Spatially Conserved Spiral Wave Activity During Human Atrial Fibrillation

BACKGROUND

Atrial fibrillation is the most common cardiac arrhythmia in the world and increases the risk for stroke and morbidity. During atrial fibrillation, the electric activation fronts are no longer coherently propagating through the tissue and, instead, show rotational activity, consistent with spiral wave activation, focal activity, collision, or partial versions of these spatial patterns. An unexplained phenomenon is that although simulations of cardiac models abundantly demonstrate spiral waves, clinical recordings often show only intermittent spiral wave activity.

METHODS

In silico data were generated using simulations in which spiral waves were continuously created and annihilated and in simulations in which a spiral wave was intermittently trapped at a heterogeneity. Clinically, spatio-temporal activation maps were constructed using 60 s recordings from a 64 electrode catheter within the atrium of N=34 patients (n=24 persistent atrial fibrillation). The location of clockwise and counterclockwise rotating spiral waves was quantified and all intervals during which these spiral waves were present were determined. For each interval, the angle of rotation as a function of time was computed and used to determine whether the spiral wave returned in step or changed phase at the start of each interval.

RESULTS

In both simulations, spiral waves did not come back in phase and were out of step." In contrast, spiral waves returned in step in the majority (68%; P=0.05) of patients. Thus, the intermittently observed rotational activity in these patients is due to a temporally and spatially conserved spiral wave and not due to ones that are newly created at the onset of each interval.

CONCLUSIONS

Intermittency of spiral wave activity represents conserved spiral wave activity of long, but interrupted duration or transient spiral activity, in the majority of patients. This finding could have important ramifications for identifying clinically important forms of atrial fibrillation and in guiding treatment.

From transabdominal to totally extra-peritoneal robotic ventral hernia repair: observations and outcomes

PURPOSE

While robotic-assisted hernia repair has increased the popularity of minimally invasive hernia surgery, selecting between the types of approaches is a challenge for both experts and novices alike. In this study, we compared a single surgeon's early experience transitioning from transabdominal hernia repair with sublay mesh in either the pre-peritoneal or retrorectus space (TA-SM) and enhanced-view totally extra-peritoneal (eTEP) ventral hernia repair in the peri-operative and long-term post-operative time periods.

METHODS

We conducted a retrospective review of 50 eTEP and 108 TA-SM procedures to collect demographics, intraoperative details, and 30-day and 1-year post-operative outcomes. Statistical analysis was performed utilizing Chi-square analysis, Fisher's test, and two sample t-tests with equal variances.

RESULTS

There were no significant differences in patient demographics or comorbidities. eTEP patients had larger defects (109.1 cm² vs. 31.8 cm², p = 0.043) and mesh used (432.8 cm² vs. 137.9 cm², p = 0.001). Operative times were equivalent (158.3 ± 90.6 min eTEP and 155.8 ± 65.2 min TA-SM, p = 0.84), but conversion to alternate procedure type was higher for the transabdominal approach (4% eTEP vs. 22% TA-SM, p < 0.05). Hospital stay was less in the eTEP cohort (1.3 days vs. 2.2 days, p < 0.05). Within 30 days, there were no significant differences in emergency visits or hospital readmissions. There was a greater propensity for eTEP patients to develop seromas (12.0% vs. 1.9%, p < 0.05). At 1 year, there was no statistically significant difference in recurrence rate (4.56% eTEP vs. 12.2% TA-SM, p = 0.28) respective to average time to recurrence (9.17 months eTEP vs. 11.05 months TA-SM).

CONCLUSION

The eTEP approach can be adopted safely and efficiently, and may have superior peri-operative outcomes including fewer conversions and reduced hospital stay.

Epidemiology and impact of frailty in patients with atrial fibrillation in Europe

BACKGROUND

Frailty is a medical syndrome characterised by reduced physiological reserve and increased vulnerability to stressors. Data regarding the relationship between frailty and atrial fibrillation (AF) are still inconsistent.

OBJECTIVES

We aim to perform a comprehensive evaluation of frailty in a large European cohort of AF patients.

METHODS

A 40-item frailty index (FI) was built according to the accumulation of deficits model in the AF patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry. Association of baseline characteristics, clinical management, quality of life, healthcare resources use and risk of outcomes with frailty was examined.

