Pacemaker Dependency after Cardiac Surgery: A Systematic Review of Current Evidence

Optimizing Patient Selection for Physiological Pacing in Bradyarrhythmia: Factors Associated With High Ventricular Pacing Burden

Background

Right ventricular (RV) pacing is established as the most common ventricular pacing (VP) strategy for patients with symptomatic bradyarrhythmia. Some patients with high VP burden suffer deterioration of left ventricular (LV) function, termed pacing-induced cardiomyopathy (PICM). Patients who pace > 20% of the time from the RV apex are at increased risk of PICM, but independent predictors of increased RV pacing burden have not been elucidated in those who have a permanent pacemaker (PPM) inserted for bradyarrhythmia.

Methods

We aimed to identify factors that are associated with increased VP burden > 20%, hence determining those at risk for resultant PICM. In this retrospective cohort study, we identified the most recent 300 consecutive cardiac implantable electronic device (CIED) implants in our center and collected past medical history, electrocardiogram (ECG), echo, medication and pacemaker check data.

Results

A total of 236 individuals met inclusion criteria. Of the patients, 35% had RV pacing burden < 20%, while 65% had VP burden ≥ 20%; 96.2% of patients with complete heart block (CHB) paced > 20% (P = 0.002). Utilization of DDD or VVI (75.2% and 89.2% of patients, respectively) without mode switch algorithms was associated with VP > 20% (P < 0.001). Male or previous coronary artery bypass grafting (CABG) patients also statistically paced > 20%. Other factors trending towards significance included prolonged PR interval, atrial fibrillation or more advanced age.

Conclusion

High-grade atrioventricular (AV) block was associated with an RV pacing burden > 20% over 3 years but this was not consistent in patients with only transient episodes of high-grade AV block. We found a significant association between high VP% and male sex, previous CABG and the absence of mode switching algorithms.

How robust are recommended waiting times to pacing after cardiac surgery that are derived from observational data?

AIMS

For bradycardic patients after cardiac surgery, it is unknown how long to wait before implanting a permanent pacemaker (PPM). Current recommendations vary and are based on observational studies. This study aims to examine why this variation may exist.

METHODS AND RESULTS

We conducted first a study of patients in our institution and second a systematic review of studies examining conduction disturbance and pacing after cardiac surgery. Of 5849 operations over a 6-year period, 103 (1.8%) patients required PPM implantation. Only pacing dependence at implant and time from surgery to implant were associated with 30-day pacing dependence. The only predictor of regression of pacing dependence was time from surgery to implant. We then applied the conventional procedure of receiver operating characteristic (ROC) analysis, seeking an optimal time point for decision-making. This suggested the optimal waiting time was 12.5 days for predicting pacing dependence at 30 days for all patients (area under the ROC curve (AUC) 0.620, P = 0.031) and for predicting regression of pacing dependence in patients who were pacing-dependent at implant (AUC 0.769, P < 0.001). However, our systematic review showed that recommended optimal decision-making time points were strongly correlated with the average implant time point of those individual studies (R = 0.96, P < 0.001). We further conducted modelling which revealed that in any such study, the ROC method is strongly biased to indicate a value near to the median time to implant as optimal.

CONCLUSION

When commonly used automated statistical methods are applied to observational data with the aim of defining the optimal time to pacing after cardiac surgery, the suggested answer is likely to be similar to the average time to pacing in that cohort.

Iatrogenic Atrioventricular Block

Iatrogenic atrioventricular (AV) block can occur in the context of cardiac surgery, percutaneous transcatheter, or electrophysiologic procedures. In cardiac surgery, patients undergoing aortic and/or mitral valve surgery are at the highest risk for developing perioperative AV block requiring permanent pacemaker implantation. Similarly, patients undergoing transcatheter aortic valve replacement are also at increased risk for developing AV block. Electrophysiologic procedures, including catheter ablation of AV nodal re-entrant tachycardia, septal accessory pathways, para-Hisian atrial tachycardia, or premature ventricular complexes, are also associated with risk of AV conduction system injury. In this article, we summarize the common causes for iatrogenic AV block, predictors for AV block, and general management considerations.

The prevalence of permanent pacemaker implantation after open-heart surgeries; eight years of experience in Tehran heart center

BACKGROUND

We aimed to evaluate the prevalence of permanent pacemaker implantation (PPI) among open-heart surgery patients.

METHODS

We reviewed data from 23 461 patients undergoing open-heart surgeries between 2009 and 2016 in our heart center in Iran. A total of 18 070 patients (77%) had coronary artery bypass grafting (CABG), 3 598 (15.3%) valvular surgeries, and 1 793 (7.6%) congenital repair procedures. Finally, 125 patients who received PPI following open-heart surgeries were enrolled in our study. We defined the demographic and clinical characteristics of all these patients.

