Cardiac resynchronization therapy: present and future.

Cardiac resynchronization therapy (CRT) via biventricular pacing (BVP) is a well-established therapy for patients with heart failure with reduced ejection fraction and left bundle branch block, who remain symptomatic despite optimal medical therapy. Despite the long-standing clinical evidence, as well as the familiarity of cardiac electrophysiologists with the implantation technique, CRT via BVP cannot be achieved or may result ineffective in up to one-third of the patients. Therefore, new alternative techniques, such as conduction system pacing and left ventricular pacing, are emerging as potential alternatives to this technique, not only in case of BVP failure, but also as a stand-alone first choice due to several potential advantages over traditional CRT. Specifically, due to its procedural characteristics, left bundle branch area pacing appears to be the most convincing technique, showing comparable efficacy outcomes when compared with traditional CRT, not increasing short-term device-related complications, as well as improving procedural times. However, transvenous leads remain a major limitation of all these pacing modalities. To overcome this limit, a leadless left ventricular endocardial pacing has been developed as an additional tool to achieve a left endocardial activation, although being still associated with non-negligible pitfalls, limiting its current use in clinical practice. This article focuses on the current state and latest progresses in cardiac resynchronization therapy.

Rationale and design of the health economics evaluation registry for remote follow-up: TARIFF.

AIMS: The aims of the study are to develop a cost-minimization analysis from the hospital perspective and a cost-effectiveness analysis from the third payer standpoint, based on direct estimates of costs and QOL associated with remote follow-ups, using Merlin@home and Merlin.net, compared with standard ambulatory follow-ups, in the management of ICD and CRT-D recipients. METHODS AND RESULTS: Remote monitoring systems can replace ambulatory follow-ups, sparing human and economic resources, and increasing patient safety. TARIFF is a prospective, controlled, observational study aimed at measuring the direct and indirect costs and quality of life (QOL) of all participants by a 1-year economic evaluation. A detailed set of hospitalized and ambulatory healthcare costs and losses of productivity that could be directly influenced by the different means of follow-ups will be collected. The study consists of two phases, each including 100 patients, to measure the economic resources consumed during the first phase, associated with standard ambulatory follow-ups, vs. the second phase, associated with remote follow-ups. CONCLUSION: Remote monitoring systems enable caregivers to better ensure patient safety and the healthcare to limit costs. TARIFF will allow defining the economic value of remote ICD follow-ups for Italian hospitals, third payers, and patients. The TARIFF study, based on a cost-minimization analysis, directly comparing remote follow-up with standard ambulatory visits, will validate the cost effectiveness of the Merlin.net technology, and define a proper reimbursement schedule applicable for the Italian healthcare system. TRIAL REGISTRATION: NCT01075516.

Closed loop stimulation is effective in improving heart rate and blood pressure response to mental stress: report of a single-chamber pacemaker study in patients with chronotropic incompetent atrial fibrillation.

