Current Insights and Future Directions in the Treatment of Heart Failure with Preserved Ejection Fraction.

Heart failure is a clinical syndrome associated with poor quality of life, substantial healthcare resource utilization, and premature mortality, in large part related to high rates of hospitalizations. The clinical manifestations of heart failure are similar regardless of the ejection fraction. Unlike heart failure with reduced ejection fraction, there are few therapeutic options for treating heart failure with preserved ejection fraction. Molecular therapies that have shown reduced mortality and morbidity in heart failure with reduced ejection have not been proven to be effective for patients with heart failure and preserved ejection fraction. The study of pathophysiological processes involved in the production of heart failure with preserved ejection fraction is the basis for identifying new therapeutic means. In this narrative review, we intend to synthesize the existing therapeutic means, but also those under research (metabolic and microRNA therapy) for the treatment of heart failure with preserved ejection fraction.

Vulnerable Atherosclerotic Plaque: Is There a Molecular Signature?

Atherosclerosis and its clinical manifestations, coronary and cerebral artery diseases, are the most common cause of death worldwide. The main pathophysiological mechanism for these complications is the rupture of vulnerable atherosclerotic plaques and subsequent thrombosis. Pathological studies of the vulnerable lesions showed that more frequently, plaques rich in lipids and with a high level of inflammation, responsible for mild or moderate stenosis, are more prone to rupture, leading to acute events. Identifying the vulnerable plaques helps to stratify patients at risk of developing acute vascular events. Traditional imaging methods based on plaque appearance and size are not reliable in prediction the risk of rupture. Intravascular imaging is a novel technique able to identify vulnerable lesions, but it is invasive and an operator-dependent technique. This review aims to summarize the current data from literature regarding the main biomarkers involved in the attempt to diagnose vulnerable atherosclerotic lesions. These biomarkers could be the base for risk stratification and development of the new therapeutic drugs in the treatment of patients with vulnerable atherosclerotic plaques.

Cellular and Molecular Targets for Non-Invasive, Non-Pharmacological Therapeutic/Rehabilitative Interventions in Acute Ischemic Stroke.

BACKGROUND: Cerebral circulation delivers the blood flow to the brain through a dedicated network of sanguine vessels. A healthy human brain can regulate cerebral blood flow (CBF) according to any physiological or pathological challenges. The brain is protected by its self-regulatory mechanisms, which are dependent on neuronal and support cellular populations, including endothelial ones, as well as metabolic, and even myogenic factors. OBJECTIVES: Accumulating data suggest that "non-pharmacological" approaches might provide new opportunities for stroke therapy, such as electro-/acupuncture, hyperbaric oxygen therapy, hypothermia/cooling, photobiomodulation, therapeutic gases, transcranial direct current stimulations, or transcranial magnetic stimulations. We reviewed the recent data on the mechanisms and clinical implications of these non-pharmaceutical treatments. METHODS: To present the state-of-the-art for currently available non-invasive, non-pharmacological-related interventions in acute ischemic stroke, we accomplished this synthetic and systematic literature review based on the Preferred Reporting Items for Systematic Principles Reviews and Meta-Analyses (PRISMA). RESULTS: The initial number of obtained articles was 313. After fulfilling the five steps in the filtering/selection methodology, 54 fully eligible papers were selected for synthetic review. We enhanced our documentation with other bibliographic resources connected to our subject, identified in the literature within a non-standardized search, to fill the knowledge gaps. Fifteen clinical trials were also identified. DISCUSSION: Non-invasive, non-pharmacological therapeutic/rehabilitative interventions for acute ischemic stroke are mainly holistic therapies. Therefore, most of them are not yet routinely used in clinical practice, despite some possible beneficial effects, which have yet to be supplementarily proven in more related studies. Moreover, few of the identified clinical trials are already completed and most do not have final results. CONCLUSIONS: This review synthesizes the current findings on acute ischemic stroke therapeutic/rehabilitative interventions, described as non-invasive and non-pharmacological.

