Use of the inverse solution guidance algorithm method for RF ablation catheter guidance.

INTRODUCTION: We previously introduced the inverse solution guidance algorithm (ISGA) methodology using a Single Equivalent Moving Dipole model of cardiac electrical activity to localize both the exit site of a re-entrant circuit and the tip of a radiofrequency (RF) ablation catheter. The purpose of this study was to investigate the use of ISGA for ablation catheter guidance in an animal model. METHODS: Ventricular tachycardia (VT) was simulated by rapid ventricular pacing at a target site in eleven Yorkshire swine. The ablation target was established using three different techniques: a pacing lead placed into the ventricular wall at the mid-myocardial level (Type-1), an intracardiac mapping catheter (Type-2), and an RF ablation catheter placed at a random position on the endocardial surface (Type-3). In each experiment, one operator placed the catheter/pacing lead at the target location, while another used the ISGA system to manipulate the RF ablation catheter starting from a random ventricular location to locate the target. RESULTS: The average localization error of the RF ablation catheter tip was 0.31 ± 0.08 cm. After analyzing approximately 35 cardiac cycles of simulated VT, the ISGA system's accuracy in locating the target was 0.4 cm after four catheter movements in the Type-1 experiment, 0.48 cm after six movements in the Type-2 experiment, and 0.67 cm after seven movements in the Type-3 experiment. CONCLUSION: We demonstrated the feasibility of using the ISGA method to guide an ablation catheter to the origin of a VT focus by analyzing a few beats of body surface potentials without electro-anatomic mapping.

Specific Electrocardiograph Intervals Predict Hospitalization with Atrial Fibrillation in Those with Chronic Kidney Disease.

INTRODUCTION: Atrial fibrillation (AF) is common in patients with chronic kidney disease (CKD) and is associated with higher rates of hospitalization compared to those without AF. Whether routine electrocardiographic parameters are predictive of future hospitalizations with AF is not clear. METHODS: The present study is an analysis of a prospective cohort of 2,759 patients without baseline AF from the Chronic Renal Insufficiency Cohort, a large prospective multicenter study of patients with nondialysis-dependent CKD. Unadjusted and adjusted Cox regression models were fit to examine the association of baseline categories of QTc, QRS, and PR intervals with time to first hospitalization with AF. Restricted cubic splines were used to display nonlinear associ-ations. RESULTS: The mean age of subjects at baseline was 58 ± 11 years, 55% were male, and 44% were Black. The mean follow-up was 6.6 years during which 224 participants experienced a hospitalization with AF. The association of baseline QTc interval with risk of AF hospitalization was nonlinear, such that the lowest and highest quartiles of QTc (<407 and >431 ms, respectively) had higher adjusted risk of AF hospitalization, compared with the second quartile (407-416 ms) (aHR Q1:Q2 1.58, 95% CI 1.03-2.41; p = 0.03; aHR Q4:Q2 1.84, 95% CI 1.22-2.78; p < 0.01). Longer QRS was associated with a higher risk of hospitalization with AF among the subgroup of patients with a history of heart failure (HF). PR interval was not associated with AF hospitalization. DISCUSSION/CONCLUSION: The association of QTc with risk for hospitalization with AF among patients with CKD is nonlinear, while the association of longer QRS with AF hospitalization is restricted to patients with baseline HF. Electrocardiography may represent a simple and widely accessible method for risk stratification of future AF in patients with CKD.

Comparison between TightRail rotating dilator sheath and GlideLight laser sheath for transvenous lead extraction.

