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Backgorund: Hereditary transthyretin(vATTR) cardiac amyloidosis has extremely different features according to the type of transthyretin(TTR) mutation. Data about electrocardiographic findings(ECG) in vATTR are limited and not informative of genotype correlation. Aim of this study is to analyze ECG characteristics and their correlation to clinical and echocardiographic aspects in patients with vATTR, focusing on different TTR mutations., Methods and Results: This is a multicentric, retrospective, observational study performed in six Italian referral centres. We divided patients in two groups, according to the previously described phenotypic manifestations of the TTR mutation. Of 64 patients with vATTR, 23(36%) had prevalent cardiac(PC) TTR mutations and 41(64%) patients had a prevalent neurological(PN) TTR mutations. Patients with PC mutations were more frequently males and older, with advanced NAC staging. At baseline ECG, atrial fibrillation was more common in patients with PC, while pacemaker induced rhythm in PN mutations. PQ and QRS durations were longer and voltage to mass ratio was lower in PC mutations. Different TTR mutations tend to have distinctive ECG features., Conclusions: ECG in vATTR is extremely heterogeneous and the specific mutations are associated with distinct instrumental and clinical features. The differences between PN and PC vATTR are only partially explained by the different degree of cardiac infiltration., Competing Interests: Declaration of Competing Interest The authors report there are no competing interests to declare., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Data on the incidence and factors associated with de novo atrial fibrillation (AF) in patients with wild-type transthyretin cardiac amyloidosis (ATTRwt-CA) is limited. We described the incidence and factors associated with de novo AF in patients diagnosed with ATTRwt-CA to drive tailored arrhythmia screening., Methods: Multicenter, retrospective, observational cohort study performed in six referral centers for CA. All consecutive patients diagnosed with ATTRwt-CA between 2004 and 2020 with >6-month follow up (FU) were enrolled and divided into three groups according to presence of AF: (1)patients with 'known AF'; (2)patients in 'sinus rhythm' and (3)patients developing 'de novo AF' during FU. Incidence and factors associated with AF in patients with ATTRwt were the primary outcomes., Results: Overall, 266 patients were followed for a median of 19 [11-33] months: 148 (56%) with known AF, 84 (31.6%) with sinus rhythm, and 34 (12.8%) with de novo AF. At Fine-Gray competing risk analysis to account for mortality, PR (sub-distribution hazard ratio [SHR] per Δms: 1.008, 95% C.I. 1.001-1.013, p = 0.008), QRS (SHR per Δms: 1.012, 95% C.I. 1.001-1.022, p = 0.046) and left atrial diameter ≥ 50 mm (SHR: 2.815,95% C.I. 1.483-5.342, p = 0.002) were associated with de novo AF. Patients with at least two risk factors (PR ≥ 200 ms, QRS ≥ 120 ms or LAD≥50 mm) had a higher risk of developing de novo AF compared to patients with no risk factors (HR 14.918 95% C.I. 3.242-31.646, p = 0.008)., Conclusions: At the end of the study almost 70% patients had AF. Longer PR and QRS duration and left atrial dilation are associated with arrhythmia onset., Competing Interests: Declaration of Competing Interest none to declare for the present work. All authors participated in the research and preparation of the manuscript., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Introduction: Refractory angina (RA) is considered the end-stage of coronary artery disease, and often has no interventional treatment options. Coronary sinus Reducer (CSR) is a recent addition to the therapeutic arsenal, but its efficacy has only been evaluated on small populations. The RESOURCE registry provides further insights into this therapy., Methods: The RESOURCE is an observational, retrospective registry that includes 658 patients with RA from 20 centers in Europe, United Kingdom and Israel. Prespecified endpoints were the amelioration of anginal symptoms evaluated with the Canadian Cardiovascular Society (CCS) score, the rates of procedural success and complications, and MACEs as composite of all-cause mortality, acute coronary syndromes, and stroke., Results: At a median follow-up of 502 days (IQR 225-1091) after CSR implantation, 39.7% of patients improved by ≥2 CCS classes (primary