chronic atrial sensing threshold was , 1 mV requiring atria) sensitivities of at least 0.35 mV to achieve reliable atrial sensing. Atrial lead placement during AF is feasible and reduces implantation time. However, bipolar atrial leads and the option to program high atrial sensitivities are required. [source] "Sensing alternans" in a patient with a newly implanted pacemakerCLINICAL CARDIOLOGY, Issue 3 2006Amgad N. Makaryus M.D. Abstract This report describes the case of an 80-year-old man with a history of coronary artery disease who presented with acute pericarditis secondary to pacemaker lead perforation of the ventricular wall 2 days after undergoing dual lead pacemaker implantation. The electrocardiogram revealed sinus rhythm with an intra-atrial conduction delay and intermittent failure of atrial sensing as evidenced by alternating atrial spikes in every other P wave. The noted pericardial effusion and the likely shifting of the atrial lead with each alternate beat caused the "sensing alternans" that was seen on the admission electrocardiogram. [source] | ||||||||||