Association of a device-based remote management heart failure pathway with outcomes: TriageHF Plus real-world evaluation

AIMS

Clinical pathways have been shown to improve outcomes in patients with heart failure (HF). Although patients with HF often have a cardiac implantable electronic device, few studies have reported the utility of device-derived risk scores to augment and organize care. TriageHF Plus is a device-based HF clinical pathway (DHFP) that uses remote monitoring alerts to trigger structured telephone assessment for HF stability and optimization. We aimed to evaluate the impact of TriageHF Plus on hospitalizations and describe the associated workforce burden.

METHODS AND RESULTS

TriageHF Plus was a multi-site, prospective study that compared outcomes for patients recruited between April 2019 and February 2021. All alert-triggered assessments were analysed to determine the appropriateness of the alert and the workload burden. A negative-binomial regression with inverse probability treatment weighting using a time-matched usual care cohort was applied to estimate the effect of TriageHF Plus on non-elective hospitalizations. A post hoc pre-COVID-19 sensitivity analysis was also performed. The TriageHF Plus cohort (n = 443) had a mean age of 68.8 ± 11.2 years, 77% male (usual care cohort: n = 315, mean age of 66.2 ± 14.5 years, 65% male). In the TriageHF Plus cohort, an acute medical issue was identified following an alert in 79/182 (43%) cases. Fifty assessments indicated acute HF, requiring clinical action in 44 cases. At 30 day follow-up, 39/66 (59%) of initially symptomatic patients reported improvement, and 20 (19%) initially asymptomatic patients had developed new symptoms. On average, each assessment took 10 min. The TriageHF Plus group had a 58% lower rate of hospitalizations across full follow-up [incidence relative ratio: 0.42, 95% confidence interval (CI): 0.23-0.76, P = 0.004]. Across the pre-COVID-19 window, hospitalizations were 31% lower (0.69, 95% CI: 0.46-1.04, P = 0.077).

CONCLUSIONS

These data represent the largest real-world evaluation of a DHFP based on multi-parametric risk stratification. The TriageHF Plus clinical pathway was associated with an improvement in HF symptoms and reduced all-cause hospitalizations.

Clinical Pathways Guided by Remotely Monitoring Cardiac Device Data: The Future of Device Heart Failure Management?

Research examining the utility of cardiac device data to manage patients with heart failure (HF) is rapidly evolving. COVID-19 has reignited interest in remote monitoring, with manufacturers each developing and testing new ways to detect acute HF episodes, risk stratify patients and support self-care. As standalone diagnostic tools, individual physiological metrics and algorithm-based systems have demonstrated utility in predicting future events, but the integration of remote monitoring data with existing clinical care pathways for device HF patients is not well described. This narrative review provides an overview of device-based HF diagnostics available to care providers in the UK, and describes the current state of play with regard to how these systems fit in with current HF management.

Use of a device-based remote management heart failure care pathway is associated with reduced hospitalization and improved patient outcomes: TriageHF Plus real-world evaluation

Background

Heart failure (HF) is a leading cause of hospital admission. However, prompt identification of worsening HF using implantable device data and proactive intervention may reduce hospitalizations.

The validated TriageHF algorithm in enabled ICD/CRT devices uses sensor data to risk stratify patients for HF hospitalization in the next 30 days. TriageHF Plus is a novel device-based HF care pathway (DHFP) that uses “high” risk status as the trigger for remote intervention (see Figure 1 for pathway overview). Outcomes after DHFP implementation in a clinical setting have not been examined.

Purpose

To evaluate the impact of TriageHF Plus clinical pathway on hospitalisation rates.

Methods

A prospective, multi-center evaluation comparing monthly hospitalization rates for patients enrolled in a DHFP with a concurrent standard of care (SoC) cohort and characterizing staffing resources necessary to implement the DHFP. The DHFP cohort received telephonic assessment and guideline-directed clinical care upon transition to high-risk status. Propensity scores (PS) were applied to DHFP and SoC cohorts to allow unbiased comparison. A negative binomial model was fitted to the monthly number of all-cause hospitalizations with treatment group (DHFP vs. SoC) as a covariate, using PS as weights.

Results

Between 09/11/2019 and 06/24/2021, 758 patients were included in the study (443 DHFP, 315 SoC). Proportion CRT 76%/ 89% and LVEF <50% 78%/ 66% for DHFP/ SoC, respectively.

