Pacemaker Algorithm Research Articles

An automatic pacemaker algorithm causing exertional intolerance.

An automatic pacemaker algorithm causing exertional intolerance.

Pifalls in the interpretation of pacemaker ECGs

The analysis of the pacemaker ECG is usually regarded as difficult and may generate rather mediocre interpretations. It is acommon opinion that apacemaker ECG can only be analyzed if the type of pacemaker (single-, dual-, triple-chamber, manufacturer, model) and its programming are known. The following pitfalls illustrate how to achieve aclinically meaningful ECG interpretation in daily practice, even if these details are not known. Asystematic approach to ECG interpretation is particularly crucial in this context: Basic rhythm (Pwaves, intrinsic or paced rhythm), paced QRS complex (axis, width, bundle branch block morphology), signs of pacemaker malfunction (under‑/oversensing, loss of capture), arrhythmia to which the pacemaker reacts, or activity of any pacemaker algorithm. Many small details should not be overlooked and many questions can be answered if a few principles are applied. Understanding of the pacemaker ECG can improve the life of adevice patient at the touch of abutton.

P878Utility of continuous monitoring of respiratory distress index with pacemaker's algorithm in the detection of obstructive sleep apnea syndrome

P878Utility of continuous monitoring of respiratory distress index with pacemaker's algorithm in the detection of obstructive sleep apnea syndrome

Inhibition and restoration of CRT pacing – What is the mechanism?

The electrocardiogram (ECG) interpretation in patients with cardiac resynchronization therapy (CRT) may be challenging. The difficulty increases if not well-known pacemaker algorithm is turned on. We show a T-wave protection algorithm (LVTP) in a patient with CRT. Accelerated sinus rhythm and intermittent oversensing in left ventricular channel resulted in loss of CRT pacing. The restoration of biventricular pacing occurred when atrial rate decreased. We provide detailed descriptions of the electrocardiogram and intracardiac electrogram. LVTP may confuse ECG examination interpretation, especially in patients with accelerated atrial rhythm and oversensing in left ventricular channel.

Rationale and Design for a Monocentric Prospective Study: Sleep Apnea Diagnosis Using a Novel Pacemaker Algorithm and Link With Aldosterone Plasma Level in Patients Presenting With Diastolic Dysfunction (SAPAAD Study).

Previous studies showed good agreement between pacemaker respiratory disturbance index (RDI) and polysomnography for diagnosis of severe sleep apnea (SA). The aim of this study is to investigate the diagnostic accuracy of RDI compared with apnea-hypopnea index (AHI) from a cardiorespiratory sleep study for the diagnosis of severe SA within patients requiring a pacemaker and meeting diastolic dysfunction criteria. Secondary objectives are as follows: correlation between plasma aldosterone level and SA severity, diagnostic accuracy of RDI for moderate SA, prevalence of SA among patients with diastolic dysfunction, occurrence of arrhythmias, and improvement of RDI with continuous positive airway pressure therapy. We designed a monocentric prospective nonrandomized study of prevalent cases to include 68 patients with a 6-month follow-up. Both RDI and AHI will be compared 2 months after implantation and after 1 month of continuous positive airway pressure treatment in patients with severe SA. This is the first study that examines diagnostic accuracy of pacemaker algorithm for the diagnosis of SA and correlation with plasma aldosterone levels in patients with diastolic dysfunction.Protocol version: V04. 04/04/2017 Trial registration: ClinicalTrials.gov NCT02751021

Predictors of successful atrial and ventricular auto capture pacemaker algorithm post implantation: single-centre experience.

Aim The aim of the present study was to assess the possible predictors of successful threshold optimization from a second-generation device (Evia DR-T Biotronik), with automatic atrial and ventricu...

Pacing Spikes All Over.

Ventricular safety pacing (VSP) is used to avoid cross talk by delivering ventricular stimulus shortly after an atrial-paced event if ventricular-sensed event occurs. Although VSP is a protective feature that exists for decades in different pacing devices, there are some reports of unfavorable outcomes of this algorithm. More so, health care providers sometimes face difficulties in interpreting and dealing with VSP strips. This case report discusses an important pacemaker algorithm and encourages further attention to possible pitfalls and hence avoids unnecessary interventions.

