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In patients with cardiovascular, pulmonary, muscular and neurological diseases, cardiopulmonary exercise testing (CPET) is a valuable tool providing clinically-relevant diagnostic and prognostic information by evaluation of exercise response. CPET requires to be performed in dedicated centers able to correctly carry out the examination and to carefully evaluate the results. CPET analyzes functional capacity revealing both symptomatic and asymptomatic intolerance to exercise. One of the most important advantages for clinicians derived by the use of CPET, beyond standard exercise electrocardiography testing, is the capability not only to grade the severity of the disease, but also to distinguish between different causes of dyspnea and exercise impairment. Indications for CPET use in clinical practice are increasing in the last decades, evolving beyond the routine use as a training tool in athletes. In fact, CPET represents an important step in the management of patients with heart failure or pulmonary hypertension, as suggested by international guidelines. CPET role in helping for the selection of patients candidate to heart transplantation is also well known. Beyond its clinical usefulness, scientific interest in CPET is constantly expanding, mainly due to the safety of the exam and to the huge size of the pathophysiological information that it offers. The aim of this paper is to simply explain everyday applications and potential further purposes of CPET in clinical practice. Our review is intended both for physicians approaching CPET for the first time and for clinicians with an interest in expanding their knowledge in this field.
Subject(s)
Exercise Test , Humans , Exercise Test/methods , Cardiologists , Exercise Tolerance/physiology , Dyspnea/diagnosis , Dyspnea/physiopathology , Dyspnea/etiology , Heart Failure/diagnosis , Heart Failure/physiopathology , Cardiovascular Diseases/diagnosis , Prognosis , Electrocardiography/methods , Heart TransplantationABSTRACT
Background: Tricuspid regurgitation (TR) is common and severe or greater TR is linked to poor prognosis. Treatment of TR with transcatheter edge-to-edge repair has emerged as a safe and potentially effective therapy in these patients. However, the impact of transcatheter tricuspid repair on functional capacity remains to be elucidated. Case summary: We describe the case of a 77-year-old woman complaining of heart failure symptoms, undergoing transcatheter edge-to-edge valve repair for severe TR with the PASCAL Ace® device. One month later, cardiopulmonary exercise testing (CPET) showed significant improvement in peak O2 uptake and O2 pulse compared with the test performed before the procedure. Discussion: A positive impact of novel transcatheter edge-to-edge valve repair on symptoms and quality of life in patients with severe or greater TR at prohibitive surgical risk has recently emerged. The presence of severe TR has prognostic relevance, and novel percutaneous tricuspid valve repair systems have emerged in the last few years. Cardiopulmonary exercise testing is an established tool to assess functional capacity and prognosis in heart failure patient. Detecting functional capacity improvement after transcatheter edge-to-edge repair for severe TR can be challenging, and CPET may arise as a promising tool to help these purposes.
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Background: Myocardial infiltration by primary cardiac neoplasm is a rare entity, providing diagnostic and therapeutic challenges. The pathological spectrum includes more frequently benign forms. Refractory heart failure, pericardial effusion, and arrhythmias due to infiltrative mass are the most common clinical manifestations. Case summary: We describe the case of a 35-year-old man complaining of shortness of breath and weight loss in the last 2 months. A previous acute myeloid leukaemia treated with allogenic bone marrow transplant was reported. Transthoracic echocardiography revealed an apical thrombus in the left ventricle, with inferior and septal hypokinesia conditioning a mildly reduced ejection fraction, circumferential pericardial effusion, and abnormal right ventricular thickening. Cardiac magnetic resonance confirmed diffuse thickening of the right ventricular free wall due to myocardial infiltration. Positron emission tomography showed the presence of neoplastic tissue with increased metabolic activity. A pericardiectomy was performed showing a widespread cardiac neoplastic infiltration. Histopathological analysis done on right ventricular pathological samples obtained during cardiac surgery revealed the presence of a rare and aggressive cardiac anaplastic T-cell non-Hodgkin lymphoma. Few days after the operation, the patient developed refractory cardiogenic shock and unluckily died before initiating an adequate antineoplastic therapy. Discussion: Primary cardiac lymphoma is not frequent, and the lack of specific symptoms makes the diagnosis extremely challenging and often limited to autopsy findings. Our case highlights the importance of an appropriate diagnostic algorithm, requiring non-invasive multimodality assessment imaging and then invasive cardiac biopsy. This approach may allow an early diagnosis and an adequate therapy for this otherwise fatal pathology.
