Pretest Cycle Research Articles

Strategi Pembelajaran Metacognitive-Scaffolding Untuk Meningkatkan Kemampuan Numerasi Siswa Kelas III SD Negeri Lembursawah 1

This study aims to determine the effectiveness of the application of metacognitive-scaffolding learning strategies to improve the numeracy skills of third-grade students of SD Negeri Lembursawah 1. Metacognitive-scaffolding learning is a learning strategy that helps students to involve their metacognitive abilities in the process and learning outcomes to improve students' numeracy skills, considering the lack of students' understanding of their numeracy skills. This is unfortunate because numeracy skills have as important a role as literacy skills. Through this numeracy ability, students are expected to be able to apply and solve various mathematical concepts in everyday life. The research method applied in this research is Classroom Action Research (CAR). The data collection instruments used were questionnaires, pre-tests, post-test, and document studies. The results showed that there was an increase in student learning outcomes after the implementation of the metacognitive-scaffolding learning strategy, which was indicated by an average value of 59.1 which was included in the Less category, while after the implementation of the action through the metacognitive-scaffolding learning strategy showed an increase that could be seen from the results of Post-Test cycle 2 with an average value of 70.2 in the Good category. Meanwhile in the Pre-Test cycle 1, the number of students who had not completed as many as 19 out of 42 students with 16 students in the Less category and 3 others in the Very Poor category. The increase in student learning outcomes also continued with the number of students who had not completed only 3 out of 42 students in the Less category after the Post-Test cycle 2 was implemented.

Meningkatkan Hasil Belajar IPA Materi Perubahan Wujud Benda Menggunakan Video Animasi Pada Siswa Kelas IV SDK 077 Kewapante

This study aims to improve science learning outcomes material changes in the form of objects. This research is Classroom Action Research (PTK) conducted in 2 cycles where each cycle consists of 3 meetings, which consists of 4 stages, namely planning, implementing, observing and reflecting. The subjects in this study were fourth grade students at SDK 077 Kewapante, totaling 37 students consisting of 23 male students and 14 female students. Data collection techniques used in this study were tests, observation and documentation. The data analysis technique used is the analysis of test results and observation results. The research results show that the use of animated videos can improve student learning outcomes. The increase in student learning outcomes can be seen in the results of the pretest cycle I with a total score of 1,479 with an average of 39.9, and the percentage of completeness of 5.4% increased 45.9% to the results of the posttest cycle I where the total value was 3,028 with an average of 81. 8 and the percentage of completeness is 51.3%. while in cycle II there was an increase with a total value of 3,450 with an average of 93.2 and a completeness percentage of 100%.

Improving Student Mathematics Learning Outcomes Through the Problem Based Learning (PBL) Learning Model on Linear Program Material in Class XI SMA Negeri 1 Tigabinanga

This study aims to find out that the Problem Based Learning (PBL) learning model can improve the mathematics learning outcomes of class XI students of SMA Negeri 1 Tigabinanga on linear programming material. The subjects in this study were 34 students of class XI IPA 5 at SMA Negeri 1 Tigabinanga and the object of this study was to increase students' mathematics learning outcomes through the Problem Based Learning model. The research instruments used were tests and reflective journals. This research is a classroom action research (PTK) which lasts for two cycles. The results of data analysis were obtained from the results of students' mathematics learning which increased from cycle I to cycle II after applying the Problem Based Learning learning model. In the pre-test cycle I, the average class value was 60.35 and the classical completeness was 20.59%. The results of the post-test cycle I obtained an average value of 74.12 with a classical completeness of 47.06%. Where there is an increase of 13.77 with an N-Gain value of 0.23 which is included in the low category. And the second cycle for the pre-test obtained an average value of 66.44 with a classical completeness of 32.35%. Meanwhile, the post-test results obtained an average value of 85.26 with classical completeness of 88.24%. In cycle II, the average increase was 18.71 and the N-Gain value obtained was 0.50, which is included in the medium category and has reached an indicator of cycle success. So, based on the results of this study, the learning outcomes of class XI IPA 5 SMA Negeri 1 Tigabinanga can be increased by using the Problem Based Learning learning model.

