Left bundle branch area versus conventional pacing after transcatheter valve implant for aortic stenosis: the LATVIA study

BACKGROUND

Atrioventricular block (AVB) is a frequent complication in patients undergoing transcatheter aortic valve implantation (TAVI). Right apex ventricular pacing (RVP) represents the standard treatment but may induce cardiomyopathy over the long term. Left bundle branch area pacing (LBBAP) is a promising alternative, minimizing the risk of desynchrony. However, available evidence with LBBAP after TAVI is still low.

OBJECTIVE

To assess the feasibility and safety of LBBAP for AVB post-TAVI compared with RVP.

METHODS

Consecutive patients developing AVB early after TAVI were enrolled between 1 January 2022 and 31 December 2022 at three high-volume hospitals and received LBBAP or RVP. Data on procedure and at short-term follow-up (at least 3 months) were collected.

RESULTS

A total of 38 patients (61% men, mean age 83 ± 6 years) were included; 20 patients (53%) received LBBAP. Procedural success was obtained in all patients according to chosen pacing strategy. Electrical pacing performance at implant and after a mean follow-up of 4.2 ± 2.8 months was clinically equivalent for both pacing modalities. In the LBBAP group, procedural time was longer (70 ± 17 versus 58 ± 15 min in the RVP group, P = 0.02) and paced QRS was shorter (120 ± 19 versus 155 ± 12 ms at implant, P < 0.001; 119 ± 18 versus 157 ± 9 ms at follow-up, P < 0.001). Complication rates did not differ between the two groups.

CONCLUSION

In patients with AVB after TAVI, LBBAP is feasible and safe, resulting in a narrow QRS duration, either acutely and during the follow-up, compared with RVP. Further studies are needed to evaluate if LBBAP reduces pacing-induced cardiomyopathy in this clinical setting.

Atrial arrhythmias and heart failure: a "modern view" of an old paradox

BACKGROUND

Heart failure (HF) and atrial arrhythmias (AAs) are two clinical conditions that characterize the daily clinical practice of cardiologists. In this perspective review, we analyze the shared etiopathogenetic pathways of atrial arrhythmias, which are the most common cause of atrial arrhythmias-induced cardiomyopathy (AACM) and HF.

HYPOTHESIS

The aim is to explore the pathophysiology of these two conditions considering them as a "unicum", allowing the definition of a cardiovascular continuum where it is possible to predict the factors and to identify the patient phenotype most at risk to develop HF due to atrial arrhythmias.

METHODS

Potentially eligible articles, identified from the Electronic database (PubMed), and related references were used for a literature search that was conducted between January 2022 and January 2023. Search strategies were designed to identify articles that reported atrial arrhythmias in association with heart failure and vice versa. For the search we used the following keywords: atrial arrhythmias, atrial fibrillation, heart failure, arrhythmia-induced cardiomyopathy, tachycardiomyopathy. We identified 620 articles through the electronic database search. Out of the 620 total articles we removed 320 duplicates, thus selecting 300 eligible articles. About 150 titles/abstracts were excluded for the following reasons: no original available data, no mention of atrial arrhythmias and heart failure crosstalk, very low quality analysis or evidence. We excluded also non-English articles. When multiple articles were published on the same topic, the articles with the most complete set of data were considered. We preferentially included all papers that could provide the best evidence in the field. As a result, the present review article is based on a final number of 104 references.

RESULTS

While the pathophysiology of AACM and Heart Failure with reduced ejection fraction (HFrEF) has been studied in detail over the years, the causal link between atrial arrhythmias and heart failure with Preserved Ejection Fraction (HFpEF) has been often subject of interest. HFpEF is strictly related to AAs, which has always been considered significant risk factor. In this review we described the pathophysiological links between atrial fibrillation and heart failure (Fig. 1). Furthermore, we illustrated and discussed the preclinical and clinical predicting factors of AF and HFpEF, and the corresponding targets of the available therapeutic agents. Finally, we outlined the patient phenotype at risk of developing AF and HFpEF.

CONCLUSIONS

In this review, we underline how these two clinical conditions (AF and HFpEF) represent a "unicum" and, therefore, should be considered as a single disease that can manifest itself in the same phenotype of patients but at different times. Furthermore, considering that today we have few therapeutic strategies to treat these patients, it would be good to make an early diagnosis in the initial stages of the disease or intervene even before the development of signs and symptoms of HF. This is possible only by paying greater attention to patients with predisposing factors and carrying out a targeted screening with the correct diagnostic methods. A systemic approach aimed at improving the immuno-metabolic profile of these patients by lowering the body mass index, threatening the predisposing factors, lowering the mean heart rate and reducing the sympathetic nervous system activation is the key strategy to reduce the clinical impact of this disease. This article is protected by copyright. All rights reserved.

365 ANALYSIS OF PIVOT POINTS AND SLOW CONDUCTION AREAS IN PATIENTS UNDERGOING ATRIAL FIBRILLATION ABLATION

Introduction

Little is known about progression of atrial fibrillation (AF) from paroxysmal to persistent form. Electrical remodeling may play a pivotal role in the arrhythmia transition. The aim of the study was the characterization of the atrial electrical substrate in patients suffering from AF.

Methods

Twenty-seven patients were included in the study (14 with paroxysmal AF and 13 with persistent AF). Two simultaneous electroanatomical maps of the left atrium were collected using PentaRay catheter using the parallel mapping feature [first map during sinus rhythm and a second one with an extrastimulus from coronary sinus (CS)]. We analyzed the propagation of the wavefront and we identified zones of abnormal conduction: slow conduction (SC) corridors and pivot points (PP). SC corridors were defined by the slowing of conduction velocity; pivot points were zones in which propagation pattern changed the direction of 90° or more. Maximum delay between the recording dipoles located at the extremities of the PentaRay splines was calculated. At each of these sites, EGMs were collected and analyzed in terms of amplitude and duration. We checked if areas of abnormal conduction during sinus rhythm were present or they disappeared by delivering an extrastimulus from the coronary sinus.

Results

The average number of collected EGMs per map was 4790 ± 1333 (PAF 4829 ± 1407; PsAF 4745 ± 1402).

Total abnormal conduction areas in the 27 patients were 62, 65% of which were slow conduction. Pivot points and slow conduction manifested a trend to cluster in some areas: both of them were mostly present at the ostia of pulmonary veins, in a specific segment between LAA ostium and mitral annulus and in the posterior wall. During sinus rhythm, pivot points were 29, while pacing from distal CS catheter the same zones showed normal conduction in 14 cases: they were still present in 60% in PAF group and 50% in PsAF. Slow conduction corridors, instead, show a trend to remain while pacing from CS: 76% in the first group and 78% in the second one.

