Patient with sick sinus syndrome and implanted dual-chamber pacemaker with reduced P-wave duration following low interatrial septal pacing: Case report.

INTRODUCTION: A dual-chamber pacemaker (DDD/R) for a sinus node disease is sometimes referred to as a physiological pacemaker as it maintains atrioventricular synchrony, however several clinical trials have proved its inferiority to a nonphysiological single-chamber ventricular back-up pacing. PATIENT CONCERNS: A subject of the study is a 74-year-old woman with a sick sinus syndrome (SSS) and a previously implanted physiological DDD/R pacemaker. The SSS was diagnosed because of patient's very slow sinus rhythm of about 36 bpm, and due to several episodes of dizziness. After the DDD/R implantation the percentage of atrial pacing approached 100%, with almost none ventricular pacing. DIAGNOSES: Sick sinus syndrome, complete Bachmann's bundle block, atrial fibrillation, atrial flutter. INTERVENTIONS: The patient was previously implanted with a physiological DDD/R pacemaker. Several years after the implantation, the atrial fibrillation was diagnosed and the pulmonary vein isolation was then performed by cryoablation. During the follow-up after pulmonary vein isolation, the improvement of mitral filling parameters was assessed using echocardiography. Shortly thereafter the patient developed the persistent paroxysm of a typical atrial flutter which was successfully terminated using a radiofrequency ablation. No recurrence thereof has been observed ever since (24 months). OUTCOMES: The atrial electrode of the pacing system was implanted within the low interatrial septal region that resulted in a reduced P-wave duration compared to native sinus rhythm P-waves. The said morphology was deformed because of the complete Bachmann bundle block. That approach, despite a nonphysiological direction of an atrial activation, yielded relatively short P-waves (paced P-wave: 179 ms vs intrinsic sinus P-wave: 237 ms). It also contributed to a significantly shorter PR interval (paced PR: 204 ms vs sinus rhythm PR: 254 ms). CONCLUSIONS: The authors took into consideration different aspects of alternative right atrial pacing sites. This report has shown that in some patients with a sinus node disease, low interatrial septal pacing can reduce the P-wave duration but does not prevent from the development of atrial arrhythmias.

Lower rate limit for pacing by cardiac resynchronization defibrillators: Should lower rate programming be reconsidered?

BACKGROUND: No real-world large database associates lower rate limit (LRL) programming and survival of subjects with cardiac resynchronization therapy-defibrillators (CRT-Ds). OBJECTIVE: The purpose of this study was to test the hypothesis that lower LRL programming is independently associated with survival, and that LRL and heart rate score (HrSc) are associated. METHODS: All dual-chamber CRT-D devices in the Remote Patient Monitoring (RPM) ALTITUDE database (2006-2011) were queried. Baseline HrSc was defined as the percentage of all atrial sensed and paced beats in the tallest 10-beat histogram bin postimplant. LRL was assessed during repeated RPM uploads. Using a Cox model multivariable analysis, relationships between LRL, survival, HrSc, and other variables were evaluated. Survival was determined by query of death indices. RESULTS: Data analyzed included 61,881 subjects (mean follow-up 2.9 years). LRL ranged from 40 to 85 bpm. Baseline lower LRL was associated with younger age, less atrial fibrillation, female sex, and lower HrSc (P <.001 for all covariates). Lower LRL was associated with improved survival, with LRL 40 associated with the largest survival benefit. This was significant for all 3 HrSc subgroups (P <.001). An interaction between HrSc and LRL was observed, with the largest survival difference between HrSc groups observed at LRL-40 (P <.001). CONCLUSION: LRL programming and HrSc were associated, and lower values of both were associated with improved survival in a large database of CRT-D subjects. Relationships between survival, LRL programming, and HrSc merit further study.

Gain in real-world cardiac resynchronization therapy efficacy with SyncAV dynamic optimization: Heart failure hospitalizations and costs.

