Sinus Node Dysfunction Group Research Articles

EVALUATION OF EARLY OUTCOMES OF PERMANENT PACEMAKER IMPLANTATION IN HYPERTENSIVE PATIENTS WITH BRADYARRHYTHMIAS

Objective: This study aims to describe the clinical characteristics and the features of bradyarrhythmias on 24-hour Holter monitoring and to evaluate the early outcomes of permanent pacemaker implantation in hypertensive patients with bradyarrhythmias. Subjects and method: This cross-sectional study was conducted on 57 subjects with hypertension and bradyarrhythmias who were indicated for permanent pacemaker implantation. Results: The most common clinical symptoms recorded were fatigue, dizziness, and chest pain, accounting for 47.4%, 45.6%, and 42.1% respectively. The majority of patients had sinus node dysfunction (73.7%) and most underwent dual-chamber permanent pacemaker implantation (87.7%). The 24-hour Holter monitoring results showed that 42.1% had sinus atrial block - sinus pause in the sinus node dysfunction group and 15.8% of patients had third-degree atrioventricular block (AV block) in the AV block group. A good treatment outcome was observed in 72.0% of cases. Age > 70 (OR: 6.1; 95% CI: 1.2-30.1), female gender (OR: 4.2; 95% CI: 1.2-15.4), and single-chamber pacemaker (OR: 8.9; 95% CI: 1.5-52.1) were associated with a higher risk of moderate to poor treatment outcomes. Conclusion: Permanent pacemaker implantation generally tends to have good short-term outcomes. However, it should be noted that older age, female, and single-chamber pacemaker implantation in association with worse outcomes.

Sinus node dysfunction after heart transplantation-An analysis of risk factors and atrial pacing burden.

We investigated the development of sinus node dysfunction (SND) requiring pacemaker implantation after heart transplant (HTx) especially regarding pacing burden in these patients. Patients requiring a pacemaker for SND were compared to all other patients in an HTx cohort including transplant patients from 1981 to 2016. Sinus node dysfunction requiring pacemaker implantation developed in 118 patients (10%). These patients had received a biatrial anastomosis more frequently than those in the No SND group 95.8% vs 90.0% (P=.042). The ratio of reperfusion time to aortic cross-clamp time was significantly smaller in the SND group compared to the No SND group 71.7% vs 80.3% (P=.033). This also holds for the ratio of reperfusion time to ischemia time, which was 23.2% and 28.6%, respectively (P=.032). Pacing burden decreased from 90.5% to 66.3% after 2years and remained around this value in the remaining 4years of follow-up. We identified the biatrial anastomosis and a low ratio of reperfusion time to aortic cross-clamp time as well as to ischemia time as risk factors for SND requiring pacing. After implantation pacemakers continue to pace for over 60% of the time after 6years.

Prediction of Sinus Node Dysfunction in Patients with Paroxysmal Atrial Fibrillation and Sinus Pause

Background and Objectives: Sinus pause association of paroxysmal atrial fibrillation (PAP) is generally considered a sinus node dysfunction (SND) known as tachycardia-bradycardia syndrome (TBS). Cure of tachyarrhythmias in some patients with prolonged pauses on termination of tachyarrhythmia resulted in an improvement in sinus node function and/or a return to normal ranges thus avoiding the need for permanent pacing. The purpose of this study was to investigate the electrophysiological and clinical characteristics as well as their sinus node function in patients with prolonged pauses and PAP. Methods and Results: Of 1266 PAP patients undergoing radiofrequency catheter ablation (RFCA), 122 patients with pauses (>2 s) were studied. The mean maximum symptomatic prolonged pause on termination of tachycardias was 2.67 ± 1.4 s (2.0–12.6 s). SND developed in 32 patients. There was no difference between the patients with and without SND in terms of the age and sex. Patients were divided into two groups based on the intracardiac electrophysiology study after the RFCA procedure. Eleven patients (8 men, 3 women; age 30–72 years, mean 48.2 ± 9.3 years) were placed in a normal sinus node function (NSF) group, and 17 patients (12 men, 5 women; age 37–75 years, mean 62.2 ± 7.5 years) were in an SND group. There was no significant difference in gender, left atrial dimension, left ventricular ejection fraction, blood pressure, or the longest pause between the two groups. RFCA was successful in 28 patients. Electrophysiological data show that corrected sinus node recovery time (CSNRT) was 409 ± 152 ms in NSF group patients and 558 ± 178 ms in SND group before the ablation procedure (P 2 cycle lengths in 12 patients. In the multivariate analysis, prolonged pauses on termination of tachyarrhythmia, frequency of pauses, and mean heart rate after ablation were independent predictors of SND. Conclusions: (1) Catheter ablation of atrial fibrillation (AF) is effective in treating paroxysmal AF-related TBS; (2) in some patients, there is progressive improvement of sinus node function after elimination of AF, an indication that these sinus pauses may be a manifestation of tachycardia-mediated remodeling of the sinus node, and that permanent pacemaker implantation is unnecessary; (3) among the extrinsic and intrinsic causes of SND, intrinsic causes are seldom reversible and some causes of extrinsic SND may be reversible; and (4) prolonged pauses on termination of PAF, frequency of pauses (>2.0 s), and mean heart rate after ablation were independent predictive factors of SND.