Conclusions

SC corridors are fixed alterations of atrial substrate, while pivot sites may be more dynamic entities: both of them may have a key role in remodeling atrial structures and atrial fibrillation progression and maintenance. These may represent future targets for AF therapy and prevention.

27 PROGNOSTIC FACTORS IN POST-OPERATIVE ATRIAL FIBRILLATION: A COHORT STUDY IN 53.387 PATIENTS

Introduction

Post-operative atrial fibrillation (POAF) represents the most common arrhythmia in the post-operative setting, with a peak incidence from day 0 to 5 after surgery and it represents a main cause of morbidity, mortality, length of stay, thromboembolic events and stroke. Cardiothoracic surgery has the highest rates of POAF, while data about other surgeries are contrasting amongst various studies. Aim of this study was to detect POAF onset in the 28 days after surgery and to better assess its predictors, especially the role of inflammation.

Methods

This is a retrospective single center cohort study of 53.387 patients undergoing surgery from January 2016 to January 2020. Patients were classified in four groups according to types of surgery performed: (I) orthopedic surgery, (II) not thoracic nor abdominal surgery, (III) abdominal and esophageal surgery and (IV) lung and cardiovascular surgery. Kaplan–Meier estimates were used to draw the cumulative incidence curves by surgery groups; finally, they were compared with a log-rank test. Furthermore, multivariable Cox proportional hazards (PH) models of prognostic factors were used. Confounders were selected according to a review of the literature, statistical relevance, and consensus opinion by an expert group of physicians and methodologists. After fitting the model, the PH assumption was examined on the basis of Schoenfeld residual.

Results

The primary endpoint of AF onset occurred in 570 patients (1.1%) with a mean incidence after surgery of 3.4±2.6 days. 90 patients died (0.17%) after an average of 13.7±8.4 days.

The Kaplan-Meier analysis showed the lowest 28-day event-free survival in group IV and the highest in group I (log-ranks test p=0.0001). In patients who developed AF, levels of C-Reactive Protein (CRP) were higher than the others (mean 0,70+0.03 log10 mg/dL versus mean 0,40+0.01 log10 mg/dl; p &lt;0.0001) with higher levels in group III and group IV. In the univariable Cox regression, CRP was a strong predictor of AF (HR per 1 unit increase in log-scale, 2.64; 95% C.I,1.74–4.0; p&lt;0.0001). This was confirmed at the multivariable analysis, adjusting for confounding factors like age, gender, length of stay in hospital and group of surgery (adjusted HR per 1 mg/dL increase in log-scale, 1.81; 95% CI,1.18–2.79; p = 0.007). Other strong predictors of POAF were age (HR per 1 year increase, 1.06; 95% CI, 1.04–1.08; p&lt; 0.0001) and surgery of group III and IV (HR, 23.62; 95% CI, 5.65–98.73; p&lt; 0.0001 and HR,6.26; 95% CI, 1.48–26.49; p 0.013, respectively).The PH assumption was not violated (p=0.12).

Conclusions

POAF represents a frequent complication of surgery and major burden for healthcare. Inflammation may represent a major driver in its pathophysiology, especially in non-cardiac surgery, in which manipulation of cardiac tissue is avoided. This may explain the poor response to antiarrhythmic drugs and its self-limiting nature, which expires when post-operative inflammation turns off.

113 RIGHT VENTRICULAR FREE WALL LONGITUDINAL STRAIN AS THE SOLE MARKER OF RIGHT VENTRICLE SYSTOLIC DYSFUNCION IN HYPERTROPHIC CARDIOMYOPATHY: A CLINICAL CASE

Background

The introduction of Cardiac-MRI (cMRI) in clinical practice has considerably improved risk stratification of patients with hypertrophic cardiomyopathy (HCM). However, the prediction of adverse outcome based on imaging markers remains suboptimal. Right ventricular (RV) involvement is an emerging finding in this disease of unknown clinical value. The identification of accurate and sensible imaging markers to detect morpho-functional alterations of the RV is therefore essential to establish, in the future, any prognostic impact of RV involvement in HCM in order to improve risk stratification. RV free wall longitudinal strain (RV-FWLS) is a promising marker to unveil subclinical RV dysfunction despite normal conventional indices of RV systolic function; however, RV-FWLS has been scarcely explored in HCM patients.

Case Summary

A 29-year-old man with sarcomeric HCM due to MYBPC3 mutation was referred to our Institution. Trans-Thoracic Echocardiography (TTE) showed left ventricular (LV) apical hypertrophy (27 mm) with an ace of spades morphology and mid-ventricular obstruction (peak gradient 38 mmHg). LV-EF was normal (62%) while LV global longitudinal strain was significantly impaired (-9.3% with a reverse apical sparing pattern). 2nd-degree diastolic dysfunction and left atrial enlargement (maximum volume: 42 ml/m2) were observed. No LV apical aneurysm nor paradoxical diastolic flow at the apex were noted. RV hypertrophy was present (maximum thickness 8 mm) with normal conventional indices of RV systolic function: TAPSE 26 mm, S’ TDI 12 cm/s, FAC 50%. In contrast, RV-FWLS was significantly reduced (–16%). cMRI confirmed normal bi-ventricular function in presence of left and right hypertrophy (maximum wall thickness 28 and 12 mm, respectively) and LV apical thinning. At tissue characterization, elevated native T1 and T2 values were evident in the apex (1071 +/- 45 ms and 54 +/- 6 ms, respectively) and a significant amount of patchy LGE was present in the mid-apical segments of the LV (28% of LV mass) and of the RV. After consideration of clinical and imaging data, an s-ICD for primary prevention was implanted.

Discussion

The present case highlights known issues and poses new challenges in managing HCM patients. First, it confirms the central role of cMRI, demonstrating its unique capability to spot myocardial fibrosis, guiding our decision to implant an s-ICD in our patient. Second, it draws attention to RV involvement in HCM, an emerging finding in this condition. MYBPC3 mutation has been associated with RV hypertrophy. Both of these conditions, together with patchy RV-LGE, were found in our patient. Notably, RV-FWLS was the only RV systolic index to be impaired and might represent an early and more accurate marker of RV systolic dysfunction compared to other conventional indices, including RV-EF by cMRI. Future studies assessing the prognostic value of RV involvement, including RV-LGE and RV-FWLS, are needed in HCM patients to potentially refine risk stratification in this challenging population.

The pharmacology of anticoagulant drug treatment options in COVID-19 patients: reviewing real-world evidence in clinical practice

INTRODUCTION

The optimal anticoagulation strategy for venous thromboembolism (VTE) prevention among COVID-19 patients, hospitalized or in the community setting, is still challenging and largely based on real-world evidence.

AREAS COVERED

We analyzed real-world data regarding the safety and effectiveness of anticoagulant treatment, both parenteral and oral, for VTE prevention or atrial fibrillation (AF)/VTE treatment among COVID-19 patients.