endpoint), and 76% by ≥1 class. Procedural success was achieved in 96.7% of attempts, with 3% of procedures aborted mostly for unsuitable coronary sinus anatomy. Any complication occurred in 5.7% of procedures, but never required bailout surgery nor resulted in intra- or periprocedural death or myocardial infarction. One patient developed periprocedural stroke after inadvertent carotid artery puncture. At the last available follow-up, overall mortality and MACE were 10.4% and 14.6% respectively. At one, three and five years, mortality rate at Kaplan-Meier analysis was 4%, 13.7%, and 23.4% respectively., Conclusions: CSR implantation is safe and reduces angina in patients with refractory angina., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background To investigate the relationship between 1-year outcome and diastolic dysfunction (DD) and frailty and/or physical performance (PP) in older adults admitted to hospital for acute coronary syndrome (ACS). Methods and results Older (age ≥ 70 years) hospitalized for ACS and receiving coronary artery angiography ± percutaneous coronary intervention were included. Before discharge a complete transthoracic echocardiogram (TTE) was performed with the assessment of DD, following the 2016 American Society of Echocardiography/European Association of Cardiovascular Imaging algorithm. Seven different scales of frailty and PP were assessed. The relationship between DD and tests of frailty and PP was investigated, as well as the association with the 1-year occurrence of all-cause death or re-hospitalization. Overall, 329 patients were included in the analysis. Patients were stratified in two groups: DD grade 0-1 versus 2-3. Those with undetermined degree of DD have been excluded by the analysis (n = 106). Mean age of the groups was 77 ± 5 vs 79 ± 6 years, respectively. Scales of frailty and/or PP were significantly poor in patients with DD grade 2-3 compared to the others. After multivariate Cox regression (considering age, female sex, haemoglobin, albumin, clinical presentation, LVEF and SPPB) DD (degree 2-3 vs. 0-1) emerged as an independent predictor of the composite endpoint (HR 1.69, 95%CI 1.04-2.75, p = 0.033). This was mainly driven by 1-year re-hospitalization (HR 2.01, 95%CI 1.22-3.27, p < 0.001). Conclusions In older ACS patients the assessment of DD is related to parameters of frailty and PP and it is an independent predictor of 1-year outcome., Competing Interests: Declaration of competing interest No authors reported conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Competing Interests: Declaration of competing interest The authors report no relationships that could be construed as a conflict of interest.

Background: To assess whether coronary bypass (CABG) or stenting reduce the risk of mortality and myocardial infarction (MI) compared with optimal medical therapy (OMT) in stable coronary artery disease (CAD)., Methods: We performed a systematic review and network meta-analysis of contemporary randomized controlled trials comparing OMT, CABG and different stent types in stable CAD. All-comer trials were included if the rate of patients with acute myocardial infarction (AMI) was≤20%. Endpoints were all-cause mortality and MI., Results: Ninety-seven trials including 75,754 patients were analyzed at a weighted mean follow up of 42.5 months. Compared to OMT, CABG was associated with a lower risk of death (OR = 0.84; 95%CI:0.71-0.97). After exclusion of trials in left main and/or multivessel disease(LM/MVD) this benefit was not statistically significant (OR = 0.89; 95%CI:0.74-1.06). CABG was associated with a lower risk of MI (OR = 0.67;95%CI: 0.49-0.91) showing, however, a certain degree of inconsistency (p=0.10). None of the stent types included was associated with a lower risk of death. However, durable-polymer-CoCr-everolimus-eluting stent, by mixed evidence, after exclusion of either LM/MVD (OR = 0.73;95%CI: 0.54-0.98) or all-comer/post-MI trials (OR = 0.62;95%CI:0.39-0.98) was associated with a lower risk of MI than OMT. Similar findings, by indirect evidence, were confirmed for bio-absorbable-polymer-CoCr-sirolimus eluting stent (LMV/MVD trials excluded OR = 0.46; 95%CI = 0.29-0.74, all-comer/post-MI trials excluded: OR = 0.41;95%CI:0.22-0.79)., Conclusions: In stable CAD, CABG reduces the risk of mortality and MI compared to OMT, especially in patients with higher extent of CAD. Our study suggests that some of second and latest-generation