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Background: Echocardiographic Pulmonary to Left Atrial Ratio (ePLAR) represents an accurate and sensitive non-invasive tool to estimate the trans-pulmonary gradient. The prognostic value of ePLAR in hospitalized patients with COVID-19 remains unknown. We aimed to investigate the predictive value of ePLAR on in-hospital mortality in patients with COVID-19. Methods: One hundred consecutive patients admitted to two Italian institutions for COVID-19 undergoing early (<24 h) echocardiographic examination were included; ePLAR was determined from the maximum tricuspid regurgitation continuous wave Doppler velocity (m/s) divided by the transmitral E-wave: septal mitral annular Doppler Tissue Imaging e'-wave ratio (TRVmax/E:e'). The primary outcome measure was in-hospital death. Results: patients who died during hospitalization had at baseline a higher prevalence of tricuspid regurgitation, higher ePLAR, right-side pressures, lower Tricuspid Annular Plane Systolic Excursion (TAPSE)/ systolic Pulmonary Artery Pressure (sPAP) ratio and reduced inferior vena cava collapse than survivors. Patients with ePLAR > 0.28 m/s at baseline showed non-significant but markedly increased in-hospital mortality compared to those having ePLAR ≤ 0.28 m/s (27% vs. 10.8%, p = 0.055). Multivariate Cox regression showed that an ePLAR > 0.28 m/s was independently associated with an increased risk of death (HR 5.07, 95% CI 1.04−24.50, p = 0.043), particularly when associated with increased sPAP (p for interaction = 0.043). Conclusions: A high ePLAR value at baseline predicts in-hospital death in patients with COVID-19, especially in those with elevated pulmonary arterial pressure. These results support an early ePLAR assessment in patients admitted for COVID-19 to identify those at higher risk and potentially guide strategies of diagnosis and care.
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BACKGROUND: Pulmonary hypertension (PH) is a life-threatening complication of connective tissue diseases (CTD); in this study, we aimed at investigating the potential role of inducible co-stimulator (ICOS) and its ligand (ICOS-L) as biomarkers of PH in CTD. MATERIALS AND METHODS: We recruited 109 patients: 84 CTD patients, 13 patients with CTD complicated by pulmonary arterial hypertension (PAH), and 12 subjects with PAH alone. All recruited patients underwent a complete clinical and instrumental assessment along with quantitative measurement of serum ICOS and ICOS-L. RESULTS: Independently of the underlying cause, patients with PAH were older and had a lower glomerular filtration rate. Interestingly, patients with both CTD-related and CTD-unrelated PAH had higher ICOS and ICOS-L serum concentrations than CTD patients (0.0001 for both). When compared to CTD patients, those affected by CTD-PAH showed higher ICOS (440 (240-600) vs. 170 (105-275) pg/mL, p = 0.0001) and ICOS-L serum concentrations (6000 (4300-7000) vs. 2450 (1500-4100) pg/mL; p = 0.0001). In a logistic regression, ICOS and ICOS-L were associated with a diagnosis of PAH, independently from age, gender, and renal function. The corresponding receiver operating characteristic (ROC) curves demonstrated a good diagnostic performance for both ICOS and ICOS-L. CONCLUSIONS: ICOS and ICOS-L are increased in patients with PAH, irrespectively from the underlying cause, and represent promising candidate biomarkers for the diagnostic screening for PAH among CTDs patients.
ABSTRACT
The early diagnosis of pulmonary arterial hypertension (PAH) is a major determinant of prognosis in patients affected by connective tissue diseases (CTDs) complicated by PAH. In the present paper we investigated the diagnostic accuracy of cardiopulmonary exercise testing (CPET) in this specific setting. We recorded clinical and laboratory data of 131 patients who underwent a CPET at a pulmonary hypertension clinic. Out of them, 112 (85.5%) had a diagnosis of CTDs; 8 (6.1%) received a diagnosis of CTDs-PAH and 11 (8.4%) were affected PH of different etiology. Among CPET parameters the following parameters showed the best diagnostic performance for PAH: peak volume of oxygen uptake (VO2; AUC: 0.845, CI95% 0.767-0.904), ratio between ventilation and volume of exhaled carbon dioxide (VE/VCO2 slope; AUC: 0.888, CI95%: 0.817-0.938) and end-tidal partial pressures (PetCO2; AUC: 0.792, CI95%: 0.709-0.861). These parameters were comparable among CTDs-PAH and PH of different etiology. The diagnostic performance was even improved by creating a composite score which included all the three parameters identified. In conclusion, CPET is a very promising tool for the stratification of risk of PAH among CTDs patients; the use of composite measures may improve diagnostic performance.