EXPERT OPINION

The efficacy of low-molecular-weight heparin (LMWH) doses for VTE prevention correlates with COVID-19 disease status. LMWH prophylactic dose may be useful in COVID-19 patients at the early stage of the disease. LMWH intermediate or therapeutic dose is recommended in COVID-19 patients with an advanced stage of the disease. COVID-19 patients on VKAs therapy for atrial fibrillation (AF) and VTE should switch to NOACs in the community setting or LMWH in the hospital setting. No definitive data on de-novo starting of NOACs or VKAs therapy for VTE prevention in COVID-19 outpatients are available. In patients at high risk discharged after hospitalization due to COVID-19, thromboprophylaxis with NOACs may be considered.

The effects of gender on electrical therapies for the heart: procedural considerations, results and complications: A report from the XII Congress of the Italian Association on Arrhythmology and Cardiostimulation (AIAC)

Use of cardiac implantable devices and catheter ablation is steadily increasing in Western countries following the positive results of clinical trials. Despite the advances in scientific knowledge, tools development, and techniques improvement we still have some grey area in the field of electrical therapies for the heart. In particular, several reports highlighted differences both in medical behaviour and procedural outcomes between female and male candidates. Women are referred later for catheter ablation of supraventricular arrhythmias, especially atrial fibrillation, leading to suboptimal results. On the opposite females present greater response to cardiac resynchronization, while the benefit of implantable defibrillator in primary prevention seems to be less pronounced. Differences on aetiology, clinical profile, and development of myocardial scarring are the more plausible causes. This review will discuss all these aspects together with gender-related differences in terms of acute/late complications. We will also provide useful hints on plausible mechanisms and practical procedural aspects.

Atrial fibrillation and cardiac resynchronization therapy

PURPOSE OF REVIEW

Atrial fibrillation and heart failure are commonly encountered in current clinical practice. This review aims to revisit the complex interaction of these two common situations and the best treatment whenever both occurs, especially focusing on heart failure patients undergoing cardiac resynchronization therapy (CRT).

RECENT FINDINGS

It has been recently confirmed that in patients undergoing cardiac resynchronization therapy, 100% biventricular pacing percentage should be pursued. Large observational studies confirmed that atrioventricular junction ablation is very often the only way to gain 100% biventricular pacing in atrial fibrillation.

SUMMARY

On the basis of the recent observational extensive data, in patients presenting intermediate or elevated atrial tachycardia-atrial fibrillation burden, atrioventricular junction ablation may represent a fundamental tool to achieve full CRT delivery, thus, conferring marked improvements in global cardiac function, and by extension, in survival. Atrial fibrillation patients should not be excluded from CRT, provided that maximal biventricular pacing is warranted.

Multipoint Pacing versus conventional ICD in Patients with a Narrow QRS complex (MPP Narrow QRS trial): study protocol for a pilot randomized controlled trial

Background

Despite an intensive search for predictors of the response to cardiac resynchronization therapy (CRT), the QRS duration remains the simplest and most robust predictor of a positive response. QRS duration of ≥ 130 ms is considered to be a prerequisite for CRT; however, some studies have shown that CRT may also be effective in heart failure (HF) patients with a narrow QRS (<130 ms). Since CRT can now be performed by pacing the left ventricle from multiple vectors via a single quadripolar lead, it is possible that multipoint pacing (MPP) might be effective in HF patients with a narrow QRS. This article reports the design of the MPP Narrow QRS trial, a prospective, randomized, multicenter, controlled feasibility study to investigate the efficacy of MPP using two LV pacing vectors in patients with a narrow QRS complex (100–130 ms).

Methods

Fifty patients with a standard ICD indication will be enrolled and randomized (1:1) to either an MPP group or a Standard ICD group. All patients will undergo a low-dose dobutamine stress echo test and only those with contractile reserve will be included in the study and randomized. The primary endpoint will be the percentage of patients in each group that have reverse remodeling at 12 months, defined as a reduction in left ventricular end-systolic volume (LVESV) of >15% from the baseline.

Discussion

This feasibility study will determine whether MPP improves reverse remodeling, as compared with standard ICD, in HF patients who have a narrow QRS complex (100–130 ms).

Trial registration

ClinicalTrials.gov, NCT02402816. Registered on 25 March 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1698-1) contains supplementary material, which is available to authorized users.

Identification of Genetic Markers for Treatment Success in Heart Failure Patients

Background—

Cardiac resynchronization therapy (CRT) can improve ventricular size, shape, and mass and reduce mitral regurgitation by reverse remodeling of the failing ventricle. About 30% of patients do not respond to this therapy for unknown reasons. In this study, we aimed at the identification and classification of CRT responder by the use of genetic variants and clinical parameters.

Methods and Results—

Of 1421 CRT patients, 207 subjects were consecutively selected, and CRT responder and nonresponder were matched for their baseline parameters before CRT. Treatment success of CRT was defined as a decrease in left ventricular end-systolic volume >15% at follow-up echocardiography compared with left ventricular end-systolic volume at baseline. All other changes classified the patient as CRT nonresponder. A genetic association study was performed, which identified 4 genetic variants to be associated with the CRT responder phenotype at the allelic ( P <0.035) and genotypic ( P <0.031) level: rs3766031 ( ATPIB1 ), rs5443 ( GNB3 ), rs5522 ( NR3C2 ), and rs7325635 ( TNFSF11 ). Machine learning algorithms were used for the classification of CRT patients into responder and nonresponder status, including combinations of the identified genetic variants and clinical parameters.

Conclusions—

We demonstrated that rule induction algorithms can successfully be applied for the classification of heart failure patients in CRT responder and nonresponder status using clinical and genetic parameters. Our analysis included information on alleles and genotypes of 4 genetic loci, rs3766031 ( ATPIB1 ), rs5443 ( GNB3 ), rs5522 ( NR3C2 ), and rs7325635 ( TNFSF11 ), pathophysiologically associated with remodeling of the failing ventricle.

Egg quality and productive performance of laying hens fed different levels of skimmed milk powder added to a diet containing Lactobacillus acidophilus

The current trial was carried out on a commercial poultry farm to study the effect of skim milk powder (SMP) added to a diet containing Lactobacillus acidophilus on performance and egg quality of laying hens from 20 to 49 wk of age. A total of 2,400 Hy-Line W-36 laying hens were housed in 600 unenriched cages (4 hens each) located over 4 tier levels. Animals were assigned to 1 of 3 experimental treatments (0, 3, and 4). The laying hens assigned to treatments 3 and 4 received a diet enriched respectively with 3 and 4% SMP, whereas the animals in treatment 0 were fed a diet without SMP. All diets, moreover, were supplemented with L. acidophilus D2/CSL. Hen performance was determined throughout the experimental period and egg quality was measured on 30 eggs per treatment every week. Results showed that productive performance in terms of egg production, egg weight, and feed conversion ratio was not influenced by SMP at 3 or 4% of the diet. Egg quality was significantly affected by SMP included at 3 or 4% of the diet. Eggs from treatments 3 and 4, in fact, displayed higher shell thickness than those from treatment 0 (P < 0.0001). Likewise, specific gravity, Haugh unit, and shell percentage were significantly affected by the addition of SMP. In conclusion, in our study, SMP added to a diet containing L. acidophilus had no significant effects on the productive parameters of hens during the laying period, whereas significant improvements were found in certain egg quality characteristics.

