Improvement in electrocardiographic parameters of repolarization related to sudden death in patients with ventricular dysfunction and left bundle branch block after cardiac resynchronization through His bundle pacing

BACKGROUND

Cardiac resynchronization therapy (CRT) through permanent His bundle pacing (p-HBP) normalizes interventricular conduction disorders and QRS. Similarly, there are immediate and long-term changes in repolarization, which could be prognostic of a lower risk of sudden death (SD) at follow-up. We aimed to compare the changes in different electrocardiographic (ECG) repolarization parameters related to the risk of SD before and after CRT through p-HBP.

METHODS

In this prospective, descriptive single-center study (May 2019 to December 2021), we compared the ECG parameters of repolarization related to SD in patients with non-ischemic dilated cardiomyopathy, left bundle branch block (LBBB), and CRT indications, at baseline and after CRT through p-HBP.

RESULTS

Forty-three patients were included. Compared to baseline, after CRT through p-HBP, there were immediate significant changes in the QT interval (ms): 445 [407.5-480] vs 410 [385-440] (p = 0.006), QT dispersion (ms): 80 [60-100] vs 40 [40-65] (p < 0.001), Tp-Te (ms): 90 [80-110] vs 80 [60-95] (p < 0.001), Tp-Te/QT ratio: 0.22 [0.19-0.23] vs 0.19 [0.16-0.21] (p < 0.001), T wave amplitude (mm): 6.25 [4.88-10] vs - 2.5 [- 7-2.25] (p < 0.001), and T wave duration (ms): 190 [157.5-200] vs 140 [120-160] (p = 0.001). In the cases of the corrected QT (Bazzett and Friederichia) and the Tp-Te dispersion, changes only became significant at 1 month post-implant (468.5 [428.8-501.5] vs 440 [410-475.25] (p = 0.015); 462.5 [420.8-488.8] vs 440 [400-452.5] (p = 0.004), and 40 [30-52.5] vs 30 [20-40] (p < 0.001), respectively) (Table 1). Finally, two parameters did not improve until 6 months post-implant: the rdT/JT index, 0.25 [0.21-0.28] baseline vs 0.20 [0.19-0.23] 6 months post-implant (p = 0.011), and the JT interval, 300 [240-340] baseline vs 280 [257-302] 6 months post-implant (p = 0.027). Additionally, most of the parameters continued improving as compared with immediate post-implantation.

CONCLUSIONS

After CRT through His bundle pacing and LBBB correction, there was an improvement in all parameters of repolarization related to increased SD reported in the literature.

Usefulness of Multisite Ventricular Pacing in Nonresponders to Cardiac Resynchronization Therapy

Cardiac resynchronization therapy (CRT) is an established treatment for heart failure patients with myocardial dysfunction and delayed ventricular activation, but approximately 25% to 40% of patients do not respond to CRT. Left ventricular (LV) multisite pacing (MSP) has been proposed as a tool to improve CRT response. The goal of this study is to examine the safety and efficacy of LV MSP in CRT nonresponders. Between January 2018, and September 2019, the Strategic Management to Improve CRT Using Multi-Site Pacing trial prospectively enrolled 584 CRT-defibrillator recipients for established indications at 52 sites across the United States and evaluated their response at 6 months using the clinical composite score (CCS). Of the nonresponders, 102 patients had the LV MSP feature turned on and 78 patients completed the 12-month CCS evaluation. The LV MSP feature-related complication-free rate was 99.0% with a lower 95% confidence interval limit of 94.9%, which was higher than the performance goal of 90%. The proportion of nonresponders with an improved CCS from 6 to 12 months was 51.3% with a lower 95% confidence interval limit of 41.4%, which was higher than the performance goal of 5%. The estimated mean reduction in battery longevity with the LV MSP feature was about 3.6 months (estimated battery longevity of 8.87 ± 2.08 years at 6 months and 8.07 ± 2.23 years at 12 months). In conclusion, in CRT nonresponders, the use of the LV MSP feature is safe and associated with a ∼50% conversion rate with a small projected reduction in CRT-defibrillator battery longevity. LV MSP should be considered in the management of CRT nonresponders.

Optimising pacemaker therapy and medical therapy in pacemaker patients for heart failure: protocol for the OPT-PACE randomised controlled trial

INTRODUCTION

Permanent artificial pacemaker implantation is a safe and effective treatment for bradycardia and is associated with extended longevity and improved quality of life. However, the most common long-term complication of standard pacemaker therapy is pacemaker-associated heart failure. Pacemaker follow-up is potentially an opportunity to screen for heart failure to assess and optimise patient devices and medical therapy.

METHODS AND ANALYSIS

The study is a multicentre, phase-3 randomised trial. The 1200 participants will be people who have a permanent pacemaker for bradycardia for at least 12 months, randomly assigned to undergo a transthoracic echocardiogram with their pacemaker check, thereby tailoring their management directed by left ventricular function or the pacemaker check alone, continuing with routine follow-up. The primary outcome measure is time to all-cause mortality or heart failure hospitalisation. Secondary outcomes include external validation of our risk stratification model to predict onset of heart failure and quality of life assessment.

ETHICS AND DISSEMINATION

The trial design and protocol have received national ethical approval (12/YH/0487). The results of this randomised trial will be published in international peer-reviewed journals, communicated to healthcare professionals and patient involvement groups and highlighted using social media campaigns.

TRIAL REGISTRATION NUMBER

NCT01819662.