Peningkatan Hasil Belajar Siswa SMK Negeri 3 Metro Menggunakan Model Pembelajaran Problem Based Learning (PBL) Berbantuan Modul dan Jobsheet Instalasi Motor Listrik

This study aims to improve student learning outcomes in class XI TITL B in the subject of Electrical Motor Installation using the Problem Based Learning (PBL) learning model at SMK Negeri 3 Metro. This research is a Classroom Action Research with the model developed by Kemmis and Mc Taggart. The subjects of this study were 34 students of class XI TITL B in the even semester of the 2018/2019 academic year. This study consisted of two cycles with each cycle consisting of two meetings. Data collection techniques in this study used observation sheets, learning outcomes tests, and documentation. The data analysis technique used is descriptive analysis. The criteria for success in this study is that at least 75% of student learning outcomes have achieved completeness (KKM= 70). The results showed that the implementation of learning using the PBL learning model could improve the learning outcomes of class XI students in the subject of Electrical Motor Installation. This can be seen from the increase in student learning outcomes which are measured using pretest and posttest in each cycle. The percentage of completeness in the pretest cycle I showed 14.71%, then in the posttest cycle I became 55.88% an increase of 41.17%. In the second cycle pretest showed 44.12%, then in the second cycle posttest to 82.35% an increase of 38.23%. The increase in the percentage of completeness posttest I and posttest II increased by 26.47%. The conclusion of this study is that student learning outcomes increase after using the PBL model.

Peningkatan Kompetensi Siswa Kelas XII TITL 1 Keahlian Teknik Instalasi Tenaga Listrik Smk Negeri 2 Depok pada Mata Pelajaran Sistem Pengendali Elektronik Melalui Metode Kooperatif STAD Tahun Pelajaran 2018/2019

This study aims to determine the effectiveness of the Student Team Achievement Division (STAD) cooperative learning method with the help of Electronic Control System learning media in improving the competence of class XII students in Electrical Power Installation Engineering skills at SMKN 2 Depok in the subject of electronic control systems. This research is a classroom action research conducted in two cycles, with three meetings for each cycle. Each cycle in this study consisted of four stages of implementation, namely planning, implementing actions, observing, and reflecting. Data was collected using affective observation sheets, psychomotor observation sheets, and pre-test and post-test instruments. The instrument of affective observation sheet is used to determine students' competence in the affective aspect. The psychomotor observation sheet instrument was used to determine student competence in psychomotor aspects. Pre-test and post-test instruments were used to determine students' competence in cognitive aspects. The data analysis technique used is data reduction, data exposure, and conclusion drawing. The results showed an increase in student competence in the affective, psychomotor, and cognitive aspects after the implementation of the STAD technique cooperative learning method with the help of Electronic Control System learning media. In the affective aspect, there was an increase of 48.21%, with the percentage of students' affective aspects at the first meeting of 56%, increasing to 83% at the sixth meeting. In the psychomotor aspect there was an increase of 22.15%, with the average psychomotor score of students on job sheet 1 of 67.66, increasing to 82.65 on job sheet 4. In the cognitive aspect there was an increase of 110.9%, with a score of the average pre-test cycle 1 was 38.53, increased to 81.26 in the post-test cycle 2.Keywords: student competence, student team achievement division, electronic control system

Peningkatan Pemahaman Teks Bahasa Arab Melalui Metode (SQ3R)