196 high risk transmissions prompted telephone assessment, with successful contact in 182; of which, 79 (43%) identified an explanatory acute medical issue. A secondary intervention was undertaken in 44/79 (56%). High risk transmissions took on average 19 minutes per clinical assessment (initial telephone triage and 30 day follow up). The rate of hospitalizations was 58% lower in the DHFP group, compared with SoC, after PS adjustment (IRR 0.42, 95% CI: 0.23, 0.76, p=0.004), see Figure 2. Sensitivity analyses showed Covid-19 had little effect on results.

Conclusions

This is the first prospective, real-world evaluation of a device-based HF care pathway to report a reduction in hospitalizations and does so with minimal staffing time. Integrated into existing HF services, device-based remote monitoring of HF patients can improve outcomes.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Medtronic

Remotely Monitored Cardiac Implantable Electronic Device Data Predict All-Cause and Cardiovascular Unplanned Hospitalization

Background Unplanned hospitalizations are common in patients with cardiovascular disease. The "Triage Heart Failure Risk Status" (Triage-HFRS) algorithm in patients with cardiac implantable electronic devices uses data from up to 9 device-derived physiological parameters to stratify patients as low/medium/high risk of 30-day heart failure (HF) hospitalization, but its use to predict all-cause hospitalization has not been explored. We examined the association between Triage-HFRS and risk of all-cause, cardiovascular, or HF hospitalization. Methods and Results A prospective observational study of 435 adults (including patients with and without HF) with a Medtronic Triage-HFRS-enabled cardiac implantable electronic device (cardiac resynchronization therapy device, implantable cardioverter-defibrillator, or pacemaker). Cox proportional hazards models explored association between Triage-HFRS and time to hospitalization; a frailty term at the patient level accounted for repeated measures. A total of 274 of 435 patients (63.0%) transmitted ≥1 high HFRS transmission before or during the study period. The remaining 161 patients never transmitted a high HFRS. A total of 153 (32.9%) patients had ≥1 unplanned hospitalization during the study period, totaling 356 nonelective hospitalizations. A high HFRS conferred a 37.3% sensitivity and an 86.2% specificity for 30-day all-cause hospitalization; and for HF hospitalizations, these numbers were 62.5% and 85.6%, respectively. Compared with a low Triage-HFRS, a high HFRS conferred a 4.2 relative risk of 30-day all-cause hospitalization (8.5% versus 2.0%), a 5.0 relative risk of 30-day cardiovascular hospitalization (3.6% versus 0.7%), and a 7.7 relative risk of 30-day HF hospitalization (2.0% versus 0.3%). Conclusions In patients with cardiac implantable electronic devices, remotely monitored Triage-HFRS data discriminated between patients at high and low risk of all-cause hospitalization (cardiovascular or noncardiovascular) in real time.

Triage-HF plus: 12-month study of remote monitoring pathway for triage of heart failure risk initiated during the Covid-19 pandemic

Background

The Covid-19 pandemic necessitated rapid adoption of remote monitoring across cardiovascular patient cohorts. Most patients with cardiac implantable electronic devices (CIEDs) are now able to be remotely monitored using either scheduled, patient- or threshold-triggered transmissions. The validated “Triage Heart Failure Risk Score” (Triage-HFRS) is a medical algorithm within company-specific CIEDs that can risk-stratify patients as low-, medium- or high-risk of worsening heart failure (WHF) in the next 30 days based on integrated monitoring of physiological parameters. Building on a previous proof-of-concept of the Triage-HF Plus pathway, we integrated remote data with simple 5-question telephone triage within a clinical pathway to identify WHF during the first year of the Covid-19 pandemic.

Purpose

Prospective evaluation of clinical remote monitoring pathway integrating Triage-HFRS with protocolised telephone triage (Triage-HF Plus pathway).

Methods

Prospective, real-world evaluation of clinical pathway serving a large urban region over a 12-month period, using data from April 2020 to April 2021 (initiated during the first wave of Covid-19 pandemic in the UK). From a population of 435 patients with CIEDs, 87 “high” Triage-HFRS alerts were received and patients contacted for telephone triage assessment. Screening questions were designed to identify episodes of WHF and non-HF events. Intervention was at discretion of the clinical practitioner and in line with guideline-directed practice. A consecutive sample of 115 “medium” risk scores received the same triage.