Outcomes of cardiac resynchronization therapy in patients with atrial fibrillation accompanied by slow ventricular response

It remains unclear as to whether cardiac resynchronization therapy (CRT) would be as effective in patients with atrial fibrillation (AF) accompanied by slow ventricular response (AF-SVR, < 60 beats/min) as in those with sinus rhythm (SR). Echocardiographic reverse remodeling was compared between AF-SVR patients (n = 17) and those with SR (n = 88) at six months and 12 months after CRT treatment. We also evaluated the changes in QRS duration; New York Heart Association (NYHA) functional class; and long-term composite clinical outcomes including cardiac death, heart transplantation, and heart failure (HF)-related hospitalization. Left ventricular pacing sites and biventricular pacing percentages were not significantly different between the AF-SVR and SR groups. However, heart rate increase after CRT was significantly greater in the AF-SVR group than in the SR group (P < 0.001). At six and 12 months postoperation, both groups showed a comparable improvement in NYHA class; QRS narrowing; and echocardiographic variables including left ventricular end-systolic volume, left ventricular ejection fraction, and left atrial volume index. Over the median follow-up duration of 1.6 (interquartile range: 0.8–2.2) years, no significant between-group differences were observed regarding the rates of long-term composite clinical events (35% versus 24%; hazard ratio: 1.71; 95% confidence interval: 0.23–12.48; P = 0.60). CRT implantation provided comparable beneficial effects for patients with AF-SVR as compared with those with SR, by correcting electrical dyssynchrony and increasing biventricular pacing rate, in terms of QRS narrowing, symptom improvement, ventricular reverse remodeling, and long-term clinical outcomes.

Cost-Effectiveness Analysis of Natriuretic Peptide Testing and Specialist Management in Patients with Suspected Acute Heart Failure

OBJECTIVES

To determine the cost-effectiveness of natriuretic peptide (NP) testing and specialist outreach in patients with acute heart failure (AHF) residing off the cardiology ward.

METHODS

We used a Markov model to estimate costs and quality-adjusted life-years (QALYs) for patients presenting to hospital with suspected AHF. We examined diagnostic workup with and without the NP test in suspected new cases, and we examined the impact of specialist heart failure outreach in all suspected cases. Inputs for the model were derived from systematic reviews, the UK national heart failure audit, randomized controlled trials, expert consensus from a National Institute for Health and Care Excellence guideline development group, and a national online survey. The main benefit from specialist care (cardiology ward and specialist outreach) was the increased likelihood of discharge on disease-modifying drugs for people with left ventricular systolic dysfunction, which improve mortality and reduce re-admissions due to worsened heart failure (associated with lower utility). Costs included diagnostic investigations, admissions, pharmacological therapy, and follow-up heart failure care.

RESULTS

NP testing and specialist outreach are both higher cost, higher QALY, cost-effective strategies (incremental cost-effectiveness ratios of £11,656 and £2,883 per QALY gained, respectively). Combining NP and specialist outreach is the most cost-effective strategy. This result was robust to both univariate deterministic and probabilistic sensitivity analyses.

CONCLUSIONS

NP testing for the diagnostic workup of new suspected AHF is cost-effective. The use of specialist heart failure outreach for inpatients with AHF residing off the cardiology ward is cost-effective. Both interventions will help improve outcomes for this high-risk group.

Cardiovascular gene therapy for myocardial infarction

INTRODUCTION

Cardiovascular gene therapy is the third most popular application for gene therapy, representing 8.4% of all gene therapy trials as reported in 2012 estimates. Gene therapy in cardiovascular disease is aiming to treat heart failure from ischemic and non-ischemic causes, peripheral artery disease, venous ulcer, pulmonary hypertension, atherosclerosis and monogenic diseases, such as Fabry disease.

AREAS COVERED

In this review, we will focus on elucidating current molecular targets for the treatment of ventricular dysfunction following myocardial infarction (MI). In particular, we will focus on the treatment of i) the clinical consequences of it, such as heart failure and residual myocardial ischemia and ii) etiological causes of MI (coronary vessels atherosclerosis, bypass venous graft disease, in-stent restenosis).

EXPERT OPINION

We summarise the scheme of the review and the molecular targets either already at the gene therapy clinical trial phase or in the pipeline. These targets will be discussed below. Following this, we will focus on what we believe are the 4 prerequisites of success of any gene target therapy: safety, expression, specificity and efficacy (SESE).

A theoretical cardiac resynchronization therapy method to augment ventricular contraction using polymer-based actuators and mitral regurgitation reduction with devices over left ventricular endocardial pacing wire--an in-vitro study

BACKGROUND

To investigate a potential cardiac resynchronization method using high force density actuators and mitral regurgitation (MR) reduction devices.

METHODS

An 8-cm long, 0.4-mm thick, and 2-mm wide polymeric actuator strip was attached to the right ventricular (RV) pacemaker lead 4.0 cm from the edge of the leads, and 035 wire and step-up voltages (2-9 V) were given. Deformation of the pacemaker lead with polymer was studied under cine-fluoroscopy in the air and immersing it in 0.9% saline. Cantilever function was assessed by the addition of gold rings. The left ventricular (LV) lead was reinforced with dual polymer and a side branching 035 wire Y-attachment and studied. A novel nitinol-based Gore-Tex device and polymer-based technology was developed and positioned abutting the mitral valves, and was evaluated in sheep heart preparations by cine-fluoroscopy.

RESULTS

The mean deformation at 9 V for the LV leads, RV leads, and 035 wires was 3.5 ± 0.2 mm, 1.1 ± 0.1 mm, and 1.4 ± 0.1 mm, respectively, and the stopping weight was 3.8 ± 0.2 g, 3.2 ± 0.1 g, and 3.6 ± 0.3 g, respectively. With dual surfacing of polymer and driven by separate actuation circuits simultaneously, the stopping weight parameters increased to 4.8 ± 0.2 g, 4.0 ± 0.2 g, and 4.6 ± 0.1 g, respectively (>25% each; P<.01 for all). The nitinol-based Gore-Tex device and the polymer device appeared to have reduced MR significantly from grade IV to grade I (>60% by visual quantification).

CONCLUSION

There is potential for a novel theoretical cardiac resynchronization therapy method using polymer-based actuators and devices to control MR.

Implantable hemodynamic monitors

The evaluation and management of volume status in patients with heart failure is a challenge for most clinicians. In addition, such an evaluation is possible only during a personal clinician-patient interface. The ability to acquire hemodynamic data continuously with the help of implanted devices with remote monitoring capability can provide early warning of heart failure decompensation and thus may aid in preventing hospitalizations for heart failure. The data obtained also may improve the understanding of the disease process. It is important for the clinician treating patients who have heart failure to become acquainted with this type of technology and learn to interpret and use these data appropriately. This article reviews the implantable hemodynamics monitors currently available.