BACKGROUND: There are limited data on the comparative analyses of TightRail rotating dilator sheath (Philips) and laser sheath for lead extraction. OBJECTIVE: To evaluate the effectiveness and safety of the TightRail sheath as a primary or secondary tool for transvenous lead extraction (TLE). METHODS: Retrospective cohort analysis of 202 consecutive patients who underwent TLE using either TightRail sheath and/or GlideLight laser sheath (Philips) in our hospital. The study population was divided into three groups: Group A underwent TLE with laser sheath only (N = 157), Group B with TightRail sheath only (N = 22), and Group C with both sheaths (N = 23). RESULTS: During this period, 375 leads in 202 patients were extracted, including 297 leads extracted by laser sheath alone, 45 leads by TightRail sheath alone, and 33 by both TightRail sheath and laser sheaths. The most common indications included device infection (44.6%) and lead-related complications (44.1%). The median age of leads was 8.9 years. TightRail sheath (Group B) achieved similar efficacy as a primary extraction tool compared with laser sheath (Group A), with complete procedure success rate of 93.3% (vs. 96.6%, P = .263) and clinical success rate of 100.0% (vs. 98.1%, P = .513). Among 32 leads in which Tightrail was used after laser had failed (Group C), the complete procedure success rate was 75.8%. No significant difference in procedural adverse events was observed. CONCLUSION: Our single-center experience confirms that the TightRail system is an effective first-line and second-line method for TLE. Further investigation is required to guide the selection of mechanical and laser sheaths in lead extraction cases.

Termination of persistent atrial fibrillation during pulmonary vein isolation: insight from the MAGIC-AF trial.

AIMS: Controversy on the optimal ablation strategy for persistent atrial fibrillation (AF) exists with limited work evaluating a strategy of pulmonary vein isolation (PVI) alone when AF terminates during PVI. Thirty-five patients had AF termination during PVI in the Modified Ablation Guided by Ibutilide Use in Chronic Atrial Fibrillation (MAGIC-AF; ClinicalTrials.gov number: NCT01014741) study. The objective of the current study is to report the 1-year outcome after PVI alone in this unique patient group. METHODS AND RESULTS: The 1-year single procedure freedom from atrial arrhythmia off anti-arrhythmic drugs was reported for the 35 patients in the MAGIC-AF study with persistent AF termination during or upon completion of PVI. Freedom from recurrent atrial arrhythmia was achieved in 60% of patients where AF terminated during PVI. Cavotricuspid isthmus flutter was common when AF terminated to a macro re-entrant flutter during PVI, and responsible for 92% of all flutter circuits with AF termination. CONCLUSIONS: Persistent AF termination during PVI may identify a subgroup of patients who experience a similar long-term clinical outcome with PVI ablation alone when compared with other more extensive persistent AF ablation strategies. Pulmonary vein isolation alone may be an appropriate tactic in this subgroup of persistent AF patients.

The modified stepwise ablation guided by low-dose ibutilide in chronic atrial fibrillation trial (The MAGIC-AF Study).

AIMS: Complex fractionated atrial electrograms (CFAE) are targeted during persistent atrial fibrillation (AF) ablation. However, many CFAE sites are non-specific resulting in extensive ablation. Ibutilide has been shown to reduce left atrial surface area exhibiting CFAE. We hypothesized that ibutilide administration prior to CFAE ablation would identify sites critical for persistent AF maintenance allowing for improved procedural efficacy and long-term freedom from atrial arrhythmias. METHODS AND RESULTS: Two hundred patients undergoing a first-ever persistent AF catheter ablation procedure were randomly assigned to receive either 0.25 mg of intravenous ibutilide or saline placebo upon completion of pulmonary vein isolation. Complex fractionated atrial electrogram sites were then targeted with ablation. The primary efficacy endpoint was the 1-year single procedure freedom from atrial arrhythmia off anti-arrhythmic drugs. Similar procedural characteristics (procedure, fluoroscopy, and ablation times) were observed with both strategies despite a greater reduction in left atrial surface area with CFAE sites (8 vs. 1%, P < 0.0001) and AF termination during CFAE ablation with ibutilide compared with placebo (75 vs. 57%, P = 0.007). The primary efficacy endpoint was achieved in 56% of patients receiving ibutilide and 49% receiving placebo (P = 0.35). No significant differences in peri-procedural complications were observed in both groups. CONCLUSION: Despite a reduction in CFAE area and greater AF termination during CFAE ablation, procedural characteristics and clinical outcomes were unchanged when CFAE ablation was guided by ibutilide administration. CLINICAL TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov number: NCT01014741.

Persistent Atrial Fibrillation Ablation in Females: Insight from the MAGIC-AF Trial.