BACKGROUND: SyncAV, a device-based cardiac resynchronization therapy (CRT) algorithm, promotes electrical optimization by dynamically adjusting atrioventricular intervals. OBJECTIVE: The purpose of this study was to evaluate the impact of SyncAV on heart failure hospitalizations (HFHs) and related costs in a real-world CRT cohort. METHODS: Patients with SyncAV-capable CRT devices followed by remote monitoring and enrolled in Medicare fee-for-service for at least 1 year preimplant and up to 2 years postimplant were studied. Patients with SyncAV OFF were 4:1 matched to those with SyncAV ON on preimplant HFH rate, demographics, comorbidities, disease etiology, and left bundle branch block. HFHs were determined from the primary diagnosis of inpatient hospitalizations, and the cost for each event was the sum of Medicare, supplemental insurance, and patient payment. RESULTS: After 4:1 propensity score matching, 3630 patients were studied (mean age 75 ± 8 years; 1386 [38%] female), including 726 (25%) patients with SyncAV ON. The pre-CRT HFH rate was 0.338 HFH events per patient-year. Overall, CRT diminished the HFH rate to 0.204 events per patient-year (P < .001). SyncAV elicited a larger reduction in HFH rate (SyncAV ON: hazard ratio [HR] 0.52; 95% confidence interval [CI] 0.41-0.66; P < .001 and SyncAV OFF: HR 0.68; 95% CI 0.59-0.77; P < .001). After 2 years, the HFH rate was lower in the SyncAV ON group than in the SyncAV OFF group (0.143 HFHs per patient-year vs 0.193 HFHs per patient-year; HR 0.70; 95% CI 0.55-0.89; P = .003) and fewer HFHs were followed by 30-day HFH readmissions (4.41% vs 7.68%; P = .003) and 30-day all-cause hospital readmissions (7.04% vs 10.01%; P = .010). The total 2-year HFH-associated costs per patient were lower with SyncAV ON (difference $1135; 90% CI $93-$2109; P = .038). CONCLUSION: This large, real-world, propensity score-matched study demonstrates that SyncAV CRT is associated with significantly reduced HFHs and associated costs, incremental to standard CRT.

Challenges in activation of remote monitoring in patients with cardiac rhythm devices during the coronavirus (COVID-19) pandemic.

BACKGROUND: Remote monitoring (RM) technology embedded in cardiac rhythm devices permits continuous monitoring of device function, and recording of selected cardiac physiological parameters and cardiac arrhythmias and may be of utmost utility during Coronavirus (COVID-19) pandemic, when in-person office visit for regular follow-up were postponed. However, patients not alredy followed-up via RM represent a challenging group of patients to be managed during the lockdown. METHODS: We reviewed patient files scheduled for an outpatient visit between January 1, 2020 and May 11th, 2020 to assess the proportion of patients in whom RM activation was possible without office visit, and compared them to those scheduled for visit before the lockdown. RESULTS: During COVID-19 pandemic, RM activation was feasible in a minority of patients (7.8% of patients) expected at outpatient clinic for a follow-up visit and device check-up. This was possible in a good proportion of complex implantable devices such as cardiac resynchronization therapy and implantable cardioverter defibrillator but only in a minority of patients with a pacemaker the RM function could be activated during the period of restricted access to hospital. CONCLUSIONS: Our experience strongly suggest to consider the systematic activation of RM function at the time of implantation or - by default programming - in all cardiac rhythm management devices.

Effects of exercise training on physical activity in heart failure patients treated with cardiac resynchronization therapy devices or implantable cardioverter defibrillators.

OBJECTIVE: This study elucidated the effects of exercise training on physical activity, 6-min walk distance, and all-cause hospitalization rates in patients with chronic heart failure, and evaluated factors contributing to changes in physical activity. DESIGN: Prospective cohort observational study. PATIENTS AND METHODS: Patients (n =62) who completed an exercise training programme after implantable cardioverter-defibrillator or cardiac resynchronization therapy treatment between May 2017 and May 2018 were included. Patients exercised for 20-50 min 3-5 times weekly for 3 months and were assigned to the active (≥ 10 min/day) or non-active (< 10 min/day) group based on changes in walking times between baseline and 3 months, as assessed by the International Physical Activity Questionnaire. RESULTS: The 6-min walk distance improved in both groups with exercise training. Physical activity level did not increase in some patients, despite improvements in exercise tolerance. Depression improved significantly in the active group, but no correlation was found with physical activity. Factors contributing to physical activity changes were not identified. The all-cause hospitalization rate was lower in the active group during follow-up (mean 10.5 months). CONCLUSION: Exercise training effectively increased 6-min walk distance regardless of physical activity. Non-active patients experienced increased all-cause hospitalizations. Increasing physical activity improves patient outcomes.

CRT Survey II: a European Society of Cardiology (ESC) survey of cardiac resynchronization therapy-an Irish subset analysis.