Predictors of successful atrial and ventricular auto capture pacemaker algorithm post implantation: single-centre experience

Aim The aim of the present study was to assess the possible predictors of successful threshold optimization from a second-generation device (Evia DR-T Biotronik), with automatic atrial and ventricular capture management post implantation.Background It is mandatory in patients receiving permanent pacemakers to determine the pacing threshold at each follow-up visit. To facilitate pacing threshold measurements, complete automatic pacemaker tests are being developed. A new application of pacemaker algorithm for automatic capture verification is to detect the presence of the evoked response signal after the pacing impulse in the immediate post-implant period. The Evia DR-T (Biotronik, Berlin, Germany) is a device that utilizes this algorithm.Methods and result This was a retrospective single-centre study of 112 patients who received a dual-chamber Evia DR-T Biotronik (Biotronik, Berlin, Germany) pacemaker. Pacemaker interrogation was performed at the time of implantation and one day post implantation to evaluate the success of the automatic algorithm program, focusing on atrial and ventricular auto capture and lead pacing polarity. The sensing, atrial and ventricular threshold, impedance and indication of implantation were analysed as possible predictors.Conclusion In conclusion, automatic programming of the pacing threshold measurements using the Biotronik post-implant algorithm was successfully predicted from the sensing values and the manual threshold during lead implantation. Therefore, fewer requirements are necessary for post-implant auto program control than for presently available systems. Such pacemaker functions may reduce the time taken for device interrogation and patient discomfort during pacemaker implantation and hospitalization.

The effect of dual-chamber closed-loop stimulation on syncope recurrence in healthy patients with tilt-induced vasovagal cardioinhibitory syncope: a prospective, randomised, single-blind, crossover study

BackgroundThe closed-loop stimulation (CLS) pacemaker algorithm is a system that permanently monitors the contractile state of the myocardium and converts the intrinsic information into rate regulation. The role that the...

The effect of atrial preference pacing on paroxysmal atrial fibrillation incidence in myotonic dystrophy type 1 patients: a prospective, randomized, single-bind cross-over study

Atrial Preference Pacing (APP) is a pacemaker (PM) algorithm that supports a continuous atrial stimulation instead of a spontaneous atrial rhythm to prevent supraventricular tachyarrhythmias. The role of the APP in the prevention of atrial fibrillation (AF) is still controversial. The aim of our study was to evaluate the effect of preventive atrial pacing on AF incidence in myotonic dystrophy type I patients during a 12-month follow-up period. We studied 40 patients with myotonic dystrophy type 1 (MD1) who underwent dual-chamber PM implantation for first- and second-degree atrioventricular block. After a 1-month stabilization period, they were randomized to APP algorithm programmed OFF or ON for 6 months each, using a cross-over design. The number of AF episodes during active treatment (APP ON phases) was lower than those registered during no treatment (APP OFF phases). No statistically significant difference was found in AF episodes duration between the two phases. During the APP OFF phases and APP ON phases, the atrial pacing percentage was 0 and 98%, respectively, while the ventricular pacing percentage did not show statistically significant difference (10 vs. 8%, P =0.2). Atrial premature beats count was significantly greater during APP OFF phases than during APP ON phases. Lead parameters remained stable over time and there were no lead-related complications. Based on these 12-month follow-up data, it is concluded that APP is an efficacy algorithm for preventing paroxysmal AF in MD1 patients who underwent dual-chamber PM implantation for atrioventricular conduction disorders.

Tachycardia-induced cardiomyopathy caused by a special pacemaker algorithm

An elderly lady presented with breathlessness, fever and palpitations. She was treated for community-acquired pneumonia with antibiotics. Subsequently, she went into acute pulmonary edema. She was managed with standard heart failure medications and a trial of noninvasive ventilation. ECG showed A-V sequential pacing at a rate of 150/min with broad QRS. It was thought to be a pacemaker-related tachycardia. On pacemaker check, a special algorithm (atrial fibrillation suppression algorithm) was switched off. She subsequently improved. We here review the cause of this tachycardia-induced cardiomyoapthy.