INTRODUCTION: Closed-loop stimulation (CLS) is a form of rate-adaptive pacing capable of providing an effective pacing rate profile not only during physical exercise but also during mental stress. To test its effectiveness, CLS and accelerometer sensor (AS) rate response were compared intraindividually during a mental stress test (MST). METHODS: Thirty-six patients (mean age 78.9 ± 6.4 years) implanted with a pacemaker with the CLS algorithm (Cylos, Biotronik, Berlin, Germany) underwent MSTs in different pacing configurations: nonrate-adaptive mode (VVI), AS mode (VVIR), and CLS mode, respectively. A modified Stroop test was used in order to induce mental stress. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure, and pacing percentage burden were collected for 5 minutes before, during, and 5 minutes after the test. RESULTS: Mean peak-HR during MST was significantly higher in CLS configuration than in VVIR and VVI modes (92.8 ± 12.6 vs 78.9 ± 6.5 vs 77.8 ± 7.5; P ≤ 0.001). The average HR increase during MST was also higher in CLS configuration than in VVIR and VVI modes (22.7 ± 16.7 vs 8.2 ± 8.6 vs 6.6 ± 6.3; P ≤ 0.001). The percentage of pacing beats during MST was higher in CLS configuration than with the other two algorithms (48.4 ± 17.9 vs 27.4 ± 17.5 vs 25.8 ± 17.6; P ≤ 0.001). The average peak-SBP was significantly higher during MST in CLS mode than in VVIR and VVI configurations (172.6 ± 15.5 vs 156.7 ± 12.2 vs 145.5 ± 13.7; P ≤ 0.001). The mean SBP increase showed a similar behavior (51.8 ± 24.7 vs 18.4 ± 13.7 vs 16.4 ± 10.3; P ≤ 0.001). CONCLUSION: CLS algorithm in a single-chamber device is more effective than AS in detecting an hemodynamic demand due to an emotional stress and supplying a proper HR increase. These results are even more surprising compared to previous data in dual-chamber pacemakers, because they imply that CLS algorithm can provide an appropriate rate-modulation in patients with AF and chronotropic incompetence.

Combined Use of S-ICD and Absorbable Antibacterial Envelopes: A Proof-of-concept Study.

BACKGROUND: Absorbable antibacterial envelopes (AAEs) are currently recommended in patients undergoing a transvenous ICD implantation in cases at high risk of infection, who are now preferably implanted with a subcutaneous ICD (S-ICD). Nevertheless, experiences using a combined approach with S-ICD and AAE have not been reported. The aim of our study was to evaluate this strategy in patients at very high risk of infection. METHODS: Twenty-five patients were implanted with the S-ICD+AAE using our combined approach, restricted to patients who would fit our decisional flow algorithm identifying very high-risk patients. Patients were followed up 1 month after discharge and every 6 months thereafter. Complications were defined as device-related events requiring medical or surgical intervention for resolution and/or device reprogramming. RESULTS: Twenty-five patients (92% males, mean age 58.5±14.1 years) were implanted with the S-ICD device and the AAE using our combined approach. The most common high-infective risk factors were diabetes requiring insulin treatment (80%) and CKD requiring hemodialysis (48%), with 7 (28%) patients presenting with more than 2 risk factors. A single mild early post-operative hematoma was observed that was managed conservatively with a spontaneous resolution. Despite a very high-risk cohort, only a single late pocket infection was detected and solved conservatively with antibiotic therapy. CONCLUSIONS: The preliminary data of this proof-of-concept study show how a combined deployment of AAE and S-ICD in selected patients at very high risk of infection is a safe and feasible technique and may offer a reliable treatment option in specific and selected clinical settings.

Extraction Of Transvenous ICD Leads In An Over-ninety Years Old Patient.

There is a general consensus that once a part of an implanted cardiac device becomes infected, it is usually impossible to cure the infection without completely removing all prosthetic material from the body. Consequently the Heart Rhythm Society (HRS) included the pocket infection or erosion as a class I indication for pacemaker lead exctraction. However, the procedure still carries a high risk of life-threatening complications due to fibrotic attachments between leads, veins, valves or other endocardial structures, notwithstanding specific tools and techniques that have been developed to assist the lead removal, preventing tissue laceration.

Factors affecting signal quality in implantable cardiac monitors with long sensing vector.