Cardiac resynchronization therapy in heart failure patients with atrial fibrillation

Cardiac resynchronization therapy (CRT) is an important device-based, non-pharmacological approach that has shown, in large randomized trials, to improve left ventricular (LV) function and reduce both morbidity and mortality rates in selected patients affected by advanced heart failure (HF): New York Heart Association (NYHA) functional class III–IV, reduced LV systolic function with an ejection fraction (EF) ≤35%, QRS duration ≥120 ms, on optimal medical therapy, and who were in sinus rhythm. For the first time, the latest ESC and AHA/ACC/HRS Guidelines have considered atrial fibrillation (AF) patients, who constitute an important subgroup of HF patients, as eligible to receive CRT. Nevertheless, these Guidelines did not include a strategy for defining differentiated approaches according to AF duration or burden. In this review, the authors explain in which way AF may interfere with adequate CRT delivery, how to manage different AF burden, and finally present a brief overview on the effects of CRT in AF patients.

Cardiac Resynchronisation Therapy in Heart Failure Patients with Atrial Fibrillation

Cardiac resynchronisation therapy (CRT) is an important device-based, non-pharmacological approach that has been shown to improve left ventricular (LV) function and reduce both morbidity and mortality rates in selected patients affected by advanced heart failure (HF), with New York Heart Association (NYHA) functional class III–IV, ejection fraction (EF) ≤35%, QRS duration ≥120ms and on optimal medical therapy. Patients with atrial fibrillation (AF), who constitute an important subgroup of HF patients, are nowadays considered eligible for receiving CRT as described in the latest European Society of Cardiology (ESC) and American Heart Association/American College of Cardiology/Heart Rhythm Society (AHA/ACC/HRS) guidelines, with some relevant differences in terms of how to manage the interference of natural rhythm and biventricular pacing. In this article, the authors explain how AF may interfere with adequate CRT delivery and how to manage different AF burdens, trying to obtain the best effects of CRT in AF patients.

Insulin-treated type 2 diabetes is associated with a decreased survival in heart failure patients after cardiac resynchronization therapy

BACKGROUND

Cardiac resynchronization therapy (CRT) improves cardiac performance and survival in patients with congestive heart failure. Recent observations suggest that diabetes is associated with a worse outcome in these patients. The aim of the study was to investigate the effect of diabetes and insulin treatment on outcome after CRT.

METHODS

Diabetic status and insulin treatment were assessed in 447 patients who underwent CRT (males 80.8%, mean age 65.7 +/- 9.7 years, ejection fraction 29.9 +/- 6.11%). Patients were stratified in three groups according to the presence or absence of diabetes and insulin treatment.

RESULTS

Nondiabetic patients were 366 (79.6%), noninsulin-treated diabetic patients 62 (13.9%), insulin-treated diabetic patients 29 (6.5%). The estimated death rate was 5.15 per 100 patients-year in the nondiabetic group, 8.63 in noninsulin-treated diabetics (HR 1.59, P = 0.240), and 15.84 in insulin-treated diabetics (HR 3.05, P = 0.004). Cardiac mortality accounted for 81% of deaths in nondiabetic patients and for 56% of deaths in diabetic patients. Diabetic patients tended to have a worse recovery of left ventricular ejection fraction over time (P = 0.057) and of the distance at 6-minute walking test (6MWT) (P = 0.018).

CONCLUSIONS

Insulin-treated diabetes is associated with a worse functional recovery and a higher mortality in patients with advanced heart failure after CRT. While cardiac death accounts for the majority of deaths in nondiabetic patients, a relevant proportion of the mortality in diabetic patients seem to result from noncardiac causes.

Remission of left ventricular systolic dysfunction and of heart failure symptoms after cardiac resynchronization therapy: temporal pattern and clinical predictors

BACKGROUND

The aim of the study was to determine whether cardiac resynchronization therapy (CRT) may induce a heart failure (HF) remission phase (recovery to New York Heart Association functional class I-II and regression of left ventricular [LV] dysfunction: LV ejection fraction [EF] > or = 50%) and to define the incidence and predictors of such a process.

METHODS

Cardiac resynchronization therapy devices were successfully implanted in 520 consecutive HF patients from 1999 to 2006 (mean age 66 years, 82% male sex, New York Heart Association class > or = II, LVEF 28%, QRS 164 milliseconds, 6-minute hall walk distance 302 m) at our institution. Follow-up data were prospectively collected every 3 to 6 months. Continuous variables were stratified in tertiles.

RESULTS

Over a median follow-up of 28 months, 26% of patients achieved LV remission (rate: 16 per 100 person-years). At univariate analysis, female sex (P = .032), non-coronary artery disease (CAD) etiology (P < .001), mitral regurgitation < 2/4 (P = .022), higher EF tertile (P < .001), lower diameter and volume tertiles (both P < .001), previous conventional right ventricle pacing (P = .029), and post-CRT-paced QRS (P = .008) predicted remission. At multivariate analysis, non-CAD etiology, LVEF 30% to 35%, and LV end-diastolic volume < 180 mL were strongly associated with HF remission phase (all P < .001). Concomitance of these 3 factors yielded a significantly higher remission rate compared with either no or only 1 factor (respectively, 60 vs 7 and 11 per 100 person-years, P < .001).

CONCLUSIONS

Cardiac resynchronization therapy induces HF remission phase in 26% of patients, even after 3 years. Non-CAD etiology and moderately compromised LV function at baseline may easily predict this process.

Three Years of Cardiac Resynchronization Therapy: Could Superior Benefits be Obtained in Patients with Heart Failure and Narrow QRS?

AIM OF THE STUDY

To examine the long-term effects of cardiac resynchronization therapy (CRT) in patients presenting with heart failure (HF) and QRS </= 120 ms.

METHODS

This was a prospective, longitudinal study of 376 patients [mean age = 65 years, mean left ventricular (LV) ejection fraction (EF) = 29%, mean QRS duration = 165 ms, mean distance covered during a 6-minute hall walk (6-MHW) = 325 m], who underwent successful implantation of CRT systems. The QRS duration at baseline was </= 120 ms in 45 patients (12%) who were not pre-selected by echocardiographic criteria of dyssynchrony, and > 120 ms in the remaining 331 patients. The baseline characteristics of the 2 groups were similar. We evaluated indices of cardiac function, percentage of responders, and survival rates over a mean 28-month follow-up.

