[New frontiers in pacing: from myocardial pacing to conduction system pacing]

For many years, cardiac pacing has been based on the stimulation of right ventricular common myocardium to correct diseases of the conduction system. The birth and the development of cardiac resynchronization have led to growing interest in the correction and prevention of pacing-induced dyssynchrony. Many observational studies and some randomized clinical trials have shown that conduction system pacing (CSP) can not only prevent pacing-induced dyssynchrony but can also correct proximal conduction system blocks, with reduction of QRS duration and with equal or greater effectiveness than biventricular pacing. Based on these results, many Italian electrophysiologists have changed the stimulation target from the right ventricular common myocardium to CSP. The two techniques with greater clinical impact are the His bundle stimulation and the left bundle branch pacing. The latter, in particular, because of its easier implantation technique and better electric parameters, is spreading like wildfire and is representing a real revolution in the cardiac pacing field. However, despite the growing amount of data, until now, the European Society of Cardiology guidelines give a very limited role to CSP.

640 QRS INDEX TO PREDICT CARDIAC RESYNCHRONIZATION THERAPY RESPONSE: A TRICENTRIC STUDY

Background

Several studies have evaluated the role of QRS duration (QRSd) or QRS narrowing as predictor of response to cardiac resynchronization therapy (CRT) in order to reduce non-responders. However, their results have been conflicting. In our study we analyzed retrospectively a cohort of patients from three centers to better correlate the association between the relative change in QRS narrowing index (QI) and clinical outcome and prognosis in patients who underwent CRT implantation.

Methods

We included 398 patients in whom a CRT device was implanted in accordance with current guidelines in our three centres. Baseline clinical variables, echocardiographic parameters and pharmacological therapies were included. QRS duration before and after CRT implantation and QI [(pre implant QRS duration - QRS duration during CRT)/pre implant QRS duration × 100] were measured.

Results

Respect to echocardiographic follow up at 6 months, a significant improvement in all parameters (EF, LVEDV, LVESV) was observed. In 68% of patients, LVESV decreased by 10% or more. QI was significantly related to reverse remodelling (r = + 0.22; 95% CI: 0.11 to 0.32, p = 0.001). The cut-off value of QI that predicted best LV reverse remodelling after 6 months of CRT was 12.25% (sensitivity 65,49%, specificity 75%, area under the curve 0.7, p = 0.001).

Regarding clinical outcomes at 12 mounths, a statistically significant difference was found between patients with a QI ≤ 12.25%, and those with a QI > 12.25%, in terms of NYHA class worsening (p 0,04). Another statistically significant difference was found analyzing the relation between QI and the causes of deaths, the mean of the QI of patients who died from cardiovascular causes was lower than patients who died of other causes. (p 0,0179).

Conclusions

Therefore decrease in QRSd after CRT initiation was related to greater echocardiographic reverse remodelling and better outcome from death or cardiovascular hospitalization.

Even if larger studies are needed, QI seems to be an easy-to- measure variable that could be used or evaluated to predict CRT response.

7 EXPLOITABILITY AND DISTRIBUTION OF SLEEP APNEA AND ATRIAL FIBRILLATION BURDEN DURING LONG TERM FOLLOW-UP IN UNSELECTED DUAL-CHAMBER PACEMAKER PATIENTS

Background

Sleep Apnea (SA) and Atrial Fibrillation (AF) are common comorbidities in paced patients (pts). Modern pacemakers (PMs) are capable of storing continuous long-term reliable daily information about: 1) AF burden (AFB); 2) severity of SA, defined by a respiratory disturbances index (RDI) measured by a minute ventilation sensor-based algorithm.

Aim of the study

This retrospective study aimed to assess exploitability and distributions of daily AFB and RDI over long-term follow-up (FU) in unselected dual-chamber (DC) paced pts implanted with PMs equipped with a dedicated SA monitoring (SAM) algorithm and followed-up in their Institutions. Pts affected by permanent AF were excluded from the study.

Methods

Data from long-term FU have been collected after implant, together with pts clinical baseline characteristics. Between Aug 2013 and Oct 2018, n=210 pts were implanted with Reply 200/Kora 100 PMs (MicroPort CRM, Saluggia-VC, Italy), equipped with the SAM algorithm. At each FU visit all the daily AFB and RDI data were retrieved from the PM memory. Days of FU have been considered exploitable (Expl-FU) when both the daily AFB and RDI information were available.

Results

Data from n=864 visits are available for analysis. Pts characteristics: male 56.2%, mean age 76.4±11.1 yrs, BMI 25.6±4.4 Kg/m2; implant indication: sinus node disease 40.5%, AV block 46.2%; 37.1% of pts had a history of paroxysmal AF. The overall FU / Expl-FU durations were 1.94±1.23 / 1.48±1.14 years (23.7% of days were lost due to various technical reasons). The PMs classified RDI as valid in 92.3%±19.5% of nights (85.7% of pts showed >90% of valid nights, Figure 1). Severe or moderate SA was suspected in 43.8% and 59.5% of pts, respectively. An AFB≥25% / 50% was observed in 9.5% / 5.7% of pts (Figure 2).

Conclusions

In this retrospective study, SA and AF have been shown to highly affect unselected DC paced pts. PM devices proved to be really helpful in consistently and reliably measure both SA (RDI successfully identified in 92.3%±19.5% of nights) and AF (9.5% of pts with AFB≥25%). This is relevant to allow clinicians to implement early preventive actions to improve clinical prognosis.

Leadless pacemakers as a new alternative for pacemaker lead-related superior vena cava syndrome: A case report

Superior vena cava (SVC) syndrome is a rare disease induced by thrombosis and consequent occlusion of SVC, negatively affecting morbidity and mortality. The incidence of SVC syndrome from central venous catheters and pacemaker or defibrillator leads is increasing. Optimal treatment of pacemaker or defibrillator-related SVC syndrome is not well defined. Lead extraction causes mechanical trauma to the vessel wall. In addition, subsequent device implantation on the contralateral side can be an added factor for venous occlusion. The use of leadless pacemakers could be an interesting option to reduce the risk of SVC restenosis after lead extraction. We report a clinical case of PM leads-related SVC syndrome referred to our centers and treated with transvenous lead extraction, leadless pacemaker implantation and subsequent percutaneous angioplasty and stenting of the SVC and left innominate vein.