The purpose of this study was to determine how the application of the SQ3R method in improving understanding of Arabic texts and to determine the extent to which the understanding of Arabic text was increased through the SQ3R method. This study used a qualitative approach with a classroom action research (CAR) strategy. The subjects of this study were students of class VII B MTs Nurul Yaqin Legok Tangerang. Sources of data used: (1) informants, namely Arabic teachers in class VII B MTs Nurul Yaqin who are easy to communicate with (2) data or documents, in the form of reading texts, photos of teaching and learning activities, student test results, transcripts of interviews with students and teacher. The data collection technique used was data triangulation which included: (1) observation / observation, (2) interviews, and (3) documentation (4) written test assessments. The research process was carried out in 2 cycles, each cycle consisting of four stages, namely: (1) planning the action, (2) implementing the action, (3) observing, and (4) analyzing and reflecting. Based on the results of research carried out that the SQ3R method was able to improve students' understanding of Arabic text. With an average acquisition of 64 on the pre-test results, then increased in cycle I with an average of 84, then increased again in cycle II with an average result. Average 95.5. with an average comparison of 20 between the pre-test and post-test cycle I, and the comparison between cycle I and cycle II, namely 11.5.

PENGGUNAAN MODIF (MODEL PEMBELAJARAN BERVARIATIF) DAN MEDAN (MEDIA PEMBELAJARAN) DALAM PEMBELAJARAN PPKN

This study aims to analyze whether modif and medan can improve Civics learning outcomes class VII at MTs Negeri 2 Karanganyar. The method used was development research with a population of 315 students from 10 classes, with a random sample of 59 students. The results showed that the increase in Civics learning outcomes of students in the experimental class obtained a higher average pretest and psychological test compared to the control class, namely 80 and 65 and there was an implication on the increase in the value increase of pretest cycle I 79.3 (including good category) to 85.5 in the pretest cycle II and postest 95.9 cycle I to 98.6 (very good category) cycle II.

IMPROVING VOCABULARY USING TGT (TEAMS GAMES TOURNAMENT) METHOD

This study aims to improve vocabulary through Team Game Tournament Techniques in class IX students of one of the junior high schools conceived. The sample of this research was 32 students. The method used in this research was action research applied in two cycles. Then the data was collected by using multiple choice tests (pre-test and post-test). The results that the TGT method can be improved vocabulary students, it was showed from the table score that increased from the mean score of pre-test, post-test cycle 1 and post-test cycle 2. The mean score of pre-test was 55.94 , the mean score of the pre-test cycle was 74.37 and the mean score of the post-test cycle 2 80.31.it is assumed that the TGT method is effective to improve vocabulary students and then the use of the TGT technique makes students more motivated. Keywords: Vocabulary, TGT (Teams Games Tournament), CAR

Penerapan Model Discovery Based Learning (DBL) Berbantuan Geogebra Untuk Meningkatkan Hasil Belajar Siswa Kelas IXB SMP Negeri 4 Yogyakarta Materi Transformasi Semester 1 Tahun Pelajaran 2018/2019

The purpose of this study is to describe the application of Discovery Based Learning (DBL) assisted by GeoGebra software that can improve the learning outcomes on transformation material of Class IXB students of SMP 4 Yogyakarta Junior High School in the first semester of academic year 2018/2019. The research method used was classroom action research which consisted of four stages, namely planning, implementation, observation, and reflection. The research subjects were all IXB grade students, consisted of 34 students, while the research object was the whole process and results of mathematics learning with the application of learning using DBL assisted by GeoGebra to improve students’ learning outcomes. The research instruments were researchers, student activity observation sheets, observation sheets for teacher learning activities, student motivation questionnaire sheets, pretests, posttests, documentation, and field notes. Data analysis techniques used qualitative descriptive data analysis through three stages, namely reduction, analysis and inference of data. This research was conducted in two cycles. The results showed that the learning outcomes of Class IXB students of SMP 4 Yogyakarta Junior High School in in the first semester of academic year 2018/2019 were improved using DBL assisted by GeoGebra. The average of pretest cycle 1 was 31, 68. The average of posttest was 94.09. The increase was 62.41. The average pretest cycle 2 was 30, 88. The average posttest was 93.38. The increase was 62.50. The increase was higher than the indicator of research success, which was 50.00