Echocardiographic hemodynamic monitoring in the critically ill patient

Echocardiography has shown to be an essential diagnostic tool in the critically ill patient's assessment. In this scenario the initial fluid therapy, such as it is recommended in the actual clinical guidelines, not always provides the desired results and maintains a considerable incidence of cardiorrespiratory insufficiency. Echocardiography can council us on these patients' clinical handling, not only the initial fluid therapy but also on the best-suited election of the vasoactive/ inotropic treatment and the early detection of complications. It contributes as well to improving the etiological diagnosis, allowing one to know the heart performance with more precision. The objective of this manuscript is to review the more important parameters that can assist the intensivist in theragnosis of hemodynamically unstable patients.

Cell-based therapy in Chagas disease

Chagas disease was first described one century ago, yet the mechanisms underlying chagasic cardiomyopathy remain elusive. Disease progression often leads to heart failure and patients with this infectious cardiomyopathy have a poor prognosis. Treatment options for heart failure due to Chagas disease are not different from standard therapy. Over the past decade, cell-based therapies have emerged as a new alternative in the treatment of this disease, not only because of the possibility of replacing lost vessels and cardiomyocytes but also because these cells could potentially influence the microenvironmental changes that perpetuate the disease. In this chapter, we will review current knowledge on cell-based therapies for the treatment of Chagas disease.

Spanish Implantable Cardioverter-Defibrillator Registry. Sixth official report of the Spanish Society Of Cardiology Working Group on Implantable Cardioverter-defibrillators (2009)

INTRODUCTION AND OBJECTIVES

This article describes the findings of the 2009 Spanish Implantable Cardioverter-Defibrillator (ICD) Registry compiled by the Working Group on Implantable Cardioverter-Defibrillators of the Spanish Society of Cardiology's Electrophysiology and Arrhythmias Section.

METHODS

Each implantation team voluntarily sent prospective data recorded on a single-page document to the Spanish Society of Cardiology.

RESULTS

In total, 4108 device implantations were reported, which comprised 88.6% of the estimated total number of implantations carried out. The number of implants reported corresponded to 89 per million population and the estimated total number was 100.2 per million. The proportion of first implantations among those reported was 71.3%. Data were received from 134 centers, 17 more than in 2008. There continued to be significant regional variations between the various Spanish autonomous regions. The highest implantation rate (81%) was in men (mean age 62 years) who had severe or moderate-to-severe ventricular dysfunction and were in New York Heart Association functional class II. The most common heart condition was ischemic heart disease, followed by dilated cardiomyopathy. Indications for primary prevention accounted for 55.9% of first implantations; this figure was lower than the previous year's for the first time since 2003. The most significant increase observed was in patients with ischemic heart disease.

CONCLUSIONS

The 2009 Spanish ICD registry included data on almost 89% of all ICD implantations performed in the country. Although the number of implantations has continued to increase, it still remains far from the European average. The percentage of implantations performed for primary prevention was observed to have stabilized.

2010 World Stem Cell Summit--part 2. October 4-6, 2010, Detroit, MI, USA

The 2010 World Stem Cell Summit, held in Detroit, included topics covering new developments in the field of regenerative medicine. This conference report highlights selected presentations on the cancer stem cell hypothesis, stem cell therapy for amyotrophic lateral sclerosis, GRNOPC-1 for spinal cord injury, the use of cord blood stem cells for spinal cord injury, mesenchymal stem cell research and applications in cardiac therapy, tissue engineering, and very small embryonic-like stem cells. Investigational drugs discussed include NSI-566RSC (Neuralstem) and GRNOPC-1 (Geron Corp).

Cardiac resynchronization therapy: evaluation of ventricular dysynchrony and patient selection

Cardiac resynchronization therapy (CRT) is an established treatment modality for systolic heart failure. Aimed to produce simultaneous biventricular stimulation and correct the lack of ventricular synchrony in selected patients with congestive heart failure, CRT has shown to improve mortality and reduce hospital admissions when compared to medical treatment. At present, the indication criteria for the implantation of a CRT device include an ejection fraction of less than 35%, heart failure symptoms consistent with NYHA functional class III-IV and a QRS complex duration equal or longer than 120 milliseconds. It has been reported that 30% of patients who meet those criteria still may not derive clinical benefit from CRT. Due to the existing diversity of imagin modalities and resources for their process and analysis, a great expectation in terms of more accurate diagnosis of ventricular dyssynchrony has been raised. Reilable identification of dyssynchrony could allow us to better predict the favorable response of an individual patient to CRT and therefore offer this procedure to those individuals most likely to benefit. We review the available techniques for the study of ventricular dyssynchrony for CRT patient selection and the results of its application in clinical trials. Despite tremendous progress in the imaging technology available for the assessment and diagnosis of ventricular dyssynchrony, an ideal method has not been identified and the duration of QRS complex in the surface ECG remains the accepted criteria of dyssynchrony in the selection of patients for CRT.

[Electrical storm secondary to hypokaliemia in a patient with implantable cardioverter defibrillator]

Electrical storm in patients with implantable cardioverter defibrillator (ICDs) is a rhythmic emergency which can be immediately lethal. It occurs especially in patients with an advanced cardiomyopathy. Such arrhythmias predictor factors and triggers are rarely found. We report the case of a 73-year-old man with ischemic dilated cardiomyopathy, who underwent a complete surgical revascularisation six years ago. In 2003, this patient was hospitalised in cardiology because of a sustained ventricular tachycardia reduced by electrical shock. Because of the aggravation of the heart failure with a NYHA functional class III, electrical and echocardiographic criteria of ventricular dyssynchrony, a biventricular ICD was implanted. Three years after, the patient was hospitalized because of an electrical storm with 96 appropriate shocks. A severe hypokaliemia was the cause of this electrical storm, and the evolution was favourable after correction of the hypokaliemia. Hypokaliemia is rarely the trigger of such arrhythmias, it represents only 3 % of the causes. Its prevalence may be underestimated especially in patients with heart failure who receive high doses of diuretics.

Influence of rotary blood pumps over preload recruitable stroke work

When recovery of the cardiac function is detected in assisted hearts, the ventricular assist device can be removed. Due to the invasiveness of the surgical procedure, an accurate assessment of cardiac function is fundamental for the treatment success. The main challenge for the detection of cardiac function during assistance is to know whether the cardiac function index represents the cardiac function after pump removal independently of the pump assist rate. Therefore in this paper we present an evaluation of the influence of the pump over the slope of the preload recruitable stroke work, a cardiac function index. Analyzing data from four acute animal experiments, we found that the pump affects the stroke work, which could be corrected by the end diastolic volume. However, the data set examined was limited and further investigation is necessary.