RESULTS

PPI was required in 125 (0.53%) patients with an average age of 58 ± 15.3 years. The average hospitalization time after surgery and waiting time for PPI were 19.7 ± 10.2 and 11.4 ± 6.5 days, respectively. Atrial fibrillation was the dominant pre-operative cardiac conduction abnormality (29.6%). Also, the primary indication for PPI was complete heart block in 72 patients (57.6%). Patients in the CABG group were significantly older (P = 0.002) and were more likely to be male (P = 0.030). The valvular group longer bypass and cross-clamp times and had more left atrial abnormalities. In addition, the congenital defect group was younger and had longer ICU stay times.

CONCLUSIONS

Based on our study findings, PPI was required in 0.53% of patients following open-heart surgery due to damage to the cardiac conduction system. The current study paves the way for future investigations to identify possible predictors of PPI in patients undergoing open-heart surgeries.

Techniques to aid prediction of pacing dependence at 30 days in patients requiring pacemaker implantation after cardiac surgery

Permanent pacemaker (PPM) implantation occurs in up to 5 % of patients after cardiac surgery but there is little consensus on how long to wait between surgery and PPM insertion. Predicting the likelihood of a patient being pacing dependent 30 days after implant can aid with this timing decision and avoid unnecessary observation time waiting for intrinsic conduction to recover. In this paper, we introduce a new approach for the prediction of PPM dependency at 30 days after implant in patients who have undergone recent cardiac surgery. The aim is to create an automatic detection model able to support clinicians in the decision-making process. We first applied Synthetic Minority Oversampling Technique (SMOTE) and Bayesian Networks (BN) to the dataset, to balance the inherently imbalanced data and create additional synthetic data respectively. The six resultant datasets were then used to train four different classifiers to predict pacing dependence at 30 days, all using the same testing set. The Bagged Trees classifier achieved the best results, reaching an area under the receiver operating curve (AUC) of 90 % in the train phase, and 83 % in the test phase. The overall classification performance was clearly enhanced when using SMOTE and synthetic data created with BN to create a combined and balanced dataset. This technique could be of great use in answering clinical questions where the original dataset is imbalanced.

Permanent pacemaker post-valve surgery: Do valve type and position matter? A propensity score matching study

BACKGROUND AND AIM

This study evaluates whether aortic valve replacement (AVR) or mitral valve replacement (MVR) with biological versus mechanical prostheses is independent risk factors for permanent pacemaker (PPM) post-cardiac surgery, alongside traditionally accepted determinants.

METHODS

This study focused on single-centre retrospective analysis of 10 years of activity. Case-control 1-to-9 matching was performed for 7 pre-operative and 2 intraoperative confounding factors.

RESULTS

After matching, 617 patients were included for analysis: AVR (79.4% n=490) and MVR (20.6% n=127). PPM was implanted in 3.7% (n=18) and 3.1% (n=4), P=0.8, respectively. A further analysis for PPM rate in biological versus mechanical prostheses did not provide any significant result (P=0.6 AVR and P=0.8 MVR). Post-operative complications in AVR and MVR groups were as follows: Reopening (4.5% vs. 6.3%, P=0.4), myocardial infarction (0.8% vs. 3.2%, P=0.04), pulmonary (32.9% vs. 38.6%, P=0.3), neurological (9.2% vs. 11.8%, P=0.4), renal (9.8% vs. 7.9%, P=0.5), wound (1.4% vs. 2.4%, P=0.5), infective (5.5% vs. 8.7%, P=0.2), and multiple organ failure (4.9% vs. 5.5%, P=0.6). The length of intensive care unit (hours) and hospital stay (days) was 71±163.8 versus 106.5±243.7 (P=0.5) and 14.7±14.7 versus 18.9±20.8 (P=0.01). In-hospital mortality resulted in 4.1% for AVR and 3.9% for MVR, P=0.9.

CONCLUSION

Valve position and valve type do not affect the likelihood of requiring permanent pacing in patients undergoing isolated aortic and MVR.

RELEVANCE FOR PATIENTS

A significant proportion of patients undergoing cardiac surgery develop arrhythmias and conduction disturbances postoperatively, often requiring the implantation of a PPM. Determining factors associated with an increase likelihood of permanent pacing would allow the optimization of per- and intra-operative care, with the aim of reducing the incidence of patients requiring post-operative PPM insertion.

Iatrogenic Atrioventricular Block

Iatrogenic atrioventricular (AV) block can occur in the context of cardiac surgery, percutaneous transcatheter, or electrophysiologic procedures. In cardiac surgery, patients undergoing aortic and/or mitral valve surgery are at the highest risk for developing perioperative AV block requiring permanent pacemaker implantation. Similarly, patients undergoing transcatheter aortic valve replacement are also at increased risk for developing AV block. Electrophysiologic procedures, including catheter ablation of AV nodal re-entrant tachycardia, septal accessory pathways, para-Hisian atrial tachycardia, or premature ventricular complexes, are also associated with risk of AV conduction system injury. In this article, we summarize the common causes for iatrogenic AV block, predictors for AV block, and general management considerations.