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Pulmonary arterial hypertension (PAH) is a severe complication of connective tissue diseases (CTD). Its early diagnosis is essential to start effective treatment. In the present paper, we aimed to evaluate the role of plasma osteopontin (OPN) as a candidate biomarker of PAH in a cohort of CTD patients. OPN is a pleiotropic protein involved in inflammation and fibrogenesis and, therefore, potentially promising in this specific clinical context. We performed a cross-sectional observational study on a cohort of 113 CTD patients (females N = 101, 89.4%) affected by systemic sclerosis N = 88 (77.9%), mixed connective tissue disease N = 10 (8.8%), overlap syndrome N = 10 (8.8%) or undifferentiated connective tissue disease N = 5 (4.4%). CTD-PAH patients showed significantly higher OPN plasma values than patients with CTD alone (241.0 (188.8-387.2) vs. 200.7 (133.5-281.6) ng/mL; p = 0.03). Although OPN levels were directly correlated with age and inversely with glomerular filtration rate, they remained associated with PAH at multivariate analysis. In conclusion, OPN was significantly associated with PAH among patients with CTD, suggesting it may have a role as a non-invasive disease biomarker of PAH.
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BACKGROUND: Few biomarkers are available for early identification of pulmonary arterial hypertension (PAH) and interstitial lung disease (ILD) in systemic sclerosis (SS) and scleroderma spectrum disorders (SSD). AIMS: To evaluate Gas6, sAxl, and sMer as biomarkers for cardiopulmonary complications of SS and SSD. METHODS: In a cross-sectional observational study, we recruited 125 consecutive patients, affected by SS and SSD and referred to a tertiary-level pulmonary hypertension outpatient clinic. All patients underwent a comprehensive evaluation for identification of PAH and ILD. Gas6, sMer, and sAxl concentrations were measured with ELISA protocols, and concentrations were compared according to PAH or ILD. RESULTS: Nineteen subjects had pulmonary hypertension (PH) (14 PAH), and 39 had ILD (6 severe). Plasma sMer was increased in PAH (18.6 ng/ml IQR [11.7-20.3]) with respect to the absence (12.4 [8.0-15.8]) or other form of pulmonary hypertension (9.6 [7.4-12.5]; K-W variance p < 0.04). Conversely, Gas6 and sAxl levels were slightly increased in mild ILD (25.8 ng/ml [19.5-32.1] and 24.6 [20.1-32.5]) and reduced in severe ILD (16.6 [15.0-22.1] and 15.5 [14.9-22.4]) in comparison to no evidence of ILD (23.4 [18.8-28.1] and 21.6 [18.1-28.4]; K-W, p ≤ 0.05). Plasma sMer ≥ 19 ng/ml has 50% sensitivity and 92% specificity in PAH identification (area under the ROC curve (AUC) 0.697, p < 0.03). Values of Gas6 ≤ 24.5 ng/ml and of sAxl ≤ 15.5 ng/ml have 100% and 67% sensitivity and 47% and 86% specificity, respectively, in identifying severe ILD (Gas6 AUC 0.787, p < 0.001; sAxl AUC 0.705, p < 0.05). CONCLUSIONS: The assay of Gas6 sAxl and sMer may be useful to help in the identification of PAH and ILD in SS and SSD patients. The Gas6/TAM system seems to be relevant in cardiopulmonary complications of SS and SSD and merits further investigations.