BACKGROUND: Cardiac resynchronization therapy (CRT) has been shown to reduce mortality and morbidity in symptomatic patients with reduced left ventricular systolic function < 35%, a left bundle branch block (LBBB) and a widened QRS complex. This paper compares Irish national CRT practices with the European data that was gathered in the same multi-centre CRT Survey II. METHODS: Each recruiting centre completed an internet-based facilitating collection of information relating to health care resource utilization by each centre. A second form was completed for consecutive patients undergoing CRT implantation, to provide information on patient demographics, pre-implantation clinical evaluation and investigations, indication for implantation and the procedure as well as short-term complications and adverse events. RESULTS: A total of 85 patients from 2 centres were representative of the current Irish practice and compared with data obtained. This was 26.6% of all CRT implantations in Ireland during this period (total number 319, 88 CRT-P, 231 CRT-D). Of those receiving CRT device, mean age was 73 years, 74.1% were male, with predominantly NYHA class III symptoms, and left ventricular ejection fraction < 35%. NT-pro-BNP level was substantially elevated in most patients. 56% were in sinus rhythm, 31% in atrial fibrillation with overall mean QRS duration of 166 ms. CONCLUSIONS: Within Ireland, the majority of CRT implantation are adherent with ESC guidelines. It has also highlighted problems that are noted in other ESC member countries such as the underutilization of device therapy in women, lack of referrals from peripheral centres and further need for optimization of medical therapy before device implantation.

The relationship between ECG predictors of cardiac resynchronization therapy benefit.

INTRODUCTION: Cardiac resynchronization therapy (CRT) is an effective treatment that reduces mortality and improves cardiac function in patients with left bundle branch block (LBBB). However, about 30% of patients passing the current criteria do not benefit or benefit only a little from CRT. Three predictors of benefit based on different ECG properties were compared: 1) "strict" left bundle branch block classification (SLBBB); 2) QRS area; 3) ventricular electrical delay (VED) which defines the septal-lateral conduction delay. These predictors have never been analyzed concurrently. We analyzed the relationship between them on a subset of 602 records from the MADIT-CRT trial. METHODS & RESULTS: SLBBB classification was performed by two experts; QRS area and VED were computed fully automatically. High-frequency QRS (HFQRS) maps were used to inspect conduction abnormalities. The correlation between SLBBB and other predictors was R = 0.613, 0.523 and 0.390 for VED, QRS area in Z lead, and QRS duration, respectively. Scatter plots were used to pick up disagreement between the predictors. The majority of SLBBB subjects- 295 of 330 (89%)-are supposed to respond positively to CRT according to the VED and QRS area, though 93 of 272 (34%) non-SLBBB should also benefit from CRT according to the VED and QRS area. CONCLUSION: SLBBB classification is limited by the proper setting of cut-off values. In addition, it is too "strict" and excludes patients that may benefit from CRT therapy. QRS area and VED are clearly defined parameters. They may be used to optimize biventricular stimulation. Detailed analysis of conduction irregularities with CRT optimization should be based on HFQRS maps.

Benefits of left ventricular endocardial pacing comparing failed implants and prior non-responders to conventional cardiac resynchronization therapy: A subanalysis from the ALSYNC study.

OBJECTIVE: Cardiac resynchronisation therapy (CRT) is limited by a substantial proportion of non-responders. Left ventricular endocardial pacing (LVEP) may offer enhanced possibility to deliver CRT in patients with a failed attempt at implantation and to improve clinical status of CRT non-responders. METHODS: The ALternate Site Cardiac ResYNChronisation (ALSYNC) study was a prospective, multi-centre cohort study that included 118 CRT patients with a successfully implanted endocardial left ventricular (LV) lead, including 90 failed coronary sinus (CS) implants and 28 prior non-responders who had worsened or unchanged heart failure status after at least 6 months of optimal conventional CRT therapy. RESULTS: Patients were followed for 19 ±â€¯9 months. At baseline, prior non-responders were sicker as evidenced by a larger LV end-diastolic diameter (70 ±â€¯12 vs 65 ±â€¯9 mm, p = .03) and a trend towards larger LV end-systolic volume index (LVESVi, 95 ±â€¯51 vs 74 ±â€¯39 ml/m2, p = .07), and were more frequently anti-coagulated (96% vs 72%, p = .008) despite similar history of atrial fibrillation (54% vs 51%, p = .83). At 6 months, LVEP significantly improved LV ejection fraction (2.3 ±â€¯7.5 and 8.6 ±â€¯10.0%), New York Heart Association Class (0.4 ±â€¯0.9 and 0.7 ±â€¯0.8), LVESVi (9 ±â€¯16 and 18 ±â€¯43 ml/m2), and six-minute walk test (56 ±â€¯73 and 54 ±â€¯92 m) in prior non-responders and failed CS implants, relative to baseline (all p < .05), respectively. LVESVi reduction ≥15% was seen in 47% of the prior non-responder patients and 57% of failed CS patients. CONCLUSION: These data suggest that a sizable proportion of CRT non-responders can improve by LVEP, though to a lesser extent than failed CS implants. Clinical trial registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01277783.