Outcomes and periprocedural management of cardiac implantable electronic devices in patients with carcinoid heart disease

BACKGROUND

Carcinoid heart disease (CHD) is a rare complication of hormonally active neuroendocrine tumors that often requires surgical intervention. Data on cardiac implantable electronic device (CIED) implantation in patients with CHD are limited.

OBJECTIVE

The purpose of this study was to evaluate the experience of CIED implantation in patients with CHD.

METHODS

Patients with a diagnosis of CHD and a CIED procedure from January 1, 1995, through June 1, 2020, were identified using a Mayo Clinic proprietary data retrieval tool. Retrospective review was performed to extract relevant data, which included indications for implant, procedural details, complications, and mortality.

RESULTS

A total of 27 patients (55.6% male; mean age at device implant 65.6 ± 8.8 years) with cumulative follow-up of 75 patient-years (median 1.1 years; interquartile range 0.4-4.6 years) were included for analysis. The majority of implanted devices were dual-chamber permanent pacemakers (63%). Among all CHD patients who underwent any cardiac surgery, the incidence of CIED implantation was 12%. The most common indication for implantation was high-grade heart block (66.7%). Device implant complication rates were modest (14.8%). No patient suffered carcinoid crisis during implantation, and there was no periimplant mortality. Median time from implant to death was 2.5 years, with 1-year mortality of 15%.

CONCLUSION

CHD is a morbid condition, and surgical valve intervention carries associated risks, particularly a high requirement for postoperative pacing needs. Our data suggest that CIED implantation can be performed relatively safely. Clinicians must be aware of the relevant carcinoid physiology and take appropriate precautions to mitigate risks.

Post-operative cardiac implantable electronic devices in patients undergoing cardiac surgery: a contemporary experience

AIMS

Optimum timing of pacemaker implantation following cardiac surgery is a clinical challenge. European and American guidelines recommend observation, to assess recovery of atrioventricular block (AVB) (up to 7 days) and sinus node (5 days to weeks) after cardiac surgery. This study aims to determine rates of cardiac implantable electronic devices (CIEDs) implants post-surgery at a high-volume tertiary centre over 3 years. Implant timing, patient characteristics and outcomes at 6 months including pacemaker utilization were assessed.

METHODS AND RESULTS

All cardiac operations (n = 5950) were screened for CIED implantation following surgery, during the same admission, from 2015 to 2018. Data collection included patient, operative, and device characteristics; pacing utilization and complications at 6 months. A total of 250 (4.2%) implants occurred; 232 (3.9%) for bradycardia. Advanced age, infective endocarditis, left ventricle systolic impairment, and valve surgery were independent predictors for CIED implants (P < 0.0001). Relative risk (RR) of CIED implants and proportion of AVB increased with valve numbers operated (single-triple) vs. non-valve surgery: RR 5.4 (95% CI 3.9-7.6)-21.0 (11.4-38.9) CIEDs. Follow-up pacing utilization data were available in 91%. Significant utilization occurred in 82% and underutilization (<1% A and V paced) in 18%. There were no significant differences comparing utilization rates in early (≤day 5 post-operatively) vs. late implants (P = 0.55).

CONCLUSION

Multi-valve surgery has a particularly high incidence of CIED implants (14.9% double, 25.6% triple valve). Age, left ventricle systolic impairment, endocarditis, and valve surgery were independent predictors of CIED implants. Device underutilization was infrequent and uninfluenced by implant timing. Early implantation (≤5 days) should be considered in AVB post-multi-valve surgery.

Surgical Aortic Mitral Curtain Replacement: Systematic Review and Metanalysis of Early and Long-Term Results

The Commando procedure is challenging, and aims to replace the mitral valve, the aortic valve and the aortic mitral curtain, when the latter is severely affected by pathological processes (such as infective endocarditis or massive calcification). Given the high complexity, it is seldomly performed. We aim to review the literature on early (hospitalization and up to 30 days) and long-term (at least 3 years of follow-up) results. Bibliographical research was performed on PubMed and Cochrane with a dedicated string. Papers regarding double valve replacement or repair in the context of aortic mitral curtain disease were included. The metaprop function was used to assess early survival and complications (pacemaker implantation, stroke and bleeding). Nine papers (540 patients, median follow-up 41 (IQR 24.5–51.5) months) were included in the study. Pooled proportion of early mortality, stroke, pacemaker implant and REDO for bleeding were, respectively 16.2%, 7.8%, 25.1% and 13.1%. The long-term survival rate ranged from 50% to 92.2%. Freedom from re-intervention was as high as 90.9% when the endocarditis was not the first etiology and 78.6% in case of valvular infection (one author had 100%). Freedom from IE recurrences reached 85% at 10 years. Despite the high mortality, the rates of re-intervention and infective endocarditis recurrences following the Commando procedure are satisfactory and confirm the need for an aggressive strategy to improve long-term outcomes.