Results

Successful contact was made with 72 (82.8%) high-risk patients. Classification for high scoring patients confirmed on triage included isolated heart failure (18.3%), heart failure concurrent to medical problem (5.7%), alternative medical problem (10.3%), and recent hospital admission (8.0%); triage reassured absence of acute cause of high score in 40.2%. The sensitivity and specificity for detection of WHF was 87.9% (0.77–0.99) and 59.4% (0.50–0.69) respectively. Positive and negative predictive values were 40.3% and 94.0%, respectively. Overall accuracy was 66.2%.

Conclusions

The Triage-HF Plus pathway served as a useful remote monitoring tool for identifying patients with WHF whose care had been otherwise disrupted by the Covid-19 pandemic, allowing timely intervention and cementing the longer-term role for such models of care delivery. Crucially, in this multimorbid, high-cost population, relevant non-HF issues were also identified. The high negative predictive value further highlights the potential of proactive surveillance over conventional, periodic follow up.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Imperial Health Charity

Remote monitoring data from cardiac implantable electronic devices predicts all-cause mortality

Aims

To determine if remotely monitored physiological data from cardiac implantable electronic devices (CIEDs) can be used to identify patients at high risk of mortality.

Methods and results

This study evaluated whether a risk score based on CIED physiological data (Triage-Heart Failure Risk Status, ‘Triage-HFRS’, previously validated to predict heart failure (HF) events) can identify patients at high risk of death. Four hundred and thirty-nine adults with CIEDs were prospectively enrolled. Primary observed outcome was all-cause mortality (median follow-up: 702 days). Several physiological parameters [including heart rate profile, atrial fibrillation/tachycardia (AF/AT) burden, ventricular rate during AT/AF, physical activity, thoracic impedance, therapies for ventricular tachycardia/fibrillation] were continuously monitored by CIEDs and dynamically combined to produce a Triage-HFRS every 24 h. According to transmissions patients were categorized into ‘high-risk’ or ‘never high-risk’ groups. During follow-up, 285 patients (65%) had a high-risk episode and 60 patients (14%) died (50 in high-risk group; 10 in never high-risk group). Significantly more cardiovascular deaths were observed in the high-risk group, with mortality rates across groups of high vs. never-high 10.3% vs. <4.0%; P = 0.03. Experiencing any high-risk episode was associated with a substantially increased risk of death [odds ratio (OR): 3.07, 95% confidence interval (CI): 1.57–6.58, P = 0.002]. Furthermore, each high-risk episode ≥14 consecutive days was associated with increased odds of death (OR: 1.26, 95% CI: 1.06–1.48; P = 0.006).

Conclusion

Remote monitoring data from CIEDs can be used to identify patients at higher risk of all-cause mortality as well as HF events. Distinct from other prognostic scores, this approach is automated and continuously updated.

Pirfenidone in heart failure with preserved ejection fraction: a randomized phase 2 trial

In heart failure with preserved ejection fraction (HFpEF), the occurrence of myocardial fibrosis is associated with adverse outcome. Whether pirfenidone, an oral antifibrotic agent without hemodynamic effect, is efficacious and safe for the treatment of HFpEF is unknown. In this double-blind, phase 2 trial ( NCT02932566 ), we enrolled patients with heart failure, an ejection fraction of 45% or higher and elevated levels of natriuretic peptides. Eligible patients underwent cardiovascular magnetic resonance and those with evidence of myocardial fibrosis, defined as a myocardial extracellular volume of 27% or greater, were randomly assigned to receive pirfenidone or placebo for 52 weeks. Forty-seven patients were randomized to each of the pirfenidone and placebo groups. The primary outcome was change in myocardial extracellular volume, from baseline to 52 weeks. In comparison to placebo, pirfenidone reduced myocardial extracellular volume (between-group difference, -1.21%; 95% confidence interval, -2.12 to -0.31; P = 0.009), meeting the predefined primary outcome. Twelve patients (26%) in the pirfenidone group and 14 patients (30%) in the placebo group experienced one or more serious adverse events. The most common adverse events in the pirfenidone group were nausea, insomnia and rash. In conclusion, among patients with HFpEF and myocardial fibrosis, administration of pirfenidone for 52 weeks reduced myocardial fibrosis. The favorable effects of pirfenidone in patients with HFpEF will need to be confirmed in future trials.

