Challenging wide QRS tachycardia diagnosis: One trigger two mechanisms.

The coexistence of different types of wide QRS complex tachycardias induced by the same trigger has rarely been observed. The electrical instability and incessant nature of tachycardias can cause tachycardiomyopathy and will not allow accurate diagnosis during an electrophysiological study (EPS). In case of an electrical storm, elimination of the trigger may be the first approach to provide patient stability. We report a successfully managed case of repetitive initiation of pleomorphic ventricular tachycardia and Mahaim-type antidromic atrioventricular reentrant tachycardia, induced by a premature ventricular complex in the right ventricular outflow tract.

Combining conventional technique with fluoroscopy integration module in accessory pathway ablation.

INTRODUCTION: Accessory pathway (AP) ablation is a straightforward approach with high success rates, but the fluoroscopy time (FT) is significantly longer in conventional technique. Electroanatomical mapping systems (EMS), reduce the FT, but anatomical and activation mapping may prolong the procedure time (PT). The fluoroscopy integration module (FIM) uses prerecorded fluoroscopy images and allows ablation similar to conventional technique without creating an anatomical map. In this study, we investigated the effects of combining the FIM with traditional technique on PT, success, and radiation exposure. METHODS: A total of 131 patients who had undergone AP ablation were included in our study. In 37 patients, right and left anterior oblique (RAO-LAO) images were acquired after catheter placement and integrated with the FIM. The ablation procedure was then similar to the conventional technique, but without the use of fluoroscopy. For the purpose of acceleration, anatomical and activation maps have not been created. Contact-force catheters were not used. 94 patients underwent conventional ablation using fluoroscopy only. RESULTS: FIM into AP ablation procedures led to a significant reduction in radiation exposure, lowering FT from 7.4 to 2.8 min (p < .001) and dose-area product from 12.47 to 5.8 µGym² (p < .001). While the FIM group experienced a reasonable longer PT (69 vs. 50 min p < .001). FIM reduces FT regardless of operator experience and location of APs CONCLUSION: Combining FIM integration with conventional AP ablation offers reduced radiation exposure without compromising success rates and complication.

Procedural and short-term results of electroanatomic-mapping-guided ganglionated plexus ablation by first-time operators: A multicenter study.

INTRODUCTION: Single-center observational studies have shown promising results with fragmented electrogram (FE)-guided ganglionated plexus (GP) ablation in patients with vagally mediated bradyarrhythmia (VMB). We aimed to compare the acute procedural characteristics during FE-guided GP ablation in patients with VMB performed by first-time operators and those of a single high-volume operator. METHODS AND RESULTS: This international multicenter cohort study included data collected over 2 years from 16 cardiac hospitals. The primary operators were classified according to their prior GP ablation experience: a single high-volume operator who had performed > 50 GP ablation procedures (Group 1), and operators performing their first GP ablation cases (Group 2). Acute procedural characteristics and syncope recurrence were compared between groups. Forty-seven consecutive patients with VMB who underwent FE-guided GP ablation were enrolled, n = 31 in Group 1 and n = 16 in Group 2. The mean number of ablation points in each GP was comparable between groups. The ratio of positive vagal response during ablation on the left superior GP was higher in Group 1 (90.3% vs. 62.5%, p = .022). Ablation of the right superior GP increased heart rate acutely without any vagal response in 45 (95.7%) cases. The procedure time was longer in group 2 (83.4 ± 21 vs. 118.0 ± 21 min, respectively, p < .001). Over a mean follow-up duration of 8.0 ± 3 months (range 2-24 months), none of the patients suffered from syncope. CONCLUSION: This multi-center pilot study shows for the first time the feasibility of FE-guided GP ablation across a large group of procedure-naïve operators.

Comparison of electrophysiological characteristics of right- and left-sided Mahaim-type accessory pathways.