Impact of early (<7 days) pacemaker implantation after cardiac surgery on long-term pacemaker dependency

OBJECTIVE

We aimed to investigate pacemaker dependency after at least 1 year in patients with early (<7 days) implantation, compared to those who received a pacemaker ≥7 days after cardiac surgery. Secondary endpoints were length of hospital stay and in-hospital complications.

METHODS

Retrospective analysis of 108 consecutive patients who received a pacemaker after cardiac surgery between 06/2012 and 06/2018. Characteristics and outcomes were compared between patients with early (<7 days) and late (≥7 days) implantation. Patients were followed up with evaluation of pacemaker dependency between April and June 2019. We identified predictors of dependency by logistic regression.

RESULTS

In total, 63.9% were men, average age 71.9 ± 11.8 years; 32 (29.6%) had early implantation, and 76 (70.4%) late implantation. After a median 3.2 years [IQR 1.9, 4.5] of follow-up, 30 patients (27.8%) had died, and there was no difference in pacemaker dependency among survivors (66.7% vs. 46.5%, early vs. late respectively, p = .15). Patients in the early group had a shorter length of stay (11.5 [9.0, 14.0] vs. 15.0 [11.5, 20] days, p = .002) and less often had new-onset atrial fibrillation (AF) post-surgery (22.7% vs. 47.8%, p = .05). The only significant predictor of dependency was aortic valve replacement surgery (OR = 4.70, 95% CI [1.36 to 16.24]).

CONCLUSION

Early implantation of a permanent pacemaker (<7 days after cardiac surgery) does not impact on the proportion of patients with long-term (>12 months) pacemaker dependency, but is associated with shorter length of stay and less frequent new-onset AF. These findings warrant prospective confirmation in randomized trials.

Early Versus Delayed Pacemaker for Heart Block After Valve Surgery: A Cost-Effectiveness Analysis

BACKGROUND

A significant percentage of patients who acutely develop high-grade atrioventricular block after valve surgery will ultimately recover, yet the ability to predict recovery is limited. The purpose of this analysis was to evaluate the cost-effectiveness of two different management strategies for the timing of permanent pacemaker implantation for new heart block after valve surgery.

METHODS

A cost-effectiveness model was developed using costs and probabilities of short- and long-term complications of pacemaker placement, short-term atrioventricular node recovery, intensive care unit stays, and long-term follow-up. We aggregated the total expected cost and utility of each option over a 20-y period. Quality-adjusted survival with a pacemaker was estimated from the literature and institutional patient-reported outcomes. Primary decision analysis was based on an expected recovery rate of 36.7% at 12 d with timing of pacemaker implantation: early placement (5 d) versus watchful waiting for 12 d.

RESULTS

A strategy of watchful waiting was more costly ($171,798 ± $45,695 versus $165,436 ± $52,923; P < 0.0001) but had a higher utility (9.05 ± 1.36 versus 8.55 ± 1.33 quality-adjusted life years; P < 0.0001) than an early pacemaker implantation strategy. The incremental cost-effectiveness ratio of watchful waiting was $12,724 per quality-adjusted life year. The results are sensitive to differences in quality-adjusted survival and rates of recovery of atrioventricular node function.

CONCLUSIONS

Watchful waiting for pacemaker insertion is a cost-effective management strategy compared with early placement for acute atrioventricular block after valve surgery. Although this is cost-effective from a population perspective, clinical risk scores predicting recovery will aid in personalized decision-making.

Relation of Prolonged Pacemaker Dependency After Cardiac Surgery to Mortality

Permanent pacemaker implantation (PPI) represents a rare complication after cardiac surgery, with no uniform agreement on timing and no information on follow-up. A multicenter retrospective study was designed to assess pacemaker dependency (PMD) and long-term mortality after cardiac surgery procedures. Between 2004 and 2016, PPI-patients from 18 centers were followed. Time-to-event data were evaluated with semiparametric regression Cox models and semiparametric Fine and Gray model for competing risk framework. Of 859 (0.90%) PPI-patients, 30% were pacemaker independent (PMI) at 6 months. PMD showed higher mortality compared with PMI (10-year survival 80.1% ± 2.6% and 92.2% +2.4%, respectively, log-rank p-value < 0.001) with an unadjusted hazard ratio for death of 0.36 (95% CI 0.20 to 0.65, p< 0.001 favoring PMI) and an adjusted hazard ratio of 0.19 (95% CI 0.08 to 0.45, p< 0.001 with PMD as reference). Crude cumulative incidence function of restored PMI rhythm at follow-up at 6 months, 1 year and 12 years were 30.5% (95% CI 27.3% to 33.7%), 33.7% (95% CI 30.4% to 36.9%) and 37.2% (95% CI 33.8% to 40.6%) respectively. PMI was favored by preoperative sinus rhythm with normal conduction (SR) (HR 2.37, 95% CI 1.65 to 3.40, p< 0.001), whereas coronary artery bypass grafting and aortic valve replacement were independently associated with PMD (HR 0.63, 95% CI 0.45 to 0.88, p = 0.006 and HR 0.807, 95% CI 0.65 to 0.99, p = 0.047 respectively). Time-to-implantation was not associated with increased rate of PMI. Although 30% of PPI-patients are PMI after 6 months, PMD is associated with higher mortality at long term.