INTRODUCTION: Atrial fibrillation (AF) ablation is less frequently performed in women when compared to men. There are conflicting data on the safety and efficacy of AF ablation in women. The objective of this study was to compare the clinical characteristics and outcomes in a contemporary cohort of men and women undergoing persistent AF ablation procedures. METHODS AND RESULTS: A total of 182 men and 53 women undergoing a first-ever persistent AF catheter ablation procedure in The Modified Ablation Guided by Ibutilide Use in Chronic Atrial Fibrillation (MAGIC-AF) trial were evaluated. Clinical and procedural characteristics were compared between each gender. The primary efficacy endpoint was the 1-year single procedure freedom from atrial arrhythmia off anti-arrhythmic drugs. Women undergoing catheter ablation procedures were older than men (P < 0.001). The duration of AF and associated co-morbidities were similar between both genders. Single procedure drug-free atrial arrhythmia recurrence occurred in 53% of the cohort with no difference based on gender (men = 54%, women = 53%; P = 1.0). Procedural (P = 0.04), fluoroscopic (P = 0.02), and ablation times (P = 0.003) were shorter in women compared to men. Periprocedural complications and postablation improvement in quality of life were similar between men and women. CONCLUSION: Women undergoing a first-ever persistent AF ablation procedure were older but had similar clinical outcomes and complications when compared with men.

Multi-sensor esophageal temperature probe used during radiofrequency ablation for atrial fibrillation is associated with increased intraluminal temperature detection and increased risk of esophageal injury compared to single-sensor probe.

BACKGROUND: Radiofrequency (RF) ablation in the posterior left atrium has risk of thermal injury to the adjacent esophagus. Increased intraluminal esophageal temperature has been correlated with risk of esophageal injury. The objective of this study was to compare esophageal temperature monitoring (ETM) using a multi-sensor temperature probe with 12 sensors to a single-sensor probe during catheter ablation for atrial fibrillation (AF). METHODS AND RESULTS: We compared the detection of intraluminal esophageal temperature rises in 543 patients undergoing RF ablation for AF with ETM. Esophageal endoscopy (EGD) was performed on all patients with maximum esophageal temperature ≥ 39°C. Esophageal lesions were classified by severity as mild or severe ulcerations. Four hundred fifty-five patients underwent RF ablation with single-sensor ETM and 88 patients with multi-sensor ETM. Thirty-nine percent of patients with single-sensor versus 75% with multi-sensor ETM reached a maximum detected esophageal temperature ≥ 39°C (P < 0.0001). Esophageal injury was detected by EGD in 29% of patients with maximum temperature ≥ 39°C by single-sensor versus 46% of patients with multi-sensor ETM (P = 0.021). Thirty-nine percent of patients with lesions in the single-sensor probe group had severe ulcerations compared to 33% of patients in the multi-sensor probe group (P = 0.641). CONCLUSIONS: Intraluminal esophageal temperature ≥ 39°C is detected more frequently by the multi-sensor temperature probe versus the single-sensor probe, with more frequent esophageal injury and with comparable severity of injury. Despite detecting esophageal temperature rises in more patients, the multi-sensor probe may not have any measurable benefit compared to a single-sensor probe.

Multidisciplinary care of patients receiving cardiac resynchronization therapy is associated with improved clinical outcomes.

AIMS: Although cardiac resynchronization therapy (CRT) reduces morbidity and mortality in patients with heart failure, a significant minority of patients do not respond adequately to this therapy. The objective of this study was to examine the impact of a 'multidisciplinary care' (MC) approach on the clinical outcome in CRT patients. METHODS AND RESULTS: The clinical outcome in patients prospectively receiving MC (n = 254) was compared with a control group of patients who received conventional care (CC, n = 173). The MC group was followed prospectively in an integrated clinic setting by a team of subspecialists from the heart failure, electrophysiology, and echocardiography service at 1-, 3-, and 6-months post-implant. All patients had echocardiographic-guided optimization at their 1-month visit. The proportional hazards model (adjusting for all covariates) and Kaplan-Meier time to first event curves were compared between the two groups, over a 2-year follow-up. The long-term outcome was measured as a combined endpoint of heart failure hospitalization, cardiac transplantation, or all-cause mortality. The clinical characteristics between the MC and CC groups at baseline were comparable (age, 68 ± 13 vs. 69 ± 12; NYHA III, 90 vs. 82%; ischaemic cardiomyopathy 55 vs. 64%, P = NS, respectively). The event-free survival was significantly higher in the multidisciplinary vs. the CC group (P = 0.0015). A significant reduction in clinical events was noted in the MC group vs. the CC group (hazard ratio: 0.62, 95% CI: 0.46-0.83, P = 0.001). CONCLUSION: Integrated MC may improve 2-year event-free survival in patients receiving cardiac resynchronization therapy. Prospective randomized studies are needed to validate our findings.