The Effectiveness of Antiplatelet Therapy and the Factors Influencing It in Patients with Acute Coronary Syndrome before and during the COVID-19 Pandemic.

Background and Objectives: Dual antiplatelet therapy (DAPT) is essential in the treatment of patients with acute coronary syndrome (ACS). The objective of this study was to evaluate the effectiveness of antiplatelet medication in our practice and to investigate the factors that influence it. Materials and Methods: A prospective cohort observational study was conducted, in which 193 patients with ACS were enrolled. The patients were stented in the catheterization laboratory between May 2019 and October 2020, before and during the COVID-19 pandemic, and were receiving DAPT. Their platelet functions were tested using a Multiplate Analyzer. In addition to this, clinical data, demographics, laboratory tests, and cardiovascular risk factors were also analyzed. Results: 43.46% of the patients treated with aspirin were found to be resistant to it. This phenomenon was more common in men (48.17% vs. 31.48%, p = 0.036), and it was associated with being under the age of 50 (OR: 2.08; 95% CI: 1.11-3.90) and weighing over 70 kg (OR: 3.00; 95% CI: 1.21-7.40). Most of the patients treated with clopidogrel were in the optimal treatment window, while about half of the patients treated with ticagrelor had an exaggerated pharmacological response. Among the laboratory parameters, leukocytosis and platelet count were found to be determinants of platelet reactivity for both the aspirin and ticagrelor treatments. Conclusions: Many patients treated with antiplatelet agents are outside of the treatment window. The results obtained showed that low doses of gastro-resistant aspirin tablets are ineffective, and their efficacy can be influenced by various clinical and laboratory factors. Patients receiving ticagrelor have significantly reduced platelet reactivity, influenced only by certain laboratory indicators. The pandemic significantly influenced the results of the platelet aggregation tests only in patients treated with clopidogrel.

Cardiac Amyloidosis with Discordant QRS Voltage between Frontal and Precordial Leads.

Among the different types, immunoglobulin light chain (AL) cardiac amyloidosis is associated with the highest morbidity and mortality. The outcome, however, is significantly better when an early diagnosis is made and treatment initiated promptly. We present a case of cardiac amyloidosis with left ventricular hypertrophy criteria on the electrocardiogram. After 9 months of follow-up, the patient developed low voltage in the limb leads, while still maintaining the Cornell criteria for left ventricular hypertrophy as well. The relative apical sparing by the disease process, as well as decreased cancellation of the opposing left ventricular walls could be responsible for this phenomenon. The discordance between the voltage in the frontal leads and precordial leads, when present in conjunction with other findings, may be helpful in raising the clinical suspicion of cardiac amyloidosis.

Electrocardiographic Patterns in Patients with Neurally Mediated Syncope.

The baseline electrocardiogram (ECG) is less informative in neurally mediated syncope (NMS) than in arrhythmic syncope. However, some of the ECG patterns present in NMS can have diagnostic and prognostic value in such patients. Electrocardiographic documentation of a syncopal spell and thus identification of the ECG changes can be performed during tilt table test (TTT) or during prolonged ECG monitoring. This work reviews the specific ECG patterns in NMS, which are primarily related to the cardioinhibitory reflex. In addition, there are other ECG findings present in patients with NMS that are being analyzed, such as increased heart rate variability as well as specific QRS voltage patterns. In addition to the diagnostic and prognostic value, these ECG patterns in NMS may help improving the selection of patients for pacemaker implant.

Isolated very low QRS voltage predicts response to tilt-table testing in patients with neurally mediated syncope.