Devices in heart failure; diagnosis, detection and disease modification.

Introduction/background: Implantable cardiac devices are widely used in chronic heart failure (CHF) therapy. This review covers current CHF treatment with electronic cardiac devices, areas of discussion and emerging technologies. Sources of data: A comprehensive search of available literature resources including Pubmed, MEDLINE and EMBASE was performed. National and international guidelines were accessed. Areas of agreement: Excessive right ventricular pacing is detrimental to cardiac function. Cardiac resynchronization therapy is beneficial in specific individuals with CHF. Areas of controversy: Implantable cardioverter defibrillators might not benefit all. Optimizing CRT delivery. Remote monitoring seems not to be of benefit in CHF. Growing points: Device-based optimization. Areas timely for developing research: Personalization of device therapy. Focussing implantable cardioverter defibrillator therapy. What to do at implantable cardioverter defibrillator box change?

Impact of the Relationship between the Defibrillation Threshold (DFT) and Clinical Outcomes in Recipients of Modern Era Implantable Cardioverter Defibrillator (ICD).

Defibrillation threshold (DFT) testing during implantable cardioverter defibrillator (ICD) implantations is considered necessary for appropriate shock therapy and to measure the safety margin. However, the relationship between the DFT with modern era devices and the clinical outcome, including the total mortality is limited, which may lead to DFT testing itself being questioned. This study aimed to evaluate the relationship between the DFT and clinical outcome in ICD recipients.We enrolled 81 consecutive patients (66 males, aged 64.6 ± 13.8 years) who received an ICD implantation and underwent DFT testing. The DFT was measured with a step-by-step method in the patients upon implant. Further, we evaluated the relationship between the DFT and the clinical outcome, which included major cardiac adverse events and any cause of death.The mean DFT was 11.6 ± 9.24J in total. In 40 patients (49.4%), VF was terminated by a low output (5J), whereas 11 patients (13.6%) had a high DFT. The rates of atrial fibrillation were significantly higher in the high DFT group (63.6% versus 24.2%, P = 0.007). During the observational period (median 432 days; range from 151 days to 1146 days), the incidence of clinical events occurred in 22 patients (27.2%) in total. In a multivariate analysis, a high DFT was the only predictive factor for the incidence of the clinical outcome (OR 4.54, 95% CI 1.03-21.9, P = 0.045).

Methods, accuracy and clinical implications of atrial fibrillation detection by cardiac implantable electronic devices.

Atrial fibrillation (AF) is the most common arrhythmia in the developed countries and is associated with an increased risk of thromboembolic events and heart failure. Episodes of AF are often asymptomatic and intermittent, eluding diagnosis with non-continuous monitoring techniques. Cardiac implantable electronic devices (CIEDs) represent the gold standard for detecting asymptomatic AF. Improper CIED programming may however increase the risk of false-positive detection of atrial tachyarrhythmias, leading to inappropriate clinical management of patients. A faster rate and a longer duration of the tachyarrhythmic episodes, in addition to a greater AT/AF burden, have been proposed as potential criteria for differentiating between CIED-detected atrial tachyarrhythmias and true AF. Nonetheless, manual overreading of intracardiac electrograms recorded by the CIED remains crucial for a correct diagnosis. Asymptomatic atrial tachyarrhythmias may carry a higher risk of systemic thromboembolism, though clinical thromboembolic risk factors seem to play a greater if not absolute role in prognostication. In addition, there is no clear temporal relationship between CIED-detected atrial tachyarrhythmias and stroke, and the anticoagulation strategy to be pursued in these patients is still a matter of debate and the focus of current prospective randomized studies.

Toward Sex-Specific Guidelines for Cardiac Resynchronization Therapy?