RESULTS

Both groups experienced similar long-term increases in 6-MHW, and decreases in New York Heart Association functional class and LV end-systolic volume (all comparisons P < 0.0001 in both groups). Time interaction of changes in LVEF and percentage of responders were significantly different (P = 0.03 and P = 0.004, respectively), in favor of the narrow QRS group, where the changes were sustained and persisted at 2 and 3 years. The long-term death rate from HF was lower in the group with narrow than in the group with wide QRS complex (P = 0.04; log-rank test).

CONCLUSIONS

CRT confers considerable long-term clinical, functional, and survival benefits in patients presenting with HF and narrow QRS, not preselected by echocardiographic criteria of dyssynchrony. Caution is advised before denying CRT to these patients on the basis of QRS width only.

Four-Year Efficacy of Cardiac Resynchronization Therapy on Exercise Tolerance and Disease Progression

OBJECTIVES

The goal of this study was to investigate the effects of cardiac resynchronization therapy (CRT) in heart failure patients with permanent atrial fibrillation (AF) and the role of atrioventricular junction (AVJ) ablation.

BACKGROUND

Cardiac resynchronization therapy has been proven effective in heart failure patients with sinus rhythm (SR). However, little is known about the effects of CRT in heart failure patients with permanent AF.

METHODS

Efficacy of CRT on ventricular function, exercise performance, and reversal of maladaptive remodeling process was prospectively compared in 48 patients with permanent AF in whom ventricular rate was controlled by drugs, thus resulting in apparently adequate delivery of biventricular pacing (>85% of pacing time), and in 114 permanent AF patients, who had undergone AVJ ablation (100% of resynchronization therapy delivery). The clinical and echocardiographic long-term outcomes of both groups were compared with those of 511 SR patients treated with CRT.

RESULTS

Both SR and AF groups showed significant and sustained improvements of all assessed parameters (model p < 0.001 for all parameters). However, within the AF group, only patients who underwent ablation showed a significant increase of ejection fraction (p < 0.001), reverse remodeling effect (p < 0.001), and improved exercise tolerance (p < 0.001); no improvements were observed in AF patients who did not undergo ablation.

CONCLUSIONS

Heart failure patients with ventricular conduction disturbance and permanent AF treated with CRT showed large and sustained long-term (up to 4 year) improvements of left ventricular function and functional capacity, similar to patients in SR, only if AVJ ablation was performed.

Clinical predictors of marked improvement in left ventricular performance after cardiac resynchronization therapy in patients with chronic heart failure

BACKGROUND

Previous studies have shown that cardiac resynchronization therapy (CRT) improves cardiac performance and decreases mortality and hospital admission rates. However, it is not yet clear which patients will benefit from the procedure the most. The purpose of the study was to identify the pre-implant characteristics that better predict which patients will have the best outcome after CRT.

METHODS

In this observational study, 156 patients were studied with echocardiography and a 6-minute walking test at baseline and 12 months after CRT.

RESULTS

After CRT, we observed an increase in left ventricular ejection fraction (+29.6%, P < .0001), a decrease in left ventricular end systolic volume (-26.4%, P < .0001), in the proportion of patients with grade 2-4 mitral regurgitation (from 47.1% to 34.0%, P = .002), and with NYHA functional class III-IV (from 83.2% to 11.6%, P < .0001), an increase in exercise tolerance (+31.1%, P < .0001). Sixty-two patients had a marked increase in left ventricular ejection fraction (> 10 units); the only independent predictor of a marked effect of CRT was the nonischemic etiology of heart failure. In patients with ischemic cardiomyopathy, the benefit on ejection fraction correlates inversely with the extension of the ischemic damage.

CONCLUSIONS

CRT improves left ventricular function and exercise tolerance in the long term. The nonischemic etiology of the cardiomyopathy is the only independent predictor of a marked effect of CRT; this is probably due to the absence of ischemic, nonviable scar tissue in these patients.

Delayed Defibrillation Testing in Patients Implanted with Biventricular ICD (CRT-D): A Reliable and Safe Approach

BACKGROUND

Defibrillation testing (DT) at the end of the implantation of cardiac resynchronization pacemaker with a defibrillator (CRT-D) exposes heart failure (HF) patients to increased procedural risks. However, until now, delayed DT has not been assessed as a possible option in HF patients implanted with CRT-D.

OBJECTIVE

Aim of the present study is to assess safety and feasibility of delayed DT in HF patients treated with CRT-D.

MATERIAL AND METHODS

Two hundred and eleven consecutive patients (mean age: 65 years, mean NYHA class 3.0, mean EF: 29.3%) underwent CRT-D implantation from October 1999 to December 2004. In the first 17 patients, DT was performed at the end of CRT-D implantation. In the other 194 consecutive patients, DT was performed at 2 months after CRT-D implantation. Outcome of DT, as well as "acute" LV lead dislodgment rate were evaluated in the latter group of 194 patients undergoing a delayed DT. Also, ICD function was assessed through device telemetry analysis at 2 months.

RESULTS

At delayed DT, first shock was effective in 187 of 194 patients (96%), ineffective VF interruption at maximum energy occurred only in one patient (0.5%), and acute LV lead dislodgment was 1%. No ICD therapy failure occurred in the 2-month untested period.

CONCLUSION

DT performed 2 months after CRT-D implantation is safe and feasible; this is possibly related to the improvement of clinical conditions and hemodynamic status as well as greater lead stability 2 months after CRT-D.

Endocardial Implantation of a Cardioverter Defibrillator in Early Childhood

INTRODUCTION

Experience in endovascular/endocardial techniques for implanting implantable cardioverter defibrillators in early childhood is limited. Potentially, this type of approach could limit the surgical risk, while increasing ICD therapy efficacy. The safety and feasibility of adopting a complete endovascular/endocardial approach for implanting ICDs is assessed by considering the cases of two young children.

METHODS AND RESULTS

Two boys, aged 3 and 6 years, were implanted with ICD for a history of syncope and documented ventricular tachycardia (VT). A complete endovascular/endocardial approach was adopted consisting of positioning a bipolar pacing and sensing lead in the right ventricular (RV) apex with intravascular redundancy forming a loop in the inferior vena cava (IVC), and a caval coil placed in the IVC. Sensing values (7-8 mV), pacing threshold (0.5-0.6 V/0.5 msec), and defibrillation testing (case 1 = 10 J, case 2 = 20 J) were all acceptable. During follow-up, in both cases ICD intervened correctly. In one case, 16 months after implantation, because of change in the IVC coil-active can vector, the IVC coil was effectively repositioned to a more distal position.

