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Background:Catheter ablation is a safe and effective therapy for the treatment of supraventricular tachycardia in children. Current improvements in technology have allowed progressive reduction in radiation exposure associated with the procedure. To assess the impact of three-dimensional mapping, we compared acute procedural results collected from the Catheter Ablation with Reduction or Elimination of Fluoroscopy registry to published results from the Prospective Assessment after Pediatric Cardiac Ablation study.Methods:Inclusion and exclusion criteria from the Prospective Assessment after Pediatric Cardiac Ablation study were used as guidelines to select patient data from the Catheter Ablation with Reduction or Elimination of Fluoroscopy registry to compare acute procedural outcomes between cohorts. Outcomes assessed include procedural and fluoroscopy exposure times, success rates of procedure, and complications.Results:In 786 ablation procedures, targeting 498 accessory pathways and 288 atrioventricular nodal reentrant tachycardia substrates, average procedural time (156.5 versus 206.7 minutes, p < 0.01), and fluoroscopy time (1.2 versus 38.3 minutes, p < 0.01) were significantly shorter in the study group. Success rates for the various substrates were similar except for manifest accessory pathways which had a significantly higher success rate in the study group (96.4% versus 93.0%, p < 0.01). Major complication rates were significantly lower in the study group (0.3% versus 1.6%, p < 0.01).Conclusions:In a large, multicentre study, three-dimensional systems show favourable improvements in clinical outcomes in children undergoing catheter ablation of supraventricular tachycardia compared to the traditional fluoroscopic approach. Further improvements are anticipated as technology advances.

Background:Patients with CHD can be exposed to high levels of cumulative ionising radiation. Utilisation of electroanatomic mapping during catheter ablation leads to reduced radiation exposure in the general population but has not been well studied in patients with CHD. This study evaluated the radiation sparing benefit of using three-dimensional mapping in patients with CHD.Methods:Data were retrospectively collected from the Catheter Ablation with Reduction or Elimination of Fluoroscopy multi-institutional registry. Patients with CHD were selected. Those with previous ablations, concurrent diagnostic or interventional catheterisation and unknown arrhythmogenic foci were excluded. The control cohort was matched for operating physician, arrhythmia mechanism, arrhythmia location, weight and age. The procedure time, rate of fluoroscopy use, fluoroscopy time, procedural success, complications, and distribution of procedures per year were compared between the two groups.Results:Fifty-six patients with congenital heart disease and 56 matched patients without CHD were included. The mean total procedure time was significantly higher in patients with CHD (212.6 versus 169.5 minutes, p = 0.003). Their median total fluoroscopy time was 4.4 minutes (compared to 1.8 minutes), and their rate of fluoroscopy use was 23% (compared to 13%). The acute success and minor complication rates were similar and no major complications occurred.Conclusions:With the use of electroanatomic mapping during catheter ablation, fluoroscopy use can be reduced in patients with CHD. The majority of patients with CHD received zero fluoroscopy.

Catheter ablation procedures involve fluoroscopy and can result in significant radiation exposure to the patient and staff. From the early 1980s to 2006, there was a 600% increase in the average medical radiation dose per person per year in the USA. Toward the end of this time frame, three-dimensional (3D) mapping systems, which use magnetic or electrical fields to track catheter location and movement, became clinically available. This has allowed reduction in fluoroscopy use. The goal of this manuscript is to review the current state of zero fluoroscopy ablations. In the early 2000s, the first report of a 3D mapping system, used to replace fluoroscopy, emerged. By 2015, centers were routinely performing fluoroless ablations. Today, most centers use these systems to decrease radiation exposure. Multi-center registries now exist to quantify the changes in patient care. Increased radiation exposure is associated with increased long-term risk of cancer. Today’s 3D mapping systems allow most ablation procedures to be performed without the use of fluoroscopy. With further refinements in the available tools, coupled with increasing operator experience, radiation exposure will be eliminated for all routine ablation procedures.