[Management of infections in patients with cardiac implantable electronic devices]

Implantation of pacemakers and cardiac defibrillators is a life-saving treatment but can put our patients at risk of infections, increasing morbidity and mortality and prolonging hospitalization with a significant financial healthcare burden. A preventive strategy is crucial but, while several strategies such as administration of intravenous antibiotic therapy before implantation are well recognized, other uncertainties remain. The main gaps regard the use of periprocedural measures, including antibacterial envelope to prevent device infection, the appropriate management of antithrombotic therapy before and after device implantation and timing of device reimplantation. To address these issues, some important randomized clinical trials and a European Heart Rhythm Association consensus document have recently been published. The aim of this article is to review current knowledge on the management of infections in patients with cardiac implantable electronic devices to help not only electrophysiologists, but also physicians in their daily practice.

538 Impact of prior statin use on clinical outcomes in COVID-19 patients: data from tertiary referral hospital during COVID-19 pandemic in Italy

Aims

Epidemiological evidence suggests that anti-inflammatory and immuno-modulatory properties of statins may reduce the risk of infections and infection-related complications. In this observational multi-centre study, we aimed to assess the impact of prior statin use on coronavirus disease (COVID-19) severity and mortality.

Methods and results

Consecutive patients hospitalized for COVID-19 were considered and enrolled in four tertiary referral hospitals (Luigi Sacco Hospital, Milan; Policlinico Umberto I Hospital, Rome; Spedali Civili Hospital, Brescia; Humanitas Gavazzeni Hospital; Bergamo) From 23 February 2020 to 31 March 2020, in-hospital mortality and severity of COVID-19 assessed with National Early Warning Score (NEWS) were deemed primary and secondary outcomes, respectively. Among 842 patients enrolled, 179 (21%) were treated with statins before admission. Statin patients showed more comorbidities and more severe COVID-19 [NEWS 4 (IQR: 2–6) vs. 3 (IQR: 2–5), P < 0.001]. Despite having similar rates of intensive care unit admission, noninvasive ventilation, and mechanical ventilation, statin users appeared to show higher mortality rates. After balancing pre-existing relevant clinical conditions that could affect COVID-19 prognosis with propensity score matching, statin therapy confirmed its association with a more severe disease (NEWS ≥ 5; 61% vs. 48%, P = 0.025) but not with in-hospital mortality (26% vs. 28%, P = 0.185). At univariate logistic regression analysis, statin use was confirmed not to be associated with mortality (OR: 0.901; 95% CI: 0.537–1.51; P = 0.692) and to be associated with a more severe disease (NEWS ≥ 5 OR: 1.7; 95% CI: 1.067–2.71; P = 0.026).

Conclusions

Our results did not confirm the supposed favourable effects of statin therapy on COVID-19 outcomes. Conversely, they suggest that statin use should be considered as a proxy of underlying comorbidities, which indeed expose to increased risks of more severe COVID-19.

[Arrhythmias and sudden death in neuromuscular disorders]

Neuromuscular diseases (NMD) are a broadly defined group of disorders that all involve injury or dysfunction of peripheral nerves, neuromuscular junction or muscle, often with dominant or recessive pattern of inheritance. Cardiac involvement is uncommon, in particular with cardiomyopathies and brady/tachyarrhythmias. The causes of cardiac involvement are unclear: replacement fibrosis, alteration of membrane permeability, sympathetic hyperactivity, or accumulation of toxic metabolites can play a role in the pathogenesis of cardiac disorders. The early diagnosis is of pivotal importance to prevent evolution of the disease: electrocardiographic alterations and arrhythmias, particularly if associated with family history for cardiomyopathy or sudden death, can be an early signal of cardiomyopathy associated with NMD. Genetic analysis can improve prognostic stratification, particularly related to arrhythmic risk, and guide to a tailored therapy.

Impact of COVID-19 lockdown in patients with implantable cardioverter and cardiac resynchronization therapy defibrillators: insights from daily remote monitoring transmissions

Funding Acknowledgements

Type of funding sources: None.

Background

In Italy, a strict lockdown was imposed from 8 March 2020 to stop the spread of the Coronavirus Disease 2019 (COVID-19).

Purpose

To explore the effect of this lockdown on data transmitted by remote monitoring (RM) of implantable cardioverter and cardiac resynchronization therapy defibrillators (ICDs/CRT-Ds).

Methods

RM daily transmissions from ICDs and CRT-Ds were analyzed and compared in two consecutive 1-month frames pre- and post-lockdown: Period I (7 February–7 March 2020) and Period II (8 March–7 April 2020).

Results

The study cohort included 180 patients (81.1% male, 63.3% ICDs and 36.7% CRT-Ds) with a median age of 70 (interquartile range 62-78) years. The median value of physical activity provided by accelerometric sensors showed a significant reduction between Period I and II (13.1% [8.2-18.1%] versus 9.4% [6.3-13.8%], p < 0.001]. Eighty-nine percent of patients decreased their activity, for 43.3% the relative reduction was ≥25%. The mean heart rate decreased significantly (69.2 [63.8-75.6] bpm vs 67.9 [62.7- 75.3] bpm, p < 0.001), but with greater reduction (≈3 beats/minute) in patients aged < 70 years. Resting heart rate and thoracic impedance showed minor variations. No differences were observed in device pacing percentages and arrhythmias.

Conclusions

In cardiac patients, the lockdown imposed to contain COVID-19 outbreak significantly reduced the amount of physical activity and the mean heart rate. These side effects of in-home confinement quarantine should be taken in consideration for frail patients.

Remote monitoring temporal trends during COVID-19 pneumonia in patients with implanted defibrillators

It is unknown whether some of the clinical parameters transmitted by remote monitoring (RM) of cardiac implanted devices could show recurrent patterns caused by COVID-19 infection. Our aim was to describe RM daily temporal trends for implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) recipients during COVID-19 infection. A 65-year-old woman with a CRT-D had a sudden increase of approximately 15 bpm and 10 bpm in nocturnal and mean heart rate, respectively, 11 days before hospitalization for COVID-19 pneumonia. At the same time physical activity decreased progressively and continuously. A 78-year-old woman with an ICD showed significant changes in RM trends starting from the COVID-19-related symptoms: strong decrease in physical activity, progressive increase in mean and nocturnal heart rate, irregular trend of heart rate variability, and rapid drop in thoracic impedance. Two months later, on hospitalization, computed tomography showed a "crazy-paving" pattern of the lungs, which is a clinical picture of COVID-19 pneumonia with concomitant pleural effusion. <Learning objective: Patients with complications related to the COVID-19 infection appeared to show variations in the remote monitoring (RM) temporal trends of clinical variables daily transmitted from implanted cardiac devices. These changes may not be specific to COVID-19, but owing to the severity of the pandemic, the use of RM to capture patient's condition makes intuitive sense for early diagnosis, intervention, and additional follow-up in this high-risk population.>.