AIMS: Mahaim-type accessory pathways (MAPs) are generally right-sided due to the embryological differentiation, but left-sided localization is also possible. This study aims to compare the clinical and electrophysiological characteristics of right- and left-sided MAPs. METHODS: Of 251 patients diagnosed with AP by electrophysiological study between November 2015 and February 2020, 12 patients with MAP were included (right sided n = 8, left sided n = 4). MAP was diagnosed if; (1) no retrograde conduction; (2) anterograde decremental conduction; (3) adenosine sensitivity; and (4) Mahaim potential at successful ablation site were present. RESULTS: Ten of twelve MAPs were clustered on the lateral walls of the mitral (n = 3, 75%) and tricuspid annuli (n = 7, 87.5%). Right-sided MAPs were mostly long pathways extending toward the conduction system whereas left-sided MAPs were short extending toward the neighboring myocardium. For right- and left-sided APs, the median QRS times were 129 and 156 ms (p = .042), the median VAbl -RVApex intervals were -12 and 64 ms (p = .007), the median QRS-V(His) intervals were 16 and 86 ms (p = .120), and the median VAbl -QRS interval was -8 and 12 ms (p = .017), respectively. Coexistence of dual atrioventricular node physiology was observed only in right-sided APs (n = 3, 37.5%). CONCLUSION: MAPs are more typically located on the right but may rarely be seen on the left. Catheter ablation was associated with high success without complications.

Inappropriate tachycardia at rest as a consequence of atrial preference pacing algorithm.

A 34-year-old female with a past medical history of sick sinus syndrome which requiring placement of single chamber (atrial) permanent pacemaker (Medtronic, Minneapolis, MN, USA). One year after pacemaker implantation, the patient reported exercise intolerance and palpitation at rest. Device interrogation during clinic visit revealed 99% atrial pacing and high atrial rate episodes. What is the mechanism for high atrial rate episodes? Atrial preference pacing (algorithm is a promising method for preventing atrial tachyarrhythmia in patients with an implanted pacemaker. However, instead of using nominal search interval settings, which may not benefit patients, we should individually tailor the programming, identifying the most effective search interval and be aware of possible pro-arrhythmic effects.

Nonsustained ventricular tachycardia in heart failure with preserved ejection fraction.

BACKGROUND: Ventricular tachycardia (VT) is a common arrhythmia in heart failure with reduced ejection fraction but its incidence, predictors, and significance have not been determined in heart failure with preserved ejection fraction (HFpEF). METHODS: We performed a retrospective review of arrhythmias in two cohorts of patients with an HFpEF diagnosis. Patients in cohort 1 (n = 40) underwent routine arrhythmia surveillance with a 14-day ambulatory electrocardiogram (ECG) monitor. Patients in cohort 2 (n = 85) had cardiac pacemakers and underwent routine device interrogations. RESULTS: In cohort 1, 13 patients (32.5%) had one or more episodes of nonsustained VT (NSVT) on ambulatory ECG. In cohort 2, 38 patients (44.7%) had NSVT on cardiac pacemaker interrogations. During a median (interquartile range) follow-up of 3.0 (1.6 to 5.1) years, 15 (12%) patients died (20% of patients with NSVT versus 6.8% of those without NSVT; P = .03). In logistic regression analysis, NSVT was associated with a 3.4-fold higher odds of death (95% confidence interval 1.08 to 10.53; P = .04) in HFpEF. CONCLUSIONS: In conclusion, patients with HFpEF have a relatively high, and possibly underappreciated, burden of NSVT, which confers a higher risk of mortality. The frequent episodes of NSVT in these patients may provide insight into the mechanism of sudden cardiac death in HFpEF.

QTc dispersion as a novel marker in identifying patients requiring an epicardial approach for ablation of scar mediated ventricular tachycardia.