CONCLUSION

A complete endovascular/endocardial ICD implantation technique in early childhood is both feasible and safe. This approach avoids thoracotomy and ensures ICD therapy efficacy.

Is the left ventricular lateral wall the best lead implantation site for cardiac resynchronization therapy?

Short-term hemodynamic studies consistently report greater effects of cardiac resynchronization therapy (CRT) in patients stimulated from a LV lateral coronary sinus tributary (CST) compared to a septal site. The aim of the study was to compare the long-term efficacy of CRT when performed from different LV stimulation sites. From October 1999 to April 2002, 158 patients (mean age 65 years, mean LVEF 0.29, mean QRS width 174 ms) underwent successful CRT, from the anterior (A) CST in 21 patients, the anterolateral (AL) CST in 37 patients, the lateral (L) CST in 57 patients, the posterolateral (PL) CST in 40 patients, and the middle cardiac vein (MCV) CST in 3 patients. NYHA functional class, 6-minute walk test, and echocardiographic measurements were examined at baseline, and at 3, 6, and 12 months. Comparisons were made among all pacing sites or between lateral and septal sites by grouping AL + L + PL CST as lateral site (134 patients, 85%) and A + MC CST as septal site (24 patients, 15%). In patients stimulated from lateral sites, LVEF increased from 0.30 to 0.39 (P < 0.0001), 6-minute walk test from 323 to 458 m (P < 0.0001), and the proportion of NYHA Class III-IV patients decreased from 82% to 10% (P < 0.0001). In patients stimulated from septal sites, LVEF increased from 0.28 to 0.41 (P < 0.0001), 6-minute walk test from 314 to 494 m (P < 0.0001), and the proportion of NYHA Class III-IV patients decreased from 75% to 23% (P < 0.0001). A significant improvement in cardiac function and increase in exercise capacity were observed over time regardless of the LV stimulation sites, either considered singly or grouped as lateral versus septal sites.

Beneficial effects of biventricular pacing in patients with a "narrow" QRS

Congestive heart failure (CHF) patients with LBBB and QRS duration > 150 ms are considered the best candidates to biventricular pacing (Biv-P). However, patients with a narrow (120-150 ms) QRS may also benefit from Biv-P since true ventricular dyssynchrony may be underestimated by considering only QRS enlargement. From October 1999 to April 2002, 158 CHF patients (121 men, mean age 65 years, mean LVEF 0.29, mean QRS width 174 ms) underwent successful Biv-P implantation and were then followed for a mean time of 11.2 months. According to basal QRS duration, patients were divided in two groups, with wide QRS (> or = 150 ms, 128 patients, 81%) and with narrow QRS (< 150 ms, 30 patients, 19%). In the wide QRS group, LVEF improved from 29% to 39% (P < 0.0001), 6-minute walk test from 311 to 463 m (P < 0.0001), while NYHA Class III-IV patients decreased from 86% to 8% (P < 0.0001). In the narrow QRS group LVEF improved from 30% to 38% (P < 0.0001), 6-minute walk test from 370 to 506 m (P < 0.0001), and NYHA Class III-IV patients decreased from 60% to 0% (P < 0.0001). The data showed that in wide and narrow QRS patients, Biv-P significantly improved clinical parameters (NYHA class, 6-minute walk test, quality-of-life, and hospitalization rate) and main echocardiographic indicators. Furthermore, narrow QRS patients had a better survival rate, rapidly regained left ventricular function, and only a few patients remained in a higher NYHA class during follow-up. These patients should not be excluded "a priori" from cardiac resynchronization therapy.

Flecainide test in Brugada syndrome: a reproducible but risky tool

The flecainide test is widely used in Brugada syndrome. However, its reproducibility and safety remain ill-defined. This study included 22 patients (18 men, mean age 34 years). Mutations in the SCN5A gene were found in eight patients. Two patients had aborted sudden cardiac death, 8 had syncope/presyncope, and 12 were asymptomatic. The ECG was diagnostic in 19 patients and suggestive in 3. At baseline, 21 of 22 patients underwent a flecainide test (2 mg/kg IV bolus over 10 minutes). In 21 of 21 patients the test was diagnostic or amplified the typical ECG pattern. At the end of drug infusion, sustained VT lasting 7-10 minutes developed in two patients. A second flecainide test was performed within 2 months in 20 patients. The test was not repeated in the two patients with prior development of VT. The flecainide test was diagnostic in 20 of 20 patients. Sustained VT occurred in one patient and recurrent VF in another. The reproducibility of the flecainide test was 100%. In 4 (18%) of 22 patients major VAs were documented after the end of flecainide infusion. VA occurred in 3 (43%) of 7 patients with, versus 1 (7%) 15 without SCN5A gene mutation (P < 0.05). No diagnostic ECG changes or arrhythmias developed in 25 control patients without structural heart disease who underwent the same study protocol. This study shows a high flecainide reproducibility, supporting its diagnostic value in Brugada syndrome. However, the occurrence of major VA, significantly higher in patients with documented SCN5A gene mutation, including in asymptomatic patients, mandates the performance under appropriate medical supervision. Whether a slower rate of drug infusion can lower the risk of VA induction, while maintaining the sensitivity of the test should be explored.

Biventricular pacing via a persistent left superior vena cava: report of four cases

Persistence of left superior vena cava (LSVC) is an uncommon finding during pacemaker implantation, which may be particularly relevant in performing LV transvenous pacing. Rarely, it is further complicated by the presence of atresia of the coronary sinus ostium (CSO). This article reports the authors experience with biventricular pacing (Biv-P) in this unusual clinical setting. From October 1999 to April 2002, 158 patients underwent biventricular pacing. In four of them (mean age 62.2 years), the presence of a persistent LSVC draining into the coronary sinus (CS) was detected at implantation, associated with atresia of the CSO in two patients. A common characteristic was the angiographic finding of a large CS with few tributaries. The LV leads were successfully positioned in the middle cardiac vein in three patients and in a posterolateral vein in one patient. All vessels were large and their cannulation via downstream CS catheterization required the lead to be manipulated through sharp angles. Mean fluoroscopic exposure and procedural times were not significantly different from the overall Biv-P population. In all patients, at a mean follow-up of 11 months, sensing and capture threshold remained stable and a significant decrease in NYHA functional class and increase in LVEF were noted. The direct lead placement in large CS tributaries in the presence of persistent LSVC was feasible and safe. The leads remained stable up to a mean follow-up of nearly 1 year.

Is the outcome of cardiac resynchronization therapy related to the underlying etiology?