RESULTS

Among 10,177 patients [mean age (standard deviation) 69.0 (11.4) years, 4,103 (40.3%) females], 6,066 (59.6%) were pre-frail and 2,172 (21.3%) were frail, whereas only 1,939 (19.1%) were considered robust. Baseline thromboembolic and bleeding risks were independently associated with increasing FI. Frail patients with AF were less likely to be treated with oral anticoagulants (OACs) (odds ratio 0.70, 95% confidence interval 0.55-0.89), especially with non-vitamin K antagonist OACs and managed with a rhythm control strategy, compared with robust patients. Increasing frailty was associated with a higher risk for all outcomes examined, with a non-linear exponential relationship. The use of OAC was associated with a lower risk of outcomes, except in patients with very/extremely high frailty.

CONCLUSIONS

In this large cohort of AF patients, there was a high burden of frailty, influencing clinical management and risk of adverse outcomes. The clinical benefit of OAC is maintained in patients with high frailty, but not in very high/extremely frail ones.

Stochastic termination of spiral wave dynamics in cardiac tissue

Rotating spiral waves are self-organized features in spatially extended excitable media and may play an important role in cardiac arrhythmias including atrial fibrillation (AF). In homogeneous media, spiral wave dynamics are perpetuated through spiral wave breakup, leading to the continuous birth and death of spiral waves, but have a finite probability of termination. In non-homogeneous media, however, heterogeneities can act as anchoring sources that result in sustained spiral wave activity. It is thus unclear how and if AF may terminate following the removal of putative spiral wave sources in patients. Here, we address this question using computer simulations in which a stable spiral wave is trapped by an heterogeneity and is surrounded by spiral wave breakup. We show that, following ablation of spatial heterogeneity to render that region of the medium unexcitable, termination of spiral wave dynamics is stochastic and Poisson-distributed. Furthermore, we show that the dynamics can be accurately described by a master equation using birth and death rates. To validate these predictions in vivo, we mapped spiral wave activity in patients with AF and targeted the locations of spiral wave sources using radiofrequency ablation. Targeted ablation was indeed able to terminate AF, but only after a variable delay of up to several minutes. Furthermore, and consistent with numerical simulations, termination was not accompanied by gradual temporal or spatial organization. Our results suggest that spiral wave sources and tissue heterogeneities play a critical role in the maintenance of AF and that the removal of sources results in spiral wave dynamics with a finite termination time, which could have important clinical implications.

Improving the quality of discharge care plan in the heart failure with reduced ejection fraction (HFrEF) cohort: a quality improvement study

Background

High-quality heart failure (HF) discharge summary (DS) is the cornerstone of effective communication during the transition from specialists to primary care. The combination of continuing involvement of multidisciplinary members, varying individual tolerance to treatments, and the need for multiple investigations beget intricate HFrEF management. The quality of the information included in DS following HF-related hospitalisation varies widely and may be sub-optimal in communicating patient's in-hospital care, leading to inadequate compliance to guideline-directed medical therapy (GDMT) and increased risk of re-hospitalisation. Notwithstanding this real-world observation, there remains a paucity of consensus on the standard of measurements of HF DS.

Purpose

We aimed to optimise the transmission of information between patients and HF multidisciplinary members to improve adherence to GDMT, follow-up (F/U) care coordination and patient education in line with the National Institute for Health and Care Excellence (NICE) and the European Society of Cardiology (ESC) recommendations.

Methods

A random sampling of the HFrEF cohort discharged from the cardiac unit at our institution following HF-related hospitalisation was performed across four distinct time points matched with respective interventions. Three iterative cycles (baseline analysis and two educational interventions – departmental teaching and dissemination of innovative mnemonics sheets – THE WET TO DRY [Figure 1]) were completed using Plan-Do-Study-Act (PDSA) methodology. The quality of patients DS was objectively analysed based on the inclusion of physiological and investigation parameters, in-patient treatment, initiation/titration of GDMT, F/U care coordination, and patient education.