The Modified Ablation Guided by Ibutilide Use in Chronic Atrial Fibrillation (MAGIC-AF) Study: clinical background and study design.

BACKGROUND: Beyond pulmonary vein isolation (PVI), adjuvant ablation at the sites of complex fractionated atrial electrograms (CFAE) has been shown to improve the long-term success of catheter ablation of persistent atrial fibrillation (AF). However, this approach often requires extensive ablation due to the widespread distribution of CFAE within the left atrium. An optimal strategy would identify areas of CFAE which, when selectively targeted with ablation, result in AF termination with an acceptable long-term freedom from AF. It is possible that the intraprocedural administration of an antiarrhythmic drug may help accomplish this. OBJECTIVE: The Modified Ablation Guided by Ibutilide Use in Chronic AF (MAGIC-AF) Study is an international multicenter prospective randomized double-blinded clinical trial assessing the utility of the intraprocedural administration of 0.25 mg of intravenous ibutilide before performing CFAE ablation. The primary efficacy endpoint of this study will be the freedom from AF at 1 year after a single procedure off antiarrhythmic agents. Safety endpoints will include procedural and radiofrequency ablation time as well as overall procedural complication rate. METHODS: Patients undergoing a first ever catheter ablation procedure for persistent AF will be included. Individuals with hypertrophic cardiomyopathy, complex congenital heart disease including atrial septal defects, and ejection fraction <35% will be excluded from the study. All patients will first undergo PVI. Those patients who remain in AF will then be randomized in a 1:1 fashion to receive either 0.25 mg intravenous ibutilide or saline placebo followed by a CFAE based ablation strategy. Two hundred randomized patients will be enrolled in this study-100 in each study arm. CONCLUSION: The MAGIC-AF study will assess the utility of a combined pharmaco-ablative strategy in patients with persistent AF undergoing a CFAE based ablation strategy.

Beyond the stethoscope: managing ambulatory heart failure during the COVID-19 pandemic.

There have been nearly 70 million cases of COVID-19 worldwide, with over 1.5 million deaths at the time of this publication. This global pandemic has mandated dramatic changes in healthcare delivery with a particular focus on social distancing in order to reduce viral transmission. Heart failure patients are among the highest utilizers of health care and are at increased risk for COVID-related vulnerabilities. Effectively managing this complex and resource-intensive patient population from a distance presents new and unique challenges. Here, we review relevant data on telemedicine and remote monitoring strategies for heart failure patients and provide a framework to help providers treat this population during the COVID-19 pandemic. This includes (i) dedicated pre-visit contact and planning (i.e. confirm clinical appropriateness, presence of compatible technology, and patient comfort); (ii) utilization of virtual clinic visits (use of telehealth platforms, a video-assisted exam, self-reported vital signs, and weights); and (iii) use of existing remote heart failure monitoring sensors when applicable (CardioMEMS, Optivol, and HeartLogic). While telemedicine and remote monitoring strategies are not new, these technologies are emerging as an important tool for the effective management of heart failure patients during the COVID-19 pandemic. In general, these strategies appear to be safe; however, additional data will be needed to determine their effectiveness with respect to both process and outcomes measures.

Initial experience with a multielectrode catheter equipped with the single-axis sensor technology for high-density electroanatomical mapping in a swine model.