NonPharmacologic Management of Atrial Fibrillation Using the Dynamic Atrial Overdrive Algorithm

A concomitant condition found in many patients with atrial fibrillation (AF) commonly requires bradycardia pacing. Comparing AAI to VVI pacing, atrial pacing appears to have an apparent protective effect on the subsequent development of AF. By addressing the proposed mechanisms responsible for AF (long-short cycles, increased temporal dispersion of refractoriness, frequent atrial ectopic beats), overdrive appears to be a promising technique to postpone or even prevent entirely the development of chronic AF while reducing the incidence of paroxysmal AF. These observations led to the development of a pacing algorithm (Dynamic Atrial Overdrive-DAO) designed to provide a high percentage of atrial pacing just above the patient’s own intrinsic atrial rate. The algorithm is a dynamic stimulation technique to suppress AF effectively, overdrives the atrium just enough to prevent the intrinsic rhythm from emerging while maintaining both normal diurnal variation and rate response. Dynamic Atrial Overdrive is a unique pacemaker algorithm designed specifically for suppression of paroxysmal AF arising from either an absolute or relative bradycardia. By maintaining an atrial stimulation rate just above the intrinsic rate, the goal is to control both the atrial rate and rhythm, reducing the incidence of ectopic beats which might be a trigger, long-short cycles, or the dispersion of refractoriness from initiating AF. In addition, because the algorithm routinely searches for intrinsic atrial activity and adjusts the stimulation rate accordingly, it avoids sustained periods of rapid stimulation that may not be required. At the same time, it preserves the normal circadian rate variation in association with normal sinus function or in the presence of sinus node dysfunction if the sleep rate feature is also enabled. I N T R O D U C T I O N Atrial fibrillation (AF), the most common significant cardiac arrhythmia, affects an estimated 4 million people around the world. Its rapid and uncoordinated atrial rhythm compromises hemodynamics, decreases cardiac output, predisposes to ventricular arrhythmias, and sets the stage for thromboembolic complications. Contributing mechanisms are presumed to be the occurrence of long-short cycles, an increased temporal dispersion of refractoriness, and atrial ectopic activity. The incidence increases with age, affecting 4% of those over 60, and up to 15% of those over 70. Although it can RevIew St. Jude Medical CRMD, Sylmar, CA,

The relationship between high-frequency right ventricular pacing and paroxysmal atrial fibrillation burden

Right ventricular pacing increases the risk of persistent atrial fibrillation (AF) in the long term. The effects of right ventricular pacing on paroxysmal AF (PAF) are unknown. The aim was to examine the effect of right ventricular pacing on AF burden (AFB) in patients with symptomatic drug-resistant PAF. Pooled analysis of pacemaker-derived counters and AF diagnostic data from the Atrial Fibrillation Therapy (AFT) and Pacemaker Atrial Fibrillation Suppression (PAFS) randomized anti-AF pacemaker algorithm trials were used. Five hundred and fifty-four patients from the AFT (n = 372) and PAFS (n = 182) were studied. The individual percentages of pacing, Atrial Sense Ventricular Pace (ASVP), Atrial Pace Ventricular Pace (APVP), and Atrial Pace Ventricular Sense (APVS) as well as total ventricular pacing during synchronous rhythm (VPinSR, %) were examined for an effect on AFB. Three hundred and twenty-one (AFT, age 64 +/- 11, 55% male) and 79 (PAFS, age 71 +/- 8, 54% male) patients had complete data for analysis. Increased VPinSR was weakly associated with an increased AFB (effect size-10% VPinSR increased AFB by only 0.03%) in AFT (P = 0.04) but not PAFS (P = 0.98) or the pooled analysis (P = 0.95). None of the synchronous paced modalities (ASVP, APVP, APVS) significantly increased AFB compared with sinus rhythm (Atrial Sense Ventricular Sense) (P = ns). No pacing modality, atrial or ventricular, had a significant effect on AFB. On the basis of these data, the detrimental effect of high-frequency right ventricular pacing on AFB in paced PAF patients, unlike with persistent AF, appears to be minimal in the short term.