Novel atrioventricular sequential pacing approach using a transvenous atrial pacemaker and a leadless pacemaker: a case report

Background

The use of transvenous pacing leads is associated with the risk of developing tricuspid valve (TV) dysfunction. This develops through several mechanisms including the failure of leaflet coaptation or direct damage to the TV or to its sub-valvular apparatus and can result in significant tricuspid regurgitation (TR). Multiple approaches to pacemaker implantation after transvenous lead extraction (TLE) or surgical TV repair have been described. Placement of pacing leads across the TV is generally avoided in such circumstances.

Case summary

A 66-year-old woman presented with a year-long history of exertional dyspnoea, peripheral oedema, and postural neck pulsations. Her medical history included a dual-chamber pacemaker implantation for sinus node dysfunction 14 years ago. Echocardiography revealed severe lead-related TR. Her case was discussed in our multi-disciplinary team meeting. A decision was made to perform a TLE and implant a leadless pacemaker in an attempt to avoid open-heart surgery if possible. This was reserved as an option in the event of persistent severe TR. Transvenous extraction of the right ventricular lead was performed. The atrial lead was preserved and connected to and AAI device. A Micra AV was implanted allowing for atrioventricular (AV) synchronous pacing.

Discussion

We present the first case of successful implementation of AV sequential pacing using a dual-pacemaker approach involving the use of an AAI pacemaker and a Micra AV device. This was performed after TLE for severe lead-related TR.

Do all patients with implantable cardioverter defibrillator need a generator change? A health service evaluation of patients who underwent generator changes from a single tertiary center

BACKGROUND

The patient characteristics, therapy received and outcomes after one or more implantable cardioverter defibrillator (ICD) generator changes from contemporary practice is not well known.

METHODS

We conducted a health service evaluation of patients who underwent ICD implantation and generator change. Patients who had generator changes from February 2016 to October 2019 were identified from our database and electronic records were reviewed for patient characteristics, number of generator changes, receipt of therapy and death.

RESULTS

Our database included 88 patients with a generator change. A total of 22 patients (25.0%) received dual chamber ICD, 10 patients (11.4%) received single chamber ICD, 54 patients (61.3%) received cardiac resynchronization therapy defibrillator and 2 patients (2.3%) received subcutaneous ICD. A second generator change occurred in 18 patients and a third generator changes was performed in 6 patients. There were 29 deaths and a follow up period of 9.4 ± 2.9 years. From implant to initial generator change 39 patients had appropriate antitachycardia pacing (ATP), 6 patient had inappropriate ATP, 29 patients had appropriate shocks and 5 patients had an inappropriate shock. Between the 1st and 2nd generator change and the 2nd and 3rd there were no cases of inappropriate ATP or shock. Overall, 42 patients out of the 88 had appropriate therapy (47.7%) and 7 patients had inappropriate therapy (8.0%).

CONCLUSIONS

Most patients with ICDs do not receive therapy and a minority have inappropriate therapy which typically occur before the first generator change as we observed no inappropriate therapy beyond the first generator change.

Protecting the most vulnerable during COVID-19 and beyond: a case report on the remote management of heart failure patients with cardiac implantable electronic devices

Background

Heart failure (HF) patients with cardiac implantable electronic devices (CIEDs) represent an important cohort. They are at increased risk of hospitalization and mortality. We outline how remote-only management strategies, which leverage transmitted health-related data, can be used to optimize care for HF patients with a CIED during the COVID-19 pandemic.

Case summary

An 82-year-old man with HF, stable on medical therapy, underwent cardiac resynchronization therapy implantation in 2016. Modern CIEDs facilitate remote monitoring by providing real-time physiological data (thoracic impedance, heart rate and rhythm, etc.). The 'Triage Heart Failure Risk Score' (Triage-HFRS), available on Medtronic CIEDs, integrates several monitored physiological parameters into a risk prediction model classifying patients as low, medium, or high risk of HF events within 30 days. In November 2019, the patient was enrolled in an innovative clinical pathway (Triage-HF Plus) whereby any 'high' Triage-HF risk status transmission prompts a phone call-based virtual consultation. A high-risk alert was received via remote transmission on 11 March, triggering a phone call assessment. Upon reporting increasing breathlessness, diuretics were initiated. The prescription was remotely issued and delivered to the patient's home. This approach circumvented the need for all face-to-face reviews, delivering care in an entirely remote manner.