[Echocardiographic assessment of ventricular synchrony. Implications to patient selection and treatment outcome]

Heart failure is one of the most prevalent diseases in industrialized countries. Up to 30% of the patients with advanced heart failure present disturbances in intra-ventricular conduction, and this produce asynchrony of ventricular contractility, leading to further deterioration in heart function. Cardiac resynchronization (TRC) is an increasingly important therapeutic option for a subgroup of patients with heart failure. Several methods have been show to be useful in study the mechanical asynchrony. However, there are discrepancies between the results of the different methods. The echocardiography provides the best parameters in predicting a good response.

[Ventricular bigeminy as a cause of CRT inefficacy and inappropriate cardioverter-defibrillator intervention]

Double counting of ventricular beats is not only one of the cause of an inappropriate detection of ventricular arrhythmias but a reason of lost of resynchronisation therapy. Sensing disturbances often creates the need for reprogramming of the device or additional pharmacotherapy and procedures. We present a case of 76-year-old man with CRT-D and inappropriate detection and intervention due to ventricular bigeminy. Fortunately, change of device program, potassium and magnesium supplementation was successful, without necessity of RF ablation of the ventricular ectopic beats.

Long-term survival using intra-aortic balloon pump and percutaneous right ventricular assist device for biventricular mechanical support of cardiogenic shock

Right ventricular (RV) involvement in acute inferior left ventricular (LV) myocardial infarction increases the risks of cardiogenic shock and in-hospital mortality. Acutely impaired RV performance results in reduced LV preload and, in combination with impaired LV contractility, causes severely reduced LV stroke volume and cardiac output. Here we report long-term patient survival after acute biventricular myocardial infarction (MI) using simultaneous RV support with a TandemHeart percutaneous ventricular assist device (Cardiac Assist Technologies, Pittsburgh, Pennsylvania) and LV support with an intra-aortic balloon pump. Further evaluation of completely percutaneous biventricular support in acute MI is warranted.

Medical management of the failing Fontan

The Fontan operation accomplishes complete separation of systemic venous blood from pulmonary venous circulation in patients with single ventricle anatomy. Operative survival since the first description of the Fontan operation is excellent in the current era through modifications in surgical techniques, identification of patient-specific risk factors, and advances in postoperative care. Improved early outcomes have also resulted in a decline in late mortality for patients who have undergone staged palliation with the Fontan operation. As the number of late survivors from the Fontan operation increases, caregivers will be evermore faced with the challenge of recognizing and managing the patient with failing Fontan physiology. Even after excellent early results, patients with single ventricle lesions remain at risk of progressive ventricular dysfunction, dysrhythmias, progressive hypoxemia, elevated pulmonary vascular resistance, and protein-losing enteropathy, which can result in morbidities including but not limited to, myocardial failure, thromboembolism, and stroke. Consequently, continued long-term survival of patients who undergo the Fontan operation is dependent upon preservation of single ventricle function, avoidance of late complications, and, in the patient with a failing Fontan, recognition and treatment of the underlying pathophysiologic process that has resulted in Fontan failure.

Doppler echocardiography and myocardial dyssynchrony: a practical update of old and new ultrasound technologies

Morbidity and mortality rates are higher in patients with severe left ventricular (LV) systolic dysfunction and ECG-derived prolonged QRS interval than in those with normal QRS duration. QRS duration is currently used on the grounds that it reflects the presence of ventricular dyssynchrony. However, 30–40% of patients selected on the basis of a prolonged QRS do not receive benefit by cardiac resynchronization therapy (CRT) since they do not show any significant inverse LV remodeling and QRS duration does not accurately distinguish responders to CRT. Consequently, mechanical dyssynchrony (particularly intra-ventricular dyssynchrony) seems to be much more important than electrical dyssinchrony. Pre- and post-echocardiographic assessment should require the combination of conventional and specific applications ranging from M-mode and pulsed/continuous Doppler, to pulsed Tissue Doppler, the off-line analysis of colour Tissue Velocity Imaging, Strain Rate Imaging, and real time three-dimensional reconstruction However, there is not no consensus about the best approach and the best ultrasound parameter for selecting candidates to CRT and ECG representation of abnormal cardiac conduction still remains as the main criterion in guidelines. This review is a practical update of ultrasound methods and measurements of atrio-ventricular, inter-ventricular and intra-ventricular dyssynchrony and describes experiences which used either conventional Doppler echocardiography and more advanced techniques. By these experiences, the global amount of LV dyssynchrony seems to be critical: the greater intra-ventricular dyssynchrony, the higher the possibility of significant LV inverse remodeling. After CRT, it is necessary also to evaluate the optimal atrio-ventricular delay and ventricular-ventricular delay setting that maximizes LV systolic function.

[Peripartum cardiomyopathy]

The Peripartum Cardiomyopathy is a rare form of heart disease, of uncertain etiology, more common in black and multiparous women, older than thirty years old. Is defined as development of maternal congestive heart failure, in the last month of pregnancy or within five months after delivery, with documented left ventricular systolic dysfunction, in the absence of a demonstrable cause for heart failure in a previously healthy woman. The diagnosis is commonly established with chest radiography, electrocardiogram and echocardiography. Treatment consist in medical therapy with inotropic support, afterload and preload redution, and anticoagulation. Surgical care with cardiac transplantation is indicated in severe cases with progressive left ventricular dysfunction, despite medical therapy. Prognosis seems dependent on recovery of left ventricular function and maternal mortality rates could reach 50%. Future pregnancy is not recommended in woman with persistent ventricular dysfunction. The authors present a case report in a black nuliparous woman at term, with 33 years old, without previous heart disease that presents a sudden heart failure, with ventricular dysfunction on echocardiography, after the caesarean, with recovery of normal ventricular function at 11th day of puerperium.