Subject(s)
Hypertension, Pulmonary/diagnosis , Intercellular Signaling Peptides and Proteins/genetics , Lung Diseases, Interstitial/diagnosis , Proto-Oncogene Proteins/genetics , Receptor Protein-Tyrosine Kinases/genetics , Scleroderma, Systemic/diagnosis , c-Mer Tyrosine Kinase/genetics , Aged , Biomarkers/blood , Cross-Sectional Studies , Female , Gene Expression Regulation , Humans , Hypertension, Pulmonary/blood , Hypertension, Pulmonary/complications , Hypertension, Pulmonary/genetics , Intercellular Signaling Peptides and Proteins/blood , Lung Diseases, Interstitial/blood , Lung Diseases, Interstitial/complications , Lung Diseases, Interstitial/genetics , Male , Middle Aged , Proto-Oncogene Proteins/blood , Receptor Protein-Tyrosine Kinases/blood , Scleroderma, Systemic/blood , Scleroderma, Systemic/complications , Scleroderma, Systemic/genetics , Sensitivity and Specificity , Severity of Illness Index , c-Mer Tyrosine Kinase/blood , Axl Receptor Tyrosine KinaseABSTRACT
INTRODUCTION/OBJECTIVE: In the present paper, we aimed to test the value of the red cell distribution width (RDW) coefficient of variation as a candidate biomarker for pulmonary arterial hypertension (PAH) in patients with connective tissue disorders (CTD), correlating it with the degree of cardiopulmonary impairment in these patients. METHODS: The study population included N = 141 patients with CTD and N = 59 patients affected by pulmonary hypertension of other etiologies, all referred to the Pulmonary Hypertension Clinic of the Cardiology Division of an Academic Hospital in Northern Italy for evaluation (including right catheterization). Clinical, instrumental, and laboratory data were collected and related to RDW and other full blood count indexes. RESULTS: Twenty out of 141 CTD patients (14%) received a diagnosis of PAH. In comparison to those without PAH, CTD patients with PAH displayed a larger RDW (14.9% (13.5-17.2) vs. 13.8% (13.1-15.0); p = 0.02) and a lower platelet count (205 (177-240) × 109/l vs. 244 (197.5-304.2) × 109/l; p = 0.005). Moreover, with respect to CTD patients without PAH, RDW was significantly larger also in PH of other etiologies. In contrast, the platelet count was significantly lower only in CTD-related PAH, with a value > 276 × 109/l being 100% sensitive in ruling out PAH. Finally, RDW, but not the platelet count, was related directly to systolic pulmonary arterial pressure (r = 0.381; p = 0.0008) and right ventricle diameter (r = 0.283; p = 0.015) and inversely to diffusing capacity of the lung for carbon monoxide (r = -0.325; p = 0.014). CONCLUSION: RDW is a promising candidate biomarker for the screening and the prognostic stratification of PAH in CTD patients.
Subject(s)
Connective Tissue Diseases/complications , Hypertension, Pulmonary/blood , Aged , Biomarkers/blood , Connective Tissue Diseases/blood , Erythrocyte Count , Female , Humans , Hypertension, Pulmonary/etiology , Male , Middle Aged , Platelet CountABSTRACT
AIMS: Atrial fibrillation incidence is increasing due to ageing population and electrical cardioversion (ECV) is overused because of atrial fibrillation recurrences. Study's aim was to evaluate value of novel three-dimensional echocardiographic-derived left atrial conduit (LAC) function quantification in predicting early atrial fibrillation recurrence after ECV. METHODS: We included 106 patients [74 (64-78) years] who underwent ECV for persistent nonvalvular atrial fibrillation. For all clinical data and simultaneous left atrial and left ventricular (LV) three-dimensional full-volume data sets were available before ECV. We computed LAC as: [(LV maximumâ-âLV minimum)â-â(left atrial maximumâ-âleft atrial minimum) volume], expressed as % LV stroke volume. Atrial fibrillation recurrence was checked with Holter monitoring. RESULTS: One month after ECV 66 patients were in sinus rhythm and 40 experienced atrial fibrillation recurrence. Pre-ECV patients with atrial fibrillation recurrence showed higher LAC contribution to LV filling (Pâ<â0.0001) and noninvasively estimated left atrial stiffness (Pâ<â0.0001) compared with sinus rhythm patients. There were no other differences, neither in clinical characteristics nor in LV properties. At multivariate LAC (Pâ<â0.001), left atrial stiffness (Pâ=â0.002) and volume (Pâ=â0.043) predicted early atrial fibrillation relapse, even when compared with other confounding factors. Receiver-operating characteristics area (ROC) analysis confirmed LAC as best atrial fibrillation recurrence predictor (0.84, Pâ<â0.0001), cut-off value more than 54% exhibiting reasonable sensibility-specificity (76-75%). CONCLUSION: Atrial fibrillation makes LV filling dependent on reciprocation between left atrial reservoir/conduit phases. Our data suggest that LAC larger contribution to filling in persistent atrial fibrillation patients reflects left atrial and LV diastolic dysfunction, which skews atrio-ventricular interaction that leads to atrial fibrillation perpetuation, making LAC a powerful atrial fibrillation recurrence predictor after ECV.