Discussion

The challenges posed by COVID-19 have prompted us to think differently about how we deliver care for patients, both now and following the pandemic. Contemporary CIEDs facilitate the ability to remotely monitor HF patients by providing rich physiological data that can help identify individuals at elevated risk of decompensation using automated device-generated alerts.

P549CIED infection risk score validation using US health claims data

Funding Acknowledgements

This work was supported by Medtronic

Background/Introduction: The increasing number of cardiac implantable electronic device (CIED) infections has led to increased interest in the identification of patients who may benefit from additional infection prevention measures.

Purpose

The purpose of this evaluation was to validate the predictive value of the Prevention of Arrhythmia Device Infection Trial (PADIT) risk score to identify patients at increased risk of CIED infection using a U.S. health claims data set.

Methods

A retrospective analysis using the Optum® Clinformatics® claims database was conducted to create a dataset of index procedures which either did or did not result in an infection.  The study population included both commercial and Medicare Advantage patients aged ≥18 years with at least one record of a CIED procedure between January 2011 and September 2014.  Major CIED infections, defined as an infection associated with system removal, invasive procedure without system removal, or death attributable to infection, were identified through diagnosis and procedure codes.  The dataset was randomized (stratified by PADIT score, which included prior procedures, age, depressed renal function, immunocompromised, and procedure type) into a Development Dataset (60%) and a Validation dataset (40%).  A frailty model allowing multiple procedures per patient was fit using the Development Dataset, with PADIT score as the only predictor, excluding patients with prior infection. Prior CIED infection, which was not available in the original PADIT data, was examined for additional predictive value.

Results

The data extraction resulted in a dataset of 53,554 index procedures among 51,583 patients, with 30,950 patients randomized to the Development Dataset.  The distribution of procedures was pacemakers (52%), ICD (20%), CRT (12%), and Revision/Upgrade (16%), while prior procedures were none (62%), 1 (37%), and 2 (1%). Among patients with no history of prior CIED infection, the frailty model showed that a 1 unit increase in the PADIT score predicts higher infection risk (20%) in the U.S. claims data set (Table 1). Prior CIED infection was associated with strong additional predictive value (HR 4.77, p &lt; 0.0001) after adjusting for PADIT score.

Conclusion

In the largest external validation of a CIED risk score, the PADIT risk score predicts increased CIED infection risk, identifying higher risk patients that can benefit from targeted interventions to reduce the risk of CIED infection. Prior CIED infection brings additional predictive value to the PADIT score.

Triage-HF Plus: a novel device-based remote monitoring pathway to identify worsening heart failure

Aims

Remote monitoring of patients with physiological data derived from cardiac implanted electronic devices (CIEDs) offers potential to reconfigure clinical services. The ‘Heart Failure Risk Score' (HFRS) uses input from integrated device physiological monitoring to risk‐stratify patients as low‐risk, medium‐risk, or high‐risk of a heart failure event in the next 30 days. This study aimed to evaluate a novel clinical pathway utilizing a combination of CIED risk‐stratification and telephone triage to identify patients with worsening heart failure (WHF).

Methods and results

A prospective, single‐centre, real‐world evaluation of the ‘Triage‐HF Plus' clinical pathway (HFRS in combination with telephone triage) over a 27 month period. One hundred and fifty‐seven high‐risk HFRS transmissions were referred for telephone triage assessment. Interventions were at the discretion of the clinical assessor acting in accordance with clinical guidelines. An additional 3month consecutive sample of low and medium HFRS transmissions (control group) were also contacted for telephone triage assessment (n = 98). Successful telephone contact was made in 127 (81%) of referred high‐risk HFRS cases: 71 (55.9%) were confirmed to have WHF requiring intervention; 19 (14.9%) had an alternative acute medical problem; one patient had been recently discharged from hospital with WHF; and 36 (28.0%) had no apparent cause for the high score. In the control group, only one patient had symptoms of WHF. The sensitivity and specificity of CIED‐based remote monitoring to identify WHF 98.6% (92.5–100.0%) and 63.4% (55.2–71.0%), respectively.

Conclusions

The Triage‐HF Plus clinical pathway is a potentially useful remote monitoring tool for patients with heart failure and in situ CIEDs.