drug-eluting stents may reduce the risk of MI. Future research should confirm these latter findings., Competing Interests: Declaration of competing interest The authors report no relationships that could be construed as a conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Planar diphosphonate scintigraphy is an established diagnostic tool for amyloid transthyretin (ATTR) cardiomyopathy. Characterization of the amyloid burden up to the segmental level by single photon emission computed tomography (SPECT) has not been evaluated so far., Methods: Data from consecutive patients undergoing cardiac 99m Tc-hydroxymethylene diphosphonate ( 99m Tc-HMDP) SPECT and diagnosed with ATTR cardiomyopathy at a tertiary referral center from June 2016 to April 2019 were collected., Results: Thirty-eight patients were included (median age 81 years, 79% men, 92% with wild-type ATTR). In patients with Perugini score 1, the most intense diphosphonate regional uptake was found in septal segments, particularly in infero-septal segments. Among patients scoring 2, the amyloid burden in the septum became more significant, and extended to inferior and apical segments. Finally, patients scoring 3 displayed an intense and widespread tracer uptake. All patients with Perugini score 1 had LGE in at least one antero-septal, one infero-septal, and one infero-lateral segment. All patients with score 2 displayed LGE in infero-septal, inferior, and infero-lateral segments. LGE became extensive in patients scoring 3, with all patients having at least one LGE-positive segment in each region., Conclusions: When assimilating different Perugini grades to evolutive stages of the disease, amyloid deposition seem to progress from the septum to the inferior wall and then to the other regions and from the basis to the apex. The potential of segmental analysis might be particularly relevant in patients with very limited cardiac uptake at planar scintigraphy (Perugini score 1)., Competing Interests: Declaration of competing interest There is no conflict of interest to disclose., (Copyright © 2020. Published by Elsevier B.V.)

Patients with hypertrophic cardiomyopathy (HCM) exhibit a variable phenotype with ventricular hypertrophy as the cardinal manifestation and left ventricular (LV) outflow tract obstruction (LVOTO) as a key pathophysiologic determinant. Patients with severe LVOTO usually present with exertional dyspnea, exertional syncope, and heart failure symptoms, while successful relief of LVOTO by pharmacological or invasive interventions leads to a dramatic improvement in clinical status. Proper management of obstructive HCM remains challenging and poses numerous clinical dilemmas. Since the development of surgical myectomy over half a century ago, progress in the management of LVOTO in HCM has paralleled technological advances in genetic testing, cardiac imaging, arrhythmic prophylaxis, cardiac surgery and interventional cardiology. These changes have been incorporated in dedicated scientific guidelines on both sides of the Atlantic. However, either the 2011 American guidelines or the 2014 European guidelines remain largely based on expert consensus for lack of recommendations with level of evidence A regarding any of the treatment options commonly employed in HCM. Consequently, management of obstructive HCM patients remains largely subjective and dependent on clinical judgment, local expertise, and patient preference. Following the trend that has emerged for other cardiac diseases amenable to invasive interventions, adequate evaluation and management of obstruction in HCM today requires a multidisciplinary team capable of optimizing referral, choosing the best available options, minimizing complications and ensuring state-of-the-art results. The concept of an HCM Heart Team is coming of age. This review aims to provide an update of available pharmacologic and invasive options for the management of LVOTO in HCM, either in adulthood or in childhood, highlighting areas for multidisciplinary integration and future development., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Although imaging techniques have demonstrated the existence of microvascular abnormalities in hypertrophic cardiomyopathy (HCM), a detailed histopathological assessment is lacking as well as a comparison between different phases of the disease. We aimed to compare microvasculopathy and myocardial fibrosis in hypertrophic obstructive cardiomyopathy (HOCM) versus end-stage (ES) HCM., Methods: 27 myectomy specimens of HOCM patients and 30 ES-HCM explanted hearts were analyzed. Myocardial fibrosis was quantitatively determined with dedicated software and qualitatively classified as scar-like or interstitial. Intramural coronary arteries were evaluated separately according to lumen diameter: 100-500 μ versus <100 μ. Microvasculopathy assessment included the description of medial and intimal abnormalities and stenosis grading. The two subgroups were compared considering only the anterobasal septum of ES explanted hearts., Results: Median value of fibrosis in the anterobasal septum of explanted hearts was 34.6% as opposed to 10.3% of myectomy specimens (p < 0.001). Scar-like fibrosis was widely found in ES hearts while interstitial fibrosis was distinctive of HOCM (p < 0.001). All slides showed 100-500 μ microvasculopathy without any differences between subgroups in terms of lumen narrowing, extent of the disease and type of parietal involvement. Among ES hearts these lesions were associated with scar-like fibrosis (p = 0.034). <100-μ microvasculopathy was also frequent with no differences between subgroups., Conclusions: Microvasculopathy is an intrinsic feature of HCM with similar characteristics across the natural phases of the disease. Conversely, myocardial fibrosis changes over time with ES hearts showing a three-fold greater amount, mainly scar-like. ES showed a closer association between microvasculopathy and replacement fibrosis., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Patients with heart failure (HF) and severe symptomatic functional mitral regurgitation (FMR) may benefit from MitraClip implantation. With increasing numbers of patients being treated the success of procedure becomes a key issue. We sought to investigate the pre-procedural predictors of device failure in patients with advanced HF treated with MitraClip., Methods: From April 2012 to November 2016, 76 patients with poor functional class (NYHA class III-IV) and severe left ventricular (LV) remodeling underwent MitraClip implantation at University Hospitals of Trieste and Bologna (Italy). Device failure was assessed according to MVARC criteria. Patients were subsequently followed to additionally assess the patient success after 12months., Results: Mean age was 67±12years, the mean Log-EuroSCORE was 23.4±16.5%, and the mean LV end-diastolic volume index and ejection fraction (EF) were 112±33ml/m 2 and 30.6±8.9%, respectively. At short-term evaluation, device failure was observed in 22 (29%) patients. Univariate predictors of device failure were LVEF, LV and left atrial volumes and anteroposterior mitral annulus diameter. Annulus dimension (OR 1.153, 95% CI 1.002-1.327, p=0.043) and LV end-diastolic volume (OR 1.024, 95% CI 1.000-1.049, p=0.049) were the only variables independently associated with the risk of device failure at the multivariate model., Conclusions: Pre-procedural anteroposterior mitral annulus diameter accurately predicted the risk of device failure after MitraClip in the setting of advanced HF. Its assessment might aid the selection of the best candidates to percutaneous correction of FMR., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Prognosis of hypertrophic cardiomyopathy (HCM) is particularly heterogeneous. Patients with nonobstructive HCM (NOCM) are thought to be at relatively low-risk as compared with obstructive HCM (HOCM) with no need of major treatment options. However, available evidence of NOCM comes mainly from tertiary centers where a referral bias is likely to occur. Aim of this study was to perform a systematic review and meta-analysis of the published literature on hypertrophic cardiomyopathy (HCM) in order to outline differences in presenting features and long-term outcome between NOCM and HOCM., Methods: MEDLINE/Pubmed, EMBASE and Cochrane databases up to December 31, 2016, and reviewed cited references to identify relevant studies were used. The primary endpoints were HCM-related overall mortality rate and yearly rate of cardiac death. Other endpoints were incidences of sudden and congestive heart failure deaths., Results: A total of 20 studies entered the meta-analysis on the long-term outcome of NOCM vs HOCM. They included a total of 7731 patients, 5058 patients with NOCM (65%) and 2673 patients with HOCM (35%). During the follow-up, annual mortality related to HCM averaged 1.55% in NOCM and 1.77% in HOCM (Relative