Focal atrial fibrillation originating from the coronary sinus musculature.
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Adult↗
Biomedical subjects
Vance J Plumb
Publications and source records attributed to Vance J Plumb.
Adenosine can also improve the conduction between the superior vena cava and right atrium after isolation.
A 64-year-old man with atrial tachycardia (AT) 3 years after a superior vena cava (SVC) isolation for atrial fibrillation underwent electrophysiologic testing. SVC mapping with a basket catheter revealed a more frequent activation in the SVC than in either of the atria during the AT and consequently the recovered conduction between the SVC and right atrium. The conduction improved from 3 or 4-1 conduction to 2-1 conduction after adenosine was administered. Ectopic firing in the SVC persisted even after restoration of sinus rhythm by the successful SVC isolation, which was confirmed by adenosine.
Adenosine↗
Should shocks still be administered during implantable cardioverter-defibrillator insertion?
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Defibrillators, Implantable↗
Ventricular fibrillation and defibrillation--what are the major unresolved issues?
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Cardiopulmonary Resuscitation↗
Decrease in fluoroscopic cardiac silhouette excursion precedes hemodynamic compromise in intraprocedural tamponade.
BACKGROUND: Acute pericardial tamponade is a life-threatening complication of invasive cardiovascular procedures. Survival depends on early recognition and treatment. A diagnostic test to detect pericardial fluid accumulation before a significant fall in blood pressure and without contamination of the sterile field would be valuable. OBJECTIVE: We tested the hypothesis that fluoroscopic excursion of the cardiac silhouette decreases early in the course of acute pericardial tamponade and precedes hemodynamic compromise. METHODS: The pericardial space of seven pigs was accessed by a sub-xiphoid puncture. Tamponade was produced by intrapericardial saline infusion at 20-25 mL/minute until the pericardial pressure equalized with right ventricular end diastolic pressure or the systolic blood pressure reached 40 mmHg. Supine fluoroscopic images were obtained every 2 minutes in the left anterior oblique view with simultaneous echocardiography. The fluoroscopic heart silhouette was digitized, and the maximum excursion during the cardiac cycle was quantified by custom software. The qualitative excursion of the fluoroscopic heart silhouette on randomly selected video images was also graded by two independent observers who were blinded to the time course of the experiment and the hemodynamics. RESULTS: During progressive pericardial fluid accumulation, the cardiac silhouette excursion quantified by the custom software (p < 0.001) and by video rating (p < 0.0001) was significantly reduced within 2 minutes. A statistically significant fall in blood pressure compared with baseline did not occur until 6 minutes (89 +/- 21 vs. 121 +/- 15 mmHg, p < 0.001). The interobserver agreement was very close, with a kappa statistic of 0.78. The reduction in cardiac silhouette excursion was apparent as soon as the effusion was detected by echocardiography. CONCLUSION: Cardiac silhouette excursion becomes reduced early in the course of acute pericardial fluid accumulation. This fluoroscopic observation can be used to detect impending pericardial tamponade before hemodynamic collapse.
Acute Disease↗
Prophylactic implantable cardioverter-defibrillator therapy in patients with left ventricular systolic dysfunction: a pooled analysis of 10 primary prevention trials.
Strategies to decrease sudden cardiac death in patients with left ventricular systolic dysfunction are evolving. Recent clinical trials have evaluated the role of prophylactic implantable cardioverter-defibrillators (ICDs) in patients with and without additional risk stratifiers. We pooled studies comparing treatment with and without ICDs from published data and presented abstracts, irrespective of QRS duration and etiology of systolic dysfunction. On the basis of the available clinical trials, implantation of an ICD for primary prevention of death provides a 7.9% absolute mortality reduction (p = 0.003) in patients with left ventricular (LV) systolic dysfunction who were receiving optimized medical therapy. This finding was not sensitive to the exclusion of any individual trial. The ICD is an effective primary preventative measure in patients who are at risk for death; however, the application of this therapy needs to be individualized for the patient, similar to drug therapies in LV systolic dysfunction. In health care settings without unlimited resources, optimal use of this therapy will require better risk stratification methods or lowering of the initial device cost.