BACKGROUND: A number of patients with neurally mediated syncope (NMS) have isolated QRS complexes of very low voltage (≤0.3 mV) in the frontal plane leads on the 12-lead electrocardiogram (ECG). HYPOTHESIS: The aim of this study was to assess the importance of QRS voltage in predicting response to tilt-table testing (TTT) in patients with suspected NMS. METHODS: We included 216 patients (age: 49 ± 20 years, 103 men) with suspected NMS who had either a positive or negative response to TTT (n = 91 TTT+, and n = 125 TTT-). The QRS voltage was measured in mV on 12-lead ECGs performed within 3 days of the TTT. The lowest QRS voltage (QRSmin), as well as the voltage in each of the 12 leads was also determined. RESULTS: Very low voltage (QRSmin  ≤ 0.3 mV) in the frontal leads was significantly more prevalent in the TTT+ group than in the TTT- group (74 vs 22%, respectively; P  < .001). Patients in the TTT+ group had significantly lower QRSmin when compared to patients in the TTT- group. QRSmin predicted a positive tilt-table test in a multivariate model that also included patient gender, height, history of presyncope, QRS duration, and left ventricular end-diastolic diameter indexed to height. ROC analysis showed that QRSmin of ≥0.3 mV discriminated between TTT+ and TTT- patients with a sensitivity of 78% and specificity of 68%. CONCLUSION: Isolated very low QRS voltage in the frontal leads predicts a positive response to TTT in patients with suspected NMS.

A new simplified electrocardiographic score predicts clinical outcome in patients treated with CRT.

Aims: Cardiac Resynchronization Therapy (CRT) reduces morbidity and mortality for patients with heart failure and wide QRS complex, but up to 1/3 of patients are "non-responders" to the therapy. This study examines the ability of a simple standard electrocardiogram (ECG)-based scoring system to predict clinical outcome. Methods and results: Four hundred and ninety-one consecutive patients with CRT-implants (79% males, mean age 71 years, LVEF 24%, 59% with ischemic cardiomyopathy, 83% in NYHA class III) were included from a single large volume centre. All patients met standard indications for CRT, and were followed for 3 years after CRT implantation. Three ECG parameters were measured on the post-implant ECG, and compared to pre-implantation measurements: QRS duration, time to intrinsicoid deflection onset (ID) in V1 lead, amplitude change in V1 lead. Each positive ECG variable was given a numerical value of 1 to create the score (ranging 0-3). Clinical outcome was assessed as a composite of all-cause death, left ventricular assist device implantation, cardiac transplantation and HF hospitalization. Event-free survival was predicted by shortening of QRS duration ≥20 ms (HR 0.66 [95% CI 0.48-0.90] P = 0.009), ≥50% decreased summed R + S amplitude in V1 lead (HR 0.67 [0.49-0.90] P = 0.009) and ≤40 msec ID time in lead V1 during pacing (HR 0.63 [0.46-0.86] P = 0.004). The total score was an independent predictor for both event-free survival (HR 0.65 [0.54-0.77] P < 0.001) and for ≥10% left ventricular ejection fraction improvement (OR 1.7 [1.3-2.3] P < 0.001). Conclusions: Composite data from 12-lead ECG during CRT-treatment can be used in a simple score to predict long-term clinical outcome.

Increased perforation risk with an MRI-conditional pacing lead: a single-center study.