Risk: 0.89, 95% confidence intervals: 0.68 to 1.17, p=0.40). Overall, 5 studies reported significantly higher mortality for HOCM, 3 higher mortality for NOCM, and 12 no significant differences., Conclusion: This large study-level meta-analysis shows that long-term mortality of patients with NOCM is not negligible and not significantly different from HOCM., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: The role of percutaneous mitral valve repair (PMVR) in patients with end-stage heart failure (HF) and functional mitral regurgitation (FMR) is unclear., Methods: Seventy-five consecutive patients with FMR grade≥3+ and severe HF symptoms despite optimal medical therapy and resynchronization therapy underwent PMVR with the MitraClip system (Abbott, Abbott Park, IL, USA) at 3 centers. Clinical evaluation, echocardiography and pro-BNP measurement were performed at baseline and at 6-month., Results: Mean age was 67±11years, logistic EuroSCORE=23±18%, left ventricle ejection fraction (LVEF) 30±9%. In 6 patients (8%) PMVR was performed as a bridge to heart transplant; many patients were dependent from iv diuretics and/or inotropes. Rate of serious adverse in-hospital events was 1.3% (1 patient who died after conversion to cardiac surgery). Sixty-three patients (84%) were discharged with MR≤2+. At 6-month, 4 patients died (5%), 80% had MR≤2+ and 75% were in New York Heart Association class ≤II. Median pro-BNP decreased from 4395pg/ml to 2594pg/ml (p=0.04). There were no significant changes in LV end-diastolic volume (222±75ml vs. 217±79, p=0.19), end-systolic volume (LVESV, 154±66ml vs. 156±69, p=0.54) and LVEF (30±9% vs. 30±12%, p=0.86). Significant reverse remodeling (reduction of LVESV≥10%) was observed in 25%, without apparent association with baseline characteristics. The number of hospitalizations for HF in comparison with the 6months before PMVR were reduced from 1.1±0.8 to 0.3±0.6 (p<0.001)., Conclusions: In extreme risk HF patients with FMR, PMVR improved symptoms and reduced re-hospitalization and pro-BNP levels at 6months, despite the lack of LV reverse remodeling., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Background: Many ICD carriers experience inappropriate shocks, but the relative merits of dual- /single-chamber devices for arrhythmia discrimination still remain unclear. We explored possible advantages of the atrial data provided by dual-chamber implantable defibrillators (ICD) for discrimination of real-life supraventricular/ventricular tachyarrhythmias (SVT/VT)., Methods: 100 dual-chamber traces from 24 ICD were blindly reviewed in dual-chamber and simulated single-chamber (with/without discriminator data) reading modes by five electrophysiologists who determined chamber of origin and provided Likert-scale "confidence" ratings. We assessed 1) intra/interobserver concordance; 2) diagnostic accuracy, using expert diagnoses as a reference standard; 3) ROC curves of sensitivity/specificity of "likelihood perception" scores, generated by combining chamber-of-origin diagnostic judgments with Likert-scale "confidence" ratings. We also assessed diagnostic accuracy of automated discrimination by all possible dual-/single-chamber algorithm configurations., Results: Interobserver concordance was "substantial" (modified Cohen kappa-test values for dual-/single-chamber, 0.79/0.68); intraobserver concordance "almost complete" (kappa ≥ 0.89). Dual-chamber mode provided best diagnostic sensitivity/specificity (99%/92%) and highest reader confidence (p<0.001). Area under ROC curves of sensitivity/specificity values for the "likelihood perception" score (representing electrophysiologists' perceptions of the likelihood that an episode was of ventricular origin) was highest in dual-chamber mode (0.98 vs. 0.93 for both single-chamber modes; p<0.001). Regarding automated discrimination, all four dual-chamber configurations conferred 100% sensitivity (specificity values ranged 39%-88%), whereas single-chamber configurations appeared inferior (best sensitivity/specificity combination, 89%/64%)., Conclusions: Availability of the atrial channel helps in reducing inappropriate ICD therapies by providing relevant advantages in terms of both appropriate cardiologist's post-hoc discrimination of SVT/VT (improving program tailoring) and automated arrhythmia discrimination., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)