Pirfenidone in Heart Failure with Preserved Ejection Fraction-Rationale and Design of the PIROUETTE Trial

BACKGROUND

The PIROUETTE (PIRfenidOne in patients with heart failUre and preserved lEfT venTricular Ejection fraction) trial is designed to evaluate the efficacy and safety of the anti-fibrotic pirfenidone in patients with chronic heart failure and preserved ejection fraction (HFpEF) and myocardial fibrosis. HFpEF is a diverse syndrome associated with substantial morbidity and mortality. Myocardial fibrosis is a key pathophysiological mechanism of HFpEF and myocardial fibrotic burden is strongly and independently associated with adverse outcome. Pirfenidone is an oral anti-fibrotic agent, without haemodynamic effect, that leads to regression of myocardial fibrosis in preclinical models. It has proven clinical effectiveness in pulmonary fibrosis.

METHODS

The PIROUETTE trial is a randomised, double-blind, placebo-controlled phase II trial evaluating the efficacy and safety of 52 weeks of treatment with pirfenidone in patients with chronic HFpEF (symptoms and signs of heart failure, left ventricular ejection fraction ≥ 45%, elevated natriuretic peptides [BNP ≥ 100 pg/ml or NT-proBNP ≥ 300 pg/ml; or BNP ≥ 300 pg/ml or NT-proBNP ≥ 900 pg/ml if in atrial fibrillation]) and myocardial fibrosis (extracellular matrix (ECM) volume ≥ 27% measured using cardiovascular magnetic resonance). The primary outcome measure is change in myocardial ECM volume. A sub-study will investigate the relationship between myocardial fibrosis and myocardial energetics, and the impact of pirfenidone, using ³¹phosphorus magnetic resonance spectroscopy.

DISCUSSION

PIROUETTE will determine whether pirfenidone is superior to placebo in relation to regression of myocardial fibrosis and improvement in myocardial energetics in patients with HFpEF and myocardial fibrosis (NCT02932566).

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov (NCT02932566) https://clinicaltrials.gov/ct2/show/NCT02932566.

Cardiac implantable electronic device (CIED) infections are expensive and associated with prolonged hospitalisation: UK Retrospective Observational Study

Background

There are limited reports outlining the financial cost of treating cardiac implantable electronic device (CIED) infection outside the United States. This study aimed to determine the average treatment cost of CIED infection in a large UK tertiary referral centre and compared costs of different treatment pathways that are recognised in the management of CIED infection (early versus delayed re-implantation).

Methods

We retrospectively analysed cost and length of stay (LOS) data for consecutive patients undergoing infected CIED extraction with cardiac resynchronization therapy (CRT-D [with defibrillator], CRT-P [with pacemaker]), implantable cardioverter-defibrillators (ICDs) and permanent pacemakers (PPMs).

Results

Between January 2013 and March 2015, complete data was available for 84 patients (18 [21.4%] CRT-D, 24 [28.6%] ICDs and 42 [50.0%] PPMs). When all cases were considered the cost of infection ranged from £5,139 (PPM) to £24,318 (CRT-D). Considering different treatment strategies; 41 (48.8%) underwent CIED extraction and re-implantation during the same admission (early re-implant strategy (ER). 43 (51.2%) underwent extraction, but were then discharged home to be re-admitted for day-case re-implantation (delayed re-implant strategy (DR)). Median LOS was significantly shorter in DR compared to ER (5.0 vs. 18.0 days, p<0.001). The total cost of CIED infection episode was similar for both treatment strategies (median £14,241.48 vs. £14,741.70 including wearable defibrillator (Lifevest) and outpatient antibiotics costs, ER vs. DR; p = 0.491).

Conclusion

CIED infections are expensive and associated with significant health-economic burden. When all device types were considered, a DR strategy is associated with reduced LOS without an increased cost penalty.

Totally Leadless Dual-Device Implantation for Combined Spontaneous Ventricular Tachycardia Defibrillation and Pacemaker Function: A First Report

Subcutaneous implantable cardioverter defibrillators (S-ICDs) provide effective defibrillation, while also reducing the risk of long-term lead problems. However, S-ICDs do not offer bradycardia or antitachycardia pacing and therefore use has been limited. Combined implantation of an S-ICD with a leadless pacemaker (LP) has been proposed to overcome this limitation. Although a handful of combined S-ICD/LP implantations have been reported for Nanostim (St Jude Medical, St Paul, MN) as well as Micra LP (Medtronic, Minneapolis, MN) systems, none have documented delivery of appropriate shock therapies for spontaneous ventricular tachycardia. We report the first case of effective defibrillation for spontaneous ventricular tachycardia in a patient with combined Micra LP and S-ICD.