PURPOSE: Electrical artefacts are frequent in implantable cardiac monitors (ICMs). We analyzed the subcutaneous electrogram (sECG) provided by an ICM with a long sensing vector and factors potentially affecting its quality. METHODS: Consecutive ICM recipients underwent a follow-up where demographics, body mass index (BMI), implant location, and surface ECG were collected. The sECG was then analyzed in terms of R-wave amplitude and P-wave visibility. RESULTS: A total of 84 patients (43% female, median age 68 [58-76] years) were enrolled at 3 sites. ICMs were positioned with intermediate inclination (n = 44, 52%), parallel (n = 35, 43%), or perpendicular (n = 5, 6%) to the sternum. The median R-wave amplitude was 1.10 (0.72-1.48) mV with P waves readily visible in 69.2% (95% confidence interval, CI: 57.8%-79.2%), partially visible in 23.1% [95% CI: 14.3%-34.0%], and never visible in 7.7% [95% CI: 2.9%-16.0%] of patients. Men had higher R-wave amplitudes compared to women (1.40 [0.96-1.80] mV vs 1.00 [0.60-1.20] mV, P = .001), while obese people tended to have lower values (0.80 [0.62-1.28] mV vs 1.10 [0.90-1.50] mV, P = .074). The P-wave visibility reached 86.2% [95% CI: 68.3%-96.1%] in patients with high-voltage P waves (≥0.2 mV) at surface ECG. The sECG quality was not affected by implant site. CONCLUSION: In ordinary clinical practice, ICMs with long sensing vector provided median R-wave amplitude above 1 mV and reliable P-wave visibility of nearly 70%, regardless of the position of the device. Women and obese patients showed lower but still very good signal quality.

Economic analysis of remote monitoring of cardiac implantable electronic devices: Results of the Health Economics Evaluation Registry for Remote Follow-up (TARIFF) study.

BACKGROUND: Remote monitoring (RM) of cardiac implantable electronic devices has been demonstrated to improve outpatient clinic workflow and patient management. However, few data are available on the socioeconomic impact of RM. OBJECTIVE: The aim of this study was to assess the costs and benefits of RM compared with standard care (SC). METHODS: We used 12-month patient data from the Health Economics Evaluation Registry for Remote Follow-up (TARIFF) study (N = 209; RM: n = 102 (48.81%); SC: n = 107 (51.19%)). Cost comparison was made from 2 perspectives: the health care system (HCS) and patients. The use of health care resources was defined on the basis of hospital clinical folders. Out-of-pocket expenses were reported directly by patients. RESULTS: HCS perspective: The overall mean annual cost per patient in the SC group (€1044.89 ± €1990.47) was significantly higher than in the RM group (€482.87 ± €2488.10) (P < .0001), with a reduction of 53.87% being achieved in the RM group. The primary driver of cost reduction was the cost of cardiovascular hospitalizations (SC: €`886.67 ± €1979.13 vs RM: €432.34 ± €2488.10; P = .0030). Patient and caregiver perspective: The annual cost incurred by patients was significantly higher in the SC group than in the RM group (SC: €169.49 ± €189.50 vs RM: €56.87 ± €80.22; P < .0001). Patients' quality-adjusted life-years were not significantly different between the groups. Provider perspective: The total number of inhospital device follow-up visits was reduced by 58.78% in the RM group. CONCLUSION: RM of patients with cardiac implantable electronic devices (CIEDs) is cost saving from the perspectives of the HCS, patients, and caregivers. Introducing appropriate reimbursements will make RM sustainable even for the provider, i.e. the hospitals which provide the service and encourage widespread adoption of RM.

Assessment of the dynamics of atrial signals and local atrial period series during atrial fibrillation: effects of isoproterenol administration.