Efektivitas Pendekatan Open Ended Dalam Pembelajaran Matematika

The purpose of this study is to describe the application of Discovery Based Learning (DBL) assisted by GeoGebra software that can improve the learning outcomes of Class IXB students of SMP 4 Yogyakarta in the first semester of 2018/2019 academic year transformation material.The research method used is classroom action research which consists of four stages, namely planning, implementation, observation, and reflection. The research subjects were all 9B grade 9B Yogyakarta students, amounting to 34 students, while the research object was the whole process and results of mathematics learning with the application of learning using DBL assisted by GeoGebra to improve student learning outcomes of the class. The research instruments were researchers, student activity observation sheets, observation sheets for teacher learning activities, student motivation motivation questionnaire sheets, pre tests, test posts, documentation and field notes. Data analysis techniques use qualitative descriptive data analysis through three stages, namely reduction, analysis and inference of data.This research was conducted in two cycles. The results showed that the learning outcomes of Yogyakarta 4 Public Middle School students in class 9B in semester 1 of school year 2018/2019 were transformed using DBL assisted by GeoGebra, the average pre test cycle 1 was 31, 68. Average test post was 94.09. The increase is 62.41. The average pre test cycle 2 is 30, 88. The average test post is 93.38. The increase is 62.50. This increase is higher than the indicator of research success, which is 50.00.

THE USE OF CAMTASIA VIDEO EDITOR TO IMPROVE THE STUDENTS’ PRONUNCIATION SKILL AT ENGLISH STUDY PROGRAM IAIN METRO LAMPUNG

This research is aimed to know whether Camtasia could improve the students’ pronunciation skill at the first semester English Education Study Program IAIN Metro Lampung in the Academic Year of 2018/2019. This research is carried out on the subject of English Phonology.The design of this research was a classroom action research. It was conducted in two cycles. The data collection method in this research was observation, test, documentation, and field note. the cycle I the average score of pre-test cycle I was 60, 3 and the average of post-test in cycle I was 64, 5. In the post-test in cycle II the average score was 75, 8. There are some progresses after being given treatment through video produce by camtasia. The students are very interested in following and doing the assignment given by the researcher. From the result of the discussion above, it can be conclude that the use of Camtasia can improve the students’ pronunciation skill at the first semester English Education Study Program IAIN Metro Lampung in the Academic Year of 2018/2019. Key words: Pronunciation, Camtasia, Video, Editor

PENERAPAN MODEL PEMBELAJARAN THINK TALK WRITE PADA MATA PELAJARAN PENDIDIKAN KEWARGANEGARAAN UNTUK MENINGKATKAN HASIL BELAJAR SISWA

This research is motivated by the reality of the field when making initial observations that menunyarat that students are considered less active, less attention to the lessons described by teachers. One of the goals of this research is to improve the learning process by using Think Talk Write learning model which aims to improve student learning outcomes. The research design is done through two cycles, starting from planning, execution, observation, reflection, and continuing with next cycle planning. Classroom Action Research took place from January 12, 2017 to March 42017 by using data collection tools from test results and learning outcomes learning instruments. Students' learning outcomes in each cycle experienced an increase evidenced from the results of the cycle I 73% and 86% cycle II. Reinforced by the average of pretest result in cycle 1 is 54,16 while for result of postest for cycle I is 71,25, mean that in cycle I mean result of student learning up 17,09%, while for postest cycle II average 80.4 means that in cycle II the average of student learning outcomes up 9.15%. Based on the data, if the average pretest of cycle I is 54,16 and posttest result of cycle II 80,4 then the average increase of student learning result from pretest cycle I until post cycle II is 26,24%. Thus it can be concluded that using the Think Talk Write (TTW) model can improve student learning outcomes. So it is recommended for teachers related to education to apply and develop the Think Talk Write (TTW) learning model as an alternative in improving student learning outcomes.