Background Catheter ablations have been traditionally performed with the use of fluoroscopic guidance, which exposes the patient and staff to the inherent risks of radiation. We have developed techniques to eliminate the use of fluoroscopy during cardiac ablations and have been performing completely fluoroless catheter ablations on our patients for over 5 years. Methods We present a retrospective analysis of the safety, efficacy, and feasibility data from 500 consecutive patients who underwent nonfluoroscopic catheter ablation, targeting a total of 639 arrhythmias, including atrioventricular reciprocating tachycardia (AVRT), atrioventricular nodal reentrant tachycardia (AVNRT), atrial tachycardia (AT), atrial fibrillation (AF), premature ventricular contractions (PVCs), and ventricular tachycardia (VT). We perform fluoroless ablations using intracardiac electrograms, electroanatomic mapping, and for most cases intracardiac echocardiography. Our experience includes exclusively endocardial cardiac ablations. Results The mean follow-up was 20.5 months. Recurrence rate for AVRT was 6.5%, for AVNRT 2.5%, for macro-reentrant AT 6.4%, for focal AT 5.4%, for AF 22.6%, for PVC 6.7%, and for VT 21.4%. Major complications occurred in five patients (1.0%); minor complications occurred in three patients (0.6%). No deaths occurred. Fluoroscopy was used in one instance, for 0.3 minutes, to confirm venous access. Conclusions Completely fluoroless catheter ablations may be routinely performed for all endocardial ablations without compromising safety, efficacy, or procedural duration.

Fluoroless catheter ablation of all endocardial cardiac arrhythmias is feasible using current, and often standard, electrophysiology laboratory equipment. This article lays out a road map for performing fluoroless ablations, safely and efficaciously. We outline optimizing intracardiac echocardiography, performing complex ablations with radiofrequency and cryoballoon technology.

Purpose Cryothermal ablation (CTA) for atrioventricular nodal reentrant tachycardia (AVNRT) is considered safer than radiofrequency ablation (RFA) since it eliminates the risk of inadvertent AV block. However, it has not been widely adopted due to high late recurrence rate (LRR). In an effort to improve LRR, we evaluated a new approach to cryothermal mapping (CTM): “time to tachycardia termination” (TTT). Methods This single-center study had 88 consecutive patients who underwent CTA using TTT for AVNRT. The CTA catheter was positioned in sinus rhythm at the posteroseptal tricuspid annulus, and then AVNRT was induced. The CTA target site was identified by prompt tachycardia termination in ≤20 s during CTM. Procedural success was defined as no inducible AVNRT and ≤1 single AV nodal echoes. Results Acute procedural success was achieved in 87 of 88 patients (98.9 %) and was similar to prior studies for both CTA and RFA. No permanent AV block was observed. LRR was 3.7 % at a mean follow-up of 19.7 months. LRR was equivalent to that commonly reported for RFA and improved when compared to conventional CTA. Conclusion TTT for CTA of AVNRT provides enhanced safety and similar long-term efficacy when compared to RFA. Based upon this experience, TTT provides an enhancement to conventional CTA that appears to result in improved long-term outcomes. In light of these findings, it seems reasonable to undertake additional randomized trials to determine whether RFA or CTA using TTT is the optimal approach for the catheter ablation of AVNRT.

Mean arterial pressure (MAP) has traditionally been derived from systolic and diastolic pressures, weighted 1/3 systolic and 2/3 diastolic. No correction is made for the increasing time dominance of systole with increasing heart rates. In a previous study, we developed a new and more accurate heart rate-corrected MAP formula from central aorta pressure determinations in a large number of patients: MAP = DP + [0.33 + (HR x 0.0012)] x [PP] where SP and DP are systolic and diastolic pressure and HR is heart rate. The current study validates the new MAP formula in the same patient at increasing paced heart rates. A central aorta catheter was used to obtain computer-determined systolic, diastolic, and MAP in 12 patients. Values were obtained at baseline and then at increasing right atrial paced heart rates. The new and standard MAP formula-derived values were compared with computer-determined values. The new formula showed a much closer correlation with the computer-derived values for MAP. Standard MAP calculations for MAP can easily be improved by inclusion of a heart rate factor.