Oral anticoagulation and clinical outcomes in COVID-19: An Italian multicenter experience

BACKGROUND

Since the body of evidence addressing the coagulation derangements caused by Coronavirus disease (COVID-19) has been constantly growing, we investigated whether pre-hospitalization oral anticoagulation (OAC) or in-hospital heparin treatment could have a protective role among COVID-19 patients.

METHOD

In this cohort study, consecutive COVID-19 patients admitted to four different Italian Institutions were enrolled. Baseline demographic, clinical, laboratory, and radiological characteristics, as well as in-hospital treatment and outcomes were evaluated. The primary outcome was mortality.

RESULTS

A total of 844 COVID-19 patients were enrolled as study cohort, n = 65 (7.7%) taking OACs prior to hospitalization. Regarding clinical outcomes, OAC patients developed acute hypoxemic respiratory failure (AHRF) more frequently than non-OAC patients as well as presenting a higher mortality rate (44.6% vs 19.8%, p < 0.001). At overall multivariate logistical regression, use of heparin (n = 394, 46.6%) was associated with a better chance of survival to hospital discharge (OR 0.60 [0.38-0.94], p < 0.001), in particular in patients with AHRF, with no association found with the use of OACs. In a sub-analysis, the highest mortality rate was found for AHRF patients when heparin was not administered.

CONCLUSION

In our cohort, OACs appeared to be ineffective in reducing mortality rate, while heparin resulted to be a useful treatment when lung disease was sufficiently severe, potentially suggesting a crucial role of microthrombosis in severe COVID-19. Due to the relatively small number of COVID-19 patients treated with OACs included in our analysis and their higher number of comorbidities, larger studies are needed in order to confirm our findings.

Impact of prior statin use on clinical outcomes in COVID-19 patients: data from tertiary referral hospitals during COVID-19 pandemic in Italy

BACKGROUND

Epidemiological evidence suggests that anti-inflammatory and immunomodulatory properties of statins may reduce the risk of infections and infection-related complications.

OBJECTIVE

We aimed to assess the impact of prior statin use on coronavirus disease (COVID-19) severity and mortality.

METHODS

In this observational multicenter study, consecutive patients hospitalized for COVID-19 were enrolled. In-hospital mortality and severity of COVID-19 assessed with National Early Warning Score (NEWS) were deemed primary and secondary outcomes, respectively. Propensity score (PS) matching was used to obtain balanced cohorts.

RESULTS

Among 842 patients enrolled, 179 (21%) were treated with statins before admission. Statin patients showed more comorbidities and more severe COVID-19 (NEWS 4 [IQR 2-6] vs 3 [IQR 2-5], p < 0.001). Despite having similar rates of intensive care unit admission, noninvasive ventilation, and mechanical ventilation, statin users appeared to show higher mortality rates. After balancing pre-existing relevant clinical conditions that could affect COVID-19 prognosis with PS matching, statin therapy confirmed its association with a more severe disease (NEWS ≥5 61% vs. 48%, p = 0.025) but not with in-hospital mortality (26% vs. 28%, p = 0.185). At univariate logistic regression analysis, statin use was confirmed not to be associated with mortality (OR 0.901; 95% CI: 0.537 to 1.51; p = 0.692) and to be associated with a more severe disease (NEWS≥5 OR 1.7; 95% CI 1.067-2.71; p = 0.026).

CONCLUSIONS

Our results did not confirm the supposed favorable effects of statin therapy on COVID-19 outcomes. Conversely, they suggest that statin use should be considered as a proxy of underlying comorbidities, which indeed expose to increased risks of more severe COVID-19.

Clinical Discussions in Antithrombotic Therapy Management in Patients With Atrial Fibrillation: A Delphi Consensus Panel

Background

In recent years, direct-acting oral anticoagulants (DOACs) have entered clinical practice for stroke prevention in non-valvular atrial fibrillation or prevention and treatment of venous thromboembolism. However, remaining uncertainty regarding DOAC use in some clinical scenarios commonly encountered in the real world has not been fully explored in clinical trials.

Methods

We report on use of a Delphi consensus process on DOAC use in non-valvular atrial fibrillation patients. The consensus process dealt with 9 main topics: (i) DOACs vs vitamin K antagonists in atrial fibrillation (AF) patients; (ii) therapeutic options for patients with stable total time in range treated with vitamin K antagonists; (iii) therapeutic options for patients aged > 85 years; (iv) therapeutic management of hyperfiltering patients; (v) pharmacologic interactions; (vi) therapeutic options in the long-term treatment (prevention) of patients with AF and acute coronary syndrome after the triple therapy; (vii) low doses of DOACs in AF patients; (viii) ischemic stroke in patients inappropriately treated with low doses of DOACs; (ix) management of patients taking DOACs with left atrial appendage thrombosis.

Results

A total of 101 physicians (cardiologists, internists, geriatricians, and hematologists) from Italy expressed their level of agreement on each statement by using a 5-point Likert scale (1 = strongly disagree; 2 = disagree; 3 = somewhat agree; 4 = agree; 5 = strongly agree). Votes 1-2 were considered to be disagreement; votes 3-5 were considered to be agreement. Agreement among the respondents of ≥ 66% for each statement was considered consensus. A brief discussion of the results for each topic is also reported.

Conclusions

In clinical practice, there is still uncertainty on DOAC use, especially in elderly, fragile, comorbid, and hyperfiltering patients.

Second European Society of Cardiology Cardiac Resynchronization Therapy Survey: the Italian cohort

AIM

Adherence to guidelines was not homogeneous in Europe, according to the survey on cardiac resynchronization therapy conducted in 2008-2009. The aim of our study was to compare the results in the Italian and European cohorts of the Second European Cardiac Resynchronization Therapy Survey.

METHODS

Patients' characteristics, procedural data and follow-up were collected. Italian records were compared with European countries.

RESULTS

Italian hospitals enrolled 526 patients. The italian cohort was older (71.6 ± 9.5 vs. 68.4 ± 10.8; P < 0.00001), had less severe NYHA class (>II 47.2 vs. 59.6%; P < 0.00001), higher ejection fraction (30.3 ± 7.4 vs. 28.4 ± 8.2%; P < 0.00001), and less atrial fibrillation prevalence (34.4 vs. 41.2%; P = 0.00197) than the European cohort. Italian patients were more frequently hospitalized for heart failure in the previous year (51.9 vs. 46.2%; P = 0.01118) and had lower mean QRS duration (151 ± 26 vs. 157 ± 27 ms; P < 0.0001). CRT-D were more often implanted in Italian patients (79.3 vs. 69.3%; P < 0.00001). The complication rate was similar (4.6% vs. 5.6%; ns). The rate of use of ACEi/ARBs in Italy was lower than in Europe (77.2 vs. 86.9%; P < 0.00001). Patients were followed up in the implantation centre (92.1 vs. 86%; P = 0.00014), but rarely with remote monitoring (25.9 vs. 30%; P = 0.04792).