THE UTILIZATION OF JIGSAW TECHNIQUE TO IMPROVE WRITING ABILITY IN TEACHING REPORT TEXT

AbstractThis study was designed to improve the students’ writing ability of report text by using Jigsaw technique. This study was conducted in two cycles by following the procedures of the action research. There are planning, implementing, observing, and reflecting. Each cycle consisted of two meetings. The data of the study were gathered through the following instruments, namely observation checklist, questionnaire and test. The subjects of this study were 32 students at eleventh grade of Administrasi Perkantoran (AP) program in academic year 2016-2017 of Nurulhidayah Pasundan Vocational School. The finding of the study indicated that Jigsaw technique was effective in enhancing the students’ motivation and participation. From the result of questionnaire, it showed that 74% students participated actively in the first cycle and 80% students participated in the second cycle. This implied that the first criteria of success had been fulfilled. Furthermore, the finding of the study indicated that Jigsaw technique was successful in improving students’ writing of report text. The improvement could be seen from the increase of students’ mean writing score from 55.09 in the pre-test cycle, and 74.62 in the first cycle increase become 80.46 in the second cycle. If it calculated into class percentage, there were 4 students (12.5 %) who passed KKM in the pre-test. Meanwhile, in the cycle 1, there were 24 students (75%) who passed KKM and it gained which was in the post-test cycle 2 there were 29 students (90.62%) who passed KKM. So, it indicated that the second criteria of success has been achieved. Keywords: Jigsaw technique, writing ability, teaching report text.

PENGGUNAAN MEDIA AUDIO UNTUK MENINGKATKAN KEMAMPUAN MENYIMAK CERITA RAKYAT PADA PADA MATA PELAJARAN BAHASA INDONESIA KELAS V SD NEGERI LENGKONG

This study aims to determine the improvement of listening ability in grade V students in Lengkong State Elementary School using audio media. The type of research used is a case study with Classroom Action Research (collaborative Classroom Action). The form of collaborative classroom action research with colleagues as observers. The subject of this research is the students of grade V of State Elementary School Lengkong which amounted to 18 people. The object of this research is the ability to listen to folklore. The research design used was Kemmis and Mc.Taggart. Data collection methods used in this study are: 1) test, 2) observation, and 3) field notes. Data analysis technique is done descriptively qualitative. The results showed that learning to listen to folklore using audio media can improve the ability of listening to folklore. Based on the results of the pretest cycle 1 students on average get the score of listening ability to students in the first cycle, the students get an average score of 50, then on cycle II score The average class increased to 87.5, this shows there is an increase in listening ability in grade V students on the material Responding to events that occur around orally.

Penerapan Model Pembelajaran Cooperative Learning Tipe Jigsaw II untuk Meningkatkan Aktivitas dan Hasil Belajar Siswa Pada Mata Pelajaran Dasar Teknik Mesin

The purpose of this research is to develop activities and result student learning outcomes inMechanical Engineering Basic using Cooperative Learning Model Type Jigsaw II on XTP1 students atSMKN 6 Bandung. Research method used is the Classroom Action Research (CAR) which consists ofthree cycles. The study conducted by learning begins with pretest and posttest each cycle. Average yieldfor the specialist group activity each cycle as follows: Cycle I 44.16% (being), increase in cycle II to56.83% (being), cycle III to 86% (very high). Then the average home group activity for each cycle asfollows: cycle I 37.5%, increase in cycle II to 69.79% (high). Increased again the third cycle to 93.83%(very High). From the activity affect students’ learning result in each cycle of learning, especially pretestresult and posttest scores : pretest cycle I 48.91 and posttest 63.78 (up 14.84). 61.89 cycle II pretest andposttest 78.78 (up 16.89), 72.56 cycle III pretest and posttest 86.89 (up 14.33). Based on Analysis ofresearch data obtained in the field I nt can be concluded that the application of Cooperation LearningModel Type Jigsaw II can be increase the activity learning and learning result outcomes in subjectMechanical Engineering Basic of XTP1 at SMKN 6 Bandung.

Using cognitive pre-testing methods in the development of a new evidenced-based pressure ulcer risk assessment instrument.