Background: Isolated ventricular noncompaction (IVNC) is characterized by multiple prominent trabeculations and deep intertrabecular recesses. Some reports prove that the chronic heart failure may occur in approximately half of the patients. In this report we investigate the correlation between the number of non compacted segments and entity of systolic dysfunction from the registry and subregistries of the SIEC., Method: To identify the correlation between ventricular dysfunction and number of segments involved in non compaction we evaluated a consecutive series of 238 patients affected by non compaction, from the SIEC (Società Italiana di Ecografia Cardiovascolare) registry. The average age of patients was 41.5 years (range: 1-92 years), 137 were males and 101 females. In 122 cases we found ventricular systolic dysfunctions with an EF average of 34.6%. The number of affected segments by non-compactation and diastolic dysfunction were found to be non-independent predictors of LV systolic dysfunction., Conclusion: From the analyses we carried out, it seems that ventricular dysfunction seems to be completely independent from the segment numbers of non compacted segments., (Copyright (c) 2009. Published by Elsevier Ireland Ltd.)

Background: In patients with severe heart failure, sinus rhythm and wide QRS complex biventricular (BiV) pacing leads to clinical and haemodynamic improvement, but the immediate reversibility of these changes is not known., Methods: We assessed the acute and medium-term (3-month) haemodynamic effects of BiV pacing and of switching to other pacing modalities in 21 patients with severe heart failure, sinus rhythm and QRS>or=130 ms. Haemodynamic studies were performed: 1) at the time of implantation of a BiV pacing device, during AAI pacing, atrial synchronous right ventricular (RV) pacing, atrial synchronous left ventricular (LV) pacing and atrial synchronous BiV pacing (all at 100 bpm); 2) after 3 months of continuous BiV pacing--with evaluations being made by switching to RV and the other pacing modalities., Results: At both the acute and medium-term evaluations, BiV pacing provided the greatest improvement in cardiac index. Switching from BiV to RV pacing led to a more marked decrease in the cardiac index at 3 months. No strict correlation was evident between acute and medium-term effects of BiV pacing on cardiac index., Conclusion: Cardiac resynchronization by BiV pacing provides acute/medium-term improvements in cardiac index. Sudden, medium-term failure of LV stimulation can lead to an even more pronounced haemodynamic derangement than that inducible by RV pacing at baseline. Acute haemodynamic evaluations do not seem to provide a powerful way for identifying medium-term responders.

Internal cardioversion can restore sinus rhythm with energies below 6-10 J, often without anaesthesia/sedation. We investigated its safety and short-/medium-term efficacy in patients with persistent atrial fibrillation (AF) with left ventricular dysfunction (defined as ejection fraction < or = 40%). Among 34 patients with persistent AF who agreed to receive internal cardioversion, 16 had left ventricular dysfunction and 18 did not (the groups were similar as regards age, duration of AF and pretreatment with amiodarone). Internal CV was performed delivering 3.0/3.0-ms biphasic shocks between coil catheters using a step-up protocol. Sinus rhythm was always restored. General anaesthesia (administered only when discomfort was not tolerated) was required only in 2 of the 16 (12.5%) patients with left ventricular dysfunction. The defibrillation threshold was similar in patients with and without left ventricular dysfunction (10.2+/-6.9 vs. 8.4+/-4.9 J; p=0.37). Short-term (within 72 h) AF recurrence rates in the presence and absence of left ventricular dysfunction were 19% (3/16) and 6% (1/18), respectively (p=0.51). After cardioversion, all patients received antiarrhythmic drugs (mostly amiodarone in patients with left ventricular dysfunction and class IC agents in the remainder). With mean follow-up periods of about 220 days, AF recurrence rates among patients with and without left ventricular dysfunction were 50% (8/16) and 28% (5/18), respectively (p=0.328). We conclude that even in patients with left ventricular dysfunction, internal CV is safe and effective, minimizing risks from anaesthesia. Although these patients may have a higher risk of short- or medium-term AF recurrence, 6-month maintenance of sinus rhythm is possible in about 50% of cases.