INTRODUCTION: Epicardial exit sites of ventricular tachycardia (VT) are frequently encountered during VT ablation requiring an epicardial ablation approach for successful elimination of VT. We sought to assess the utility of repolarization markers in identifying individuals requiring an epicardial ablation approach in addition to an endocardial approach. METHODS: 32 patients who underwent successful ablation for scar mediated VT were included in the study. Fourteen patients who required a combined endocardial and epicardial VT ablation were defined as epicardial VT group (Epi) whereas 18 patients who were successfully ablated from the endocardium alone constituted the endocardial VT group (Endo). Repolarization markers during sinus rhythm were compared between the two groups. RESULTS: A higher QTc max and QTc dispersion were seen in the Epi group compared to Endo group (479 ± 34 vs 449 ± 20, p = 0.008 and 63 ± 13 vs 38 ± 8, p = 0.001, respectively). Ts-p and Ts-p/Tp-e were higher in the Epi group (166 ± 23 vs 143 ± 23, p = 0.008 and 1.55 ± 0.26 vs 1.3 ± 0.21, p < 0.005). On multivariate regression, QTc dispersion was an independent predictor of the need for an epicardial approach to ablation. A QTc dispersion more than 51.5 msec identified individuals requiring a combined epicardial and endocardial approach to ablation with a sensitivity of 92.9% and a specificity of 100%. CONCLUSIONS: Patients requiring an epicardial ablation have a higher QTc dispersion. A value greater than 51.5 msec reliably differentiates between the two groups with high sensitivity and specificity.

A single-centre cohort and short-term follow-up of patients who developed persistent new onset left bundle branch block after transcatheter aortic valve replacement.

Background: The most common conduction abnormality after transcatheter aortic valve replacement (TAVR) is new-onset left bundle branch block (LBBB) with an exact frequency that varies based on the valve system used for TAVR. PPM implantation in patients with persistent new onset LBBB post TAVR is controversial. The primary objective of this study is to report PPM utilisation and mortality in this patient population.Methods: A TAVR registry included patients older than 18 years who underwent TAVR between March 2012 and June 2015 at University of Minnesota Medical Centre. After exclusion, 151 patients were divided into two groups; patients with persistent new onset LBBB after TAVR (new LBBB, n = 47) and patients without persistent new onset LBBB (no new LBBB, n = 104).Results: Among the 151 patients, 47 (31.1%) patients developed new-onset LBBB after the procedure and persisted at discharge. Left ventricular ejection fraction (LVEF) (52.5 ± 11.1 vs. 56.4 ± 10.8, p: .047) and mean aortic valve gradient (40.6 ± 11.5 vs. 45.7 ± 14.1, p: .022) were significantly higher in no new LBBB group. Among those with new LBBB, there was a significantly higher rate of PPM implant during index hospitalisation (14.9%, vs. 0%, p < .001). LVEF remained significantly lower at 1 year follow up in new LBBB group compared to no new LBBB group (51.8 ± 11.2 vs. 57.6 ± 8.3, p: .002). Also in new LBBB group, there was a non-significantly higher rate of all-cause mortality in 1 year compared to no new LBBB group (14.9% vs. 9.6% p: .34). There were no significant differences between patients with and without new LBBB with respect to PPM implant after discharge in 1 year (2.13% vs. 3.8% p: .58), length of stay (7.3 ± 7.3 vs. 5.9 ± 2.7 p: .09), post-op atrial fibrillation (AF) (16.3% vs. 8.5% p: .20).Conclusions: New onset LBBB was frequent conduction problem post TAVR and one-third of patients with new onset LBBB persisted at discharge. New LBBB after TAVR was associated with a higher risk of PPM implantation during the index hospitalisation but not after discharge. Our findings suggest that early PPM implantation for post-TAVR LBBB is not indicated without complete or high degree AV block. Further research is required to identify the patients with new LBBB who would progress to advanced AV block or heart failure.

Impact of defibrillation threshold testing on burden of heart failure hospitalizations.

