A new and simple method for distinguishing complete from incomplete block through the cavotricuspid isthmus.

BACKGROUND: A complete line of block (CLOB) in the cavotricuspid isthmus (CTI) is the endpoint of typical atrial flutter ablation. Before CTI block is obtained, a progressive CTI conduction delay due to an incomplete line of block (InLOB) can be difficult to distinguish from CLOB. The purpose of this study was to assess a new simple approach based on the changes in atrio-ventricular (AV) conduction delays during septal and lateral right atrial pacing, to distinguish a CLOB from an InLOB during typical atrial flutter (AFL) ablation. METHODS AND RESULTS: Forty patients who presented an InLOB before a CLOB, and a stable (AV) conduction delay at 600 ms cycle length pacing (when in sinus rhythm), during AFL ablation were included in this study. A 24-pole mapping catheter was positioned so that 2 adjacent dipoles bracketed the targeted CTI line of block (LOB), with proximal dipoles lateral to the LOB and distal dipoles in the coronary sinus. Two pacing sites were lateral (position L1 and L2) and one was septal (position S) to the LOB, with locations L1 and S closest to the LOB. During L1, L2 and S site pacing, the delay between the pacing artefact and the peak of the R wave in a surface ECG (lead II) was measured. We measured the following conduction delays (mean +/- SD in ms), during InLOB versus CLOB: (L1 to R) 320.5 +/- 68.0 versus 367.0 +/- 62.0, p = 0.001; (L2 to R) 333.0 +/- 59.0 versus 338.0 +/- 62.0, p = 0.663, (S to R) 259.4 +/- 51.5 versus 247.1 +/- 55.5, p = 0.987. We calculated the following data during an InLOB versus a CLOB: (L1R-L2R) -12.3 +/- 7 versus 20.2 +/- 12.7, p = 0.001; (L1R-SR) 51.1 +/- 21.5 versus 120.1 +/- 16.6, p < 0.05. The sensitivity, specificity, positive and negative predictive values for CLOB with (L1R-SR > 94 ms) and with (L1R-L2R > 0 ms) were respectively; 100%, 98%, 98% and 100%. CONCLUSIONS: This study establishes that lateral versus septal right atrial pacing sites combined with the measure of AV conduction delay on a surface ECG can be useful to distinguish a CLOB from an InLOB during AFL ablation.

Predictive value of myocardial tomoscintigraphy in asymptomatic diabetic patients after percutaneous coronary intervention.

OBJECTIVE: This study was designed to assess the prognostic value of myocardial tomoscintigraphy perfusion imaging after percutaneous coronary intervention (PCI) in asymptomatic diabetic patients. METHODS: One hundred and fourteen diabetic patients were followed up during 27+/-16 (mean+/-SD) months after the myocardial tomoscintigraphy. PCI-related events were studied after myocardial tomoscintigraphy stress testing and included major cardiac events (MACE) (cardiovascular death, myocardial infarction) and revascularization (bypass surgery or new PCI). Stress myocardial tomoscintigraphy imaging was performed 5+/-5 months after PCI and ischemia was considered as present if at least 2 contiguous segments were showing reversible defects. RESULTS: Persistent silent ischemia was found in 49/114 (43%) patients. No difference was observed between the two groups for MACE: four among the 65 (6%) non ischemic patients versus 2 among the 49 (4%) ischemic patients (NS). In contrast, 15 (31%) among the ischemic patients and 4 (6%) among the non ischemic patients underwent iterative revascularization (p<0.01). The relative risk of revascularization for patients with significant ischemia was 5.5 versus non ischemic patients (p<0.001). CONCLUSION: After PCI, in asymptomatic diabetic patients followed by myocardial tomoscintigraphy a high frequency of persistent silent ischemia was found and associated with a high risk for repeat interventional procedure, although no increase in major cardiac events was observed.

A randomized clinical trial of continuous flow nitrous oxide and nalbuphine infusion for sedation of patients during radiofrequency atrial flutter ablation.

BACKGROUND: In patients with common atrial flutter (CAF), radiofrequency ablation (RFA) causes discomfort. Patients undergoing RFA often feel pain which is difficult to control as the mechanisms are unclear. HYPOTHESIS: Inhaled nitrous oxide (N2O) is a potent sedative-analgesic-anxiolytic agent that may relieve anxiety and discomfort during CAF ablation. METHODS AND RESULTS: In a prospective randomized study, the effect of Inhaled N2O was compared with that of intravenous sedation with Nalbuphine during CAF ablation in 76 patients (64 +/- 13 years, 56 men). We used a 24 pole mapping catheter around the tricuspid annulus and a 8-mm tip ablation catheter for each patient. Forty-two patients (group 1) underwent radiofrequency (RF) application to the cavotricuspid isthmus 5 minutes after the beginning of inhalation of a (50% N2O/50% O2) mixture. Thirty-four patients (group 2), underwent the first RF application 15 minutes after the end of an infusion of Nalbuphine (20 mg delivered over 15 minutes). Ablation-related anxiety and discomfort were assessed using a visual analog scale (VAS) ranging from 0 to 100 mm, with 0 correlating to the statement "no pain at all" and 100 with "the worst possible pain." The VAS score was determined at the end of each application. The number of RF applications (group 1; 10 +/- 8 vs group 2; 11 +/- 6, P = NS) and procedure duration (group 1; 75 +/- 53 minutes vs group 2; 72 +/- 45 minutes, P = NS), were similar for the two groups. N(2)O sedation compared with nalbuphine infusion reduced VAS for anxiety (10 mm +/- 8 vs 58 mm +/- 22, P < 0.05) and for discomfort (18 mm +/- 9 vs 45 mm +/- 34, P < 0.01), respectively. Although there was more frequent vomiting in group 1; 7 of 42 (17%) than in group 2; 3 of 34 (9%), P < 0.05, patients were less likely to have hypotension during the procedure 1 of 42 (2.5%) versus 4 of 34 (12%), P < 0.05, respectively. CONCLUSION: Inhalation of a (50% N2O/50% O2) mixture during RF ablation for atrial flutter is a safe and efficient way to reduce anxiety and discomfort caused by RF applications.