Results

Sixty-six patients, mean±SD age 74.6±12.8y were enrolled between 2018–2021. The baseline reporting of presenting complaints, trigger and investigation findings were high and consistent throughout all cycles. A positive trend was observed in the reporting of physiological parameters and in-patient treatment post-interventions. Patient education and vaccines offered remained low despite improving compliance. As such, a consensus on the provision of nurse-led pre-discharge review label and interactive patient personal passport (Figure 1) was achieved via a group of cardiologists and HF specialist nurses to address identified practice gap from preceding PDSA cycles. Full adherence to GDMT and the inclusion of F/U pathway were observed following the provision of nurse-led review label (Figure 2).

Conclusion

This study demonstrates that educational interventions – departmental teaching and innovative mnemonics can be effective in improving the quality of HF DS. Structured nurse-led review label and interactive patient personal passport are feasible interventions, which can be implemented at minimal cost to sustain adherence to GDMT, F/U care coordination and individualised patient education.

Funding Acknowledgement

Type of funding sources: None.

Cecal bascule - An unusual cause of intestinal obstruction: A case report

INTRODUCTION

Cecal bascule is a rare type of cecal volvulus occurring in the elderly population with a male predominance. It is a condition where the cecum folds upward upon itself.

IMPORTANCE

There are only a handful of case reports published about cecal bascule. This is the first case being reported from Pakistan.

CASE PRESENTATION

A 68 year old female, known hypertensive and osteoporosis presented in the ER with complaints of vomiting, abdominal distension and absolute constipation. Radiology was non-diagnostic. She was treated with cecectomy and anastomosis. Post operatively she developed ileus for which was managed. She was subsequently discharged at 8th day post op.

CLINICAL DISCUSSION

The management of cecal bascule is always surgery with predilection towards cecopexy or cecetomy to prevent recurrence. This manuscript is as per the SCARE case report checklist [1].

Characteristics and health status of patients with and without confirmed HFpEF

Aims

Patients with heart failure with preserved ejection fraction (HFpEF) are usually older and multi-morbid and diagnosis can be challenging. The aims of this cohort study were to confirm diagnosis of HFpEF in patients with possible HFpEF recruited from primary care, to compare characteristics and health status between those with and without HFpEF, and to determine factors associated with health status in patients with HFpEF.

Methods

Patients with presumed HFpEF were recruited from primary care practices and underwent clinical assessment and diagnostic evaluation as part of a longitudinal cohort study. Health status was measured by Montreal Cognitive Assessment (MOCA), 6-minute walk test, symptoms, and the Kansas City Cardiomyopathy Questionnaire (KCCQ), and quality of life (QoL) by EQ-5D-5L visual analogue scale (VAS).

Results

151 patients (mean age 78.5±8.6 years, 40% women, mean EF 56% + 9.4) were recruited and 93 (61.6%) were confirmed HFpEF (those without HFpEF had other HF and cardiac diagnoses). Patients with and without HFpEF did not differ by age, MOCA, blood pressure, heart rate, NYHA class, proportion with atrial fibrillation, Charlson Comorbidity Index, or NT-ProBNP levels. Patients with HFpEF were more likely to be women, overweight or obese, frail, and to be more functionally impaired by 6 minute walk distance and gait speed than those without. Although not statistically significant, patients with HFpEF had clinically significant differences (&gt;5 points) on the physical limitations, symptom burden and clinical summary subscales of the KCCQ, but did not differ by other subscales or by EQ-5D-5L VAS (70±17 vs 73±19, p=0.385). More patients with HFpEF reported daytime dyspnoea (63% vs 46%, p=0.035) and fatigue (81% vs 61%, p=0.008), but not other symptoms compared to those without HFpEF. For both groups BMI was moderately negatively correlated with KCCQ subscale scores, and 6 minute walk distance was positively correlated with KCCQ subscales.

Conclusions

Nearly 40% were not confirmed as HFpEF indicating the challenges of diagnosis. Patients with confirmed HFpEF differed by sex, overweight/obesity, frailty, functional impairment, and symptoms but not by age or comorbidities from those without HFpEF. These differences were reflected in some subscale scores of the KCCQ, but not how patients reported their quality of life on the KCCQ QoL subscale and EQ-5D-5L VAS. Older patients with HFpEF reported relatively high QoL despite poor health status by functional impairment, frailty and symptoms.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Institute of Health Research School of Primary Care Research

P1419Persistent atrial fibrillation terminates during ablation more often using dispersion mapping than with fractionated electrogram mapping

Introduction

Persistent AF termination rates have increased since the advent of AF driver mapping, with a recent meta-analysis (Baykaner Circ AE 2018) of over 3200 patients showing improved 12 month freedom from AF/AT.  However,  recent randomised clinical trials have cast doubt on the efficacy of complex fractionated atrial electrograms (CFAE) based mapping strategies. We

set out to study a consecutive single centre series pre-and post- use of spatio-temporal dispersion (STD) to identify termination rates between the two approaches.