CONCLUSION

The survey demonstrates important similarities as well as substantial differences regarding most of the aspects evaluated. Efforts to implement adherence to guidelines will be endorsed in Italy.

Use of the new rotating dilator sheath TightRail™ for lead extraction: A bicentric experience

AIM

The aim of this study is to assess the safety and efficacy of the new bidirectional rotational mechanical sheath TightRail™ (Spectranetics) for lead extraction.

METHODS AND RESULTS

This is a bicentric prospective study that included patients who underwent a transvenous lead extraction (TLE) in two Italian centers (San Raffaele Hospital and Humanitas Gavazzeni Hospital). From November 2016 to December 2018, 26 patients underwent a TLE procedure in which the TightRail™ was used. The new TightRail Sub-C was used in 20 (76%) patients to overcome the fibrosis between the vessel and the first rib. Median age was 69 (IQR 60.7-79.5) years. The indication for TLE were infection (57.7%) or lead dysfunction (42.3%). A total of 57 leads (range 1-4), 40 of which using the TightRail (range 1-4), were extracted. Overall mean implant duration was 98.2.0 ± 66.5 months. Mean age of the lead extracted with the TightRail sheath was 99.1 ± 70.2 months and was higher compared to that of the leads extracted manually (84.4 ± 60.3 months, P = .001). The overall clinical success was 100% and complete procedural success without the use of a snare was achieved in 98.3%. There were no cases of death or major complications and only two minor complications occurred. All patients were event-free at 6-month follow-up.

CONCLUSION

This initial experience using the TightRail™ suggests a high safety and efficacy profile for extractions in a wide range of lead age.

The influence of age on the psychological profile of patients with cardiac implantable electronic devices: results from the Italian population in a multicenter study conducted by the European Heart Rhythm Association

BACKGROUND

Cardiac implantable electronic devices (CIEDs) are widely used to treat bradyarrhythmias or improve the prognosis of patients with heart failure (HF).

AIMS

To evaluate age-related (≤ 75 vs. > 75 years) attitudes, worries, psychological effects and needs in an Italian CIEDs population.

METHODS

Patients attending their periodical ambulatory evaluation received a questionnaire conceived by the European Heart Rhythm Association Scientific Initiatives Committee as part of a multicenter, multinational snapshot survey. Seven countries participated in the study, and 1646 replies were collected. Of these, 437 (27%) were from Italy. Present results refer to the Italian population only. CIEDs were stratified into devices to treat bradycardia or HF.

RESULTS

The use of CIEDs was more common in advanced age. Older patients needed less information about CIEDs than younger ones (p = 0.044), who would prefer to be better informed about CIEDs-related consequences on psychologic profile (p = 0.045), physical (p < 0.001) and sexual (p < 0.001) activities, and driving limitations (p = 0.003). When compared to older subjects, younger individuals experienced more difficulties (p = 0.035), especially in their professional (p < 0.001) and private life (p = 0.033), feeling their existence was limited by the device (p < 0.001). Conversely, quality of life (HRQL) more often improved in the elderly (p = 0.001). Information about what to do with CIEDs at the end of life is scant independently of age.

CONCLUSIONS

HRQL after CIEDs implantation improves more frequently in older patients, while the psychological burden of CIEDs is usually higher in younger patients. End of life issues are seldom discussed.

Effects of immune system status on long-term results of cardiac resynchronization therapy

AIM

Cardiac resynchronization therapy (CRT) is an effective therapy for patients with reduced systolic function and enlarged QRS. Recently, some Authors have demonstrated that the presence of positive antinuclear antibodies (ANAs) may play a role in the development of heart failure in a population of patients implanted with PM.

METHODS

We investigated the effect of positive ANAs in 90 patients (mean age 71±8 years) implanted with a CRT device in our Centre between May 2010 and June 2013. To assess for immunologic contribution to CRT outcome, patients were divided into positive and negative ANAs (ANA +, ANA -), considering as positive patients with an ANAs dilution > 1:80. The primary endpoint was constituted by a combined endpoint of death or first hospitalization for heart failure; secondary endpoints were constituted by: 1) incidence of first hospitalization for heart failure; and 2) total cause mortality.

RESULTS

After a mean follow-up of 1200 days, primary endpoint occurred in 11 patients (30%) of ANA+ group and in 8 patients (15.1%) of ANA-group. The significant difference is due to difference in heart failure events (27% vs. 11.3%, P<0.05), whilst difference in total mortality did not reach statistical significance (10.8% vs. 3.8%).

CONCLUSION

Immune status seems to play a role in patients with congestive heart failure. If this immunological alteration is a determinant or a consequence of heart failure remains unclear.

[Acute results of left ventricular endocardial pacing for cardiac resynchronization therapy obtained with a transapical approach]

Although cardiac resynchronization therapy (CRT) is considered a milestone in the treatment of patients affected with chronic congestive heart failure, reduced left ventricular ejection fraction and enlarged QRS, up to 30% of patients can be considered clinical non-responders to this treatment. In these patients, optimization of atrioventricular and interventricular intervals could be of some help, but results of trials are not univocal on the benefit of this procedure. In the last years, left ventricular endocardial pacing for CRT has emerged as a possible solution in non-responders. Several studies have demonstrated its feasibility and safety, and some reports suggest its incremental efficacy in comparison with traditional epicardial pacing, both obtained transvenously or surgically. We describe the cases of two patients already implanted with a CRT device who came to our attention for clinical non-responsiveness to CRT and who have been successfully treated with the addition of a left endocardial lead. A brief literature review on this topic is also reported.