Confounding Factors, Epidemiologic↗
Electrophysiological findings in adolescents with atrial fibrillation who have structurally normal hearts.
BACKGROUND: Atrial fibrillation (AF) is uncommon in children, and its mechanisms are unknown. This study describes the electrophysiological findings in children and adolescents with AF and the outcome of catheter ablation. METHODS AND RESULTS: Nine adolescents with symptomatic, lone AF who failed antiarrhythmic drug therapy were evaluated. All patients had ECG-documented AF and underwent invasive electrophysiological testing. Intracardiac mapping was performed to determine the site of spontaneous onset of AF and rapidly firing atrial foci. Only the triggering focus was targeted for ablation or isolation. The patients' mean age was 15.9+/-3.3 (range, 8 to 19 years). The most common finding was rapid, irregular atrial tachycardias in the region of the pulmonary veins (n=5), left atrium (n=2), or crista terminalis (n=3). One patient had foci in both the pulmonary veins and crista terminalis. The cycle lengths ranged from 108 to 280 ms. Catheter ablation was acutely successful in 8 patients (88.9%), whereas 1 patient with multiple left atrium foci was treated with the surgical maze operation. Over a mean of 35+/-22 months, 7 patients (77.8%) were arrhythmia free on no medications, while AF recurred in 2 patients who are controlled on antiarrhythmic medications. Two patients with tachycardia-induced cardiomyopathy had resolution of their left ventricular dysfunction after ablation. CONCLUSIONS: AF in adolescents with structurally normal hearts is usually due to foci in the pulmonary veins, crista terminalis, or left atrium. These foci usually induce irregular atrial tachycardias. Catheter ablation of the foci is effective in eliminating recurrent AF.
Adolescent↗
Resumption of electrical conduction in previously isolated pulmonary veins: rationale for a different strategy?
BACKGROUND: Atrial fibrillation (AF) may recur after pulmonary vein isolation (PVI) as the result of either recurrent PV conduction or non-PV foci. This study characterized the electrophysiological findings of patients with recurrent AF after initially successful PVI and the clinical outcome after a repeat procedure. METHODS AND RESULTS: Among 185 patients undergoing PVI, 52 reported no significant improvement in their clinical course. We analyzed PV conduction in 51 PVs (15 patients) at repeat PVI. All PVs were isolated with either RF (30 W, 50 degrees C, 60 seconds) or cryoablation (-80 degrees C for 5 minutes). At repeat study, 42 of the previously isolated 51 PVs had return of conduction. All patients had recurrent conduction in > or =2 PVs, with only 1 non-PV focus identified. The mean number of RF applications required to re-isolate the PVs was fewer at the repeat compared with the initial procedure (10+/-6 versus 4+/-2, P<0.005). Over a period of 15+/-6 months, all but 1 patient was clinically improved by the second procedure. CONCLUSIONS: In patients with recurrent AF after PVI, return of PV conduction can be expected. Repeat PVI provides significant clinical benefit for these patients. These results suggest that if permanent PV isolation is the ablation strategy, different techniques may be required to improve long-term efficacy.
Atrial Fibrillation↗
Relative utility of magnetic resonance imaging and right ventricular angiography to diagnose arrhythmogenic right ventricular cardiomyopathy.