To evaluate the prevalence of clinically significant renal artery stenosis (RAS) in patients referred for coronary angiography, we analyzed data on 2,439 consecutive patients. Patients underwent selective renal angiography in conjunction with coronary angiography if refractory hypertension (blood pressure > 140/90 on two drugs) or flash pulmonary edema was present. A total of 1,089 renal arteries of 534 patients were evaluated. Twelve percent (137/1,089) of the renal arteries in 19% (101/534) of patients had > 70% diameter stenosis in at least one vessel. Bilateral renal artery stenosis was present in 26% (26/101) of patients. One hundred and thirty-two of the 137 vessels underwent stent revascularization due to clinical renovascular hypertension. Acute clinical success (< 20% diameter stenosis without death or urgent surgery) was 98% (99/101). Due to high prevalence and effective available treatment, we recommend routine screening for RAS in all patients with refractory hypertension referred for coronary angiography.

Clozapine is an atypical dibenzodiazepine antipsychotic used for resistant schizophrenia. Uncommonly, it is associated with myocarditis. We report a case of myopericarditis masquerading as an acute myocardial infarction based on presenting electrocardiogram and cardiac markers. Emergent coronary angiography confirmed the absence of epicardial coronary occlusion and revealed severe left ventricular systolic dysfunction. Immediate discontinuation of the clozapine, along with aggressive supportive care resulted in complete recovery to baseline. Cardiovascular health professionals should be aware of this uncommon but serious side effect of clozapine since failure to recognize the association may result in adverse clinical outcome and inappropriate therapy.

Atherosclerotic coronary artery disease and bronchospastic airway disease frequently coexist in older patients. There are substantial data suggesting reduced mortality with the use of beta-adrenergic blocking drugs in patients with symptomatic coronary artery disease, especially patients who have postmyocardial infarction and/or severe coronary artery disease associated with left ventricular dysfunction. Conversely, the use of beta-adrenergic blocking drugs (even selective beta(1)-adrenergic blocking drugs) has the potential of exacerbating bronchospasm. This prospective registry evaluates the safety of use of selective beta(1)-adrenergic blocking drugs in patients with symptomatic coronary artery disease and bronchospastic airway disease. A total of 835 consecutive patients with symptomatic coronary artery disease were prospectively evaluated for coexisting coronary and bronchospastic airway disease. Of these, 30 patients (mean age: 61 +/- 14 years) met the qualifying inclusion criteria. All these study patients except 1 (29/30 [96%]) reached therapeutic beta-blockade (resting heart rate

Nonfluoroscopic Catheter Ablation of Cardiac Arrhythmias in Adults Background: Catheter ablations are traditionally performed using fluoroscopic guidance, exposing both patients and medical staff to the risks of radiation. Nonfluoroscopic catheter ablation has been used successfully to treat limited types of arrhythmias in children, but whether this approach has broad application in adults is uncertain. The purpose of this study was to evaluate the feasibility, safety, and efficacy of fluoroless catheter ablation in adults being treated for a range of arrhythmias. Methods and Results: Retrospective analysis was performed in 2 patient groups (both n = 60): (1) the nonfluoroscopy (NF) group consisting of consecutive adult patients, in which catheter positioning was accomplished exclusively with intracardiac electrograms (IE), electroanatomic mapping (EAM), and intracardiac echocardiography (ICE); and (2) the fluoroscopy (F) group, in which catheter positioning was additionally guided by fluoroscopy. The patients in the F group were selected to match the types of arrhythmias in the NF group. All ablation procedures were performed by one operator. The total procedure time did not differ between groups for any specific type of arrhythmia ablated. Acute procedural success was similar in both groups (NF, 59/60 [98%] and F, 60/60 [100%]). The complications were limited to a groin pseudoaneurysm in the NF group, and pericardial effusion and groin hematoma in the F group. Conclusion: Catheter ablations were efficiently and effectively performed in adults with a variety of arrhythmias using only IE, EAM, and ICE for catheter guidance. This nonfluoroscopic technique was feasible, posed no additional safety concerns, and should be readily implementable in most electrophysiology laboratories. (J Cardiovasc Electrophysiol, Vol. 23 pp. 1078-1086, October 2012)