Subject(s)
Atrial Fibrillation/diagnostic imaging , Atrial Fibrillation/therapy , Atrial Function, Left , Echocardiography, Three-Dimensional , Electric Countershock , Heart Atria/diagnostic imaging , Ventricular Dysfunction, Left/diagnostic imaging , Ventricular Function, Left , Aged , Aged, 80 and over , Atrial Fibrillation/physiopathology , Electric Countershock/adverse effects , Electrocardiography, Ambulatory , Female , Heart Atria/physiopathology , Humans , Male , Middle Aged , Predictive Value of Tests , Recurrence , Reproducibility of Results , Retrospective Studies , Risk Factors , Time Factors , Treatment Outcome , Ventricular Dysfunction, Left/physiopathologyABSTRACT
Aims: Closed-loop stimulation (CLS) seemed promising in preventing the recurrence of vasovagal syncope (VVS) in patients with a cardioinhibitory response to head-up tilt test (HUTT) compared with conventional pacing. We hypothesized that the better results of this algorithm are due to its quick reaction in high-rate pacing delivered in the early phase of vasovagal reflex, which increase the cardiac output and the blood pressure preventing loss of consciousness. Methods and results: This prospective, randomized, single-blind, multicentre study was designed as an intra-patient comparison and enrolled 30 patients (age 62.2 ± 13.5 years, males 60.0%) with cardioinhibitory VVS, carrying a dual-chamber pacemaker incorporating CLS algorithm. Two HUTTs were performed one week apart: one during DDD-CLS 60-130/min pacing and the other during DDD 60/min pacing; patients were randomly and blindly assigned to two groups: in one the first HUTT was performed in DDD-CLS (n = 15), in the other in DDD (n = 15). Occurrence of syncope and haemodynamic variations induced by HUTT was recorded during the tests. Compared with DDD, DDD-CLS significantly reduced the occurrence of syncope induced by HUTT (30.0% vs. 76.7%; P < 0.001). In the patients who had syncope in both DDD and DDD-CLS mode, DDD-CLS significantly delayed the onset of syncope during HUTT (from 20.8 ± 3.9 to 24.8 ± 0.9 min; P = 0.032). The maximum fall in systolic blood pressure recorded during HUTT was significantly lower in DDD-CLS compared with DDD (43.2 ± 30.3 vs. 65.1 ± 25.8 mmHg; P = 0.004). Conclusion: In patients with cardioinhibitory VVS, CLS reduces the occurrence of syncope induced by HUTT, compared with DDD pacing. When CLS is not able to abort the vasovagal reflex, it seems to delay the onset of syncope.
Subject(s)
Cardiac Pacing, Artificial/methods , Hemodynamics , Secondary Prevention/methods , Syncope, Vasovagal , Tilt-Table Test/methods , Aged , Female , Humans , Male , Middle Aged , Outcome and Process Assessment, Health Care , Recurrence , Severity of Illness Index , Single-Blind Method , Syncope, Vasovagal/diagnosis , Syncope, Vasovagal/etiology , Syncope, Vasovagal/physiopathology , Time-to-TreatmentABSTRACT
AIMS: Increased right atrial size is related to adverse prognosis in pulmonary hypertension. The potential incremental value of right atrial function assessment is still unclear. We tested the relationship between right atrial two-dimensional speckle-tracking echocardiography impairment and hemodynamic, functional and clinical deterioration in patients with pulmonary hypertension. METHODS: We prospectively evaluated 36 patients (27 female, 9 male; mean age 68â±â13 years) with suspected pulmonary hypertension undergoing right heart catheterization and 16 matched controls. All patients underwent baseline evaluation by New York Heart Association functional class, 6-min walking test, brain natriuretic peptide (BNP), and standard two-dimensional echocardiography in less than 48âh of right heart catheterization. Right atrial two-dimensional speckle-tracking echocardiography was assessed by averaging all segments in standard four-chamber apical view. RESULTS: Right atrial global integral strain was significantly lower in patients compared with controls (11.40â±â5.22% vs. 25.72â±â5.95 Pâ<â0.001). Moreover, right atrial global strain, but not right atrial area or volume, was correlated with invasively measured cardiac index (CI) (râ=â0.72; Pâ<â0.0001) and pulmonary vascular resistances in all patients, even though stronger in subjects with precapillary pulmonary hypertension (râ=â-0.42, Pâ=â0.018; râ=â-0.54, Pâ=â0.007 respectively; Pâ=â0.007). It was also correlated with New York Heart Association (Pâ=â0.027), BNP (Pâ=â0.002), and 6-min walking test (Pâ=â0.006). After multivariate analysis including right atrial volume, tricuspid annular plane systolic excursion, left atrial strain, and BNP, right atrial global strain showed the strongest correlation with CI. Area under the curve optimal cutoff for predicting CI at least 2.4âl/min/m was 17% (area under the curve: 0.83, sensitivity: 90%, specificity: 54%). CONCLUSION: Right atrial global strain can identify right atrial functional impairment before structural changes and may be implemented in a comprehensive, noninvasive right heart assessment for diagnosis and follow-up of pulmonary hypertension patients.