INTRODUCTION: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by fibrofatty replacement of the RV myocardium. Two imaging techniques used to assess patients suspected of having ARVC are magnetic resonance imaging (MRI) and right ventricular angiography (RVA). Traditionally, RVA has played a central role in the diagnosis of ARVC, but the non-invasive nature of MRI and its unique ability to detect fatty tissue infiltration has increased its popularity as a diagnostic tool. The objective of this study was to assess the relative diagnostic accuracy of MRI and RVA for ARVC. METHODS AND RESULTS: Seventeen patients (9 men, 8 women; ages 42 +/- 17 [range 16-78] years) with documented ventricular arrhythmias were investigated for ARVC. A positive diagnosis of ARVC was based on criteria set forth by the ISFC Working Group on Cardiomyopathies and Dysplasia. ECG-gated spin-echo and gradient-echo MR images in multiple planes and RAO/LAO RV angiograms were compared for diagnostic concordance. Based on working group criteria, 7 patients were diagnosed with ARVC. In ten patients, MRI suggested ARVC. The remaining 7 patients had no MRI findings suggestive of the disease. Four patients with MRI findings of ARVC were incorrectly diagnosed based on Task Force criteria. Conversely, 1 patient with a normal MRI met Task Force criteria for the diagnosis of ARVC. Based on RV angiograms, 7 patients had findings suggestive of ARVC. The 10 patients without AVRD (based on RVA) also did not meet the necessary criteria for diagnosis of ARVC using Task Force standards. RVA was 100% specific and 100% sensitive compared to MRI that was only 86% sensitive and 60% specific. MRI proved to be most reliable when the images demonstrated gross, lipomatous infiltration, evidenced by a large area of hyperintensity. When the results of MRI and RVA were congruent, the diagnosis was always accurate. CONCLUSION: RVA is more sensitive and specific to diagnose ARVC diagnosis than MRI, at least until MRI protocols are better developed. MRI results are most robust when indicators of ARVC are grossly apparent. False-positive diagnosis by MRI was primarily related to perceived motion abnormalities that were not seen by RVA. One of its greatest potential assets (fat detection) did not enhance diagnostic specificity.
Adolescent↗
Functional assessment of pulmonary vein stenosis using radionuclide ventilation/perfusion imaging.
Pulmonary vein (PV) stenosis following catheter ablation of atrial fibrillation (AF) is a new clinical syndrome. The optimal method of assessing this syndrome is not known. We evaluated radionuclide perfusion imaging, anatomic imaging, and direct measurements of PV-left atrial (LA) pressure gradients in patients suspected of having PV stenosis after catheter ablation for the treatment of AF. The study included 11 consecutive patients who were referred to a tertiary referral center for the evaluation of symptoms suggesting or imaging evidence of PV stenosis following catheter ablation for AF. All patients underwent anatomic imaging of their PVs with direct pulmonary venography or CT scanning as well as radionuclide perfusion imaging. PV stenosis (> 50% diameter) was diagnosed by venography in 6 of the 11 patients and in 16 of 44 PVs. All six patients with PV stenosis had perfusion defects in the affected pulmonary lobe. In contrast, all of the patients without anatomic evidence of PV stenosis had normal perfusion. There were 14 PVs with stenoses of > 80% of the luminal diameter, all of which had a corresponding perfusion abnormality ascertained by perfusion scanning. In all 14 PVs with a resting PV-LA gradient of > 5 mm Hg, there was a corresponding perfusion defect. PV stenosis results in decreased perfusion in the affected lobe when the resting PV-LA pressure gradient is at least 5 mm Hg or when there is 80% luminal stenosis. A perfusion scan may serve as an effective screening tool for PV stenosis and may be most useful in assessing the hemodynamic significance of an anatomic PV stenosis.
Adult↗
Evidence for longitudinal and transverse fiber conduction in human pulmonary veins: relevance for catheter ablation.
BACKGROUND: Segmental ostial ablation of the pulmonary veins (PVs) allows for successful control of paroxysmal atrial fibrillation in many patients. We hypothesized that mapping of the left atrial-PV junction with a 64-electrode basket catheter would allow characterization of conduction patterns that would identify sites where ablation is required to electrically isolate the PV. METHODS AND RESULTS: A 64-electrode basket catheter was used to map the PVs of 50 patients undergoing PV isolation procedures for the treatment of atrial fibrillation. Activation along each spline was classified as reflecting either longitudinal, transverse, or no activation. A longitudinal activation pattern recorded along a spline during sinus rhythm in right-sided PV and during CS pacing in left-sided PV before the delivery of any RF energy application had a sensitivity and specificity for a required ostial ablation site of 83% and 82%, respectively. When longitudinal activation along the spline was present during preablation recordings in both sinus rhythm and CS pacing, the sensitivity and specificity were 92% and 90%, respectively. A longitudinal activation pattern after the first RF application that produced a change in PV activation sequence had a sensitivity and specificity for sites where further ablation was required of 91% and 94%, respectively. CONCLUSIONS: Mapping of PV activation with a 64-electrode basket catheter allows characterization of conduction patterns that predict requirement for ablation. The presence of a longitudinal activation pattern is a strong predictor of ostial sites where ablative energy is required to electrically isolate the PV.
