ABSTRAKRuang Lingkup dan Cara Penelitian: Dalam bidang kardiologi untuk menilai fungsi jantung sering digunakan pembebanan. Biasanya dilakukan pembebanan dalam bentuk kerja isotonik. Pada keadaan dimana tidak dapat dilakukan kerja isotonik, dapat dilakukan pembebanan dengan kerja isometrik (handgrip test) untuk menilai fungsi jantung.Penelitian ini bertujuan untuk mengetahui pengaruh pembebanan kerja isometrik dan isotonik yang sesuai terhadap fungsi ventrikel kiri dengan STI dan konsumsi oksigen miokardium dengan Tri-produk yang menimbulkan peningkatan frekuensi jantung yang sama.Pemeriksaan dilakukan pada 50 pria sehat, usia 20-25 tahun terhadap STI (QS2, LVET, PEP dan ratio PEP/LVET), tekanan darah dan Tri-produk (FJ x TD rata-rata x LVET) dalam keadaan istirahat, waktu kerja isometrik (handgrip test) dan kerja isotonik (ergometer sepeda). Hasil penelitian dianalisis secara statistik.Hasil dan Kesimpulan: Terdapat pemendekan bermakna (p<0,05) pads lamanya QS2, LVET dan PEP pada kedua jenis kerja dibandingkan istirahat. Pemendekan QS2 dan PEP waktu kerja isotonik lebih besar secara bermakna (p<0,05) dibandingkan kerja isometrik, sedangkan pemendekan LVET waktu kerja isotonik tidak berbeda bermakna (p>0,05) dibandingkan kerja isometrik. Tidak terdapat perubahan pada fungsi ventrikel kiri yang dinilai dari ratio PEP/LVET waktu kerja isometrik dibandingkan kerja isotonik. Tekanan darah sistolik, diastolik dan rata-rata waktu kerja isometrik lebih besar secara bermakna (p<0,05) dibandingkan kerja isotonik. Tidak terdapat perbedaan bermakna {p>0,05) antara tekanan darah diastolik waktu kerja isotonik dibandingkan istirahat. Tri-produk waktu kerja isometrik adalah rata-rata 30% lebih besar dibandingkan kerja isotonik dengan peningkatan frekuensi jantung yang sama, hal mans menatakan bahwa pembebanan jantung dengan kerja isometrik cukup berat dan dapat digunakan untuk menilai fungsi jantung.

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ABSTRACT

Evaluation Of The Left Ventricular Function And Myocardial Oxygen Consumption During Isometric Work By Way Of Measurement Of Systolic Time IntervalsScope and Method of Study: Loading the heart during the evaluation of its function is a frequently used method. Usually the heart is loaded by isotonic work, like the ergo cycle or the treadmill test. But in cases where isotonic cannot be performed, loading the heart with isometric work (handgrip test) can also be used. The purpose of this research work is to examine the effect of isometric and isotonic work of equivalent intensity on the left ventricular function and on the myocardial oxygen consumption as evaluated respectively by the STI and Tri-product.

Examination of the STI (QS2, LVET, PEP and PEP/LVET), heart rate, arterial blood pressure and tri-product were performed on 50 young males, age 20 - 25 years, at rest and at the end of isometric work (handgrip test) and isotonic work (ergo cycle). The results are statistically analyzed.

Findings and Conclusions: A statistically significant (p 4 0.05) decrease in the duration of Q52, LVET and PEP is found during both kinds of work when compared to values at rest. The decrease in QS2 and PEP during isotonic work is greater as compared to those during isometric work, which is statistically significant (p 4 0.05). However, the duration of LVET during both kind of work. does not differ significantly. There is also no statistic-ally significant difference in the left ventricular function as evaluated by PEP/LVET between the two kind of work. The rise in systolic, diastolic and mean blood pressure is higher during isometric work as compared with isotonic work, which is statistically significant (p < 0.05). There is no significant difference in the diastolic blood pressure during isotonic work and rest (p > 0.05). The tri-product calculated for isometric work is on the average 30 % higher than for isotonic work, which means that loading the heart with isometric work will be sufficiently high for the purpose of evaluating the performance of the heart.