Various modalities of cardiac pacing have been proposed in the past to improve hemodynamics, either directly or indirectly. Some of these are conventional ways of cardiac stimulation, others such as biventricular or left ventricular pacing, represent dedicated pacing techniques. Left ventricular and biventricular pacing are successfully applied in those patients with congestive heart failure who have conduction disturbances (i.e. left bundle branch block) as they correct the ensuing intra- and interventricular dyssynchrony. This is the reason why these pacing modalities are described as cardiac resynchronization therapy. According to the results of a series of studies, the cardiac resynchronization therapy seems to have a favourable clinical impact in terms of quality of life, morbidity and hospitalization rate. On-going and future studies should assess the impact of resynchronization therapy on overall mortality and its cost-effectiveness profile in specific subgroups of patients. Other open issues regard (i) the convenience of using biventricular pacing as a pacing-alone therapy or in combination with ventricular defibrillation capability, especially for potential candidates to heart transplantation, and (ii) the ways to identify properly the responders to resynchronization therapy.

Two cases of idiopathic restrictive cardiomyopathy in young age are reported. This rare kind of restrictive cardiomyopathy is characterized by the absence of specific histologic features of myocardial abnormalities. In both cases (aged 12 and 9 years at diagnosis), the clinical picture was characterized by severe and slowly progressive congestive heart failure. The electrocardiogram showed biventricular hypertrophy, right bundle branch block and pseudoinfarctional Q waves. Echocardiography revealed moderate pericardial effusion, biatrial enlargement, and normal or nearly normal biventricular dimensions and systolic function. Cardiac catheterization disclosed the typically restrictive filling pattern. Right ventricular endomyocardial biopsy demonstrated moderate interstitial fibrosis and cellular hypertrophy without any evidence of infiltrative or storage myocardial disease or endocardial pathology. One patient underwent cardiac transplantation, whereas in the other, transplantation was contraindicated because of longstanding pulmonary hypertension and liver cirrhosis. The knowledge of this rare entity may correctly orient the diagnostic process in children suspected of having restrictive myocardial disease. Heart, or even heart-lung, transplantation must be considered in cases with congestive heart failure before irreversible damage occurs in many organs.

We studied ventricular volumes and ejection fraction by radionuclide angiography (equilibrium technique) in 15 patients (aged 3-48 years) with double inlet ventricle not yet submitted to corrective surgery. The end-diastolic volume (measured in nine cases) ranged from 108 to 219 ml/m2 (156 +/- 32), being lower than the normal theoretical value (right plus left ventricle) in six cases. Ejection fraction ranged from 30 to 77% (56.4 +/- 13). The value was significantly higher in the subgroup of 10 patients with a dominant left ventricle as compared to the five cases with dominant right or indeterminate ventricular morphology (63.2 +/- 8.3 versus 42.8 +/- 9, P less than 0.01). In seven of the 15 patients, measurements were obtained both at rest and during dynamic exercise in the semi-upright position. The end-diastolic and end-systolic volumes, stroke volume, ejection fraction underwent a slight non-significant reduction (from 158 +/- 29 to 147 +/- 24 ml/m2, from 58 +/- 16 to 56 +/- 24 ml/m2, from 100 +/- 27 to 90 +/- 24 ml/m2, from 64% +/- 9 to 61% +/- 13). During exercise, ventricular volumes mostly behaved as follows: slight reduction of end-systolic volume, decrease of end-diastolic volume, no increase (no change or decrease) of ejection fraction.(ABSTRACT TRUNCATED AT 250 WORDS)