Simulated Obstructive Sleep Apnea Increases P-Wave Duration and P-Wave Dispersion.

BACKGROUND:A high P-wave duration and dispersion (Pd) have been reported to be a prognostic factor for the occurrence of paroxysmal atrial fibrillation (PAF), a condition linked to obstructive sleep apnea (OSA). We tested the hypothesis of whether a short-term increase of P-wave duration and Pd can be induced by respiratory manoeuvres simulating OSA in healthy subjects and in patients with PAF. METHODS:12-lead-electrocardiography (ECG) was recorded continuously in 24 healthy subjects and 33 patients with PAF, while simulating obstructive apnea (Mueller manoeuvre, MM), obstructive hypopnea (inspiration through a threshold load, ITH), central apnea (AP), and during normal breathing (BL) in randomized order. The P-wave duration and Pd was calculated by using dedicated software for ECG-analysis. RESULTS:P-wave duration and Pd significantly increased during MM and ITH compared to BL in all subjects (+13.1 ms and +13.8 ms during MM; +11.7 ms and +12.9 ms during ITH; p<0.001 for all comparisons). In MM, the increase was larger in healthy subjects when compared to patients with PAF (p<0.05). CONCLUSION:Intrathoracic pressure swings through simulated obstructive sleep apnea increase P-wave duration and Pd in healthy subjects and in patients with PAF. Our findings imply that intrathoracic pressure swings prolong the intra-atrial and inter-atrial conduction time and therefore may represent an independent trigger factor for the development for PAF

Simulated Obstructive Sleep Apnea Increases P-Wave Duration and P-Wave Dispersion

<div><p>Background</p><p>A high P-wave duration and dispersion (Pd) have been reported to be a prognostic factor for the occurrence of paroxysmal atrial fibrillation (PAF), a condition linked to obstructive sleep apnea (OSA). We tested the hypothesis of whether a short-term increase of P-wave duration and Pd can be induced by respiratory manoeuvres simulating OSA in healthy subjects and in patients with PAF.</p><p>Methods</p><p>12-lead-electrocardiography (ECG) was recorded continuously in 24 healthy subjects and 33 patients with PAF, while simulating obstructive apnea (Mueller manoeuvre, MM), obstructive hypopnea (inspiration through a threshold load, ITH), central apnea (AP), and during normal breathing (BL) in randomized order. The P-wave duration and Pd was calculated by using dedicated software for ECG-analysis.</p><p>Results</p><p>P-wave duration and Pd significantly increased during MM and ITH compared to BL in all subjects (+13.1ms and +13.8ms during MM; +11.7ms and +12.9ms during ITH; p<0.001 for all comparisons). In MM, the increase was larger in healthy subjects when compared to patients with PAF (p<0.05).</p><p>Conclusion</p><p>Intrathoracic pressure swings through simulated obstructive sleep apnea increase P-wave duration and Pd in healthy subjects and in patients with PAF. Our findings imply that intrathoracic pressure swings prolong the intra-atrial and inter-atrial conduction time and therefore may represent an independent trigger factor for the development for PAF.</p></div

Clinical characteristics by study population.

<p>Clinical characteristics by study population.</p

Mean P-wave duration measured in a single lead over all sectors (95% CI).

<p>The two sectors which comprise the manoeuvres are shaded grey. We observed significant differences for ITH and MM vs BL during the manoeuvre (both p<0.001). The P-wave duration did not change during the course of the BL (p = 0.99) and AP (p = 0.94) manoeuvre. All analyses were adjusted for PAF status, heart rate, age, BMI, and sex. BL = baseline (normal breathing). ITH = inspiration through a threshold load (simulating an obstructive hypopnea). MM = Mueller manoeuvre (simulating an obstructive apnea). AP = end-expiratory breath holding (simulating central apnea).</p

Differences in P-wave mean and Pd in ms during breathing manoeuvres in all patients (n = 57).

<p>Differences in P-wave mean and Pd in ms during breathing manoeuvres in all patients (n = 57).</p

Leishmaniose tegumentar americana: flebotomíneos de área de transmissão no Norte do Paraná, Brasil American cutaneous leishmaniasis: phlebotominae of the area of transmission in the North of Parana, Brazil

Dos casos de leishmaniose tegumentar diagnosticados no Laboratório de Ensino e Pesquisa de Análises Clínicas da Universidade Estadual de Maringá-PR (Brasil), a maioria está relacionada a áreas, no Norte do Paraná, que vem sendo ocupadas desde a década de 1940, quando se iniciou extenso desmatamento naquela Região. A vegetação nativa, já em grande parte destruída, é constituída por mata densa do tipo tropical de transição para subtropical. A paisagem no seu conjunto é de planalto, com clima tropical de transição para subtropical, temperaturas médias anuais entre 20&deg;C e 22&deg;C e média do mês mais quente superior a 22&deg;C. Das florestas nativas restam poucas e esparsas manchas de vegetação, geralmente modificadas, ao longo das bacias dos rios Ivaí, Paranapanema e Paraná, e seus afluentes. Neste ambiente foram feitas 24 capturas de flebotomíneos, 2 por mês, de outubro de 1986 a setembro de 1987, das 18 horas à l hora do dia seguinte. As capturas, com armadilhas de Shannon, foram realizadas às margens de mata modificada, tendo sido classificados 16.496 flebotomíneos, pertencentes na sua quase totalidade a 13 espécies. Observou-se prevalência de Lutzomyia whitmani com 11.188 (67,82%) exemplares, seguido por Lutzomyia intermedia com 2.900 (17,58%) e Lutzomyia migonei com 1.491 (9,03%). Lutzomyia whitmani e Lutzomyia intermedia vêm mostrando grande capacidade de adaptação nos ambientes antrópicos, onde têm destacado papel na transmissão de leishmaniose.<br>Most of the cases of cutaneous leishmaniasis diagnosed in the laboratory of the State University of Maringá, Paraná, Brazil, are related to areas of northern Paraná State, which have been settled since 40 years age, when the destructions of vast areas of forest in this region was begun. The native vegetation, already, in large part, destroyed is constituted of dense forest of the type found in the transition from tropical to subtropical regions. The landscape is constituted of plateau with a climate of transition from tropical to subtropical and annual mean temperatures of 20&deg;C to 22&deg;C, the mean of the hottest month being superior to 22&deg;C. The native forests are represented by small, sparse patches of vegetation, with some modification in the basins of the rivers Ivaí, Paranapanema and Paraná and their tributaries. In this environment 24 captures of phlebotomines were made - 2 per month from October 1986 to September 1987, between 6 P.M. and 1 A.M. The captures with Shannon trap were made in the outlying forest of Palmital farm. The majority of the 16,496 phlebotomines were classified into 13 species. Lutzomyia whitmani was predominant with 11,188 (67.82%) specimens, followed by Lutzomyia intermedia with 2,900 (17.58%) and Lutzomyia migonei with 1,481 (9.03%). Lutzomyia whitmani and Lutzomyia intermedia have been manifesting great capacity of adaptation in modified environments, where they have played a significant role in transmission of leishmaniasis