Background: Defibrillation threshold testing (DT) following implantable cardioverter defibrillator (ICD) implantation has not shown to improve mortality. However, the impact of DT on burden of heart failure (HF) hospitalisations has not been well defined.Methods: We studied retrospectively consecutive patients who underwent ICD implantation or generator change between 2008 and 2014. Primary outcome was burden of HF hospitalisations within 30 days following implantation. Secondary outcomes were mortality, stroke, and ICD shock within 30 days and one-year mortality.Results: Three hundred and eleven of 501 patients (62%) were in DT+ group versus 190 (38%) were in DT- group. The percentage of new implantations was higher in DT+ group than in DT- group (69% vs 39%, p < .001) but the distributions of NYHA function classes were similar between two groups. The burden of HF hospitalisations at 30-days was significantly higher in DT+ group than in DT- group (17.4% vs 4.7%, HR 0.842, 95% CI 0.774-0.915, p < .0001). No difference in mortality, stroke or ICD shocks was found between two groups at 30 days and mortality at 1 year.Conclusions: DT after new ICD or generator replacement was associated with increased HF hospitalisation rates at 30 days after ICD implant in a non-trial HF population. However, there was no association between DT and mortality, stroke and ICD shocks at 30 days or mortality at 1 year. The increased burden of HF hospitalisation in this observational study requires validation by randomised studies.

Co-occurrence of late potential and discrete prepotential on ablation site in a case of cardiac crux located premature ventricular complexes successfully ablated within the middle cardiac vein.

Some premature ventricular complexes (PVCs) originate from the coronary venous system. The great cardiac vein and the anterior cardiac vein are the most frequent localizations. The middle cardiac vein is an unusual anatomy for a point of origin for PVC. We present here a case of frequent PVCs with characteristic electrocardiographic features, which we successfully ablated inside the middle cardiac vein.

Multiple Non-Essential Transition Metals Are Accumulated in Carotid Atherosclerotic Plaques: Missing Link in Atherosclerosis?

Population studies revealed that metal exposure through food, environment, and smoking was related with increased risk of cardiovascular disease. In this study, we determined complex chemical elements in surgical carotid endarterectomy specimens and carotid tissues from autopsies without atherosclerosis. Atherosclerotic plaques from 41 endarterectomies and normal carotid tissue from 30 autopsies were collected and elemental composition was determined by inductively coupled plasma optical emission spectrometry (ICP-OES) method. Eleven (26.8%) patients never smoked in carotid endarterectomy group. One patient was brass souvenir worker and one was goldsmith and others did not have direct contact with metals in the carotid endarterectomy group. Na, Cu, Mn, Bi, Co, Mo, Ni, Pb, Sb, Se, Sn, Ti, and W levels were not different between two groups. Bi, Co, Mo, Pb, Ti, and W were below the detection limit of ICP-OES in both groups. Concentrations of Mg, K, Ca, P, Fe, B, Zn, Al, As, Cr, Pt, and Hg were significantly higher in carotid endarterectomies than normal carotid tissue samples. Cd and S values were significantly higher in autopsy samples. There is significant multiple non-essential transition metal accumulation in atherosclerotic carotid endarterectomy plaques. The cardiovascular consequences of metal toxicity have not been researched adequately due to large emphasis on the role of cholesterol in atherosclerosis. High level of non-essential transition metal elements in the carotid atherosclerotic plaques may add the missing link of atherogenesis and may necessitate new treatment and prevention strategies in carotid disease if confirmed by further research.

Vagus nerve stimulation: An evolving adjunctive treatment for cardiac disease.