Relation of QRS duration to response to cardiac resynchronization therapy

Left bundle branch block (LBBB) is the most reliable electrocardiographic predictor of responsiveness to cardiac resynchronization therapy (CRT). However, not all patients with LBBB will respond to CRT. Our aim was to investigate the interaction between QRS duration, LBBB-type morphology, and the responsiveness to CRT. We retrospectively analyzed electrocardiograms of 243 patients who underwent CRT implantation according to current clinical indications. A 6-month reduction of left ventricular end-systolic volume >15% was used to identify CRT responders. The clinical end point consisted of death, hospitalization for heart failure and sustained rapid ventricular tachyarrhythmias. An LBBB morphology was present in 169 patients (70%) and 101 of these (60%) were responders to CRT. Analyzing the interaction between QRS duration and CRT responsiveness in patients with LBBB, a "U shaped" distribution resulted, with nonresponders clustered between 120 and 130 ms and above 180 ms. The receiver operating characteristic curve analysis identified 178 ms as the optimal cut-off value of QRS to predict a nonresponsiveness to CRT (area under the curve = 0.67 [95% confidence interval 0.57 to 0.76]). At multivariate analysis, only an ischemic cause and a QRS ≥178 ms were independent predictors of nonresponsiveness to CRT (area under the curve = 0.75). Patients with LBBB with QRS ≥178 ms had greater likelihood of adverse clinical events during a mean follow-up of 32 months (p = 0.049). In conclusion, in patients with LBBB undergoing CRT, a marked QRS widening (i.e., ≥178 ms) is related to worse echocardiographic responsiveness and lower event free survival rate compared with patients with an intermediate QRS widening.

Further evidence for the topography and connectivity of the corpus callosum: an FMRI study of patients with partial callosal resection

BACKGROUND AND PURPOSE

This functional MRI study was designed to describe activated fiber topography and trajectories in the corpus callosum (CC) of six patients carrying different degree of partial callosal resection.

METHODS

Patients receiving gustatory, tactile, and visual stimulation according to a block-design protocol were scanned in a 1.5 Tesla magnet. Diffusion tensor imaging (DTI) data were also acquired to visualize spared interhemispheric fibers.

RESULTS

Taste stimuli evoked bilateral activation of the primary gustatory area in all patients and foci in the anterior CC, when spared. Tactile stimuli to the hand evoked bilateral foci in the primary somatosensory area in patients with an intact posterior callosal body and only contralateral in the other patients. Callosal foci occurred in the CC body, if spared. In patients with an intact splenium central visual stimulation induced bilateral activation of the primary visual area as well as foci in the splenium itself.

CONCLUSION

Present data show that interhemispheric fibers linking sensory areas crossed through the CC at the sites where the different sensory stimuli evoked activation foci, and that topography of callosal foci evoked by sensory stimulation in spared CC portions is consistent with that previously observed in subjects with intact CC.

Effects of smoking in patients treated with cardiac resynchronization therapy

Smoking is associated with increased morbidity and mortality in cardiac patients. However, data on the prognostic impact of smoking in heart failure (HF) patients on cardiac resynchronization therapy with defibrillator (CRT-D) are absent. We investigated the effects of smoking on all-cause mortality and on a composite endpoint (all-cause death/appropriate device therapy), appropriate and inappropriate device therapy, in 649 patients with HF who underwent CRT-D between January 2003 and October 2011 in 6 Centers (4 in Italy and 2 in USA). 68 patients were current smokers, 396 previous-smokers (patients who had smoked in the past but who had quit before the CRT-D implant), and 185 had never smoked. The risk of each endpoint by smoking status was evaluated with both Kaplan-Meier and Cox proportional-hazard analysis. After adjusting for age, left ventricular ejection fraction, QRS width and ischemic etiology, both current and previous smoking were independent predictors of all-cause death [HR = 5.07 (95 % CI 2.68-9.58), p < 0.001 and HR = 2.43 (95 % CI 1.38-4.29), p = 0.002, respectively) and of composite endpoint [HR = 1.63 (1.04-2.56); p = 0.033 and HR = 1.46 (1.04-2.04) p = 0.027]. In addition, current smokers had a significantly higher rate of inappropriate device therapy compared to never smokers [HR = 21.74 (4.53-104.25), p = 0.005]. Our study indicates that in patients with HF who received a CRT-D device, current and previous smoking increase the event rate per person-time of death and of appropriate and inappropriate ICD therapy more than other known negative prognostic factors such as age, left ventricular dysfunction, prolonged QRS duration and ischemic etiology.

[Remarks on the guideline recommendations for cardioverter-defibrillator implantation for primary prevention of sudden cardiac Death in patients with severe ventricular dysfunction. Consensus Document of the Italian Association of Hospital Cardiologists (ANMCO)/Italian Society of Cardiology (SIC)/Italian Association of Arrhythmology and Cardiac Pacing (AIAC)]

The indications for implantable cardioverter-defibrillator (ICD) therapy for the prevention of sudden cardiac death in patients with severe left ventricular dysfunction have rapidly expanded over the last 10 years on the basis of the very satisfying results of the numerous randomized clinical trials that have provided the framework for guidelines. However, the analysis of clinical practice in the real world has highlighted some important criticisms in the complex process of selection-management of those patients candidates for ICD therapy: 1) approximately one fourth of all ICD implantations is not justified by clinical evidence, 2) approximately one half of patients with an indication for ICD therapy do not undergo implantation, 3) the benefits from ICD therapy do not apply uniformly to all patients, 4) the relationship between the lifesaving benefit and the potential for harm of ICD therapy is still scarcely known. The main reason for this clinical scenario can be ascribed to the guideline recommendations that are based only on few standard cut-off criteria and therefore too generic and insufficiently detailed. This does not help cardiologists in their decision-making process, and results in fear, uncertainty, and sometimes emotional choices. The aim of this consensus document is to discuss current guideline recommendations and to provide the Italian cardiologists with the most updated information to optimize the selection of patients with severe left ventricular dysfunction who should receive ICD therapy.

Risk stratification in Brugada syndrome: results of the PRELUDE (PRogrammed ELectrical stimUlation preDictive valuE) registry

OBJECTIVES

The PRELUDE (PRogrammed ELectrical stimUlation preDictive valuE) prospective registry was designed to assess the predictive accuracy of sustained ventricular tachycardia/ventricular fibrillation (VTs/VF) inducibility and to identify additional predictors of arrhythmic events in Brugada syndrome patients without history of VT/VF.

BACKGROUND

Brugada syndrome is a genetic disease associated with increased risk of sudden cardiac death. Even though its value has been questioned, inducibility of VTs/VF is widely used to select candidates to receive a prophylactic implantable defibrillator, and its accuracy has never been addressed in prospective studies with homogeneous enrolling criteria.

METHODS

Patients with a spontaneous or drug-induced type I electrocardiogram (ECG) and without history of cardiac arrest were enrolled. The registry included 308 consecutive individuals (247 men, 80%; median age 44 years, range 18 to 72 years). Programmed electrical stimulation was performed at enrollment, and patients were followed-up every 6 months.

RESULTS

During a median follow-up of 34 months, 14 arrhythmic events (4.5%) occurred (13 appropriate shocks of the implantable defibrillator, and 1 cardiac arrest). Programmed electrical stimulation performed with a uniform and pre-specified protocol induced ventricular tachyarrhythmias in 40% of patients: arrhythmia inducibility was not a predictor of events at follow-up (9 of 14 events occurred in noninducible patients). History of syncope and spontaneous type I ECG (hazard ratio [HR]: 4.20), ventricular refractory period <200 ms (HR: 3.91), and QRS fragmentation (HR: 4.94) were significant predictors of arrhythmias.