The Impact of the Cox-Maze Technique on Freedom From Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia observed with concomitant cardiac surgery. Surgical options include a cut-and-sew technique Maze (CAS) and a cryoablation/bipolar technique Maze (CB). There are limited data comparing the long-term outcomes of these 2 techniques.

METHODS

All patients who underwent either CAS or CB Maze between 2011 and 2018 were included in the study. Chi-square test and Fisher's exact test or Student's t test were used to compare differences between baseline characteristics. Kaplan-Meier survival curves were generated for each group. Cumulative incidence functions were generated for AF recurrence and Fine-Gray competing-risk regression was used to determine predictors for AF recurrence.

RESULTS

A total of 482 patients underwent open surgical ablation. Of those, 287 had CAS and 198 had CB. All procedures were concomitant with cardiac surgery. There was similar long-term mortality between the CAS and CB cohorts (22.3% vs 17.4%; log-rank P = .91). There was no difference in pacemaker implantation (11.1% vs 11.3%; P = .813) or long-term freedom from AF recurrence (73.3% vs 78.2%; P = .294). On Fine-Gray competing-risk regression, New York Heart Association functional class IV (hazard ratio [HR], 2.07; P = .03), concomitant aortic valve replacement (HR, 3.02; P = .01), and concomitant CABG + valve (HR, 2.36; P = .02) were significant independent predictors for AF recurrence; Maze type was not a predictor.

CONCLUSIONS

These data indicate no difference between the CAS vs CB with respect to freedom from long-term AF. Both techniques may be appropriate based on surgeon experience and patient characteristics.

Leadless pacemaker implantation under direct visualization during valve surgery

OBJECTIVE

The leadless cardiac pacemaker is typically implanted percutaneously and has been widely used for patients who have already undergone valve surgery. We sought to determine the feasibility and safety of implanting the leadless pacemaker under direct visualization during valve surgery.

METHODS

We performed a retrospective analysis of consecutive adult patients (n = 15) who underwent implantation of a leadless pacemaker under direct visualization at the time of valve surgery. Indications for single-chamber pacing were sick sinus syndrome with pauses (53.3%), atrial fibrillation with slow ventricular rates (13.3%) or complete heart block (6.6%), and elevated risk for postoperative heart block (26.6%). Leadless pacemaker performance and pacing percentage were assessed.

RESULTS

Patients' age was 67.5 ± 17 years, 6 patients (40%) were male, and 14 patients (93%) had atrial fibrillation. Isolated tricuspid valve replacement was performed in 5 patients (33.3%), and the remainder underwent multivalve surgery that included concomitant tricuspid valve repair/replacement. In 93% of the patients (n = 14), the immediate post-cardiopulmonary bypass pacing thresholds were normal (≤2.0 V at 0.24 ms) and normalized in the remaining patient by the next morning. The impedance/sensing values were normal and stable through follow-up (151 ± 119 days) in all patients. Reliable leadless pacemaker performance allowed for deferral of temporary epicardial wires in 11 patients (73%). There were no procedural complications or device malfunction.

CONCLUSIONS

Leadless cardiac pacemaker implantation during valve surgery is feasible and safe. This hybrid approach to pacing may simplify the perioperative management of patients undergoing valve surgery who have an indication for single-chamber pacing.

Long-term risk of heart failure and mortality following mitral valve surgery in patients with and without right ventricular pacemaker

OBJECTIVES

Patients undergoing mitral valve surgery are at risk of developing postoperative conduction blocks and have a high incidence of heart failure (HF). Mitral valve surgery often results in reduced left ventricular systolic ejection fraction following surgery and the imposition of dyssynchrony with right ventricular (RV) pacing may further compromise stroke volume. Our aim was to investigate the risks of HF and mortality in patients with vs without RV pacemaker placement (PPM) after mitral valve surgery.

METHODS

Using Danish nationwide databases, we identified all patients undergoing mitral valve repair or replacement surgery between 1997 and 2017, who were free from HF at baseline. The association of PPM implanted within 30 days following surgery with long-term risks of HF and mortality was investigated by multivariable Cox regression models.

RESULTS

Of 4072 patients (33% female), 248 (6%) had a PPM implanted at 30-day postsurgery. Patients with PPM were older (68 vs 63 years), had a higher prevalence of concomitant aortic valve surgery (15% vs 11%), ischemic heart disease (13% vs 8%), and atrial fibrillation (19% vs 12%), compared with patients without PPM. Over a median follow-up of 5 years, 68 (27%) vs 825 (22%) patients with vs without PPM developed HF and 74 (30%) vs 1018 (27%) died. In multivariable-adjusted models, the hazard ratios associated with PPM were 1.00 (0.78-1.30), P = .93 for HF, and .96 (0.76-1.21), P = .72 for mortality.