This study was designed to examine the importance of the underlying cardiac pathology on outcome of cardiac resynchronization therapy (CRT), hypothesizing that myocardial infarction scar and other noncontractile segments represent limitations to the ability to resynchronize cardiac contraction in patients with congestive heart failure associated with dilated cardiomyopathy. From October 1999 to April 2002, 158 patients (mean age 65 years, 121 men) were included in a single center, longitudinal, comparative study. All patients had dilated cardiomyopathy and indications for CRT with a mean QRS duration of 174 ms. The patient population was divided into a coronary artery disease (CAD) group that included patients with significant CAD, and no indication, or a contraindication for revascularization, and a non-CAD group that included patients with nonischemic dilated cardiomypopathy. Follow-up data were collected at 3, 6, and 12 months, and yearly thereafter. The median follow-up was 11.2 months. In the CAD group, the LVEF increased from 0.29 to 0.34 (P < 0.0001), the 6-minute walk test distance increased from 310 to 463 m (P < 0.0001), and the percentage of patients in NYHA functional Class III-IV decreased from 83% to 23% (P = 0.04). In the non-CAD group, LVEF increased from 29% to 42% (P < 0.0001), the 6-minute walk test distance increased from 332 to 471 m (P < 0.0001), and the percentage of patients in NYHA functional Class III-IV decreased from 79% to 5%, (P < 0.0001). Comparison of the two groups showed that patients in the non-CAD group had a significantly greater increase in LVEF (P = 0.007) and decrease in NYHA class (P < 0.05). Patients with CAD or non-CAD significantly improved clinically during CRT. Non-CAD patients had a greater increase in LVEF and decrease in NYHA functional class than patients with CAD.

Relief of drug refractory angina by biventricular pacing in heart failure

Since cardiac resynchronization therapy (CRT) improves LV function at the cost of low energetic expenditure, the authors hypothesized that it may increase the threshold of drug refractory angina in selected patients with CHF and CAD who are not amenable to myocardial revascularization. From October 1999 to April 2002, 75 patients with CHF and CAD were treated with CRT. Drug refractory angina occurred nearly daily in 8 of the 75 patients. The mean age of these eight men was 71 years, mean NYHA functional Class 3.4 +/- 0.5, mean QRS duration (QRSd) 168 +/- 20 ms, and mean left ventricular ejection fraction (LVEF) 0.29 +/- 0.4. Diffuse CAD not amenable to myocardial revascularization was confirmed on angiography. At baseline, no patient was able to complete a 6-minute walk test because of angina. In the 6 months before CRT, the mean number of hospitalizations per patient for management of CHF or angina was 3.1 +/- 0.3. All patients underwent successful CRT. Mean QRSd decreased to 141 +/- 16 ms (P = 0.01 vs baseline). After 9 +/- 6.1 months, LVEF increased to 0.317 +/- 0.028 (P = 0.03 vs baseline), while the NYHA class decreased to 2.6 +/- 0.5 (P = 0.02 vs baseline). All patients also experienced a marked decrease in angina episodes, from a mean of 8.3 +/- 11.6 to 0.6 +/- 1.3 episodes/week (P < 0.05), and completed a 6-minute walk test, covering a mean distance of 337 +/- 68 m (vs 237 +/- 136 m at baseline, P = 0.007). No further hospitalization was necessary. The beneficial effects of CRT on overall cardiac function may include a better control of angina in severely symptomatic patients.

Programmed electrical stimulation in Brugada syndrome: how reproducible are the results?

INTRODUCTION

Inducibility of ventricular arrhythmias at programmed electrical stimulation (PES) ranges between 50% and 80% of patients with Brugada syndrome. However, the variety of PES protocols and the lack of data relative to a control group or to ventricular arrhythmia reproducibility contribute to a still undefined interpretation of PES outcome in Brugada syndrome.

METHODS AND RESULTS

Twenty-one patients with Brugada syndrome (18 men and 3 women; mean age 34 years; 9/21 symptomatic; 8/21 with SCN5A gene mutation) underwent a PES protocol from two right ventricular sites. The endpoint was PES protocol completion or induction of sustained or reproducible (>6 consecutive inductions) nonsustained (>6 beats) fast ventricular arrhythmia. In 17 of 21 patients with Brugada syndrome, PES was repeated 2 months later to test ventricular arrhythmia reproducibility. Twenty-five healthy patients (17 men; mean age 36 years) formed the control group. In patients with Brugada syndrome, ventricular arrhythmia inducibility rate at PES was high (18/21 patients [85%]) and increased with protocol aggressiveness, independent of clinical presentation. In control subjects, no ventricular arrhythmias were induced. Among patients with Brugada syndrome, 14 (82%) of 17 patients remained inducible at a second PES.

CONCLUSION

In our experience, ventricular arrhythmia inducibility in patients with Brugada syndrome, at variance with healthy controls, is high and does not correlate with clinical presentation. PES inducibility is deeply influenced by the protocol used. PES outcome is reproducible at a mid-term follow-up mainly if a categorical endpoint (inducible vs noninducible) is used. The need to assess the predictive value of specific PES protocols in targeted studies is widely emerging and is confirmed by our results.

Inferior vena cava loop of the implantable cardioverter defibrillator endocardial lead: a possible solution of the growth problem in pediatric implantation

The ICD is an important treatment option in adults and children with life-threatening tachyarrhythmias. The possibility of lead displacement caused by growth and the lack of dedicated leads and devices poses special problems in pediatric ICD implantation. We describe our experience in three children in whom we left a redundant lead loop within the inferior vena cava (IVC) is allow for further growth. Since February 1998, three children underwent ICD implantation at our institution. A lead (screw-in) was advanced into the right ventricular apex, and a loop was created in the IVC by progressively withdrawing the stylet and pushing in the lead. Satisfactory sensing and pacing threshold values were obtained and a successful single 16-J defibrillation test was performed. No complications were encountered. After a mean follow-up of 16 months, with a mean increase in body weight and height of 4.1 +/- 0.5 Kg and 6.3 +/- 0.4 cm, respectively, chest X ray showed some release of additional lead length, in the absence of dislodgments, while significant changes in pacing/sensing parameters were not found. In conclusion, the creation of a loop within the IVC allows the lead to adjust for growth in children receiving an ICD. This approach is feasible and safe.