The role of existing and novel cardiac biomarkers for cardioprotection

Cardioprotection is an all-encompassing term for physico-biochemical or therapeutic interventions which slow or ameliorate the progression of cardiomyocyte necrosis. There are a number of established and novel biomarkers to assess coronary artery disease at initiation, ischemia, necrosis and myocardial dysfunction. Established biomarkers such as creatine kinase-MB, cardiac troponins and natriuretic peptides have been utilized for the assessment of cardioprotection, especially during surgery. Novel markers are currently being investigated for detection and risk assessment in patients with acute coronary syndromes. Ischemia-modified albumin is used for the early detection of cardiac ischemia and could be a potential biomarker for assessing the early cardioprotective effects of damage-limiting interventional measures.

Cardiac resynchronization therapy: left or left-and-right for optimal symptomatic effect--the LOLA ROSE study

AIMS

Biventricular (BiV) pacing and left univentricular (LUV) pacing can each produce clinical benefits in heart failure. The impact of modern refinements in pacing optimization on the relative benefits of these two modes is unknown. We aimed to compare these two modes in patients with heart failure, using Echo-based optimization of each pacing mode.

METHODS AND RESULTS

Paired data were collected on 18 patients (age 72 +/- 8 years; 16 male) with refractory heart failure symptoms, sinus rhythm, and LBBB with QRS duration>120 ms. Patients were randomized to an initial 8 weeks of either BiV or LUV pacing, followed by 8 weeks of the other mode, in a blinded cross-over design. Echocardiography was used to optimize atrioventricular delay for both modes and right ventricular-left ventricular offset for BiV mode. Peak oxygen consumption (baseline 13.6 +/- 2.7; BiV 15.8 +/- 3.0; LUV 15.2 +/- 3.1 mL/kg/min), 6 min walk distance (baseline 258 +/- 47; BiV 290 +/- 63; LUV 287 +/- 69 m), and scores on SF36 health questionnaire (baseline 41.5 +/- 16.8; BiV 58.6 +/- 19.6; LUV 51.8 +/- 21.3) did not differ between BiV and LUV modes. New York Heart Association class was significantly better in BiV than in LUV mode (P < 0.01).

CONCLUSION

In this pilot study, we found no differences in major clinical outcome measures between the two modes of resynchronization.

Predictors of a Positive Response to Biventricular Pacing in Patients with Severe Heart Failure and Ventricular Conduction Delay

BACKGROUND

Cardiac resynchronization therapy (CRT) is recommended in patients with ejection fraction <35%, QRS width> 120 ms, and New York Heart Association (NYHA) functional class III or IV despite optimal medical therapy. We aimed to define demographic, clinical, and electrocardiographic predictors of positive clinical response to CRT.

METHODS AND RESULTS

Hundred consecutive patients fulfilling the recommended criteria were implanted with a CRT device. Demographic, clinical, two-dimensional echocardiographic and electrographic parameters were measured at baseline and after 6 months of simultaneous biventricular pacing. A positive response to CRT included an improvement of at least one NYHA functional class associated with an absence of hospitalization for worsening heart failure. At the end of follow-up, 12 patients were dead and 71% of the patients were classified as responders. After 6 months of CRT, the ejection fraction was significantly higher (P = 0.035) in responders versus nonresponders. Multivariate analysis identified three independent predictors of positive response to CRT: an idiopathic origin of the cardiomyopathy (P = 0.043), a wider QRS before implantation (P = 0.017), and a narrowing of the QRS after implantation (P = 0.037).

CONCLUSION

An idiopathic origin of the cardiomyopathy, a wider QRS before implantation, and a narrowing of the QRS width after implantation were identified as independent predictors of clinical positive response to CRT.

Autologous hematopoietic stem cell transplantation in systemic lupus erythematosus patients with cardiac dysfunction: feasibility and reversibility of ventricular and valvular dysfunction with transplant-induced remission

Patients with cardiac dysfunction may be at increased risk of cardiac toxicity when undergoing hematopoietic stem cell transplantation (HSCT), which may preclude them from receiving this therapy. Cardiac dysfunction is, however, common in systemic lupus erythematosus (SLE) patients. While autologous HSCT (auto-HSCT) has been performed increasingly for SLE, its impact on cardiac function has not previously been evaluated. We, therefore, performed a retrospective analysis of SLE patients who had undergone auto-HSCT in our center to determine the prevalence of significant cardiac involvement, and the impact of transplantation on this. The records of 55 patients were reviewed, of which 13 were found to have abnormal cardiac findings on pre-transplant two-dimensional echocardiography or multi-gated acquisition scan: impaired left ventricular ejection fraction (LVEF) (n = 6), pulmonary hypertension (n = 5), mitral valve dysfunction (n = 3) and large pericardial effusion (n = 1). At a median follow-up of 24 months (8-105 months), there were no transplant-related or cardiac deaths. With transplant-induced disease remission, all patients with impaired LVEF remained stable or improved; while three with symptomatic mitral valve disease similarly improved. Elevated pulmonary pressures paralleled activity of underlying lupus. These data suggest that auto-HSCT is feasible in selected patients with lupus-related cardiac dysfunction, and with control of disease activity, may improve.

Exercise training in systolic and diastolic dysfunction: effects on cardiac function, functional capacity, and quality of life

BACKGROUND

Exercise training improves functional capacity in patients with systolic dysfunction (SD), but the role of exercise training in diastolic dysfunction (DD) is unclear. We compared the responses of patients with exercise intolerance and SD or DD to 16 weeks of exercise training.

METHODS

Fifty-one patients with SD and DD were enrolled in exercise training, which was completed in 24 patients with SD (22 men, 62 +/- 8 years old, ejection fraction <35%) and 18 patients with DD (9 men, 65 +/- 5 years old, ejection fraction >45%). Peak VO2, quality of life (Minnesota Living with Heart Failure and Hare-Davis questionnaires), and echocardiographic measures (ejection fraction, systolic and diastolic tissue velocity, and filling pressure) were performed at baseline and after 16 weeks of training.