CONCLUSIONS

Postoperative implantation of a permanent RV pacemaker does not alter the long-term risks of HF and mortality following mitral valve surgery.

Permanent pacemaker implantation after cardiac surgery: Optimization of the decision making process

BACKGROUND

Conduction disturbances necessitating permanent pacemaker (PPM) implantation after cardiac surgery occur in 1% to 5% of patients. Previous studies have reported a low rate of late PPM dependency, but there is lack of evidence that it might be related to implantation timing. In this study, we sought to determine whether PPM implantation timing and specific conduction disturbances as indications for PPM implantation are associated with late pacemaker dependency and recovery of atrioventricular (AV) conduction.

METHODS

Patients with a PPM implanted after cardiac surgery were followed in an outpatient clinic. Two outcomes were assessed: AV conduction recovery and PPM dependency, defined as the absence of intrinsic rhythm on sensing test in VVI mode at 40 bpm.

RESULTS

Of 15,092 patients operated between September 2008 and March 2019, 185 (1.2%) underwent PPM implantation. One hundred seventy-seven of these patients met the criteria for inclusion into this study. Follow-up data were available in 145 patients (82%). Implantation was performed at ≤6 days after surgery in 58 patients (40%) and at >6 days after surgery in 87 patients (60%). The median time from implantation to last follow-up was 890 days (range, 416-1998 days). At follow-up, 81 (56%) patients were not PPM dependent. Multivariable analysis showed that PPM implantation at ≤6 days after surgery is a predictor of being not PPM dependent (odds ratio [OR], 5.40; 95% confidence interval [CI], 2.43-12.04; P < .001) and of AV conduction recovery (OR, 4.96; 95% CI, 2.26-10.91; P < .001). Sinus node dysfunction as indication for PPM implantation was predictive of being not PPM dependent (OR, 6.59; 95% CI, 1.67-26.06; P = .007).

CONCLUSIONS

We recommend implanting a PPM on postoperative day 7 to prevent unnecessary implantations and avoid prolonged hospitalization.

Incidence of permanent pacemaker implantation after valve replacement surgery : Cardiac structure and function at 1-year follow-up

BACKGROUND

Our study aimed to explore the incidence and risk factors of permanent pacemaker implantation (PPI) after valve replacement surgery (VR). The influence of long-term pacemaker dependency on cardiac structure and function at the 1‑year follow-up was also assessed.

METHODS

The demographic and surgical data of all consecutive patients who underwent VR between 2013 and 2016 were collected. Univariate and multivariate analyses were performed to identify variables independently associated with PPI after VR. A 1‑year follow-up was undertaken of patients who underwent dual-chambers pacemaker after VR because of complete atrioventricular block (AVB). Long-term pacemaker dependency and recovery of cardiac structure and function were evaluated.

RESULTS

There were 5320 consecutive patients with VR. The incidence of postoperative PPI was 2.42%. Multivariate analysis indicated that among the 62 patients who underwent PPI due to AVB and sick sinus syndrome, isolated aortic valve replacement (AVR; OR: 2.24, p < 0.05), VR combined with ventricular septal defect (VSD) repair (OR: 6.78, p < 0.05), and VR with aortic root and arch surgery (OR: 4.14, p < 0.05) were independent predictors of PPI after surgery. In total, 89.6% (43/48) of the survivors showed pacemaker dependency. Of these 43 patients, 24 had enlarged left heart before VR. Compared with preoperative values, the left atrial and left ventricular end-diastolic diameter post-PPI decreased significantly, while left ventricular ejection fraction was not significantly different.

CONCLUSION

Isolated AVR, VR concomitant with VSD repair, and VR with aortic root and arch surgery are independent predictors of PPI after VR. The majority of patients do not recover from AVB disorders and there is no significant negative effect on recovery of cardiac structure and function.

Immediate and long-term need for permanent cardiac pacing following aortic valve replacement

Introduction: Atrioventricular (AV) node conduction disturbances are common following surgical aortic valve replacement (SAVR), and in some cases the patient needs a permanent pacemaker (PPM) implantation before discharge from hospital. Little is known about the long-term need for PPM and the PPM dependency of these individuals. We determined the incidence of PPM implantation before and after discharge in SAVR patients. Methods: We studied 557 consecutive patients who underwent SAVR for aortic stenosis in Iceland between 2002 and 2016. Timing and indication for PPM were registered, with a new concept, ventricular pacing proportion (VPP), defined as ventricular pacing ≥90% of the time, being used to approximate pacemaker dependency. The median follow-up time was 73 months. We plotted the cumulative incidence of pacemaker implantation, treating death as a competing risk. Results: Of the 557 patients, 22 (3.9%) received PPM in the first 30 days after surgery, most commonly for complete AV block (n = 14) or symptomatic bradycardia (n = 8); Thirty-eight other patients (6.8%) had a PPM implanted >30 days postoperatively, at a median of 43 months after surgery (range 0‒181), most often for AV block (n = 13) or sick-sinus syndrome (n = 10). The cumulative incidence of PPM implantation at 1, 5, and 10 years postoperatively was 5.0%, 9.2%, and 12.3%, respectively. During follow-up, 45.0% of the 60 patients had VPP ≥90%. Conclusion: The cumulative incidence of permanent pacemaker implantation following SAVR was about 12% at 10 years, with every other patient having VPP ≥90% during follow-up. This suggests that AV node conduction disturbances extend significantly beyond the perioperative period.