CONCLUSIONS

Our data show that VT/VF inducibility is unable to identify high-risk patients, whereas the presence of a spontaneous type I ECG, history of syncope, ventricular effective refractory period <200 ms, and QRS fragmentation seem useful to identify candidates for prophylactic implantable cardioverter defibrillator.

Critical appraisal of cardiac implantable electronic devices: complications and management

Population aging and broader indications for the implant of cardiac implantable electronic devices (CIEDs) are the main reasons for the continuous increase in the use of pacemakers (PMs), implantable cardioverter-defibrillators (ICDs) and devices for cardiac resynchronization therapy (CRT-P, CRT-D). The growing burden of comorbidities in CIED patients, the greater complexity of the devices, and the increased duration of procedures have led to an augmented risk of infections, which is out of proportion to the increase in implantation rate. CIED infections are an ominous condition, which often implies the necessity of hospitalization and carries an augmented risk of in-hospital death. Their clinical presentation may be either at pocket or at endocardial level, but they can also manifest themselves with lone bacteremia. The management of these infections requires the complete removal of the device and subsequent, specific, antibiotic therapy. CIED failures are monitored by competent public authorities, that require physicians to alert them to any failures, and that suggest the opportune strategies for their management. Although the replacement of all potentially affected devices is often suggested, common practice indicates the replacement of only a minority of devices, as close follow-up of the patients involved may be a safer strategy. Implantation of a PM or an ICD may cause problems in the patients’ psychosocial adaptation and quality of life, and may contribute to the development of affective disorders. Clinicians are usually unaware of the psychosocial impact of implanted PMs and ICDs. The main difference between PM and ICD patients is the latter’s dramatic experience of receiving a shock. Technological improvements and new clinical evidences may help reduce the total burden of shocks. A specific supporting team, providing psychosocial help, may contribute to improving patient quality of life.

Actions elicited during scheduled and unscheduled in-hospital follow-up of cardiac devices: results of the ATHENS multicentre registry

AIM

The number of cardiac implantable electronic devices (CIEDs) is continuously growing and this translates into a high number of in-hospital follow-ups. This workload justifies the increasing popularity of remote monitoring systems for the follow-up of CIEDs. The ATHENS registry was designed to find out what actions are taken during in-hospital follow-up of CIEDs at 10 different centres in Northern Italy.

METHODS AND RESULTS

Between 1 March 2010 and 30 June 2010, all patients who came to our centres for a follow-up of their CIEDs were enrolled in the registry. We defined as visit with an action (VWA) a follow-up that elicited an action in that patient. The primary endpoint was the prevalence of VWA on the whole population. The secondary endpoints were: prevalence of VWA on the pacemaker (PM) population; prevalence of VWA on the implantable cardioverter defibrillator (ICD) population; prevalence of VWA on the cardiac resynchronization therapy (CRT) population; predictors of VWA in univariate and multivariate analyses. A total of 3362 patients were recruited. The primary endpoint was reached in 762 patients, 22.8% of patients (95% CI 21.4-24.3). The prevalence of action was highest for CRT (29.8%), followed by PM (22.8%) and ICD (18.6%). In a multivariate model, the prevalence of action was higher for CRT, than for PM and was lowest for ICD and it was higher for unscheduled visits and first visits than for scheduled visits.

CONCLUSIONS

Our registry demonstrates that 'some actions' are taken during about 20% of scheduled in-hospital follow-up of CIEDs. These data should encourage the use of remote follow-up systems.

A Guide to the Use of Left Ventricular Analysis with 3D Echo in Dyssynchrony

Data from single-centre studies suggest that echocardiographic parameters of mechanical dyssynchrony may improve patient selection for cardiac resynchronisation therapy (CRT). To our knowledge, the only published multicentre trial that compared 12 echocardiographic methods, the Predictors of response to cardiac resynchronization therapy (PROSPECT) trial, stated that none of the echocardiographic measurements of ventricular dyssynchrony applied in the study were able to distinguish responders from non-responders. Realtime 3D echocardiography is able to measure left ventricular (LV) size, function and dyssynchrony to identify the presence and extension of scar tissue and to evaluate where the site of latest mechanical activation is. After CRT device implantation, it also allows physicians to detect where the first mechanical activation secondary to LV pacing is located. Indeed, it can be useful in interventricular (VV) delay optimisation of the device after the implantation and, in single-centre studies, it was able to predict response to CRT and to identify responders from non-responders. Care must be taken to optimise temporal resolution, but now volume rates of 70–80vps can be easily obtained in the majority of cases. VV optimisation using realtime 3D echocardiography is feasible and intuitive, but time-consuming compared with traditional methods based on Doppler or algorithms. In this article we illustrate our approach to LV analysis with realtime 3D echocardiography in the study of dyssynchrony.

An observational registry on efficacy and safety of the right ventricular outflow tract as a site for ICD leads: results of the EFFORT (EFFicacy Of Right ventricular outflow Tract as site for ICD leads) registry

BACKGROUND

Although pacing from the right ventricular outflow tract (RVOT) has been shown to be safe and feasible in terms of sensing and pacing thresholds, its use as a site for implantable cardioverter defibrillator (ICD) leads is not common. This is probably due to physicians' concerns about defibrillation efficacy. To date, only one randomized trial, involving 87 enrolled patients, has evaluated this issue.

OBJECTIVE

The aim of this observational study has been to compare safety (primary combined end point: efficacy of a 14-J shock in restoring sinus rhythm, R wave amplitude >4 mV and pacing threshold <1 V at 0.5 ms) and efficacy (in terms of effectiveness of a 14-J shock in restoring sinus rhythm after induction of VF, secondary end point) of two different sites for ICD lead positioning: RVOT and right ventricular apex (RVA).

METHODS

The study involved 185 patients (153 males; aged 67 ± 10 years; range, 28-82 years). Site of implant was left to physician's decision. After implant, VF was induced with a 1-J shock over the T wave or--if this method was ineffective--with a 50-Hz burst, and a 14-J shock was tested in order to restore sinus rhythm. If this energy was ineffective, a second shock at 21 J was administered and--eventually--a 31-J shock followed--in case of inefficacy--by a 360-J biphasic external DC shock. Sensing and pacing thresholds were recorded in the database at implant, together with acute (within 3 days of implant) dislodgement rate.