Methods

We recruited consecutive patients over 18 months at a single high volume tertiary centre undergoing first redo ablation for persistent AF. Patients were all

mapped using Pentarray to mark areas of substrate using the spatio-temporal dispersion (STD) method (Seitz JACC 2017).

Ablation was performed by a single operator using catheters to standardise equipment and workflow, to enable true

comparison of mapping and ablation results in a consecutive series.

Results

In total 38 patients were studied at redo ablation for persistent AF (age 69, 87% male, LA diameter 4.5cm). Termination of persistent

AF to SR (30%) or AT (70%) was obtained in 30/38 (79%) of the group with STD based substrate ablation vs. 1/38 (3%) in patients mapped

with CFAE targeting using identical equipment and operator (p &lt; 0.001). Procedure time was no different between STD and CFAE based

approaches (263 vs. 248 mins, p = ns). Figure shows STD patterns (red arrows) on Pentarray in a 67 year old man anterior to left inferior

pulmonary vein (A), where ablation terminated AF to sinus rhythm. At 12 month follow up, 30/38 (79%) patients were in sinus rhythm with no AF detected on ECG or continuous monitoring.

Conclusions

In this single centre series of persistent AF ablations, the use of STD mapping increased rates of termination compared to a fractionation based mapping strategy alone, without increasing overall procedure time. Clinical outcome data suggest this translates into better 12 month clinical outcomes, and motivate prospective randomised trials to definitively study this technique.

Abstract Figure.

Mapping and Ablation of Rotational and Focal Drivers in Atrial Fibrillation

Drivers are increasingly studied ablation targets for atrial fibrillation (AF). However, results from ablation remain controversial. First, outcomes vary between centers and patients. Second, it is unclear how best to perform driver ablation. Third, there is a lack of practical guidance on how to identify critical from secondary sites using different AF mapping methods. This article addresses each of these issues.

Reinvigorating the clinical examination for the 21st century

At its most fundamental level, the clinical encounter between a patient and their doctor seeks to solve a mystery. Clinicians uncover clues through the history, physical examination, and ancillary tests to arrive at a diagnosis and develop a management plan. Despite advances in technology, the majority of clinical diagnoses are still reached through the history and physical examination without the use of laboratory and imaging tests. However, in the modern American hospital, clinicians spend as little as 12% of their time in direct contact with patients and their families. This has led to a decline in clinical examination skills and contributes to diagnostic error. There is a growing movement to return clinicians and trainees back to the bedside. In 2017, we formed the Society of Bedside Medicine to encourage innovation, education, and research on the role of the clinical encounter in 21st century medicine. Over the last 3 years, we have embraced the following 6 strategies to reinvigorate the practice of the clinical examination: 1) be present with the patient; 2) practice an evidence‑based approach to the physical exam; 3) create opportunities for intentional practice of the physical exam; 4) recognize the power of the physical examination beyond diagnosis; 5) use point‑of‑care technology to aid in diagnosis and reinforce skills; and 6) seek and provide specific feedback on physical examination skills. By employing these strategies in both teaching and practice, clinicians can maximize the value of time spent with patients and renew the importance of the clinical examination in 21st century practice.

Clinical Implications of Ablation of Drivers for Atrial Fibrillation: A Systematic Review and Meta-Analysis

BACKGROUND

The outcomes from pulmonary vein isolation (PVI) for atrial fibrillation (AF) are suboptimal, but the benefits of additional lesion sets remain unproven. Recent studies propose ablation of AF drivers improves outcomes over PVI, yet with conflicting reports in the literature. We undertook a systematic literature review and meta-analysis to determine outcomes from ablation of AF drivers in addition to PVI or as a stand-alone procedure.

