Factors Associated with Recurrence of Accessory Pathway Conduction After Radiofrequency Catheter Ablation

Catheter ablation of 215 accessory pathways (APs) using radiofrequency current (RF) was attempted in 204 consecutive patients. Two hundred twelve of the 215 (99%) APs were successfully ablated. After a minimum follow-up period of 1 month (mean 8.5 ± 5.4 months), AP conduction had returned in 17 patients (8%). Recurrence of AP conduction was manifest by atrioventricular (AV) reentrant tachycardia in six patients, palpitations suggestive of AV reentrant tachycardia in five patients, ventricular preexcitation on electrocardiogram in five patients, and inducible AV reentrant tachycardia during a follow-up electrophysiological study in one asymptomatic patient. AP conduction returned as early as 12 hours and as late as 4.7 months, but was evident within 2 months of ablution in 15 of 17 (88%) patients. AP conduction recurred in 12%-14% of anteroseptal, right free-wall, and posteroseptal APs, but only 5% of left free-wall APs (P < 0.01). Retrograde only conducting APs (concealed APs) had recurrence of AP conduction more frequently (16%) than APs that exhibited antegrade conduction (5.5%; P < 0.01). Failure to record AP potentials from the ablation electrode, reflecting poor AP localization, was a strong predictor for recurrence of AP conduction. AP conduction returned in 19% of 48 APs when AP potentials were not recorded, compared to 5% of 164 APs where AP potentials were recorded from the ablation electrode (P < 0.01). The time to block of AP conduction from the onset of RF current application was longer in APs with recurrence of conduction (4.9 ± 6.1 sec vs 2.9 ± 3.4 sec; P < 0.02). Recurrence of AP conduction was more frequent when the stability of the ablation electrode was poor (12% of 41 APs vs 7% of 171 APs with stable electrode placement], and when the AP had multiple components (11% of 36 APs ablated at multiple sites vs 7% of 176 APs where AP was ablated at a single site), but these were not statistically significant. All 17 patients with recurrence of AP conduction underwent a second successful ablation. In conclusion, the overall incidence of recurrence of AP conduction is low, but is higher for right free-wall and septal APs, concealed APs, and probably relates to poor AP localization.     

Robust Model‐Based Quantification of Global Ventricular Torsion from Spatially Sparse Three‐Dimensional Time Series Data by Orthogonal Distance Regression: Evaluation in a Canine Animal Model Under Different Pacing Regimes

Background : Quantification of global ventricular rotational deformation, expressed as twist or torsion, and its dynamic changes is important in understanding the pathophysiology of heart disease and its therapy. Various techniques, such as sonomicrometry, allow tracking of specific sites within the myocardium. Quantification of twist from such data requires a longitudinal reference axis of rotation. Current methods require specific positioning and numbers of myocardial markers and assumptions about temporal positional evolution that may be violated during dyssynchronous contraction. Methods : We present a new method to assess myocardial twist that makes minimal fully explicit assumptions while removing extraneous assumptions, by performing a least squares orthogonal distance regression of all position data on an ellipsoidal ventricular model. Rotational deformation is quantified in terms of the ellipsoid's internal coordinate system, allowing intuitive visualization. Results : We tested this method on a set of sparse, noisy sonomicrometric crystal data in dogs under different pacing regimes to model dyssynchrony and cardiac resynchronization. We found that this method yielded robust and plausible data. This technique is also fully automated while identifying when data may be insufficient for reliable quantification of rotational deformation. Conclusion : This approach may allow future analysis of myocardial contraction with less tracking sites and relaxed positioning requirements while identifying situations where data are insufficient for reliable quantification of rotational deformation. (PACE 2013; 36:13–23)     

JOINT COMPLAINTS IN PSORIASIS PATIENTS

Four hundred and fifty-nine psoriasis patients seen at the Department of Dermatology, Bowman Gray School of Medicine of Wake Forest University, responded to a questionnaire concerning current or past joint complaints. Of these, 17% reported a previous diagnosis of psoriatic arthritis, and over 53% had a current or past history of arthralgias. Additional information on those patients reporting arthralgias focused on the cutaneous sites of involvement with psoriasis and which joints were most likely to be involved in patients with various types of arthritis. Previous treatments for skin involvement with psoriasis were more aggressive in those patients with a diagnosis of psoriatic arthritis. A significant proportion of patients presenting to dermatologists for treatment of psoriasis have joint complaints, and the percentage of patients with psoriatic arthritis is greater than generally appreciated by non-dermatologists.     

SELECTED ASPECTS OF PENICILLIN ALLERGY

SUMMARY.— Skin tests for immediate hypersensitivity with penicillin derivatives and haemagglutination tests for penicilloyl-specific IgG and IgM antibodies are useful in the prevention, diagnosis and management of clinical adverse reactions mediated by IgE antibodies. In rare instances, the skin tests themselves may cause clinical adverse reactions. Under suitable conditions, hyposensitization or temporary loss of skin sensitivity can be successfully brought about, even in individuals with a high degree of immediate hypersensitivity.
Delayed hypersensitivity plays a role in mediating certain non-urticarial forms of penicillin allergy, including some cases of exanthematous eruptions. The degree of delayed hypersensitivity consistently fluctuates to lower levels after administration of therapeutic doses of penicillin.
Preliminary data are presented which suggest that infants who are given penicillin at birth form IgM penicilloyl-specific serum antibodies much less frequently and in lower titres than occur after penicillin therapy later in life.     