BACKGROUND: The autonomic nervous system (ANS) plays an important role in the genesis and maintenance of atrial fibrillation (AF), but quantification of its electrophysiologic effects is extremely complex and difficult. Aim of the study was to evaluate the capability of linear and non-linear indexes to capture the fine changing dynamics of atrial signals and local atrial period (LAP) series during adrenergic activation induced by isoproterenol (a sympathomimetic drug) infusion. METHODS: Nine patients with paroxysmal or persistent AF (aged 60 +/- 6) underwent electrophysiological study in which isoproterenol was administered to patients. Atrial electrograms were acquired during i) sinus rhythm (SR); ii) sinus rhythm during isoproterenol (SRISO) administration; iii) atrial fibrillation (AF) and iv) atrial fibrillation during isoproterenol (AFISO) administration. The level of organization between two electrograms was assessed by the synchronization index (S), whereas the degree of recurrence of a pattern in a signal was defined by the regularity index (R). In addition, the level of predictability (LP) and regularity of LAP series were computed. RESULTS: LAP series analysis shows a reduction of both LP and R index during isoproterenol infusion in SR and AF (RSR = 0.75 +/- 0.07 RSRISO = 0.69 +/- 0.10, p < 0.0001; RAF = 0.31 +/- 0.08 RAFISO = 0.26 +/- 0.09, p < 0.0001; LPSR = 99.99 +/- 0.001 LPSRISO = 99.97 +/- 0.03, p < 0.0001; LPAF = 69.46 +/- 21.55 LPAFISO = 55 +/- 24.75; p < 0.0001). Electrograms analysis shows R index reductions both in SR (RSR = 0.49 +/- 0.08 RSRISO = 0.46 +/- 0.09 p < 0.0001) and in AF (RAF = 0.29 +/- 0.09 RAFISO = 0.28 +/- 0.08 n.s.). CONCLUSIONS: The proposed parameters succeeded in discriminating the subtle changes due to isoproterenol infusion during both the rhythms especially when considering LAP series analysis. The reduced value of analyzed parameters after isoproterenol administration could reflect an important pro-arrhythmic influence of adrenergic activation on favoring maintenance of AF.

[The "Appropriatezza ECO Milano" project. Assessment of appropriateness of indications, prescriptions and clinical utility of two-dimensional Doppler echocardiography among inpatients and outpatients of Milan, Italy]. / Progetto "Appropriatezza ECO Milano". Valutazione basale dell'appropriatezza delle indicazioni, della modalità delle prescrizioni e dell'utilità clinica dell'esame ecocardiografico bidimensionale color Doppler all'interno delle aziende ospedaliere e sul territorio.

BACKGROUND: The value of echocardiography in the diagnosis and follow-up of most cardiovascular diseases is well established, even though the ever-increasing demand for the use of this technique is not always justifiable. The "Appropriatezza ECO Milano" project was developed among hospitals in Milan (Italy) to foster a rational use of echocardiography. The aim of this study was to evaluate and improve appropriateness of requests for two-dimensional color Doppler echocardiography, considering indications, prescription behaviors and clinical utility in both the outpatient and inpatient settings. METHODS: Following several meetings, a consensus was reached whereby a multicenter, observational study would be undertaken. We assessed the value of each request in agreement with the 2003 American College of Cardiology/American Heart Association/American Society of Echocardiography guidelines. An ad hoc Microsoft Access database was developed to collect study data, which refer to May 2007. Eleven hospitals participated in the study. RESULTS: 4130 echocardiographic examinations were considered (2300 performed in men and 1830 performed in women; mean age 64 +/- 16 years); 1701 examinations were performed in hospitalized patients and 2429 in outpatients. The incidence of pathological findings was higher in hospitalized patients (73%) than in outpatients (53%) (Pearson chi2 = 29, p<0.001). A higher additional clinical value was found in hospitalized vs non-hospitalized patients (48 vs. 35%, Pearson chi2 = 99; p <0.001). In both settings, the majority of echocardiographic examinations were requested by cardiologists (inpatients 36%, outpatients 54%). The most appropriate examinations were performed more frequently in class I or class IIA hospitalized patients (73%) than in outpatients (52%) (Pearson chi2 = 277, p<0.001). Furthermore, the least accurate the indication, the less the clinical utility found in examinations requested from hospitals and outpatient clinics (64 vs 61% in class I patients, Pearson chi2 = 413, p<0.001; 5 vs 11% in class III patients, Pearson chi2 = 584, p<0.001). Conclusions. Our data confirm an inadequate level of appropriateness of requests for two-dimensional color Doppler examinations in either inpatients or outpatients. After over 10 years of passively observing and recording this trend, a timely resolution of these issues is topical in order to improve the implementation of criteria and to guarantee cost-effective and high-quality cardiovascular care.