Atrial Fibrillation↗
Improved suppression of recurrent atrial fibrillation with dual-site right atrial pacing and antiarrhythmic drug therapy.
OBJECTIVES: We compared the safety, tolerance and effectiveness of overdrive high right atrial (RA), dual-site RA and support (DDI or VDI) pacing (SP) in patients with symptomatic atrial fibrillation (AF) and bradycardias. BACKGROUND: Optimal pacing methods for AF prevention remain unclear. METHODS: Patients (n = 118) were randomized to each of three pacing modes in a crossover trial. RESULTS: Mode adherence was superior for dual-site RA (5.8 months) compared with SP (3.3 months; p < 0.001) and high RA pacing (4.7 months; p = 0.006). Adverse event-free survival improved with dual-site RA (p = 0.007 vs. SP) and was comparable to high RA (p = 0. 75). AF-free survival trended to improve with dual-site RA (hazard ratio [HR] 0.715, p = 0.07 vs. SP) but not high RA (HR = 0.71, p = 0.19) or when dual-site RA was compared with high RA (HR = 0.835, p = 0.175). Time-to-recurrence was longer in dual-site RA (1.77 months) compared with high RA (0.62 months, p < 0.09) or SP (0.44 months, p < 0.05). In antiarrhythmic drug-treated patients, dual-site RA reduced recurrence risk compared with SP (HR = 0.638, p = 0.011) and high RA (HR = 0.669, p = 0.06). In patients with < or =1 AF event/week, dual-site RA improved AF suppression (HR = 0.464, p = 0.004 vs. SP; HR = 0.623, p = 0.006 vs. high RA). Dual-site RA improved AF-free and mode survival (p < 0.03 vs. high RA, p < 0.001 vs. SP) and reduced asymptomatic AF (p < 0.01 vs. high RA). CONCLUSION: Dual-site RA is safe and better tolerated than high RA and SP. In patients on antiarrhythmics, dual-site RA prolonged and high RA trended to prolong time-to-recurrent AF compared with SP. Dual-site RA provides superior symptomatic and asymptomatic AF prevention compared with high RA in patients with symptomatic AF frequency of < or =1/week.
Aged↗
Endocardial wave front organization during ventricular fibrillation in humans.
OBJECTIVES: This study was designed to characterize the organization of ventricular fibrillation (VF) on the endocardium of humans. BACKGROUND: Most proposed mechanisms for the maintenance of VF postulate the propagation of a number of activation wave fronts that reenter to maintain the arrhythmia. We tested the hypothesis that, in patients undergoing internal cardioverter-defibrillator implantation, VF consists primarily of a few large wave fronts on the endocardium. METHODS: Electrograms were recorded from a 36-electrode catheter in the left ventricle of 16 patients during VF. Activation times were chosen for a 2-s epoch for each fibrillation episode, and a two-dimensional Kolmogorov-Smirnov test was performed to determine if activation occurred randomly along the catheter over that time interval. The maximum cross-correlation was found for all possible pairs of electrodes on the catheter, and these values were plotted relative to the distance between the two electrodes. An exponential curve was then fit to the data, and a length constant was determined. Activation times were grouped into wave fronts along the catheter, and the lengths of the wave fronts were estimated. RESULTS: The Kolmogorov-Smirnov test showed that activation was not random along the catheter in any of the patients studied. The correlation length determined was 9 +/- 2 cm. The number of wave fronts recorded by the catheter was 9.2 +/- 2.9 wave fronts/s. The length of the pathway of each wave front along the catheter was 6.5 +/- 4.5 cm. CONCLUSIONS: Ventricular fibrillation is well organized on the endocardial surface of humans, consisting primarily of a few large wave fronts on the order of 6 to 9 cm.
Adult↗