Long-term follow-up after atrioventricular nodal ablation and pacing: low incidence of sudden cardiac death

Sudden cardiac death (SCD) has been reported in patients with drug refractory AF who underwent AV nodal ablation and pacing. However, whether SCD in these patients is related to the underlying heart disease or to the ablating and pacing procedure remains uncertain. Between May 1987 and January 1997, AV nodal ablation was performed in 585 patients (mean age 66 +/- 11 years) with drug-resistant, paroxysmal (n = 308) or chronic (n = 277) AF in 12 Italian centers. Lone AF was present in 133 patients. After AV junction ablation, patients underwent VVIR (454 patients) or DDDR (131 patients) pacemaker implantation. At a follow-up of 33.6 +/- 24.2 months, 80 (13.7%) deaths were recorded: 40 noncardiac, 23 nonsudden, and 17 sudden cardiac death (3%, 1.04% per year). Among five variables, including age. NYHA functional class, presence of heart disease, paroxysmal or chronic AF, previous embolic events, and LVEF, the presence of heart disease (P = 0.007) and a LVEF < 0.45, (P = 0.003) were associated with a higher risk of SCD. Analysis of SCD-free survival by log-rank test showed a higher incidence of SCD in patients with LVEF < 0.45 (P = 0.0001) and with coronary artery disease (P = 0.005). In this large cohort, a low incidence of long-term SCD after AV nodal ablation and pacing for drug-refractory AF was observed. The presence of underlying heart disease and the extent of baseline LV dysfunction were associated with an increased likelihood of SCD.

Noncontact system-guided simplified right atrial linear lesions using radiofrequency transcatheter ablation for treatment of refractory atrial fibrillation

This article describes our experience with a staged "hybrid" approach to the treatment of drug resistant AF, in which the completeness of a single linear lesion in the RA was verified with a noncontact mapping system. Inferior vena cava-tricuspid annulus ablation was performed and followed by the creation of a single intercaval lesion. The study population consisted of 24 patients with a 3.4 +/- 1.6-year history of drug resistant, severely symptomatic, lone paroxysmal (n = 19), or persistent (n = 5) AF. During a follow-up of 8 +/- 2.6 months, 12 (50%) patients remained asymptomatic and 6 (25%) had a significant decrease in AF episodes, while the arrhythmia was unchanged in 5 (21%) patients and aggravated in 1 (4%) patient. Overall, a favorable clinical result was achieved in 18 (75%) patients.

Incidence and clinical significance of transformation of atrial fibrillation to atrial flutter in patients undergoing long-term antiarrhythmic drug treatment

AIMS

To investigate the rate of transformation of atrial fibrillation to atrial flutter in patients taking antiarrhythmic drugs for the prophylaxis of atrial fibrillation, we retrospectively analysed data from 305 consecutive patients with paroxysmal atrial fibrillation (155 male; mean age 63 +/- 11 years) treated with ventricular rate controlling drugs, antiarrhythmic drugs, or without drugs.

METHODS AND RESULTS

At a mean follow-up of 9 months (range 1-24) all patients experienced recurrence of arrhythmia: 48 (14.6%, Group A) suffered Type 1 atrial flutter, and 257 (85.4%, Group B) atrial fibrillation. The relative rate of recurrence of atrial flutter vs atrial fibrillation was similar in patients without treatment or with ventricular rate controlling drugs (from 6.8% to 14.6%, P=ns). However, recurrence was higher (25%) in patients administered antiarrhythmic drug therapy. The relative risk in these patients was 3.02 times greater, compared with patients without treatment, or treated with rate controlling drugs (P<0.001). There were no differences between groups concerning the baseline clinical characteristics and the clinical consequences of the recurrence; patients with atrial flutter had a lower rate of conversion to sinus rhythm (42% vs 64%) and a higher rate of hospital admission (69% vs 36%) compared with those with atrial fibrillation. Six patients (8.5%) experienced 1:1 atrioventricular conduction during atrial flutter with a ventricular rate of 240-280 beats x min(-1).

CONCLUSION

Our data suggest that the use of antiarrhythmic drugs for the prophylaxis of atrial fibrillation is associated with a threefold increase in the probability of Type 1 atrial flutter recurrence, as opposed to atrial fibrillation, which may have important clinical consequences, but which did not in our study.

Should ablation of atrial flutter be discouraged in patients with documented atrial fibrillation?

Atrial fibrillation and atrial flutter often coexist in the same patient. The purpose of this article is to provide an analysis of the mechanisms underlying the transformation from atrial fibrillation into atrial flutter and to investigate the long-term clinical benefits following ablation of atrial flutter in relation to recurrences of atrial fibrillation. Experimental studies in the human atrium demonstrated that in most instances atrial fibrillation is a triggering rhythm for atrial flutter. However, a review of the most recent studies shows a low percentage of recurrence of atrial fibrillation after successful catheter ablation for atrial flutter. The risk factors for this recurrence are the presence of structural heart disease, increased left atrial dimension and volume, a previous history of atrial fibrillation, and the failure of multiple antiarrhythmic drugs, inducibility of atrial fibrillation by a standard programmed electrical stimulation protocol after catheter ablation. These data, together with the high success rate of catheter ablation for atrial flutter, suggest to perform radiofrequency catheter ablation for atrial flutter in patients with documented atrial fibrillation.

Isradipine in the treatment of peripheral occlusive vascular disease of the lower limbs: a pilot study

The long-term effects of isradipine on peripheral occlusive vascular disease of the lower limbs were investigated in 23 normotensive patients with stable Fontaine stage IIa disease and with an absolute pain-free interval (treadmill speed 4 km/h, no incline) of 300 - 700 m, and Doppler ankle - arm arterial pressure index of less than 0.80 in at least one leg. Using a double-blind, parallel-group design, patients received either 2.5 mg isradipine twice daily or placebo for 12 months. Both isradipine (n = 11) and placebo (n = 12) increased the absolute pain-free interval mean values; the increases were not significantly different. Similar trends were observed in the mean values for relative pain-free interval and ankle--arm arterial pressure index. In a subgroup of patients with a baseline absolute pain-free interval of greater than 500 m, isradipine (n = 6) significantly (P less than 0.001) increased both the absolute and the relative pain-free intervals and increased the ankle--arm arterial pressure index compared with placebo (n = 7). The favourable effects of long-term isradipine treatment suggest that isradipine could positively interfere with factors involved in the progression of atherosclerotic lesions or improve collateral vessel flow.

Microcirculation and hemorheology in NIDDM patients

The authors studied 10 patients with non-insulin-dependent diabetes mellitus and 5 controls matched for age, sex, blood lipids, and smoking habit. The two groups were also comparable for hemorheologic characteristics as evaluated by viscosimetry on whole blood, plasma and serum, erythrocyte filtration and aggregation. The microcirculation was studied in the subjects of both groups by microalbuminuria determination, retinal fluorangiography, and capillaroscopic examination of the bulbar conjunctive and nail folds. None of the patients presented microalbuminuria values higher than the upper limit of normal (20mg/24h). Fluoroangiographic alterations were observed in 4 patients, and all 10 presented capillaroscopic alterations at the bulbar conjunctiva (microaneurysms, erythrocyte aggregates) and nail folds (more frequently of the fingers than toes). Similar alterations were detected in controls. Thus these abnormalities seem independent of hemorheologic values.