Simple and efficient identification of conduction gaps in post-ablation recurring atrial flutters.

AIMS: Cavo-tricuspid isthmus (CTI) radiofrequency (RF) ablation is a curative therapy for common atrial flutter (AFl), but is associated with a recurrence rate of 5-26%. Although complete bidirectional conduction block is usually achieved, the recurrence of AF is due to recovered conducting isthmus tissue through which activation wavefronts pass. We evaluated a simple and efficient electrophysiological strategy, which pinpoints the ablation target. METHODS AND RESULTS: Twenty-five patients (19 men), mean age 61 +/- 6, with recurrent AFl required a repeat ablation, 250 +/- 160 days after a successful RF CTI procedure. Transverse CTI conduction was monitored during AFl or coronary sinus (CS) pacing by a 24-pole mapping catheter positioned in the right atrium (RA), with the distal poles in the CS, proximal poles on the lateral RA, and intermediate poles on the CTI. A slow conduction area traversing the CTI (velocity, 37 +/- 22 vs. 98 +/- 26 cm/s on either side, P < 0.05) and a lower potential amplitude than at both sides (0.2 +/- 0.15 vs. 0.5 +/- 0.5 mV, P < 0.05), defined by a bayonet-shaped depolarization sequence, were considered to represent the incomplete line of block (InLOB). An ablation catheter was progressively dragged up to this InLOB, from the tricuspid annulus to the inferior vena cava, analysing the widely separated double potentials (DPs) until these coalesced. In nine patients (35%), the target conduction gap was a coalesced fractionated atrial potential within the InLOB (duration, 77 +/- 12 ms), and in 16 patients (65%), a narrow DP toward the healthy margins of this InLOB (duration, 28 +/- 15 ms). Adopting this strategy yields 100% successful re-ablation of recurring AFl leading to bidirectional block, with a mean 2.7 +/- 1.4 RF applications. CONCLUSION: Transverse CTI mapping precisely locates the InLOB and helps find conduction gaps along the CTI in re-ablation procedures for common AFl.

Factors affecting the management of outcome in elderly patients with acute myocardial infarction particularly with regard to reperfusion. Data from the French regional RICO survey.

BACKGROUND: Acute myocardial infarction (AMI) in elderly patients is often unrecognized and associated with poor prognosis. OBJECTIVES: To investigate management and efficacy of reperfusion therapy to the elderly patients with AMI. METHODS: From the January 1, 2001 to October 31, 2002, 964 patients with AMI were included in the French regional RICO survey. The patients were divided into three groups: younger (<70 years old), elderly (70-79 years old) and very elderly (>or=80 years old). RESULTS: Distribution of groups was 56, 27, and 16%, respectively. The longest time delay to first request for medical attention was found in the very elderly group (30 and 55 vs. 90 min, respectively, p < 0.05). Rate of lysis fell significantly with increasing age (35, 22 and 9%, respectively, p < 0.001) but the time delay to lysis was similar for the 3 groups. The proportion of patients who benefited from primary percutaneaous transluminal coronary angioplasty decreased with age (21, 15, 11%, respectively, p < 0.001), but time delay to balloon angioplasty was similar and no difference in mortality rate was observed between the three groups after reperfusion. The incidence of in-hospital cardiovascular events (cardiogenic shock and recurrent myocardial infarction/ischemia) and in-hospital mortality increased with age (5, 13, 17%, respectively, p < 0.001). Moreover, multivariate analysis showed that only ejection fraction and Killip >1 were independent predictive factors for in-hospital cardiovascular mortality, respectively (OR 5.15, 95% CI 2.08-12.74, p < 0.0001 and OR 3.81, 95% CI 1.90-7.65, p < 0.0001), whereas age, sex, diabetes and anterior location were not significant. CONCLUSION: Our data in an unselected population indicate that very elderly patients were characterized by increased pre-hospital delays and less frequent utilization of reperfusion therapy, although no difference in the mortality in reperfused patients could be observed between the three age groups.

Long-term prognosis of patients with acute coronary syndrome and moderate coronary artery stenosis.

We evaluated the clinical outcome and the prognostic factors at 6-year follow-up of patients with acute coronary syndrome without critical coronary arterial narrowing. The mean follow-up was 73 +/- 19 months. Mortality rate was 13%, and 20 patients (12%) had major cardiac event, 8 patients (5%) had stroke and 10 patients (6%) underwent revascularization. Multivariate analysis matched for age and ejection factor showed that moderate disease (stenosis 40-59%) (OR = 2.713, p < 0.024) was an independent predictive factor of major cardiac event.