RESULTS

Patients with SD and those with DD showed similar baseline peak VO2 (11.9 +/- 2.5 vs 12.5 +/- 4.1 mL/[kg min], P = .55) and E/E' ratio (21 +/- 13 vs 14.4 +/- 15, P = .07), but different systolic velocity (3.4 +/- 1.0 vs 5.5 +/- 1.7 cm/s, P < .001), diastolic velocity (3.9 +/- 1.5 vs 5.1 +/- 1.8 cm/s, P = .05), and ejection fraction (26 +/- 8% vs 55 +/- 9%, P < .001). Baseline quality of life scores were worse in patients with SD. There was a similar increment in peak VO2 in SD (24%, P = .001) and DD (30%, P < .001) after exercise training, but this did not correlate with improved diastolic parameters. Quality of life scores improved in both SD and DD, although SD scores remained significantly worse.

CONCLUSIONS

In patients with exercise limitation attributed to DD, the improvement in peak VO2 and quality of life with exercise training is similar to those with SD, but unrelated to changes in diastolic function.

[Correction of ventricular late potentials with drug and non-drug methods in patients with essential hypertension]

The aim of the work was to evaluate the effects of drug and non-drug methods of treatment of patients with essential hypertension (EH) on ventricular late potentials (VLP). One hundred and thirteen patients with I to II stage EH aged 30 to 73 (mean age 53 +/- 9.7 years) were included in the study. VLP were registered by recording signal-averaged ECG (SA-ECG) before and after treatment with antihypertensive preparations (lisinopril, nifedipine) and intravenous ozone therapy. VLP were detected in 34 (30%) of the EH patients. The study found a decrease in the frequency of VLP detection from 40% (8 patients) to 10% (2 patients) after therapy with the ACE inhibitor lisinopril. In the group of patients who received monotherapy with the calcium antagonist nifedipine the number of subjects with VLP before and after the treatment was the same, 3 patients or 20%. In the group receiving bi-component therapy with lisinopril, an ACE inhibitor, and nifedipine, a calcium antagonist, the number of patients with VLP fell from 4 subjects (28.6%) to 1 subject. These data were confirmed with significant SA-ECG parameters. The study also revealed that ozone therapy as a part of complex treatment of EH improved SA-ECG parameters, which manifested by a decrease in VLP from 29.7% to 14.1%.

Closed Loop Stimulation Improves Ejection Fraction in Pediatric Patients with Pacemaker and Ventricular Dysfunction

BACKGROUND

The aim of this prospective study was to evaluate the effect of the closed loop stimulation (CLS) on the ejection fraction in pediatric patients, affected by complete atrioventricular block (CAVB) or CAVB and sinus node dysfunction (SND), with a previously implanted pacemaker (PM) and ventricular dysfunction. The role of electrical therapy in the treatment of pediatric patients with congenital atrioventricular (AV) blocks has been shown. Conventional right ventricular pacing seems to affect ventricular function. Up to now, the feasibility and the long-term results of biventricular pacing in pediatric patients were not entirely clear.

METHODS

In eight pediatric patients with a previously implanted single or dual chamber PM, ventricular dysfunction, and CAVB or SND and CAVB, a dual chamber PM INOS(2+)-CLS (Biotronik GmbH, Berlin, Germany) was implanted. The effect of the physiological modulation of CLS pacing mode on the ejection fraction was evaluated by Echo-Doppler examination. Measurements were performed before the substitution of the old PM and for up to 2 years of follow-up.

RESULTS

All patients showed correct electrical parameters at implantation and during follow-up. The mean value of the ejection fraction measured before the replacement of the old PM was 36 +/- 7%, while after 2 years it was 47 +/- 1% (P < 0.003). No patient showed any worsening of the ejection fraction, while only one showed no improvement.

CONCLUSIONS

DDD-CLS pacing seems to improve ventricular function in pediatric patients with CAVB and/SND in spite of the use of the apical right conventional stimulation.

Ventricular dyssynchrony in dilated cardiomyopathy: the role of biventricular pacing in the treatment of congestive heart failure

Despite advances in pharmacologic therapy, the prognosis of patients with advanced congestive heart failure (CHF) remains poor. Many of these patients have cardiac conduction abnormalities, such as left bundle-branch block or interventricular conduction delays, that can lead to ventricular dyssynchrony (abnormal ventricular activation that results in decreased ventricular filling and abnormal ventricular wall motion). Biventricular pacing is an alternative, nonpharmacologic therapy under active investigation for the treatment of CHF. Resynchronization devices with transvenous leads in the right atrium, right ventricle, and left ventricle (via the coronary sinus) have been implanted in patients to provide atrial triggered biventricular pacing. The use of such devices has been associated with improvement in ejection fraction, dP/dt, stroke work, and functional class. The proposed mechanisms involved in improving ventricular function with biventricular pacing include improved septal contribution to ventricular ejection, increased diastolic filling times, and reduced mitral regurgitation. This article reviews the pathophysiology of ventricular dyssynchrony and examine insights from clinical trials that are evaluating cardiac resynchronization therapy for CHF.

Noncompaction of ventricular myocardium involving both ventricles

AIM

We aimed to present a case with ventricular myocardial noncompaction involving both ventricles.

METHODS AND RESULTS

Noncompaction of ventricle is a rare and unclassified congenital cardiac malformation is due to an arrest in intrauterine endomyocardial morphogenesis. We presented a ventricular myocardial noncompaction case involving both left and right ventricles. The physical examination of this case is consistent with mitral regurgitation and the echocardiographic findings are consistent with noncompaction of ventricular myocardium involving both ventricles with left ventricular systolic failure.

CONCLUSION

Transthoracic echocardiography is a useful clinical tool for diagnosing noncompaction of both the right and left ventricular myocardium. The LVNC definition can also be utilized for RVNC, which this diagnosis has never been reported in a Turkish patient.

Delayed Enhancement Magnetic Resonance Imaging Predicts Response to Cardiac Resynchronization Therapy in Patients With Intraventricular Dyssynchrony

OBJECTIVES

We evaluated the ability of delayed enhancement magnetic resonance imaging (DE-MRI) to predict clinical response to cardiac resynchronization therapy (CRT).

BACKGROUND

Cardiac resynchronization therapy reduces morbidity and mortality in selected heart failure patients. However, up to 30% of patients do not have a response. We hypothesized that scar burden on DE-MRI predicts response to CRT.