RESULTS

The combined primary end point was reached in 57 patients in the RVOT group (0.70%) and in 81 patients in the RVA group (0.79%). The 14-J shock was effective in 159 patients, 63 in the RVOT group (77%) and 86 in the RVA group (83%). Both the primary and the secondary end points are not statistically different. R wave amplitude was significantly lower in the RVOT group (10.9 ± 5.2 mV vs. 15.6 ± 6.4 mV, p < 0.0001), and pacing threshold at 0.5 ms was significantly higher (0.64 ± 0.25 V vs. 0.52 ± 0.20 V, p < 0.01), but these differences do not seem to have a clinical meaning, given that the lower values are well above the accepted limits in clinical practice.

CONCLUSIONS

Efficacy and safety of ICD lead positioning in RVOT is comparable to RVA. Even if we observed statistically significant differences in sensing and pacing threshold, the clinical meaning of these differences is--in our opinion--irrelevant.

Diffusion tensor tracking of callosal fibers several years after callosotomy

Diffusion tensor imaging (DTI) can provide more detailed in vivo information on the structural preservation of transected white matter tracts than conventional imaging methods. Here we show for the first time tracks of severed callosal fibers up to 17 years from resection. Five patients subjected to complete or partial callosotomy several years before the study were examined with DTI and compared to a normal control. Transected fibers were traced in all patients and were more clearly visible in the anterior and posterior parts than in the middle of the commissure. These findings suggest that microstructural changes persist for many years in the severed fibers, as also reflected by fractional anisotropy and apparent diffusion coefficient values, enabling a reconstruction of the longitudinal organization of severed central tracts that could not be achieved with previous techniques.

Coronary artery spasm as a cause of ST elevation and inappropriate implantable cardioverter defibrillator intervention

Coronary artery spasm can cause both brady- and tachyarrhythmia, through induction of AV block (usually linked to coronary spasm of the right coronary artery) or ventricular tachycardia/fibrillation linked to extensive myocardial ischemia. The electrocardiographic aspect of coronary artery spasm is an ST segment elevation. We describe the case of patient implanted with an implantable cardioverter defibrillator (ICD) for unexplained syncope which, during coronary artery spasm, received an inappropriate device firing due to ST segment elevation, leading to a double count of the QRS by the ICD.

Atrial flutter: from ECG to electroanatomical 3D mapping

Atrial flutter is a common arrhythmia that may cause significant symptoms, including palpitations, dyspnea, chest pain and even syncope. Frequently it’s possible to diagnose atrial flutter with a 12-lead surface ECG, looking for distinctive waves in leads II, III, aVF, aVL, V1,V2. Puech and Waldo developed the first classification of atrial flutter in the 1970s. These authors divided the arrhythmia into type I and type II. Therefore, in 2001 the European Society of Cardiology and the North American Society of Pacing and Electrophysiology developed a new classification of atrial flutter, based not only on the ECG, but also on the electrophysiological mechanism. New developments in endocardial mapping, including the electroanatomical 3D mapping system, have greatly expanded our understanding of the mechanism of arrhythmias. More recently, Scheinman et al, provided an updated classification and nomenclature. The terms like common, uncommon, typical, reverse typical or atypical flutter are abandoned because they may generate confusion. The authors worked out a new terminology, which differentiates atrial flutter only on the basis of electrophysiological mechanism.

Contribution of the corpus callosum to bilateral representation of the trunk midline in the human brain: an fMRI study of callosotomized patients

Human brain studies have shown that the cutaneous receptors of trunk regions close to the midline are represented in the first somatosensory cortex (SI) of both hemispheres. The present study aims to establish whether in humans, as in non-human primates, the bilateral representation of the trunk midline in area SI depends on the corpus callosum. Data were obtained from eight callosotomized patients: three with complete callosal resection, one with a partial posterior resection including the splenium and the callosal trunk, and four with partial anterior resections sparing the splenium and in one case also the posterior part of the callosal trunk. The investigation was carried out with functional magnetic resonance imaging. Unilateral tactile stimulation was applied by rubbing ventral trunk regions close to the midline (about 20 x 10 cm in width) with a soft cotton pad (frequency 1 Hz). Cortical activation foci elicited by unilateral stimulation of cutaneous regions adjacent to the midline were detected in the contralateral post-central gyrus (PCG), in a region corresponding to the trunk ventral midline representation zone of area SI, as described in a previous study of intact subjects. In most patients, activation foci were also found in the ipsilateral PCG, again as in subjects with an intact corpus callosum. The data confirm that the skin regions adjacent to the trunk midline are represented bilaterally in SI, and indicate that ipsilateral activation is at least partially independent of the corpus callosum.

Right Ventricular versus Biventricular Antitachycardia Pacing in the Termination of Ventricular Tachyarrhythmia in Patients Receiving Cardiac Resynchronization Therapy: The ADVANCE CRT-D Trial

BACKGROUND

The purpose of this investigation is to compare the efficacy of antitachycardia pacing (ATP) delivered via the right ventricular (RV) lead versus ATP delivered simultaneously via the right and left ventricular leads (biventricular [BiV]) in the termination of ventricular tachyarrhythmia (VT) in patients receiving cardiac resynchronization therapy (CRT) with ICD capabilities.

METHODS AND RESULTS

The ADVANCE CRT is a prospective, multicenter, randomized, parallel trial evaluating RV versus BiV ATP in the termination of VT in CRT patients. The study will test the hypothesis that BiV ATP is superior to RV ATP in the termination of VT and fast VT. All patients with class I and IIa indications for an ICD implantation and CRT are included. The sample size has been estimated to 400 participants followed for 12 months to show a 10% benefit of BiV versus RV ATP. The efficacy of BiV ATP to terminate all VT presents the primary endpoint. The investigation is expected to be completed in 2007.

CONCLUSIONS

The ADVANCE CRT trial is the first large randomized clinical investigation evaluating the efficacy of BiV ATP in patients under CRT and ICD therapy.

QT dispersion on ECG Holter monitoring and risk of ventricular arrhythmias in patients with dilated cardiomyopathy

Background.

QT dispersion (QTd) is increased in patients with dilated cardiomyopathy. Increased QTd has been associated with the risk of sudden death. We studied: a) the relation between QTd on 12-lead ECG and QTd-ECG Holter; b) the relation between QTd apex (QTda) and QTd end (QTde) on ECG Holter and the risk of ventricular arrhythmias in patients with dilated cardiomyopathy.