METHODS

Database search was done using the terms atrial fibrillation and ablation or catheter ablation and driver or rotor or focal impulse or FIRM (Focal Impulse and Rotor Modulation). We pooled data using random effects model and assessed heterogeneity with I² statistic.

RESULTS

Seventeen studies met inclusion criteria, in a cohort size of 3294 patients. Adding AF driver ablation to PVI reported freedom from AF of 72.5% (confidence interval [CI], 62.1%-81.8%; P<0.01) and from all arrhythmias of 57.8% (CI, 47.5%-67.7%; P<0.01). AF driver ablation when added to PVI or as stand-alone procedure compared with controls produced an odds ratio of 3.1 (CI, 1.3-7.7; P=0.02) for freedom from AF and an odds ratio of 1.8 (CI, 1.2-2.7; P<0.01) for freedom from all arrhythmias in 4 controlled studies. AF termination rate was 40.5% (CI, 30.6%-50.9%) and predicted favorable outcome from ablation(P<0.05).

CONCLUSIONS

In controlled studies, the addition of AF driver ablation to PVI supports the possible benefit of a combined approach of AF driver ablation and PVI in improving single-procedure freedom from all arrhythmias. However, most studies are uncontrolled and are limited by substantial heterogeneity in outcomes. Large multicenter randomized trials are needed to precisely define the benefits of adding driver ablation to PVI.

Myocardial viability of the peri-infarct region measured by T1 mapping post manganese-enhanced MRI correlates with LV dysfunction

BACKGROUND

Manganese-enhanced MRI (MEMRI) detects viable cardiomyocytes based on the intracellular manganese uptake via L-type calcium-channels. This study aimed to quantify myocardial viability based on manganese uptake by viable myocardium in the infarct core (IC), peri-infarct region (PIR) and remote myocardium (RM) using T1 mapping before and after MEMRI and assess their association with cardiac function and arrhythmogenesis.

METHODS

Fifteen female swine had a 60-minute balloon ischemia-reperfusion injury in the LAD. MRI (Signa 3T, GE Healthcare) and electrophysiological study (EPS) were performed 4 weeks later. MEMRI and delayed gadolinium-enhanced MRI (DEMRI) were acquired on LV short axis. The DEMRI positive total infarct area was subdivided into the regions of MEMRI-negative non-viable IC and MEMRI-positive viable PIR. T1 mapping was performed to evaluate native T1, post-MEMRI T1, and delta R1 (R1_post-R1_pre, where R1 equals 1/T1) of each territory. Their correlation with LV function and EPS data was assessed.

RESULTS

PIR was characterized by intermediate native T1 (1530.5 ± 75.2 ms) compared to IC (1634.7 ± 88.4 ms, p = 0.001) and RM (1406.4 ± 37.9 ms, p < 0.0001). Lower post-MEMRI T1 of PIR (1136.3 ± 99.6 ms) than IC (1262.6 ± 126.8 ms, p = 0.005) and higher delta R1 (0.23 ± 0.08 s^-1) of PIR than IC (0.18 ± 0.09 s^-1, p = 0.04) indicated higher myocardial manganese uptake of PIR compared to IC. Post-MEMRI T1 (r = -0.57, p = 0.02) and delta R1 (r = 0.51, p = 0.04) of PIR correlated significantly with LVEF.

CONCLUSIONS

PIR is characterized by higher manganese uptake compared to the infarct core. In the subacute phase post-IR, PIR viability measured by post-MEMRI T1 correlates with cardiac function.

The Value of Physical Examination: A New Conceptual Framework

The physical examination defines medical practice, yet its role is being questioned increasingly, with statistical comparisons of diagnostic accuracy often the sole metric used against newer technologies. We set out to highlight seven ways in which the physical examination has value beyond diagnostic accuracy to reaffirm its place in the core skills of a physician and guide future research, teaching, and curriculum design. We show that this more comprehensive approach to the physical examination of its "utility" beyond that of reaching a diagnosis can be beneficial to both doctor and patient.