Predictors of pacing-dependency in patients with cardiovascular implantable electronic devices

BACKGROUND

Data on the prevalence and predictors for the development of pacing-dependency in patients with cardiovascular implantable electronic devices (CIEDs) are sparse.

METHODS

Pacing-dependency defined as an absence of intrinsic rhythm of ≥ 30 bpm was determined in 802 consecutive patients with CIEDs who visited the documented pacemaker or implantable cardioverter- defibrillator outpatient clinic for routine follow-up.

RESULTS

A total of 131 (16%) patients were found to be pacing-dependent 67 ± 70 months after CIED implant. Multivariate analysis revealed a significant association between pacing-dependency and the following clinical variables: second or third-degree atrioventricular (AV) block at implant (OR = 19.9; 95% CI: 10.9-38.5, p < 0.01), atrial fibrillation at implant (OR = 2.15; 95% CI: 1.16-4.05, p = 0.02), left ventricular ejection fraction (LVEF) ≤ 30% (OR = 2.06; 95% CI: 1.03-4.15, p = 0.04), B-type natriuretic peptide (BNP) > 150 pg/mL (OR = 2.12; 95% CI: 1.16-3.97, p = 0.02), chronic kidney disease (OR = 1.86; 95% CI: 1.08-3.26, p = 0.03), and follow-up duration after implantation > 5 years (OR = 3.29; 95% CI: 1.96-5.64, p < 0.01). None of the remaining clinical variables including age, gender, diabetes mellitus, underlying heart disease, prior cardiac surgery or medication during follow-up including betablockers and amiodarone predicted pacing-dependency.

CONCLUSIONS

Pacing-dependency is associated with second or third-degree AV-block at implant, atrial fibrillation before implant, low LVEF, elevated BNP, chronic kidney disease and follow-up duration after implant.

Permanent pacing and conduction recovery in patients undergoing cardiac surgery for active infective endocarditis in an Australian Tertiary Center

BACKGROUND

Postoperative heart block is common among patients undergoing surgery for infective endocarditis (IE). Limited data exists allowing cardiologists to predict who will require permanent pacemaker (PPM) implantation postoperatively. We aimed to determine the rate of postoperative PPM insertion, predictors for postoperative PPM, and describe PPM utilization and rates of device-related infection during follow-up.

MATERIALS AND METHODS

A retrospective analysis was performed of 191 consecutive patients from a single institution who underwent cardiac surgery for IE between 2001 and 2017. Preoperative and operative predictors for postoperative PPM were evaluated using univariate and multivariate logistic regression.

RESULTS

The rate of postoperative PPM implantation was 11% (17/154). The PPM group had more preoperative prolonged PR interval alone (33% vs 12%; P = .03), coexistent prolonged PR and QRS durations (13% vs 2%; P = .01), infection beyond the valve leaflets (82% vs 41%; P = .001), aortic root debridement (65% vs 23%; P = <.001), patch repair (47% vs 20%; P = .01), postoperative prolonged PR interval (50% vs 24%; P = .01), and prolonged QRS duration (47% vs 15%; P = .001). On multivariate analysis, infection beyond the valve leaflets emerged as an independent predictor for postoperative PPM (odds ratio, 1.94, 95% confidence interval, 1.14-3.28; P = .014). A reduction in PPM utilization was observed in five patients while eight patients continued to show significant ventricular pacing with no underlying rhythm at 12 months. There were no device-related infections.

CONCLUSION

Postoperative PPM was required in 11% of patients undergoing surgery for IE over a 16-year period. Infection beyond the valve leaflet was an independent predictor for postoperative PPM insertion.

Severe brady-arrhythmias in systemic lupus erythematosus: prevalence, etiology and associated factors

Background

Severe brady-arrhythmias, requiring a permanent pacemaker (PPM), have been sparsely reported in systemic lupus erythematosus (SLE). The aim of this study was to describe the characteristics of such arrhythmias in a defined lupus cohort.

Patients and methods

The database of the Toronto Lupus Clinic ( n = 1366) was searched for patients who received a PPM. Demographic, clinical, immunological and therapeutic variables along with electrocardiographic (ECG) and echocardiographic findings (based on the last available test prior to PPM) were analyzed. Patients with a PPM (cases) were compared with age-, sex- and disease duration-matched patients without a PPM (controls). Analysis was performed with SAS 9.0; p < 0.05 was considered significant.