56-38: Pacemaker implantation after cardiac surgery: are we implanting to soon?

Purpose of the study: Bradyarrhythmias occuring during or shortly after cardiac surgery are important indications for permanent pacing. The aim of the study was to find out whether patients after cardiac surgery are appropriately indicated for pacemaker implantation, i.e. if they still need pacing in the long term follow-up. Method used: This was a retrospective study of patients who underwent cardiac surgery and were indicated for dual chamber pacemaker in the perioperative period between January 2012 and December 2014. Adequate pacing indication was defined as need for ventricular pacing in more than 5 % of the time during the period from implantation to first pacemaker control in patients with atrioventricular block (AVB) or more than 5% atrial pacing during the same time period in case of sinus node dysfunction (SND). Summary of results: Overall, 27 patients were included, 17 (63%) with AVB and 11 with (41%) SND. The mean time of the period from implantation to first pacemaker control was 98 ± 42 days. In the AVB group, 3 patients (17.6%) were paced in less than 5%. In SND group it was only 1. Time from surgery to pacemaker implantation was not different for the appropriate implanted patients compared to the inappropriate implanted ones (median 8[range 2–83] vs. 9[6–17], p = NS). Conclusion: Nearly 20% of AVB patients implanted in the perioperative period recovered atrioventricular conduction during the observed period, showing that improvement can occur later than in guidelines mentioned 7 days after surgery. Percentage of patients that don't require pacemaker could be even higher due to unsuitable pacemaker programming in some patients (e.g. too high base rate or not activated preference of atrial pacing). Implantation of permanent pacemakers in the perioperative period due to AVB might be premature in significant proportion of the patients.

Sleep-disordered breathing predicts sinus node dysfunction in persistent atrial fibrillation patients undergoing pulmonary vein isolation

BackgroundThe indications for catheter ablation have been expanded to include persistent atrial fibrillation (AF) to enable a high degree of sinus rhythm maintenance. We occasionally encounter patients undergoing pacemaker implantation in whom sick sinus syndrome became clinically evident after ablation. This study investigated whether underlying sinus node dysfunction (SND) during persistent AF can be predicted before deciding the indications for ablation. Methods and resultsIn total, 87 consecutive patients with persistent AF who underwent catheter ablation between January 2010 and July 2011 were enrolled in the study. Nocturnal polysomnography as well as transthoracic and transesophageal echocardiography were performed in all patients before ablation. We used the double Lasso catheter and electroanatomical mapping-guided extensive encircling pulmonary vein isolation (EEPVI) method. We performed electrophysiological studies after EEPVI, and SND was defined as a corrected SN recovery time of ≥550ms. SND was detected in 42 (48%) patients (SND group); the other patients showed normal sinus node function (NSN group). The apnea/hypopnea index (AHI) was significantly greater in the SND group than in the NSN group (25.7±13 vs. 17.5±11, p=0.002). Multivariate analysis revealed that moderate to severe sleep-disordered breathing (defined as AHI≥15) was an independent predictor of SND after catheter ablation for persistent AF. ConclusionThe results suggest that underlying SND in patients with persistent AF can be predicted by evaluating sleep-disordered breathing before catheter ablation.

Early and Late Indications for Implantation of Cardiac Pacemakers in Patients After Heart Transplantation: A Single-Center Experience

Background Data regarding the incidence and predictors of permanent pacemaker (PPM) implantation following cardiac transplantation are still limited and inconsistent. The aim of our study was to assess the incidence and indications for PPM implantation in cardiac transplant recipients in a single center. Methods We retrospectively analyzed the records of 508 consecutive patients including 425 men and an overall mean age of 45 y who underwent heart transplantation from 1988 to 2011 at our institution, using the biatrial surgical technique. Results Twenty-three (4.5%) subjects developed intermittent third-degree atrioventricular block (AVB) or sinus node dysfunction (SND) requiring PPM: 7 early (<3 months) and 16, late (>3 months) after transplantation. The incidence of AVB was higher than SND early (0.98% vs 0.4%; P < .05) and late (2.4% vs 0.8%; P < .01). The time from transplantation to PPM implantation was shorter among the SND group compared with the AVB group early (mean, 4.5 vs 6.5 weeks; P < .05) and late (mean, 4 vs 7 years; P < .05). Conclusion The incidence of PPM after heart transplantation was 4.5%. AVB was the main indication for PPM early and late after transplantation. The time interval from transplantation to PPM implantation was shorter among SND compared with AVB patients.