Methods and Results:

65 patients with dilated cardiomyopathy (33 idiopathic and 32 post-ischemic etiology; NYHA II–III) were studied. We divided the patients into: Group A -patients with not-sustained ventricular arrhythmias-; and Group B -patients without arrhythmias-. A significant direct correlation between QTd calculated from 12-lead ECG and from ECG Holter was found in all patients. QTda/24h was not significantly different in the two groups (Gr.A 59.9±7.8 msec vs Gr.B 53.6±8.4 msec p=ns) while QTde/24h was significantly higher in Group A (Gr.A 81.9±5.9 msec vs Gr.B 44.5±6.8 msec; p<0.005). In post-ischemic etiology (32 pts; 17 with arrhythmias) the correlation between QTde/24h and ventricular arrhythmias was confirmed (Gr.A 81.4±7.8 msec vs Gr.B 42.6±6.2 msec p<0.002).

Conclusions:

ECG Holter recordings can evaluate QTd as well as the QTd on 12-lead ECG. An increased QTde/24h seems to be correlated with the occurence of ventricular arrhythmias in patients with dilated cardiomyopathy and can then be a useful tool to select patients at high risk for sudden death.

Prospective assessment of integrating the existing emergency medical system with automated external defibrillators fully operated by volunteers and laypersons for out-of-hospital cardiac arrest: the Brescia Early Defibrillation Study (BEDS)

AIMS

There are few data on the outcomes of cardiac arrest (CA) victims when the defibrillation capability of broad rural and urban territories is fully operated by volunteers and laypersons.

METHODS AND RESULTS

In this study, we investigated whether a programme based on diffuse deployment of automated external defibrillators (AEDs) operated by 2186 trained volunteers and laypersons across the County of Brescia, Italy (area: 4826 km(2); population: 1 112 628), would safely and effectively impact the current survival among victims of out-of-hospital CA. Forty-nine AEDs were added to the former emergency medical system that uses manual EDs in the emergency department of 10 county hospitals and in five medically equipped ambulances. The primary endpoint was survival free of neurological impairment at 1-year follow-up. Data were analysed in 692 victims before and in 702 victims after the deployment of the AEDs. Survival increased from 0.9% (95% CI 0.4-1.8%) in the historical cohort to 3.0% (95% CI 1.7-4.3%) (P=0.0015), despite similar intervals from dispatch to arrival at the site of collapse [median (quartile range): 7 (4) min vs. 6 (6) min]. Increase of survival was noted both in the urban [from 1.4% (95% CI 0.4-3.4 %) to 4.0% (95% CI 2.0-6.9 %), P=0.024] and in the rural territory [from 0.5% (95% CI 0.1-1.6%) to 2.5% (95% CI 1.3-4.2%), P=0.013]. The additional costs per quality-adjusted life year saved amounted to euro39 388 (95% CI euro16 731-49 329) during the start-up phase of the study and to euro23 661 (95% CI euro10 327-35 528) at steady state.

CONCLUSION

Diffuse implementation of AEDs fully operated by trained volunteers and laypersons within a broad and unselected environment proved safe and was associated with a significantly higher long-term survival of CA victims.

Rate-responsive pacing regulated by cardiac haemodynamics

AIMS

Trans-valvular impedance (TVI) recording has been proposed for the assessment of cardiac haemodynamics, assuming an inverse relationship between TVI and ventricular volume. We checked whether the TVI sensor can drive the rate-responsive function of a cardiac pacemaker following changes in the inotropic regulation of the heart.

METHODS

An external DDD-R pacemaker (Ext Sophos by Medico, Padova, Italy) equipped with the TVI detecting system was tested in 30 patients on the implantation of conventional pacing leads for dual-chamber pacing. Pacing rate regulation was based on the relationship between the stroke volume and the end-diastolic volume, inferred from TVI data. After sensor calibration in basal conditions, beta-adrenergic stimulation was induced by i.v. administration of 2 microg/ml/min isoprenaline (isoproterenol) (IPN). The actual cardiac rate, the TVI waveform, the end-diastolic and systolic TVI in each cardiac cycle and the TVI-indicated rate were stored in memory as a function of time and down-loaded at the end of the session.

RESULTS

All patients with intrinsic atrial activity (28/30) showed a positive chronotropic response to IPN, coupled with a significant increase in end-diastolic TVI and a four-times larger increase in end-systolic TVI. The TVI inotropic index mirrored the sinus rate time-course, with a linear correlation between the two parameters (r(2)>0.7 in 25/28 cases). As a result, the TVI-indicated rate closely reproduced the sinus rate.

CONCLUSIONS

The study confirms the reliability of the haemodynamic information derived from TVI and supports its application in the regulation of rate-responsive pacing.

Predictive parameters of left ventricular reverse remodeling in response to cardiac resynchronization therapy in patients with severe congestive heart failure

BACKGROUND

Cardiac resynchronization therapy (CRT) is useful for the treatment of severe congestive heart failure. Unfortunately up to 30% of patients could be non-responders. The aim of our study was to find parameters to predict responsiveness to CRT.

METHODS

Fifteen patients (9 males, 6 females, mean age 67.3 +/- 7.8 years, range 52-83 years) with dilated cardiomyopathy, NYHA functional class III-IV, left ventricular (LV) ejection fraction < 35% and QRS > or = 110 ms, underwent CRT. All the patients had echocardiographic evidence of systolic dys-synchrony.

RESULTS

One patient died of electromechanical dissociation. The remaining 14 patients maintained biventricular stimulation at 6 months; mean QRS width decreased from 156 to 132 ms (p < 0.001). Ten patients (71%) were considered responders because of a reduction in LV end-systolic volume > 15%. In non-responders (4 patients, 29%) LV end-systolic volume was stable in 3 patients and increased in 1. LV ejection fraction significantly increased only in responders (p < 0.001). Responders had more severe pre-pacing dyssynchrony than non-responders (p < 0.001). Inter- (p = 0.002) and intraventricular dyssynchrony (p = 0.003) did significantly reduce after CRT only in responders. On multiple regression analysis there were two independent predictors of reverse remodeling after pacing: the baseline mitral QS-tricuspid QS (QSm-QSt) time (B = -1.7, p = 0.005) and the intraventricular dyssynchrony index (B = -1.55, p = 0.007). Pre-implant QSm-QSt of 38 ms correctly identified the two groups: responders had a value > 38 ms and non-responders < 38 ms. The pre-implant intraventricular dyssynchrony index of 28 ms was the cut-off value: responders had an index > 28 ms, non-responders < 28 ms.

CONCLUSIONS

In the literature a tissue Doppler imaging index of intraventricular dyssynchrony evaluated before implantation is used to select responders to CRT. In our work we studied interventricular and intraventricular dyssynchrony, and both the QSm-QSt time and the standard deviation of the 12 LV segment QS time were correctly able to identify responders.