Poster session 3: Pacemaker and sensor algorithm

Poster session 3: Pacemaker and sensor algorithm

A new pacemaker algorithm for the treatment of atrial fibrillation. Results of the atrial dynamic overdrive pacing trial (ADOPT)

A new pacemaker algorithm for the treatment of atrial fibrillation. Results of the atrial dynamic overdrive pacing trial (ADOPT)

Automatic beat-to-beat left heart AV normalization: is it possible?

Programming the right heart AV interval to a normal value may cause a nonphysiological left heart AV due to interatrial and interventricular conduction delays, thus affecting cardiac performance. Since AV normalization at rest and exercise may be invalidated by pacing or sensing (mode) changes, the aim of this study was to (1) study the feasibility of a mode independent pacemaker (PM) algorithm for automatic beat-to-beat left AV normalization, (2) establish normal values for the time between mitral flow A wave (Af) and ventricular activation (Va), the AfVa interval, the mechanical surrogate of left AV, and (C) determine the range of values of the interatrial electromechanical delays (IAEMDs) and the effect of RA pacing. To pace with the proper right AV, the previously reported RV-paced interventricular electromechanical delay and the interatrial electromechanical delay, either P-sensed (IAEMDs) or atrial-paced (IAEMDp) are required inputs. Data were collected during diagnostic echo Doppler studies in 84 subjects divided in three groups: (1) control with narrow QRS and no structural heart disease (n = 33, age 50 +/- 21 years, 42% men); (2) patients in sinus rhythm with diverse cardiac pathologies except LBBB (n = 39, age 69 +/- 14 years, 56% men), and (3) DDD-paced patients (n = 12, mean age 71 +/- 6 years). Normal values of AfVa were established from the control group, while IAEMDs and IAEMDp and active atrial flow time (A-peak), in all subjects. The algorithm was tested by computer simulation under all possible modes with the following calculation: RAV = N + IAEMD - IVD, where RAV is the right AV, N is the desired normal AfVa value, IAEMD is either P-sensed or A-paced, and IVD is close to zero for intrinsic narrow QRS and biventricular pacing, or 79 ms for RV pacing. The results demonstrated (1) Normal (controls) AfVa: 85 +/- 15 ms (range 52-110 ms); (2) IAEMDs (All): 84 +/- 16 ms; (3) atrial pacing prolonged IAEMDs by 57 +/- 18 ms (from 93 +/- 15 to 150 +/- 25 ms, P < 0.0001); and (4) Computer simulation of rate and mode changes validated the normalization algorithm. An automatic, beat-to-beat left AV normalization algorithm to preserve a normal AfVa without a hemodynamic sensor is feasible. The normal value of AfVa is 85 +/- 15 ms.

A new pacemaker algorithm for the treatment of atrial fibrillation: Results of the Atrial Dynamic Overdrive Pacing Trial (ADOPT)

ObjectivesThe Atrial Dynamic Overdrive Pacing Trial (ADOPT) was a single blind, randomized, controlled study to evaluate the efficacy and safety of the atrial fibrillation (AF) Suppression Algorithm (St. Jude Medical Cardiac Rhythm Management Division, Sylmar, California) in patients with sick sinus syndrome and AF. BackgroundThis algorithm increases the pacing rate when the native rhythm emerges and periodically reduces the rate to search for intrinsic atrial activity. MethodsSymptomatic AF burden (percentage of days during which symptomatic AF occurred) was the primary end point. Patients underwent pacemaker implantation, were randomized to DDDR with the algorithm on (treatment) or off (control), and were followed for six months. ResultsBaseline characteristics and antiarrhythmic drugs used were similar in both groups. The percentage of atrial pacing was higher in the treatment group (92.9% vs. 67.9%, p < 0.0001). The AF Suppression Algorithm reduced symptomatic AF burden by 25% (2.50% control vs. 1.87% treatment). Atrial fibrillation burden decreased progressively in both groups but was lower in the treatment group at each follow-up visit (one, three, and six months) (p = 0.005). Quality of life scores improved in both groups. The mean number of AF episodes (4.3 ± 11.5 control vs. 3.2 ± 8.6 treatment); total hospitalizations (17 control vs. 15 treatment); and incidence of complications, adverse events, and deaths were not statistically different between groups. ConclusionsThe ADOPT demonstrated that overdrive atrial pacing with the AF Suppression Algorithm decreased symptomatic AF burden significantly in patients with sick sinus syndrome and AF. The decrease in relative AF burden was substantial (25%), although the absolute difference was small (2.50% control vs. 1.87% treatment).