The Demise of Artificial Trans Fat: A History of a Public Health Achievement

Policy Points

• This article describes a strategic combination of research, advocacy, corporate campaigns, communications, grassroots mobilization, legislation, regulatory actions, and litigation against companies and government to secure a national policy to remove artificial trans fat from the US food system.
• Sharing lessons we learned can help inform policymakers, academics, policy practitioners, and students across disciplines. Some of our lessons are that system change means that all consumers benefit without the need for individual behavior change; research can both identify opportunities to improve health and support policy adoption; policy efforts can serve as public education campaigns; policy campaigns can drive marketplace changes; and engaging forward‐thinking companies can diffuse opposition to passing a policy.

ContextFor many decades, partially hydrogenated vegetable oil (PHO), the primary source of artificial trans fat in the American diet, was used widely in processed and restaurant foods. In the early 1990s, studies linked the consumption of artificial trans fat with heart disease. This article details how research and advocacy led to eliminating artificial trans fat from the US food supply.MethodsWe synthesized published studies of the health impact of trans fat, the legislative history of state and local trans fat bills, the Food and Drug Administration''s (FDA) regulatory docket on trans fat labeling and its declaration that PHOs are no longer Generally Recognized as Safe (GRAS), and our own files, which included strategy documents, notes from meetings with the FDA staff, correspondence between advocates and the FDA, fact sheets, press releases, news clips, and other materials.FindingsThis history of trans fat provides insights into policy strategy and advocacy best practices that resulted in the removal of trans fat from food in the United States, preventing an estimated 50,000 premature deaths a year. The lessons we learned are that system change benefits all consumers without the need for individual behavior change; research can both identify opportunities to improve health through policy and support policy adoption; policy campaigns can serve as public education campaigns; policy can drive changes to products and the marketplace; and engaging forward‐thinking companies can help diffuse opposition to passing a policy. Securing this policy required the persistence of scientists and health advocates in first discovering the risks and then using the science to secure policies to mitigate the identified harm.ConclusionsAn understanding of the tactics used to help attain the targeted policies and how challenges were addressed (such as through communications, leveraging an expanding research base and expert reports, showing that a national policy was feasible through voluntary corporate changes and state and local policy, and litigation against companies and government agencies) may provide a model for scientists, students, advocates, and policymakers. We hope this account will inform efforts to address other public health challenges, such as the current threats of excessive exposure to sodium and added sugars, which persist in the US food system.     

Brief Note: Tritiated Thymidine as a Cytocidal Agent in Human Leukemia

1. Two patients with acute leukemia had considerable decreases in leukemiccells in the peripheral blood as well as reduction in size of spleen and leukemicmasses after 10 injections of ³H-TDR given over a 5-day period. Each injectionwas 0.25 µc./Gm. body weight.

2. The pertinent aspects of cytotoxic effects of ³H-TDR are reviewed.

3. The radiation doses delivered to the nucleus are estimated from autoradiographic data.

4. Evidence is presented for the observed effects being due to ³H-TDR.

Submitted on July 19, 1965 Accepted on May 10, 1966     

The relationship of cerebral palsy subtype and functional motor impairment: a population-based study

Aim  Traditionally, cerebral palsy (CP) had been classified according to the distribution and quality of motor impairment. A standardized functional classification of gross motor skills has recently been validated – the Gross Motor Function Classification System (GMFCS). The relationship between the neurological subtype of CP and GMFCS level remains undefined in CP.
Method  The Quebec Cerebral Palsy Registry (Registre de la paralysie cérébrale au Québec [REPACQ]) over a 4-year birth interval (1999–2002 inclusive) identified 301 children with CP. Information on both CP subtype and GMFCS level was available for 243 children (138 males, 105 females) with final data extraction at a mean age of 44 months (SD 14mo, range 24–79mo). Proportions of children with a particular CP subtype at GMFCS levels I to III versus levels IV to V were determined and compared.
Results  CP subtype versus GMFCS levels I to III or IV to V was distributed proportionally as follows: spastic diplegic, 51/52 (98%) versus 1/52 (2%); spastic quadriparetic, 20/85 (24%) versus 65/85 (76%); spastic hemiplegic, 76/77 (99%) versus 1/77 (1%); dyskinetic, 4/16 (25%) versus 12/16 (75%); other (triplegic or ataxic–hypotonic), 10/13 (77%) versus 3/13 (23%). These distributions (proportions) all yielded significant ( p <0.001) Pearson χ² values.
Interpretation Neurological subtype is a powerful predictor of functional status related to ambulation. This has implications for counseling families.