BACKGROUND: Magnetic resonance imaging (MRI) has been considered contraindicated in patients with cardiac pacemakers (PPMs). Recently, Medtronic (MDT) MRI SureScan PPM (Medtronic Inc., Minneapolis, MN, USA) and leads were introduced into clinical practice in the United States of America. OBJECTIVE: To compare MDT CapSureFix 5086 MRI SureScan lead-associated perforation and dislodgement rates with MDT non-MRI SureScan active fixation leads. METHODS: We retrospectively analyzed the records of all patients implanted with MDT CapSureFix 5086 MRI SureScan leads as well as all patients implanted with MDT 4076 and 5076 leads at our institution from April 2011 to April 2014. RESULTS: Four of 72 patients implanted with MDT CapSureFix 5086 MRI SureScan leads (5.5%) had evidence of lead perforation, necessitating pericardiocentesis in three cases and lead revision in one case. Three of the four perforations were delayed perforations, presenting more than 3 weeks postimplant. Two patients implanted with MDT CapSureFix 5086 MRI SureScan leads (2.8%) had lead dislodgement. Of 420 patients implanted with MDT non-MRI SureScan leads, there were two perforations (0.47%) and four dislodgements (0.9%). There were significantly increased lead perforations associated with MDT CapSureFix 5086 MRI SureScan leads (P = 0.005) and a nonsignificant trend toward increased dislodgements (P = 0.18) when compared with MDT non-MRI SureScan leads. CONCLUSION: In contradiction to prior studies, this retrospective study suggests an increased perforation rate with MDT CapSureFix 5086 MRI SureScan leads. Most perforations were delayed perforations, presenting more than 3 weeks postimplant. Higher volume prospective studies with longer follow-up are needed to confirm our findings.

Early management of atrial fibrillation to prevent cardiovascular complications.

Atrial fibrillation (AF) is generally considered a progressive disease, typically evolving from paroxysmal through persistent to 'permanent' forms, a process attributed to electrical and structural remodelling related to both the underlying disease and AF itself. Medical treatment has yet to demonstrate clinical efficacy in preventing progression. Large clinical trials performed to date have failed to show benefit of rhythm control compared with rate control, but these trials primarily included patients at late stages in the disease process. One possible explanation is that intervention at only an early stage of progression may improve prognosis. Evolving observations about the progressive nature of AF, along with the occurrences of major complications such as strokes upon AF presentation, led to the notion that earlier and more active approaches to AF detection, rhythm-reversion, and maintenance of sinus rhythm may be a useful strategy in AF management. Approaches to early and sustained rhythm control include measures that prevent development of the AF substrate, earlier catheter ablation, and novel antiarrhythmic drugs. Improved classifications of AF mechanism, pathogenesis, and remodelling may be helpful to enable patient-specific pathophysiological diagnosis and therapy. Potential novel therapeutic options under development include microRNA-modulation, heatshock protein inducers, agents that influence Ca(2+) handling, vagal stimulators, and more aggressive mechanism-based ablation strategies. In this review, of research into the basis and management of AF in acute and early settings, it is proposed that progression from paroxysmal to persistent AF can be interrupted, with potentially favourable prognostic impact.

Acute mitral isthmus block during catheter ablation with vein of Marshall ethanol infusion: Angiographic considerations.

BACKGROUND: Achieving bidirectional mitral isthmus block is still challenging. Conventional ablation methods involve radiofrequency applications on the endocardial aspect of the lateral mitral isthmus, and often epicardial applications inside the coronary sinus. AIM: To evaluate the impact of the systematic use of ethanol infusion in the vein of Marshall on the achievement of acute mitral isthmus block of additional epicardial component lesion. METHODS: We evaluated patients referred to two centres for long-standing persistent atrial fibrillation ablation or recurrent peri-mitral flutter. All patients had pulmonary vein isolation and mitral isthmus line using ethanol infusion in the vein of Marshall for the first procedure and additional radiofrequency ablation lesion if necessary. For redo procedures, additional ablations (atrial lines and complex fractionated atrial electrogram ablations, if needed) were also performed. RESULTS: We included 149 patients, and ethanol infusion in the vein of Marshall was not performed in 27 patients (18%). Among 122 patients, 115 had long-standing persistent atrial fibrillation (94.2%) and seven had peri-mitral flutter (5.8%). The mean duration of continuous atrial fibrillation was 53 months before ablation. Acute bidirectional mitral isthmus block was obtained in 115 (94.2%) of the 122 patients who received ethanol infusion in the vein of Marshall (77% when considering the total population). The mean radiofrequency delivery time to obtain mitral isthmus block was 2.6minutes for the endocardial mitral isthmus radiofrequency ablation and 2.6minutes for the epicardial mitral isthmus radiofrequency ablation. Failure to obtain mitral isthmus block was associated with increased mitral isthmus length and left atrial dilation. No major complications related to ethanol infusion in the vein of Marshall were observed. CONCLUSION: Ethanol infusion in the vein of Marshall, when feasible (82%), was a safe approach to obtaining a high success rate (94%) of acute bidirectional endocardial and epicardial mitral isthmus block.