Results

Eighteen patients were identified, 13 (0.95%) with complete atrioventricular block and 5 (0.37%) with sick sinus syndrome. Disease duration at PPM implantation was 22 ± 12 years. Compared to controls, cases had more frequently coronary artery disease, hypertension, dyslipidemia and longer antimalarial (AM) treatment duration. The prevalence of first-degree atrioventricular block, right bundle branch block, left anterior fascicular block and septal hypertrophy was also higher. AM treatment was significantly associated with brady-arrhythmias (OR = 1.128, 95% CI = 1.003–1.267, p = 0.044). Nine patients had prior heart disease and one received a PPM two years after renal transplantation. Eight patients did not have any potential risk factors; prolonged AM therapy (mean 22 years) might have been the cause.

Conclusions

Apart from known causes, prolonged AM treatment may be associated with severe brady-arrhythmias in SLE. Certain ECG and echocardiographic characteristics may represent indicators of an ongoing damage in the conduction system.

Frequency of Recovery from Complete Atrioventricular Block After Cardiac Surgery

Best timing for permanent pacemaker implantation to treat complete atrioventricular block (AVB) after cardiac surgery is unclear, as late pacemaker dependency was found low in recent observational studies. This study aimed to identify factors associated with spontaneous recovery from AVB. In a prospective and observational cohort, all patients who underwent cardiothoracic surgery during a 14-month-period were included (n = 1,200). Risk factors of postoperative AVB were assessed by logistic regression. Among patients who developed AVB, variables associated with recovery from AVB were assessed by Cox and logistic regression. Overall incidence of postoperative AVB was 6.0%. Risk factors of AVB were age (OR 1.03 [1.00 to 1.06], p = 0.023); female gender (OR 2.06 [1.24 to 3.41], p = 0.005), active endocarditis (OR 3.31 [1.33 to 8.26], p = 0.01), and aortic valve replacement (OR 3.17 [1.92 to 5.25], p <0.001). Among aortic valve replacement, sutureless aortic valve replacement was associated with more AVB (26.7% vs 8.1%, p <0.01). Recovery from AVB occurred in 30 patients (41.7%) in a median period of 3 days [interquartile range = 1;5]. Among patients who would recover from AVB, 90% of patients did so before day 7. None of the studied variable was independently associated with recovery from AVB. In conclusion, identified risk factors of postoperative AVB after cardiac surgery were age, female gender, endocarditis, and aortic valve replacement. Because most patients who would recover did so before day 7, this study validates modern guidelines suggesting permanent pacemaker implantation on day 7.

Cardiothoracic Critical Care

High-value CCC is rapidly evolving to meet the demands of increased patient acuity and to incorporate advances in technology. The high-performing CCC system and culture should aim to learn quickly and continuously improve. CCC demands a proactive, interactive, precise, an expert team, and continuity.

Predictors of Permanent Pacemaker Implantation After Coronary Artery Bypass Grafting and Valve Surgery in Adult Patients in Current Surgical Era

Background

Permanent pacemaker (PPM) implantation after cardiac surgery is required in 0.4-6% of patients depending on cardiac surgery type. PPM implantation in the early postoperative period may reduce morbidity and postoperative hospital stay. We performed a retrospective review of electronic medical records of adult patients with coronary artery bypass grafting (CABG), valve surgery, or both, over a 3-year period. Our aim was to identify predictors of PPM requirements and PPM dependency on follow-up in the current surgical era.

Methods

After exclusion of patients with congenital heart disease, patients who already had a PPM or implantable cardioverter defibrillator (ICD), and patients with an indication for PPM or ICD before surgery, we identified 1,234 adult patients who underwent cardiac surgery between January 2007 and December 2009. A retrospective review of electronic medical records and pacemaker clinic data was performed.

Results

Patients’ mean age was 46.65 ± 16 years, and 59% were males. CABG was performed in 575 (46.6%) cases, aortic valve replacement in 263 (21.3%), mitral valve replacement in 333 (27%), and tricuspid valve replacement in 76 patients (6.2%). Twenty patients (1.6%) required implantation of a PPM postoperatively. Indications for PPM implantation included complete atrioventricular (AV) block in 13 (65%), sick sinus syndrome in three (15%), and atrial fibrillation (AF) with a slow ventricular rate in four (20%). Predictors for PPM requirement by multivariate analysis were the presence of pulmonary hypertension (P-HTN), reoperation, and left bundle branch block (LBBB) (P < 0.05). Late follow-up was available in 18 patients, at 84.5 ± 30 months. Eleven patients (61%) were PPM dependent on long-term follow-up.

Conclusions

Patients at high risk for PPM implantation after cardiac surgery include those with P-HTN, reoperation, and pre-existing LBBB. Of those receiving a PPM, about one-third will recover at least partially at long-term follow-up. We recommend preoperative assessment for risk of requiring postoperative PPM, to counsel patients about this risk and early PPM implantation in high-risk patients who are PPM dependent after surgery.