Right coronary artery (RCA) occlusion and acute myocardial infarction are rare during radiofrequency (RF) ablation of the cavotricuspid isthmus. Ventricular fibrillation (VF) or cardiac arrest in the periprocedural period may be the initial or only clinical manifestation. Septal or lateral RF delivery may increase the risk. We report 2 cases of RCA occlusion during ablation of typical atrial flutter (AFL). Angiographic and anatomical correlations are illustrated. One patient was ablated with a septal approach, the other with a lateral approach, and in each instance the RCA occluded near the ablative lesions. If septal or lateral ablation lines are contemplated during ablation of isthmus-dependent atrial flutter, fluoroscopic or electroanatomic confirmation of catheter position is pivotal. Smaller tipped catheters, energy titration (to minimally effective dose), saline irrigation, or cryoablation should also be considered to help avoid this serious complication.

Dofetilide is currently recommended as second-tier therapy to maintain sinus rhythm in patients with paroxysmal atrial fibrillation (PAF) and normal left ventricular function, yet limited data support this recommendation. We examined the safety and efficacy of dofetilide in this setting through a retrospective chart review. We evaluated patients who had symptomatic PAF, normal left ventricular function, and no significant valvular disease. The end points were complete suppression of symptomatic PAF and subjective symptomatic improvement with dofetilide treatment. Over a 3-year period, 34 patients who had failed previous antiarrhythmic therapy were included. Of these, 3 discontinued dofetilide treatment before discharge. Of the remaining 31 who continued treatment after discharge, it was eventually discontinued in 13. At 12 months, symptomatic improvement was observed in 18 of 31 patients, 6 of whom remained asymptomatic. Treatment with dofetilide in this study was successful in less than 1 in 5 patients. Despite careful precautions, serious proarrhythmias, the major limiting side effect of dofetilide, still occurred during long-term follow-up.

Ventricular Tachycardia Induced by Biventricular Pacing. Introduction: Cardiac resynchronization therapy (CRT) is a new alternative which affords symptomatic improvement in two-thirds of patients who exhibit medically refractory congestive heart failure (CHF) as well as significant prolongation of the QRS duration (>135 msec). As more experience with CRT accrues, unexpected complications of this promising therapy may become apparent. Herein, we describe a patient with severe ischemic cardiomyopathy and refractory CHF who developed incessant ventricular tachycardia (VT) after the initiation of biventricular pacing. The patient is a 75-year-old man who suffered an inferior myocardial infarction 6 years before presenting for CRT. He underwent a three-vessel CABG in 1997. Subsequently, episodes of near syncopal sustained VT developed, for which he received a dual chamber ICD. In 2001 he developed refractory CHF and ECG revealed LBBB with a QRS duration of 195 msec. Shortly after the initiation of biventricular pacing, the patient developed multiple episodes of drug resistant monomorphic VT that could be terminated only transiently by ICD therapies. Ultimately, the only intervention, which proved to be effective in eliminating VT episodes, was inactivation of LV pacing. Despite subsequent therapeutic regimen of sotalol, lidocaine, tocainide, and quinidine all subsequent attempts to reactivate LV pacing resulted in prompt VT recurrence. Conclusion: This case represents a clear example of CRT induced proarrhythmia, which required inactivation of LV pacing for effective acute management. Such an intervention should be considered in CRT patients who exhibit a notable increase in drug refractory VT episodes.