Subject(s)
Echocardiography, Doppler/instrumentation , Heart Atria/physiopathology , Hypertension, Pulmonary/diagnostic imaging , Hypertension, Pulmonary/physiopathology , Adult , Aged , Aged, 80 and over , Cardiac Catheterization , Early Diagnosis , Female , Heart Atria/diagnostic imaging , Hemodynamics , Humans , Italy , Linear Models , Male , Middle Aged , Natriuretic Peptide, Brain/blood , Prospective Studies , Sensitivity and Specificity , Walk TestABSTRACT
AIMS: The occurrence of left ventricular (LV) anodal activation during pacing with modern multipolar cardiac resynchronization therapy (CRT) systems has never been reported. The aim of our study was to demonstrate, by means of electrocardiogram (ECG) analysis, the occurrence of simultaneous cathodal-anodal LV capture with quadripolar LV leads. METHODS AND RESULTS: We studied 10 first-time recipients of a CRT device equipped with a quadripolar LV lead. During follow-up, standard supine 12-lead ECGs were obtained in available cathode-to-anode LV pacing configurations with a pulse amplitude equal to twice the pacing threshold. The occurrence of simultaneous cathodal-anodal LV capture was defined as the presence of variations in electrocardiographic ventricular activation (EVA) when the distal tip (cathode)-to-device can (anode) pacing configuration was compared with the distal tip (cathode)-to-proximal ring (anode) configuration. In eight patients, we found differences in EVA when different LV sites were paced through the unipolar LV tip and unipolar LV ring configurations. In these patients, a difference in EVA was detected in 61.5% (59 of 96) of the ECG leads (marked difference in 31.3%, slight difference in 30.2%). Changes in EVA between unipolar tip-to-can and bipolar tip-to-ring pacing that were suggestive of cathodal-anodal LV capture were found in six patients. In these patients, a total of 30 (41.7%) ECG leads showed a difference in EVA (marked difference in 20.8%, slight difference in 20.8%). CONCLUSION: In our experience, additional anodal capture by the proximal LV ring during LV pacing is provable in most recipients of a resynchronization device equipped with a multipolar LV lead.
Subject(s)
Cardiac Resynchronization Therapy Devices , Cardiac Resynchronization Therapy/methods , Electrocardiography/methods , Heart Failure/diagnosis , Heart Failure/prevention & control , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Reproducibility of Results , Sensitivity and Specificity , Treatment OutcomeABSTRACT
AIMS: Atrioventricular junction (AVJ) ablation followed by biventricular pacing is an established strategy for improving symptoms and morbidity in patients with permanent atrial fibrillation (AF), reduced left ventricular ejection fraction (LVEF), and uncontrolled ventricular rate. There is no clear evidence that such patients benefit from rate-responsive (RR) pacing. METHODS AND RESULTS: This prospective, randomized, single-blind, multicentre study was designed as an intra-patient comparison and enrolled 60 patients (age 69.5 ± 11.8 years, males 63.3%, NYHA 3.0 ± 0.6) with refractory AF and reduced LVEF (mean 32.4 ± 8.3%) treated with AVJ ablation and biventricular pacing. Two 6-minute walking tests (6MWT) were performed 1 week apart: one during VVI 70/min biventricular pacing and the other during VVIR 70-130/min biventricular pacing; patients were randomly and blindly assigned to Group A (n = 29, first 6MWT in VVIR mode) or B (n = 31, first 6MWT in VVI mode). Rate-responsive activation determined an increase of 18.8 ± 24.4 m in the distance walked during the 6MWT (P < 0.001). The increase was similar in both groups (P = 0.571). A >5% increase in the distance walked was observed in 76.7% of patients. The increase in the distance walked was linearly correlated with the increase in heart rate recorded during the 6MWT in the VVIR mode (r = 0.54; P < 0.001). CONCLUSION: In permanent AF patients with uncontrolled rate and reduced LVEF who had undergone AVJ ablation and biventricular pacing, RR pacing yields a significant gain in exercise capacity, which seems to be related to the RR-induced frequency during effort.