Mitral isthmus ablation with and without temporary spot occlusion of the coronary sinus: a randomized clinical comparison of acute outcomes

To evaluate the safety and outcomes of mitral isthmus (MI) linear ablation with temporary spot occlusion of the coronary sinus (CS). Background: CS blood flow cools local tissue precluding transmurality and bidirectional block across MI lesion.

Prevalence and types of pitfall in the assessment of mitral isthmus linear conduction block

To identify and understand clinically encountered pitfalls in the assessment of transmitral conduction block using differential coronary sinus and left atrial appendage pacing techniques in patients with left mitral isthmus linear ablation.

Length of the Mitral Isthmus But Not Anatomical Location of Ablation Line Predicts Bidirectional Mitral Isthmus Block in Patients Undergoing Catheter Ablation of Persistent Atrial Fibrillation: A Randomized Controlled Trial

INTRODUCTION Mitral isthmus (MI) ablation is an effective option in patients undergoing ablation for persistent atrial fibrillation (AF). Achieving bidirectional conduction block across the MI is challenging, and predictors of MI ablation success remain incompletely understood. We sought to determine the impact of anatomical location of the ablation line on the efficacy of MI ablation. METHODS AND RESULTS A total of 40 consecutive patients (87% male; 54 ± 10 years) undergoing stepwise AF ablation were included. MI ablation was performed in sinus rhythm. MI ablation was performed from the left inferior PV to either the posterior (group 1) or the anterolateral (group 2) mitral annulus depending on randomization. The length of the MI line (measured with the 3D mapping system) and the amplitude of the EGMs at 3 positions on the MI were measured in each patient. MI block was achieved in 14/19 (74%) patients in group 1 and 15/21 (71%) patients in group 2 (P = NS). Total MI radiofrequency time (18 ± 7 min vs. 17 ± 8 min; P = NS) was similar between groups. Patients with incomplete MI block had a longer MI length (34 ± 6 mm vs. 24 ± 5 mm; P < 0.001), a higher bipolar voltage along the MI (1.75 ± 0.74 mV vs. 1.05 ± 0.69 mV; P < 0.01), and a longer history of continuous AF (19 ± 17 months vs. 10 ± 10 months; P < 0.05). In multivariate analysis, decreased length of the MI was an independent predictor of successful MI block (OR 1.5; 95% CI 1.1-2.1; P < 0.05). CONCLUSIONS Increased length but not anatomical location of the MI predicts failure to achieve bidirectional MI block during ablation of persistent AF.

Benthic foraminiferal response to the emergence of the Isthmus of Panama and coincident paleoceanographic changes

Late Cenozoic benthic foraminiferal faunas from the Caribbean Deep Sea Drilling Project (DSDP) Site 502 (3052 m) and East Pacific DSDP Site 503 (3572 m) were analyzed to interpret bottom-water masses and paleoceanographic changes occurring as the Isthmus of Panama emerged. Major changes during the past 7 Myr occur at 6.7-6.2, 3.4, 2.0, and 1.1 Ma in the Caribbean and 6.7-6.4, 4.0-3.2, 2.1, 1.4, and 0.7 Ma in the Pacific. Prior to 6.7 Ma, benthic foraminiferal faunas at both sites indicate the presence of Antarctic Bottom Water (AABW). After 6.7 Ma benthic foraminiferal faunas indicate a shift to warmer water masses: North Atlantic Deep Water (NADW) in the Caribbean and Pacific Deep Water (PDW) in the Pacific. Flow of NADW may have continued across the rising sill between the Caribbean and Pacific until 5.6 Ma when the Pacific benthic foraminiferal faunas suggest a decrease in bottom-water temperatures. After 5.6 Ma deep-water to intermediate-water flow across the sill appears to have stopped as the bottom-water masses on either side of the sill diverge. The second change recorded by benthic foraminiferal faunas occurs at 3.4 Ma in the Caribbean and 4.0-3.2 Ma in the Pacific. At this time the Caribbean is flooded with cold AABW, which is either gradually warmed or is replaced by Glacial Bottom Water (GBW) at 2.0 Ma and by NADW at 1.1 Ma. These changes are related to global climatic events and to the depth of the sill between the Caribbean and Atlantic rather than the rising Isthmus of Panama. Benthic foraminiferal faunas at East Pacific Site 503 indicate a gradual change from cold PDW to warmer PDW between 4.0 and 3.2 Ma. The PDW is replaced by the warmer, poorly oxygenated PIW at 2.1 Ma. Although the PDW affects the faunas during colder intervals between 1.4 and 0.7 Ma, the PIW remains the principal bottom-water mass in the Guatemala Basin of the East Pacific.

The fishes of North and Middle America: a descriptive catalogue of the species of fish-like vertebrates found in the waters of North America, north of the Isthmus of Panama /

Mode of access: Internet.

The Roman Wall : an historical and topographical description of the barrier of the lower isthmus extending from the Tyne to the Solway deduced from numerous personal surveys /

Interleaved with many insertions and manuscript notes ; partly mutilated.

The birds of North and Middle America: a descriptive catalog of the higher groups, genera, species, and subspecies of birds known to occur in North America, from the Arctic lands to the Isthmus of Panama, the West Indies and other islands of the Caribbean Sea, and the Galapagos Archipelago.

Pts. 1-8, 1901-19 by Robert Ridgway; pt. 9-10, 1941-46 by Robert Ridgway, completed by Herbert Friedmann; pt. 11- , 1950- by Friedmann.

The hand-book to the Roman wall: a guide to tourists traversing the barrier of the lower isthmus.

Mode of access: Internet.

An account of the isthmus of Tehuantepec in the republic of Mexico; with proposals for establishing a communication between the Atlantic and Pacific oceans, based upon the surveys and reports of a scientific commission, appointed by the projector, Don José de Garay.

Mode of access: Internet.

The Isthmus of Suez : recited in the Theatre, Oxford, June 14, 1871 /

At head of title: Newdigate prize poem.

Panama, the isthmus and the canal,

Mode of access: Internet.

South America, social, industrial, and political; a twenty-five-thousand-mile journey in search of information in the isthmus of Panama and the lands of the equator,

Mode of access: Internet.