Doxorubicin-induced acute cardiotoxicity is associated with increased oxidative stress, autophagy, and inflammation in a murine model.

Drug-induced cardiotoxicity is a life-threatening side effect of doxorubicin (DOX) treatment that impacts patient prognosis and survival. In the majority of cases, the acute clinical form often remains asymptomatic, with few patients presenting rather nonspecific electrocardiographic abnormalities. While chronic toxicity has been more widely studied, the alterations appearing in acute cardiotoxicity are much less investigated. Thus, our in vivo study aimed to evaluate the process of DOX-induced acute myocardial toxicity by investigating oxidative stress and autophagy markers as mechanisms of myocardial toxicity in correlation with echocardiography and electrocardiography findings. Our results show that both autophagy and oxidative homeostasis were disrupted as soon as 7 days after DOX treatment, alterations that occurred even before the significant increase of NT-proBNP, a clinical marker for cardiac suffering. Moreover, we found a large number of alterations in the electrocardiography and echocardiography of treated rats. These findings suggest that DOX-induced myocardial toxicity started early after treatment initiation, possibly marking the initial phase of the unfolding process of cardiac damage. Further studies are required to completely decipher the mechanisms of DOX-induced cardiotoxicity.

A proposal for new clinical concepts in the management of atrial fibrillation.

Atrial fibrillation (AF) represents a growing public health burden. It is a complex condition, involving a number of etiologic factors and arrhythmia mechanisms associated with atrial remodeling. Greater understanding of these mechanisms may improve therapy. Current AF classification schemes are limited by simplicity. A number of risk factors predict AF onset, and additional factors are being evaluated in registry studies. Doppler imaging and Holter monitoring in high-risk patients to predict the onset of AF and progression from paroxysmal to permanent AF are promising. There is a need for a novel multifactorial classification model encompassing AF duration, symptoms, markers of atrial remodeling, and a risk score for AF onset, persistence, progression, and complications to guide treatment and prognostication. Preventing AF onset with upstream therapy is of great interest, but current data are conflicting. More study is needed to optimize rhythm control with antiarrhythmic drugs and targeted ablation to specific patient populations at an earlier stage. There is little consensus on optimal rate control and no information relating to optimum rate control in specific populations. This article highlights new concepts in AF and directions for future research.

Biomarkers of Volume Overload and Edema in Heart Failure With Reduced Ejection Fraction.

From a pathogenetic point of view, heart failure (HF) is characterized by the activation of several neurohumoral pathways with a role in maintaining the cardiac output and the adequate perfusion pressure in target organs and tissues. Decreased cardiac output in HF with reduced ejection fraction causes activation of the sympathetic nervous system, the renin angiotensin aldosterone system, arginine-vasopressin system, natriuretic peptides, and endothelin, all of which cause water and salt retention in the body. As a result, patients will present clinically as the main symptoms: dyspnea and peripheral edema caused by fluid redistribution to the lungs and/or by fluid overload. By studying these pathophysiological mechanisms, biomarkers with a prognostic and therapeutic role in the management of edema were identified in patients with HF with low ejection fraction. This review aims to summarize the current data from the specialty literature of such biomarkers with a role in the pathogenesis of edema in HF with low ejection fraction. These biomarkers may be the basis for risk stratification and the development of new therapeutic means in the treatment of edema in these patients.

Lead positioning strategies to enhance response to cardiac resynchronization therapy.