Rate-adaptive pacemaker controlled by motion and respiratory rate using neuro-fuzzy algorithm.

Rate-adaptive pacemakers use information from sensors to change the rate of heart stimulation. Until now, fuzzy-pacemaker algorithms have been used to combine inputs from sensors to improve heart rate control, but they have been difficult to implement. In this paper, a pacemaker algorithm which controlled heart rate adaptively by motion and respiratory rate was studied. After chronotropic assessment exercise protocol (CAEP) tests were performed to collect activity and respiratory rate signals, the intrinsic heart rate was inferred from these two signals by a neuro-fuzzy method. For 10 subjects the heart rate inference, using the neuro-fuzzy algorithm, gave 52.4% improved accuracy in comparison with the normal fuzzy table look-up method. The neuro-fuzzy method was applied to a real pacemaker by reduced mapping of the neuro-fuzzy look-up table.

Clinical evaluation of a pacemaker algorithm that adjusts the pacing rate during sleep using activity variance.

Even though rate responsive pacemakers are able to regulate pacing rates based on sensor activity, they are set with a minimum rate that is not adjusted to provide rate decreases during sleep. The aim of this study was to evaluate the performance of the "Sleep Rate" feature, as compared to patient diaries and a validated method that identifies sleep from wrist actigraphy. In 19 patients (15 men; age 69 +/- 8 years) with Pacesetter Trilogy DR+ pacemakers, the base rate and the sleep rate were set to 80 and 50 ppm, respectively. When the patients returned 2 days later, data recorded by the pacemaker and wrist actigraph were analyzed to find the agreement in corresponding sleep/wake periods. In 17 (89%) patients, the pacemaker went into the sleep mode. The total sleep time derived from actigraphy significantly exceeded the time during which the pacemaker was in sleep mode (1156.8 +/- 83.4 vs 307.3 +/- 77.2 minutes). Frequent reversions out of the sleep mode limited the total sleep time derived from the pacemaker. Cumulative analysis of the pacemaker data showed that the maximum time in the sleep mode was 78 minutes, and exceeded 1 hour in six instances, 30 minutes in 32 instances, and 15 minutes in 83 instances. Epoch by epoch comparisons revealed a good agreement (93.6 +/- 1.8%) during wakefulness between the corresponding actigraph and pacemaker epochs. However, only 24.6 +/- 3.7% of the corresponding epochs during sleep were identical, and the overall agreement was 54.4 +/- 3.7%. Except for one patient who reported palpitations, patients did not suffer from a pacemaker rate change. The Sleep Rate feature provides rate reduction during sleep, while assuring rapid frequency response during physical activity. However, the current algorithm does not allow long periods of slow pacing rate during continuous sleep, possibly due to its conservative design and the presence of movement arousals, which has to be improved in future generation algorithms.

Modern pacemaker algorithms in paediatric applications

Most of the pacemakers implanted in paediatrics have been developed for adults. Reduction of the physical dimensions has been the paediatric issue for years. Recent flexible microprocessor-based pacemaker technology permits the development of dedicated algorithms for small patient populations. In order to verify whether the existing adult mode switching (MS) pacemaker algorithm was capable of discriminating between physiological and pathological heart rates in children, an evaluation of the speed of change of sinus rhythm in children during exercise was performed. The maximum heart rate achieved was recorded as well.