One-Month Global Longitudinal Strain Identifies Patients Who Will Develop Pacing-Induced Left Ventricular Dysfunction over Time: The Pacing and Ventricular Dysfunction (PAVD) Study

Background

Predicting which individuals will have a decline in left ventricular (LV) function after pacemaker implantation remains an important challenge. We investigated whether LV global longitudinal strain (GLS), measured by 2D speckle tracking strain echocardiography, can identify patients at risk of pacing-induced left ventricular dysfunction (PIVD) or pacing-induced cardiomyopathy (PICMP).

Methods

Fifty-five patients with atrioventricular block and preserved LV function underwent dual-chamber pacemaker implantation and were followed with serial transthoracic echocardiography for 12 months for the development of PIVD (defined as a reduction in LV ejection fraction (LVEF) ≥5 percentage points at 12 months) or PICMP (reduction in LVEF to <45%).

Results

At 12 months, 15 (27%) patients developed PIVD; of these, 4 patients developed PICMP. At one month, GLS was significantly lower in the 15 patients who subsequently developed PIVD, compared to those who did not (n = 40) (GLS -12.6 vs. -16.4 respectively; p = 0.022). When patients with PICMP were excluded, one month GLS was significantly reduced compared to baseline whereas LVEF was not. One-month GLS had high predictive accuracy for determining subsequent development of PIVD or PICMP (AUC = 0.80, optimal GLS threshold: <−14.5, sensitivity 82%, specificity 75%); and particularly PICMP (AUC = 0.86, optimal GLS threshold: <−13.5, sensitivity 100%, specificity 71%).

Conclusions

GLS is a novel predictor of decline in LV systolic function following pacemaker implantation, with the potential to identify patients at risk of PIVD before measurable changes in LVEF are apparent. GLS measured one month after implantation has high predictive accuracy for identifying patients who later develop PIVD or PICMP.

Radionuclide Imaging of Cardiovascular Infection

Owing to expanding clinical indications, cardiac implantable electronic devices (CIEDs) are being increasingly used. Despite improved surgical techniques and the use of prophylactic antimicrobial therapy, the rate of CIED-related infection is also increasing. Infection is a potentially serious complication, with clinical manifestations ranging from surgical site infection and local symptoms in the region of the generator pocket to fulminant endocarditis. The utility of radionuclide imaging as a stand-alone noninvasive diagnostic imaging test in patients with suspected endocarditis has been less frequently examined. This article summarizes the recent advances in radionuclide imaging for evaluation of patients with suspected cardiovascular infections.

Early diagnosis of cardiac implantable electronic device generator pocket infection using ¹⁸F-FDG-PET/CT

AIMS

To examine the utility of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) in the early diagnosis of cardiac implantable electronic device (CIED) generator pocket infection.

METHODS AND RESULTS

A total of 86 patients with CIEDs were evaluated with (18)F-FDG PET/CT imaging: 46 with suspected generator pocket infection and 40 without any history of infection. (18)F-FDG activity in the region of the generator pocket was expressed as a semi-quantitative ratio (SQR)-defined as the maximum count rate around the CIED divided by the mean count rate between normal right and left lung parenchyma. All patients underwent standard clinical management, independent of the PET/CT result. Patients with suspected generator pocket infection that required CIED extraction (n = 32) had significantly higher (18)F-FDG activity compared with those that did not (n = 14), and compared with controls (n = 40) [SQR: 4.80 (3.18-7.05) vs. 1.40 (0.88-1.73) vs. 1.10 (0.98-1.40), respectively; P < 0.001]. On receiver operator characteristic analysis, SQR had a high diagnostic accuracy (area under curve = 0.98) for the early identification of patients with confirmed infection (i.e. those ultimately needing extraction)-with an optimal SQR cut-off value of >2.0 (sensitivity = 97%; specificity = 98%).

CONCLUSION

This study highlights the potential benefits of evaluating patients with suspected CIED generator pocket infection using (18)F-FDG PET/CT. In this study, (18)F-FDG PET/CT had a high diagnostic accuracy in the early diagnosis of CIED generator pocket infection, even where initial clinical signs were underwhelming.