Left ventricular lead position is one of the main determinants of CRT response. There are several approaches in LV lead positioning that include favoring an optimal anatomical position or targeting either the segment with maximal mechanical dyssynchrony or a region with maximal electrical delay. The conventional LV lead implantation faces several technical difficulties that may prevent the obtaining of a stable position and good performance of the LV lead without phrenic nerve stimulation. In addition, implant of the LV pacing lead in areas with myocardial scar may result in less than optimal cardiac resynchronization. Several strategies have been proposed to overcome all these obstacles including multimodality cardiac imaging to help in preprocedural or intraprocedural identification of the latest activated areas of the LV and the potential anatomical constraints. In selected patients, the surgical implant may be a solution to overcome these constraints. In the future, LV endocardial or epicardial multisite pacing may deliver an enhanced response to CRT.

A Prospective Study of CPAP Therapy in Relation to Cardiovascular Outcome in a Cohort of Romanian Obstructive Sleep Apnea Patients.

BACKGROUND: Despite efforts at treatment, obstructive sleep apnea (OSA) remains a major health problem, especially with increasing evidence showing an association with cardiovascular morbidity and mortality. The treatment of choice for OSA patients is Continuous Positive Airway Pressure (CPAP), which has been proven in randomized controlled trials to be an effective therapy for this condition. The impact of CPAP on the cardiovascular pathology associated with OSA remains, however, unclear. Although the effect of CPAP has been previously studied in relation to cardiovascular outcome, follow-up of the treatment impact on cardiovascular risk factors at one year of therapy is lacking in a Romanian population. Thus, we aimed to evaluate the one-year effect of CPAP therapy on lipid profile, inflammatory state, blood pressure and cardiac function, assessed by echocardiography, on a cohort of Romanian OSA patients. METHODS: We enrolled 163 participants and recorded their baseline demographic and clinical characteristics with a follow-up after 12 months. Inflammatory and cardiovascular risk factors were assessed at baseline and follow up. RESULTS: Our results show that CPAP therapy leads to attenuation of cardiovascular risk factors including echocardiographic parameters, while having no effect on inflammatory markers. CONCLUSION: Treatment of OSA with CPAP proved to have beneficial effects on some of the cardiovascular risk factors while others remained unchanged, raising new questions for research into the treatment and management of OSA patients.

Integrating Electrocardiography and Vectorcardiography in the Differential Diagnosis of Wide Complex Tachycardia in a Patient with Left Ventricular Noncompaction: A Case Report and Brief Literature Review.

A 69-year-old woman with a history of hypertension and obesity, hospitalized with atypical chest pain, was diagnosed with left ventricular noncompaction. In-hospital monitoring of the cardiac rhythm revealed multiple episodes of atrial tachycardia and one episode of wide complex tachycardia (WCT) with left bundle branch block-like morphology and a right superior QRS axis. The electrocardiographic criteria were suggestive of a supraventricular origin of the WCT. Given the importance of reaching the correct diagnosis when dealing with a WCT, we tried to further define the pattern of ventricular activation using vectorcardiography (VCG). We analyzed the QRS loops during WCT in comparison to a sinus beat, a narrow complex tachycardia beat, and a premature ventricular contraction. The fast initial activation seen in the efferent limb of the QRS loop during the WCT was thought to be reflective of the fast initial activation via the conduction system seen in SVT with aberrancy, which was our final diagnosis for the WCT episode. This case illustrates a novel use of vectorcardiography as an additional diagnostic tool in the differential diagnosis of WCT.

Usefulness of the Electrocardiogram in a Patient Presenting with Right-Sided Pneumothorax and Presyncope.

We present the case of a 71-year-old man with history of smoking, pulmonary emphysema, hypertension, multivessel coronary artery disease and prior coronary artery bypass graft surgery who presented with spontaneous right-sided pneumothorax associated with phasic changes of the QRS amplitude on the electrocardiogram. While several case reports have described QRS amplitude changes associated with left-sided pneumothorax, reports of phasic ECG changes in right-sided pneumothorax are exceedingly rare. Such changes, when present in a patient with sudden onset chest pain and dyspnea, should prompt a diagnostic workup for possible pneumothorax.