METHODS

The DE-MRI was performed on 28 heart failure patients undergoing CRT. Patients with QRS > or =120 ms, left ventricular ejection fraction < or =35%, New York Heart Association functional class II to IV, and dyssynchrony > or =60 ms were studied. Baseline and 3-month clinical follow-up, wall motion, 6-min walk, and quality of life assessment were performed. The DE-MRI was performed 10 min after 0.20 mmol/kg intravenous gadolinium. Scar measured by planimetry was correlated with response criteria.

RESULTS

Twenty-three patients completed the protocol (mean age 64.9 +/- 11.7 years), with 12 (52%) having a history of myocardial infarction. Thirteen (57%) patients met response criteria. Percent total scar was significantly higher in the nonresponse versus response group (median and interquartile range of 24.7% [18.1 to 48.7] vs. 1.0% [0.0 to 8.7], p = 0.0022) and predicted nonresponse by receiver-operating characteristic analysis (area = 0.94). At a cutoff value of 15%, percent total scar provided a sensitivity and specificity of 85% and 90%, respectively, for clinical response to CRT. Similarly, septal scar < or =40% provided a 100% sensitivity and specificity for response. Regression analysis showed linear correlations between percent total scar and change in each of the individual response criteria.

CONCLUSIONS

The DE-MRI accurately predicted clinical response to CRT. This technique offers unique information in the assessment of patients referred for CRT.

Effectiveness of carvedilol for congestive heart failure that developed long after modified Fontan operation

We report a case of a patient with severe heart failure after Fontan procedure in whom carvedilol was very effective. A 27-year-old man had intractable congestive heart failure due to severe ventricular dysfunction after Fontan operation. Central venous pressure was elevated to 29 mmHg. A right-to-left shunt was noted across a large collateral vessel between the innominate vein and the pulmonary vein. He was administered carvedilol (initial dose, 2 mg/day; maximum dose, 30 mg/day). Cardiac catheterization performed 1 year after carvedilol administration revealed a decrease in atrial pressure and improvement of ventricular function. He underwent a conversion operation to total cavopulmonary connection (TCPC) and ligation of a collateral vein communicating with the innominate and pulmonary veins. Carvedilol may be a legitimate treatment before TCPC conversion or heart transplantation for the high-risk group of patients with a failed Fontan circulation.

Diastolic asynchrony is more frequent than systolic asynchrony in dilated cardiomyopathy and is less improved by cardiac resynchronization therapy

OBJECTIVES

To compare the incidence of diastolic and systolic asynchrony, assessed by tissue Doppler imaging (TDI), in patients with congestive heart failure (CHF) and severe left ventricular (LV) dysfunction, and to assess TDI changes induced by cardiac resynchronization therapy (CRT).

BACKGROUND

Thirty percent of CRT candidates are nonresponders. Besides QRS width, the presence of echographic systolic asynchrony has been used to identify future responders. Little is known about diastolic asynchrony and its change after CRT.

METHODS

Tissue Doppler imaging was performed in 116 CHF patients (LV ejection fraction 26 +/- 8%). Systolic and diastolic asynchrony was calculated using TDI recordings of right ventricular and LV walls.

RESULTS

The CHF group consisted of 116 patients. Diastolic asynchrony was more frequent than systolic, concerning both intraventricular (58% vs. 47%; p = 0.0004) and interventricular (72 vs. 45%; p < 0.0001) asynchrony. Systolic and diastolic asynchrony were both present in 41% patients, but one-third had isolated diastolic asynchrony. Although diastolic delays increased with QRS duration, 42% patients with narrow QRS presented with diastolic asynchrony. Conversely, 27% patients with large QRS had no diastolic asynchrony. Forty-two patients underwent CRT. Incidence of systolic intraventricular asynchrony decreased from 71% to 33% after CRT (p < 0.0001), but diastolic asynchrony decreased only from 81% to 55% (p < 0.0002). Cardiac resynchronization therapy induced new diastolic asynchrony in eight patients.

CONCLUSIONS

Diastolic asynchrony is weakly correlated with QRS duration, is more frequent than systolic asynchrony, and may be observed alone. Diastolic asynchrony is less improved by CRT than systolic. Persistent diastolic asynchrony may explain some cases of lack of improvement after CRT despite good systolic resynchronization.

Perioperative management of patients with poorly functioning ventricles in the setting of the functionally univentricular heart

The patient with a functionally univentricular heart is at increased risk for ventricular dysfunction for a variety of reasons. At birth, the pulmonary and systemic circulations are in parallel, leading to pulmonary overcirculation and a volume-loaded functional ventricle. Significant atrioventricular valvar regurgitation, abnormal ventriculoarterial coupling, diastolic dysfunction, and altered ventricular geometry can also contribute to long-term ventricular dysfunction. These collected circumstances place the patient at increased risk for perioperative morbidity and mortality. We will discuss in this review the pathophysiology that leads to ventricular dysfunction at each stage of surgical palliation, as well as the strategies for perioperative management. In addition, we will highlight novel strategies for management of ventricular dysfunction.

Mechanical support of the functionally single ventricle

Children with a functionally single ventricle constitute just over 1% of congenital cardiac defects.1A majority of children with the functionally univentricular circulation undergo a three-staged reconstruction to achieve completion of the Fontan circulation. The first stage is usually performed in the neonatal period, and is either banding of the pulmonary trunk, an aorto-pulmonary shunt alone, or the shunt included as part of the first stage of reconstruction. In recent years, a conduit placed from the right ventricle to the pulmonary arteries is being used as an alternate source of flow of blood to the lungs. The second stage is the bidirectional cavopulmonary anastomosis, the two surgical variations being the so-called “hemifontan”, and “bidirectional Glenn” procedures, while the third stage is the completion of the Fontan circulation, the two surgical variations being either construction of a lateral tunnel, or placement of an extra-cardiac conduit, each being possible with or without a fenestration. In many centres, patients with the functionally univentricular circulation make up one-fifth of the total surgical volume. The syndrome of low cardiac output is quite common in this population through all three stages of reconstruction, and some of these patients will eventually require cardiac transplantation. While conventional therapy, with inotropic support and afterload reduction, remains the mainstay of therapy for the failing heart in children, mechanical support is being increasingly used.3Most of this experience is limited to extracorporeal membrane oxygenation.2–5In this review, we discuss the current experiences with extracorporeal membrane oxygenation in patients with a functionally univentricular circulation, and describes some of their unique features. We also focus on the pulsatile ventricular assist devices capable of providing support over the longer term, and other new devices that may have a role in the future in these patients.6