INTRODUCTION: magnetic-based electroanatomical mapping systems are widely used during catheter ablation. Currently, the size of the sensor incorporated in the catheter to allow its localization is large, prohibiting the placement of more than one sensor on any single catheter. As a result, multielectrode catheters cannot be tracked by the magnetic-based mapping systems. Single-axis sensors (SAS) are new generation sensors that are significantly smaller in size. The small size of these new sensors allows the placement of more than one sensor on each catheter, allowing the tracking of multielectrode catheters. The objective of this study is to test the feasibility of creating high-density magnetic electroanatomical maps using a new generation multielectrode catheter equipped with the SAS technology. METHODS AND RESULTS: anatomical reconstruction of cardiac chambers and the aorta, together with activation mapping of the right atrium during both sinus rhythm and pacing-induced premature atrial contractions (PACs), were performed in 5 swine using both a conventional mapping catheter and the novel multielectrode catheter equipped with SAS. The multielectrode mapping provided a detailed definition of cardiac anatomy while requiring shorter acquisition times. In addition, mapping of PACs origin was significantly faster using the multielectrode catheter. CONCLUSION: the novel multielectrode catheter equipped with the SAS technology can be used in combination with magnetic electroanatomical mapping systems to generate high-density anatomical reconstructions and activation maps.

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.

Accuracy of cardiac ablation catheter guidance by means of a single equivalent moving dipole inverse algorithm to identify sites of origin of cardiac electrical activation.

We have developed a system that could potentially be used to identify the site of origin of ventricular tachycardia (VT) and to guide a catheter to that site to deliver radio-frequency ablation therapy. This system employs the Inverse Solution Guidance Algorithm based upon Single Equivalent Moving Dipole (SEMD) localization method. The system was evaluated in in vivo swine experiments. Arrays consisting of 9 or 16 bipolar epicardial electrodes and an additional mid-myocardial pacing lead were sutured to each ventricle. Focal tachycardia was simulated by applying pacing pulses to each epicardial electrode at multiple pacing rates during breath hold at the end-expiration phase. Surface potentials were recorded from 64 surface electrodes and then analyzed using the SEMD method to localize the position of the pacing electrodes. We found a close correlation between the locations of the pacing electrodes as measured in computational and real spaces. The reproducibility error of the SEMD estimation of electrode location was 0.21 ± 0.07 cm. The vectors between every pair of bipolar electrodes were computed in computational and real spaces. At 120 bpm, the lengths of the vectors in the computational and real space had a 95% correlation. Computational space vectors were used in catheter guidance simulations which showed that this method could reduce the distance between the real space locations of the emulated catheter tip and the emulated arrhythmia origin site by approximately 72% with each movement. We have demonstrated the feasibility of using our system to guide a catheter to the site of the emulated VT origin.

The relationship between electrogram cycle length and dominant frequency in patients with persistent atrial fibrillation.

INTRODUCTION: Sites of complex fractionated atrial electrograms (CFAE) with a short mean cycle length (MCL) and sites with a high dominant frequency (DF) have been advocated as targets for ablation in patients with persistent atrial fibrillation (AF). However, there are little data on the relationship between theses 2 markers. This study assessed the relationship between the DF and electrogram MCL after pulmonary vein (PV) isolation in patients with persistent AF. METHODS AND RESULTS: A total of 44 patients with persistent AF were studied. Four-second bipolar electrograms were obtained with a multielectrode mapping catheter at regions throughout the left atrium after isolation of the pulmonary veins, with analysis of the MCL and DF at each site. The DF was defined as the largest frequency peak within a 2.5- to 16-Hz spectral profile generated with fast Fourier transformation of the electrogram. A total of 9,262 electrograms from the 44 patients were analyzed. The average MCL and DF post-PV isolation were 135 +/- 24 ms and 6.1 +/- 0.6 Hz, respectively. There was a statistically significant but weak correlation between the MCL and DF (r = 0.21, P < 0.001). Additionally, analysis of this relationship within each patient did not demonstrate a strong correlation (range of r values per patient =-0.18 to 0.47). CONCLUSIONS: There is a poor correlation between the electrogram MCL and DF in patients with persistent AF. Ablation strategies targeting DF and those targeting CFAE are therefore unlikely to direct ablation toward similar left atrial sites. Comparative studies are necessary to determine the effectiveness of each strategy in guiding catheter ablation of persistent AF.

How to identify and treat patient with pulmonary vein stenosis post atrial fibrillation ablation.