BackgroundVariation in development methods of Pressure Ulcer Risk Assessment Instruments has led to inconsistent inclusion of risk factors and concerns about content validity. A new evidenced-based Risk Assessment Instrument, the Pressure Ulcer Risk Primary Or Secondary Evaluation Tool - PURPOSE-T was developed as part of a National Institute for Health Research (NIHR) funded Pressure Ulcer Research Programme (PURPOSE: RP-PG-0407-10056). This paper reports the pre-test phase to assess and improve PURPOSE-T acceptability, usability and confirm content validity.MethodsA descriptive study incorporating cognitive pre-testing methods and integration of service user views was undertaken over 3 cycles comprising PURPOSE-T training, a focus group and one-to-one think-aloud interviews. Clinical nurses from 2 acute and 2 community NHS Trusts, were grouped according to job role. Focus group participants used 3 vignettes to complete PURPOSE-T assessments and then participated in the focus group. Think-aloud participants were interviewed during their completion of PURPOSE-T.After each pre-test cycle analysis was undertaken and adjustment/improvements made to PURPOSE-T in an iterative process. This incorporated the use of descriptive statistics for data completeness and decision rule compliance and directed content analysis for interview and focus group data. Data were collected April 2012-June 2012.ResultsThirty-four nurses participated in 3 pre-test cycles. Data from 3 focus groups, 12 think-aloud interviews incorporating 101 PURPOSE-T assessments led to changes to improve instrument content and design, flow and format, decision support and item-specific wording. Acceptability and usability were demonstrated by improved data completion and appropriate risk pathway allocation. The pre-test also confirmed content validity with clinical nurses.ConclusionsThe pre-test was an important step in the development of the preliminary PURPOSE-T and the methods used may have wider instrument development application. PURPOSE-T proposes a new approach to pressure ulcer risk assessment, incorporating a screening stage, the inclusion of skin status to distinguish between those who require primary prevention and those who require secondary prevention/treatment and the use of colour to support pathway allocation and decision making. Further clinical evaluation is planned to assess the reliability and validity of PURPOSE-T and it’s impact on care processes and patient outcomes.

Penerapan Metode Scramble Untuk Meningkatkan Prestasi Belajar Ski Kelas V Mi Al-Iman Sorogenen

Abstract This study aims to determine the planning scramble method is applied in teaching Islamic Cultural History (SKI), to determine the feasibility of the methods scramble on the subjects of Cultural History of Islam and this research is also expected to improve student achievement in grade V MI Al-Iman Sorogenen. This type of research is the Classroom Action Research (Classroom Action Research) conducted in MI Al-Iman Sorogenen. This study uses two cycles of learning with two meetings in the first cycle, and the first meetings on the second cycle. The method used to scramble method is applied with a group discussion on the cycle I and II. In the discussions, the students were divided into small groups resulting in effective information exchange among members. The results showed that the planning of the use of methods scramble on learning SKI class V MI Al-Iman Sorogenen running smoothly starting from the manufacture of Learning Implementation Plan (RPP), card making questions and answer cards, make sheets of pre-test and post-test, and make the observation sheet , Scramble method can also be implemented and applied in teaching Islamic Cultural History, with the effect size of 7.3. Improved student achievement shows the average value of pre test cycle I is 46.6% increase in post test becomes 53.33%. While in the second cycle showed an increase learning achievement of the average value of pre-test 53.33% increase in post-test to 80%. Thus, an increase learning achievement SKI class V MI Al-Iman Sorogenen based on the results of post test is 26.7%. Keyword: scramble method, achievement

Rate‐Dependent AV Nodal Function: Closely Bound Conduction and Refractory Properties

The atrioventricular node (AV) node conducts slowly and filters atrial impulses. Puzzlingly, the recovery (conduction time vs atrial cycle length) and refractory curve (His bundle cycle length vs atrial cycle length) characterizing AV nodal function undergo disparate rate-dependent changes. We sought the functional origin and significance of these disparate changes. Differences between the recovery and refractory curve were assessed in 30 steady state AV nodal responses (all potential paired combinations between 5 basic and 6 pretest cycle lengths imposed with S(1)S(2)S(3) protocols) in rabbit heart preparations. Five of these responses corresponded to standard premature protocols. Both basic and pretest cycle length shortenings increased pretest conduction time that in turn equally shortened the ensuing His-atrial interval at all test cycle lengths. This effect was mathematically predictable and tended to shift the refractory curve downward whereas not affecting the recovery curve. Moreover, increases in pretest conduction time also shifted the recovery and refractory curve equally rightward on their x-axis, thereby biasing curve comparison between steady states. This problem could be overcome with equivalent results either by accordingly correcting the atrial cycle length or by using the His-atrial interval as the recovery index. Recovery and refractory curves from AV nodal steady state responses including standard premature protocols only differ by the His-atrial interval that decreases with the pretest conduction time. The latter also biases curve comparison between steady states. Rate-dependent AV nodal function is best assessed with recovery curves freed from changes in pretest conduction time.