The vagus nerve is a major component of the autonomic nervous system and plays a critical role in many body functions including for example, speech, swallowing, heart rate and respiratory control, gastric secretion, and intestinal motility. Vagus nerve stimulation (VNS) refers to any technique that stimulates the vagus nerve, with electrical stimulation being the most important. Implantable devices for VNS are approved therapy for refractory epilepsy and for treatment-resistant depression. In the case of heart disease applications, implantable VNS has been shown to be beneficial for treating heart failure in both preclinical and clinical studies. Adverse effects of implantable VNS therapy systems are generally associated with the implantation procedure or continuous on-off stimulation. The most serious implantation-associated adverse effect is infection. The effectiveness of non-invasive transcutaneous VNS for epilepsy, depression, primary headaches, heart failure, and other conditions remains under investigation. VNS merits further study for its potentially favorable effects on cardiovascular disease, especially heart failure.

Premature ventricular contractions: Reassure or refer?

When patients present with palpitations, the primary care physician can perform the initial evaluation and treatment for premature ventricular contractions (PVCs). Many patients need only reassurance and do not need to see a cardiologist.

Blunted Chronotropic Response to Hypotension in Cough Syncope.

OBJECTIVES: This study compared hemodynamic and chronotropic responses to cough in cough syncope (CS) patients to those in control subjects. BACKGROUND: Cough syncope is an uncommon form of situational fainting variously attributed to both reflex and mechanical causes. We hypothesized that if baroreflex responses contribute to CS, post-cough hypotension should be associated with cardioinhibition comparable to that observed in other reflex faints. METHODS: The study population consisted of 8 CS patients (group 1), 21 patients with vasovagal syncope (group 2), and 6 patients with nonvertiginous "lightheadedness" (group 3). Testing with patients seated included volitional coughing that achieved a transient blood pressure (BP) of ≥200 mm Hg. Beat-to-beat blood pressure (systolic blood pressure [SBP]) before cough, minimum cough-induced SBP and heart rate (HR) (beats/min) after cough, and HR change during cough-induced hypotension were recorded, along with SBP recovery time from SBP nadir after cough. RESULTS: Compared to controls, cough-induced SBP drop was greater in CS patients (CS patients: -48 ± 13.1 mm Hg vs. -29 ± 11.2 mm Hg for group 2 controls; p = 0.005; or -25 ± 10 mm Hg in group 3 controls; p = 0.02), and recovery time was longer (CS: 46 ± 19 s vs. 11 ± 3.6 s in group 1 controls; p = 0.002; or 12 ± 5 s in group 3 controls; p = 0.01). Furthermore, despite greater induced hypotension, post-cough chronotropic response was less in CS patients (+15% above baseline rate) than in either group 2 (+31% above baseline rate; p < 0.001) or group 3 (+28%; p = 0.01) controls. CONCLUSIONS: In CS patients, post-cough chronotropic response is blunted compared to that in controls despite greater cough-induced hypotension favoring baroreflex cardioinhibition contribution to the pathophysiology of cough syncope.

Syncope: Assessment of risk and an approach to evaluation in the emergency department and urgent care clinic.

Syncope is among the most frequent forms of transient loss of consciousness (TLOC), and is characterized by a relatively brief and self-limited loss of consciousness that by definition is triggered by transient cerebral hypoperfusion. Most often, syncope is caused by a temporary drop of systemic arterial pressure below that required to maintain cerebral function, but brief enough not to cause permanent structural brain injury. Currently, approximately one-third of syncope/collapse patients seen in the emergency department (ED) or urgent care clinic are admitted to hospital for evaluation. The primary objective of developing syncope/TLOC risk stratification schemes is to provide guidance regarding the immediate prognostic risk of syncope patients presenting to the ED or clinic; thereafter, based on that risk assessment physicians may be better equipped to determine which patients can be safely evaluated as outpatients, and which require hospital care. In general, the need for hospitalization is determined by several key issues: i) the patient's immediate (usually considered 1 week to 1 month) mortality risk and risk for physical injury (e.g., falls risk), ii) the patient's ability to care for him/herself, and iii) whether certain treatments inherently require in-hospital initiation (e.g., pacemaker implantation). However, at present no single risk assessment protocol appears to be satisfactory for universal application, and development of a consensus recommendation is an essential next step.