An important treatment for patients with heart failure is cardiac resynchronization therapy (CRT). Even though only 20% of women were included in clinical trials for CRT, a benefit has been shown in recent studies for subgroups of women compared to their male counterparts. Given this low inclusion rate of women in clinical studies, professional society guideline-based CRT recommendations, such as those by the American College of Cardiology Foundation (ACCF)/American Heart Association (AHA)/Heart Rhythm Society (HRS), may not truly represent the best treatment for women, especially since most of the reports that showed this greater benefit in women were published after the latest guidelines. Despite having research and multiple publications regarding sex-specific heart failure outcomes and response to CRT, the ACCF/AHA/HRS guidelines have not yet been updated to account for the recent information regarding the differences in benefit for women and men with similar patient characteristics. This review discusses the physiology behind CRT, sex-specific characteristics of heart failure, and cardiac electrophysiology and summarizes the current sex-specific literature to encourage consideration of CRT guidelines for women and men separately.

Miocardiopatía dilatada idiopática tratada con infusión intracoronaria de células autólogas de médula ósea: seguimiento a largo plazo / Idiopathic dilated cardiomyopathy treated with intracoronary infusion of autologous bone marrow cells: long-term follow-up

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Análisis de bioimpedancia sistémica en pacientes portadores de dispositivos de estimulación cardiaca / Systemic bioimpedance analysis in patients with implanted cardiac stimulation devices

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Analysis of the QRS morphology in lead V1 during 24-hour Holter electrocardiogram monitoring to evaluate function of a cardiac resynchronisation therapy device in patients with sinus rhythm: a pilot study.

BACKGROUND: Cardiac resynchronisation therapy (CRT) is an important advance in the treatment of chronic heart failure. The aim of CRT is biventricular capture in all beats. However, inadequate delivery of biventricular pacing is still seen in about 30% of patients with an implanted CRT device. Device interrogation is a routine approach to assess CRT delivery. However, some reports indicate that analysis of 24-h electrocardiogram (ECG) may provide additional and important information regarding CRT function. AIM: Assessment of the adequacy of CRT delivery based on device interrogation and analysis of QRS morphology during 24-h ECG recording in patients with preserved sinus rhythm (SR). METHODS: We analysed 24-h Holter ECG recordings and data from device interrogation devices in 43 patients with preserved SR (age 56 ± 23 years, 9 women and 34 men). The obtained results were compared in an independent manner. Assessment of adequacy of CRT delivery by 24-h ECG was based on the occurrence of QRS variability, defined as a change in R wave amplitude in lead V1 by > 3 mm and/or change in QRS duration by > 40 ms and/or change in the R/S ratio. Adequate CRT delivery, i.e. complete resynchronisation, was defined as more than 95% of pacing without the defined QRS variability. RESULTS: Both methods allowed independent assessment of CRT delivery (p < 0.05 by the Fisher's exact test). In multivariate analysis, factors that were independently associated with incomplete resynchronisation included ventricular arrhythmias (each 100 ventricular beats per day increased the risk of incomplete resynchronisation 1.14-fold; confidence interval [CI] 1.036-1.25, p = 0.007), maximum heart rate (HR) (each increase by 10 bpm increased the risk 3.3-fold; CI 1.36-7.9, p = 0.008), QRS duration at the minimum HR (each increase by 10 ms increased the risk 1.74-fold; CI 1.075-2.8, p = 0.024), and the programmed atrioventricular delay (each increase by 10 ms increased the risk 2.15-fold, CI 1.18-3.9, p = 0.013). CONCLUSIONS: In patients with preserved SR, device interrogation and evaluation of 24-h ECG are complementary methods to evaluate adequate CRT delivery. Therefore, both methods should be taken into account when assessing CRT function.

Mechanical approach in the management of advanced acute and chronic heart failure: the state of the art.

Despite the progress in medical therapy, advanced heart failure (AHF) remains a global epidemic with high morbidity and mortality. Novel cardiac support strategies such as pharmacologic agents, mechanical circulatory support (MCS), and cell- or matrix-based therapies are promising for these patients. The indications, types, and timing of MCS implantation depend to a large extent on the presentation, clinical status of the patient, underlying etiology, and long-term prospects. The presence or absence of end-organ damage has a significant impact on prognosis following MCS initiation. Although many patients with acute AHF may have end-organ damage, their prospect of recovery, once appropriate therapy is instituted, is better than for patients who had AHF for longer periods of time. We consider the multidisciplinary approaches used for the management of AHF and the novel cardiac support strategies (eg, MCS). Appropriate selection of patient, device, time, and end point is essential for better outcomes.