Rate-dependent AV nodal refractoriness: a new functional framework based on concurrent effects of basic and pretest cycle length

The atrioventricular (AV) node filters atrial impulses. Underlying rate-dependent refractory properties are assessed with the effective (ERPN; longest nonconducted atrial cycle length) and functional (FRPN; shortest His bundle cycle) refractory period determined with premature protocols at different basic rates. Fast rates prolong ERPN and shorten FRPN, but these effects vary with subjects, age, and species. We propose that these opposite and variable effects reflect the net sum of concurrent cumulative and noncumulative effects associated with basic (BCL) and pretest cycle length (PTCL), respectively. To test this hypothesis, we assessed selective and combined effects of five BCL (S1S1) and six PTCL (S1S2) on ERPN, FRPN, and their subintervals (ERPN=A2H2+H2A3 and FRPN=H2A3+A3H3, where A is atrium and H is His bundle) with S1S2S3 protocols in six rabbit heart preparations. At control BCL, PTCL shortenings prolonged ERPN (113+/-12 vs. 101+/-14 ms, P<0.01) as a net result of prolonged A2H2 and curtailed H2A3. At control PTCL, BCL shortenings increased ERPN (127+/-20 vs. 101+/-14 ms, P<0.01) by prolonging A2H2. FRPN did not vary with BCL but decreased (163+/-6 vs. 175+/-10 ms, P<0.01) with PTCL that curtailed H2A3. Equal BCL and PTCL shortenings as in standard protocols prolonged ERPN but left FRPN unchanged. Notably, ERPN and FRPN significantly correlated through their H2A3 subinterval. In conclusion, BCL and PTCL are both important determinants of AV nodal refractoriness and together account for rate-induced changes in ERPN and FRPN observed during standard premature protocols. ERPN and FRPN are related variables. Similar functional rules may govern nodal refractory behavior during supraventricular tachyarrhythmias.

Unified rate-dependent atrioventricular nodal function: Consistent recovery and fatigue properties revealed with S 1S 2S 3 protocols and different recovery indexes

Rate-dependent nodal properties are commonly assessed with premature protocols performed at different basic rates. Because characteristics of responses differ with recovery time index, the true nature of nodal rate-dependent properties is elusive. The purpose of this study was to reveal consistent nodal rate-dependent properties regardless of selected recovery index. With S(1)S(2)S(3) protocols, we independently varied basic and pretest cycle lengths and thereby distinguished cumulative from noncumulative effects of rate on nodal conduction time in rabbit heart preparations. Nodal responses to 30 basic and pretest cycle length combinations (five with identical basic and pretest cycles as in standard protocols) were analyzed using both atrial (AA) and His-atrial (HA) intervals as recovery index. AA and HA curves had an identical shape for any of 30 steady-state conditions. When assessed with constant pretest cycle lengths, cumulative effects (fatigue) of shortened basic cycle lengths were also independent of recovery index. Shortening of pretest cycle length at fixed basic rates led to apparent inhibitory and facilitatory effects when assessed with AA and HA curves, respectively. These effects vanished when a single long cycle was inserted after the pretest cycle. In all responses including those obtained with standard protocols, combined effects of basic and pretest cycle lengths set nodal conduction time. S(1)S(2)S(3) protocols reveal consistent nodal recovery and fatigue properties regardless of recovery index used. Changes in nodal function curves arising from the use of different recovery indexes mainly depend on pretest effects. This study provides a new approach to a unified interpretation of nodal recovery and fatigue properties.