PURPOSE OF REVIEW: The diagnosis of pulmonary vein stenosis, following catheter ablation of atrial fibrillation, potentially carries significant morbidity for affected patients. It is important that physicians remain aware of the entity and have an understanding of how to treat such patients. There has been controversy in how to assess patients following atrial fibrillation ablation, and how to treat asymptomatic patients with pulmonary vein stenosis. This article reviews the recently published data. RECENT FINDINGS: The reported incidence of pulmonary vein stenosis is decreasing. Nonetheless, it may not be found if not sought, as even patients with severe pulmonary vein stenosis may be asymptomatic. Also, patients with symptoms may be misdiagnosed if pulmonary vein stenosis is not included in the differential diagnosis. Computed tomography (CT) and MRI have been shown to be the diagnostic modalities of choice. The treatment options for severe pulmonary vein stenosis and occlusion are primarily that of pulmonary vein angioplasty with or without stenting. Despite the observed rate of restenosis, patients derive benefit from pulmonary vein angioplasty. SUMMARY: The best imaging modalities to assess for pulmonary vein stenosis are CT and MRI. Early intervention in symptomatic patients with severe pulmonary vein stenosis is warranted; in asymptomatic patients, the data suggest that such patients will also derive benefit.

Esophageal luminal temperature measurement underestimates esophageal tissue temperature during radiofrequency ablation within the canine left atrium: comparison between 8 mm tip and open irrigation catheters.

INTRODUCTION: Evaluation of luminal temperature during left atrial ablation is used clinically; however, luminal temperature does not necessarily reflect temperature within the esophageal wall and poses a risk of atrioesophageal fistula. This animal study evaluates luminal esophageal temperature and its relation to the temperature of the external esophageal tissue during left atrial lesions using the 8 mm solid tip and the open irrigated tip catheters (OIC). METHODS AND RESULTS: A thermocouple was secured to the external surface of the esophagus at the level of the left atrium of the dogs. Luminal esophageal temperature was measured using a standard temperature probe. In four randomized dogs, lesions were placed using an 8 mm solid tip ablation catheter. In six randomized dogs, lesions were placed using the 3.5 mm OIC. The average peak esophageal tissue temperature when using the OIC was significantly higher than that of the 8 mm tip catheter (88.6 degrees C +/- 15.0 degrees C vs. 62.3 degrees C +/- 12.5 degrees C, P < 0.05). Both OIC and 8 mm tip catheter had significantly higher peak tissue temperatures than luminal temperatures (OIC: 88.6 degrees C +/- 15.0 degrees C vs 39.7 degrees C +/- 0.82 degrees C, P < 0.05) (8 mm: 62.3 degrees C +/- 12.5 degrees C vs 39.0 +/- 0.5 degrees C, P < 0.05). Both catheters achieved peak temperatures faster in the tissue as compared to the lumen of the esophagus, although the tissue temperature peaked significantly faster for the OIC (OIC: 25 seconds vs 90 seconds, P < 0.05) (8 mm: 63 seconds vs 105 seconds, P < 0.05). CONCLUSION: Despite the significant difference in actual tissue temperatures, no significant difference was observed in luminal temperatures between the OIC and 8 mm tip catheter.

Pseudo atrial flutter.

Atrial flutter typically has a cycle length of 200 ms (300 cycles/min or 5 Hz); with 4:1 conduction through the AV node, this would lead to a ventricular rate of 75 bpm. We present a case of a patient with a Parkinsonian tremor at a frequency of 300 cycles/min that masqueraded as atrial flutter on the limb leads of a 12-lead ECG. He had presented with a respiratory tract infection and his bedside rhythm monitor appeared to show atrial flutter. This appeared consistent on a printed (lead II) rhythm strip. His intrinsic sinus rate was coincidentally 75 bpm, which added to the confusion in the initial assessment of his rhythm (mistaken to be atrial flutter with 4:1 AV conduction). Advice was sought regarding management of his atrial 'arrhythmia' and the appropriateness of anticoagulation and cardioversion. A 12-lead ECG was performed and assessment of this revealed normal sinus rhythm. He therefore avoided unnecessary therapy.