Organized Sources Are Spatially Conserved in Recurrent Compared to Pre-Ablation Atrial Fibrillation: Further Evidence for Non-Random Electrical Substrates

INTRODUCTION

Recurrent atrial fibrillation (AF) after ablation is associated with reconnection of initially isolated pulmonary vein (PV) trigger sites. Substrates are often targeted in addition to PVI, but it is unclear how substrates progress over time. We studied if substrates in recurrent AF are conserved or have developed de novo from pre-ablation AF.

METHODS AND RESULTS

Of 137 patients undergoing Focal Impulse and Rotor Mapping (FIRM) at their index procedure for AF, 29 consecutive patients (60 ± 8 years, 79% persistent) recurred and were also mapped at repeat procedure (21 ± 20 months later) using carefully placed 64-pole baskets and RhythmView(TM) (Topera, Menlo Park, CA, USA) to identify AF sources and disorganized zones. Compared to index AF, recurrent AF had a longer cycle length (177 ± 21 vs. 167 ± 19 milliseconds, P = 0.01). All patients (100%) had 1 or more conserved AF rotors between procedures with surrounding disorganization. The number of sources was similar for recurrent AF post-PVI versus index AF (3.2 ± 1.4 vs. 3.1 ± 1.0, P = 0.79), but was lower for recurrent AF after FIRM+PVI versus index AF (4.4 ± 1.4 vs. 2.9 ± 1.7, P = 0.03). Overall, 81% (61/75) of AF sources lay in conserved regions, while 19% (14/75) were detected de novo.

CONCLUSION

Electrical propagation patterns for recurrent AF after unsuccessful ablation are similar in individual patients to their index AF. These data support temporospatial stability of AF substrates over 1-2 years. Trials should determine the relative benefit of adding substrate mapping and ablation to PVI for recurrent AF.

Role of Rotors in the Ablative Therapy of Persistent Atrial Fibrillation

Atrial fibrillation (AF) ablation is increasingly used to maintain sinus rhythm yet its results are sub-optimal, especially in patients with persistent AF or prior unsuccessful procedures. Attempts at improvement have often targeted substrates that sustain AF after it is triggered, yet those mechanisms are debated. Many studies now challenge the concept that AF is driven by self-sustaining disordered wavelets, showing instead that localised drivers (rotors) may drive disorder via a process known as fibrillatory conduction. Novel mapping using wide-area recordings, physiological filtering and phase analysis demonstrates rotors in human AF. Contact mapping with focal impulse and rotor modulation (FIRM) shows that localised ablation at sources can improve procedural success in many populations on long-term follow up and some newer approaches to rotor mapping are qualitatively similar. This review critically evaluates the data on rotor mapping and ablation, which advances our conceptual understanding of AF and holds the promise of substantially improving ablative outcomes in patients with persistent AF.

Value of FNAC in diagnosis of different types of thyroiditis and its comparison with clinical and biochemical findings

FNAC has developed tremendous improvement in the diagnosis of thyroiditis. The present study was designed to asses the usefulness of FNAC to diagnose various types of thyroiditis and to study their smear patterns. Over a period of one-year, 70 cases of thyroiditis have been evaluated on the basis of cytomorphological criteria and clinical findings of patients. The age ranged from 12-60 years. Majority of the cases were between 21 to 30 years of age with female preponderance in each group of thyroiditis. Among 70 cases, 26(37.14%) cases were Hashimoto's thyroiditis, 21(30%) cases were lymphocytic thyroiditis, seven (10%) cases as granulomatous thyroiditis and 16(22.8%) were non-specific thyroiditis. Further study was carried out in these 70 cases regarding biochemical thyroid status, ultrasonography and radionucleotide scan. Blood was drawn from all patients for estimation of antibody titer to compare with cytological diagnosis. It was found that, clinical examination and history of patients had limited value in the diagnosis of thyroiditis. Ultrasonography and thyroid scan could not reliably differentiate between patients with autoimmune thyroiditis and those with simple and nodular goiter. Biochemically hypothyroidism is more frequently evaluated with Hashimoto's diseases. On the other hand, hyperthyroidism was observed in most other types of thyroiditis. Cytologically diagnosed 78.72% cases of autoimmune thyroiditis had positive antibody titer. From the present study it is concluded that FNAC is a safe, reliable, cost effective and time saving method in the diagnosis of thyroiditis. Being a benign condition also reduce the rate of unnecessary operation, which can be treated conservatively.