Impact of tricuspid regurgitation and prior coronary bypass surgery on the geometry of the coronary sinus: a rotational coronary angiography study.

INTRODUCTION: The coronary sinus (CS) is often distorted in patients with advanced cardiomyopathy, making CS cannulation difficult. The objective of this study was to examine the impact of the underlying cardiac pathology on the variability of the CS anatomy, using rotational coronary venous angiography (RCVA). METHODS AND RESULTS: Seventy-nine patients undergoing RCVA for cardiac resynchronization therapy (CRT) were evaluated: age 63 +/- 15 years, 43% with prior coronary artery bypass grafting (CABG). Aspects of the CS anatomy which could impact cannulation were examined: the CS ostial angle, the posterior displacement of the CS away from the atrioventricular groove, a measure of CS curvature, and the presence of stenoses and aneurysmal dilatations. The CS ostial angle was variable (65-151 degrees, mean 119 +/- 19 degrees, <90 degrees in 8 patients) and decreased significantly (P = 0.0022) with increasing severity of tricuspid regurgitation (TR), reaching 94 +/- 18 degrees in patients with severe TR. The posterior displacement of the CS was significantly more accentuated in patients with prior CABG when compared with the patients without CABG (7.1 +/- 3.7 vs 4.5 +/- 2.8 mm; P = 0.0246). The decrease in luminal diameter at the CS-great cardiac vein (GCV) junction was 2.0 +/- 1.0 mm, being more pronounced in patients with prior CABG versus nonCABG (26 vs 20%; P = 0.042). Stenoses and aneurysmal dilatations of the CS-GCV were encountered in 4 (5%) and 6 (8%) of patients, respectively, all of them with prior CABG, representing 12% and 18% of the CABG group. CONCLUSION: The CS anatomy in patients undergoing CRT is variable, and is impacted by the severity of the underlying TR and history of a prior CABG.

Incidence and electrophysiologic properties of dissociated pulmonary vein activity following pulmonary vein isolation during catheter ablation of atrial fibrillation.

INTRODUCTION: pulmonary veins (PV) play an important role in the arrhythmogenesis of atrial fibrillation (AF). Catheter-based PV isolation is one of the primary treatments for symptomatic drug refractory AF. Following electrical isolation, isolated rhythms in the PV are encountered. The aim of this study was to assess the frequency of postisolation PV activity and classify the different rhythms observed. METHODS AND RESULTS: this single center prospective study sought to assess the dissociated activity in the PVs following their isolation during AF ablation. In 100 consecutive patients (60 paroxysmal, 40 persistent) undergoing AF ablation, dissociated PV activity was recorded using a multielectrode mapping catheter following antral PV isolation. The dissociated PV activity was classified as (1) silent, (2) isolated ectopic beats, (3) ectopic rhythm, and (4) PV fibrillation. All the PVs were successfully isolated in all the patients. In 91 of 100 patients, there was dissociated activity in at least 1 isolated ipsilateral PV group. There was no significant difference in spontaneous PV activity between patients with paroxysmal and persistent AF (91.7% vs 90%, P = 1.0). Among the 200 isolated ipsilateral PV groups, 64 of 200 (32%) were silent, 86 of 200 (43%) demonstrated isolated ectopic beats, 41 of 200 (20.5%) had ectopic rhythms and 9 of 200 (4.5%) had PV fibrillation. The average cycle length of the PV ectopic rhythm was 2594 ± 966 ms (range 1193-4750 ms). CONCLUSIONS: following PV isolation, a majority of patients demonstrate dissociated activity in at least 1 PV. This finding was evident in patients with both paroxysmal and persistent AF.