Relationship between temperature change and the requirement for a permanent pacemaker implantation in bradyarrhythmias

Some cardiovascular diseases are associated with seasonal or meteorological factors. We tried to identify the relationship between meteorological parameters and the requirement for a permanent pacemaker (PPM) implantation for advanced sinus node dysfunction (SND) and atrioventricular block (AVB). This study enrolled 656 patients (67% male, age = 76 ± 11years) who underwent a PPM implantation due to SND or AVB from January 2004 to December 2008. Using daily temperature, barometric pressure, humidity, and daylight hour records from Taipei, we evaluated the effect of these meteorological parameters within different time periods on the occurrence of SND and AVB. There were 355 patients in the SND group and 301 in the AVB group. In the AVB group, more patients presented in the spring than in other seasons (P = 0.003). In the SND group, there was no relationship with the seasons (P = 0.137). The proportion of patients with AVB did not depend on the average temperature, barometric pressure, humidity, or daylight hours within 3, 7, and 14days prior to admission (P = NS). A temperature change of greater than 11°C within 30days prior to admission was associated with a significantly higher proportion of patients with advanced AVB compared to those with advanced SND (P = 0.009). Extreme change in temperature was the most independent predictor of the development of advanced AVB. The peak occurrence of advanced AVB was in the spring. The occurrence of advanced AVB was associated with extreme temperature changes within 30days, especially in the spring.

Prediction of Underling Sinus Node Dysfunction during Chronic Atrial Fibrillation before Catheter Ablation Using Apnea/Hypopnea Index

Background: Indication of ablation has been expanded to include chronic atrial fibrillation (CAF) for enabling high degree of sinus rhythm maintenance. We have encountered patients undergoing pacemaker implantation, in whom sick sinus syndrome became clinically evident after ablation. The study aims to investigate whether underling sinus node dysfunction (SND) during CAF can be predicted before deciding the indication for ablation. Methods and Results: Sixty consecutive patients with CAF who underwent ablation between January to December 2010 were enrolled in the study. Nocturnal polysomnography as well as echocardiography was performed for all patients before ablation. We used the double Lasso catheter and electro anatomical mapping guided extensive encircling pulmonary vein isolation (EEPVI). We performed electrophysiological studies after EEPVI, and SND was defined as corrected SN recovery time of ≥550 ms. SND was detected in 26 (43%) patients (SND group); the other patients showed normal sinus node function (NSN group). The apnea/hypopnea index (AHI) was significantly greater in the SND group than in the NSN group (25.7±13 vs 15.8±10, P=0.0022). On multivariate analysis, sleep apnea syndrome (SAS) was an independent predictor of SND after ablation for CAF. Conclusion: This study suggested that underlying SND in CAF patients can be predicted by evaluating SAS before ablation.

Electrophysiological abnormalities of the atrial muscle in patients with sinus node dysfunction without tachyarrhythmias

The duration and the number of fragmented deflections of the right atrial electrograms were assessed and quantitatively measured in 74 patients who underwent endocardial catheter mapping during sinus rhythm. The bipolar electrograms were recorded at 12 sites in the right atrium. An abnormal atrial electrogram was defined as a duration of 100 ms or longer, and/or 8 or more fragmented deflections, according to our previous criteria. The patients were divided into two groups. The control group consisted of 41 age-matched patients with normal sinus node function and without paroxysmal atrial fibrillation. The study group comprised 33 patients with sinus node dysfunction but without tachyarrhythmias. Abnormal atrial electrograms were observed in 8 (19.5%) control patients, and in 16 (48.5%) sinus node dysfunction patients; p < 0.02. The total number of abnormal electrograms was 14 (2.89%) of 483 atrial electrograms in controls, and 36 (9.38%) of 384 in the study group; p < 0.0002. The mean duration (75.6 ± 17) and the mean number of fragmented deflections (4.1 ± 2) of the total atrial electrograms in the sinus node dysfunction group was significantly greater than that in controls (70.9 ± 11 and 3.6 ± 1, respectively); p < 0.01. The mean number of abnormal electrograms per patient in the study group (1.06 ± 1.8) was significantly higher than that in the control group (0.3 ± 0.8); p < 0.05. These data suggest that: (1) there is a significantly greater electrophysiological abnormality of the atrial muscle in patients with sinus node dysfunction but without paroxysmal atrial fibrillation than in age-matched controls, and (2) not only the sinus node but also the atrial muscle is electrophysiologically altered in patients with sinus node dysfunction but without tachyarrhythmias.