[Value and limitations of programmed ventricular stimulation]

The electrocardiogramme and methods of prolonged ECG recording are sufficient for diagnosing most cardiac arrhythmias. They also provide some prognostic information and allow evaluation and follow-up of treatment. However, in some situations, endocavitary electrophysiological investigations are required when the diagnosis is uncertain, that more prognostic information is required or interventional techniques (endocavitary ablation) are envisaged. The aim of this report is to summarise the value and limitations of programmed ventricular stimulation. Many of its indications have been abandoned in terms of rhythm stratification in the face of more robust parameters, in particular the left ventricular ejection fraction. However, it retains a potential utility in terms of prognosis in arrhythmogenic right ventricular dysplasia, the Brugada syndrome and operated Tetralogy of Fallot. In any event, it is important to remember that studies resulting in diagnostic or therapeutic recommendations were performed with strict protocols of stimulation in selected patients and that these recommendations can only be applied when the evaluation protocols are respected. The indications of programmed ventricular stimulation will increase in the therapeutic field with the development of new techniques of 3D mapping, new systems of catheter guiding which should extend the indications of endocavitary ablation.

[Mapping and ablation of malignant ventricular arrhythmias]

Endocavitary investigations showed that the ventricular extrasystoles originated in the common ventricular myocardium (pulmonary infundibulum) in only 9 cases whereas the majority arose from the Parkinje system either on the anterior wall of the right ventricle or in septal region of the left ventricle. The extrasystoles arising from the Parkinje system and pulmonary infundibulum differed in their duration and polymorphism (128 +/- 18 ms vs 145 +/- 13 ms, p = 0.05; 3.3 +/- 2.7 morphologies vs 1.1 +/- 0.4, p < 0.001, respectively). During the extrasystoles, the local Pukinje potential preceded the ventricular activation by variable intervals, some of which were very long, up to 150 ms. Seven applications of radiofrequency were delivered on average per patient on the most distal part of the Purkinje system leading to ablation of the specific activation. The clinical results were spectacular: 88% of patients had no further episodes of ventricular fibrillation as demonstrated by analysis of the defibrillator with an average follow-up period of more than 34 months.

Dispersion of repolarization in cardiac resynchronization therapy

BACKGROUND

Proarrhythmic effects of cardiac resynchronization therapy (CRT) as a result of increased transmural dispersion of repolarization (TDR) induced by left ventricular (LV) epicardial pacing in a subset of vulnerable patients have been reported. The possibility of identifying these patients by ECG repolarization indices has been suggested.

OBJECTIVES

The purpose of this study was to test whether repolarization indices on the ECG can be used to measure dispersion of repolarization during pacing.

METHODS

CRT devices of 28 heart failure patients were switched among biventricular, LV, and right ventricular (RV) pacing. ECG indices proposed to measure dispersion of repolarization were calculated. The effects of CRT on repolarization were simulated in ECGSIM, a mathematical model of electrocardiogram genesis. TDR was calculated as the difference in repolarization time between the epicardial and endocardial nodes of the heart model.

RESULTS

PATIENTS

The interval from the apex to the end of the T wave was shorter during biventricular pacing (102 +/- 18 ms) and LV pacing (106 +/- 21 ms) than during RV pacing (117 +/- 22 ms, P < or =.005). T-wave amplitude and area were low during biventricular pacing (287 +/- 125 microV and 56 +/- 22 microV.s, respectively, P = .0006 vs RV pacing). T-wave complexity was high during biventricular pacing (0.42 +/- 0.26, P = .004 vs RV pacing). Simulations: Repolarization patterns were highly similar to the preceding depolarization patterns. The repolarization patterns of different pacing modes explained the observed magnitudes of the ECG repolarization indices. Average and local TDR were not different between pacing modes.

CONCLUSION

In patients treated with CRT, ECG repolarization indices are related to pacing-induced activation sequences rather than transmural dispersion. TDR during biventricular and LV pacing is not larger than TDR during conventional RV endocardial pacing.

Cardiac resynchronisation therapy for patients with heart failure

Cardiac resynchronisation therapy (CRT) is a non-pharmacological treatment for heart failure. The method 'resynchronises' the contraction of the right and left ventricles, resulting in better cardiac output, thus improving symptoms. This article discusses symptoms, morbidity and mortality of heart failure; potential benefits of CRT to patients' quality of life; and the implications of CRT for nursing practice.

Effect of continuous positive airway pressure on ventricular ectopy in heart failure patients with obstructive sleep apnoea

BACKGROUND

Obstructive sleep apnoea (OSA) elicits a number of cardiovascular perturbations that could lead acutely or chronically to increased ventricular ectopy in patients with heart failure (HF). We tested the hypothesis that treatment of OSA with continuous positive airway pressure (CPAP) in patients with HF would reduce the frequency of ventricular premature beats (VPBs) during sleep in association with reduced sympathetic nervous system activity.

METHODS

Following optimisation of medical treatment, 18 HF patients with OSA and >10 VPBs per hour of sleep were randomised to a control group (n = 8) or a treatment group who received CPAP (n = 10). The frequency of VPBs and urinary norepinephrine (noradrenaline) concentrations during total sleep time were determined at baseline and after 1 month.

RESULTS

Control patients did not experience any significant changes in apnoea-hypopnoea index (AHI), mean nocturnal O(2) saturation, or the frequency of VPBs. In contrast, there was a significant reduction in AHI (p<0.001), an increase in minimum O(2) saturation (p = 0.05), a reduction in urinary norepinephrine concentrations (p = 0.009), and a 58% reduction in the frequency of VPBs during total sleep (from mean (SE) 170 (65) to 70 (28) per hour, p = 0.011) after 1 month of CPAP treatment.

CONCLUSIONS

In patients with HF, treatment of co-existing OSA by CPAP reduces the frequency of VPBs during sleep. These data suggest that reductions in VPBs and other ventricular arrhythmias through treatment of OSA might improve the prognosis in patients with HF.