In atrial fibrillation, it is known that hemodynamics vary according to the preceding R-R intervals. However, the informations of blood flow dynamics have not been available because of the methodological limitations. In this study, blood flow dynamics of atrial fibrillation were assessed using pulsed Doppler echocardiography. The subjects were 160 consecutive patients with atrial fibrillation and without left ventricular asynergy. Using a commercially-available pulsed Doppler instrument (Aloka SSD-910), blood flow patterns in the left ventricle were investigated from the apical long-axis view. The results were as follows: 1. In 22 of the 160 cases (14%), systolic blood flow in the central or apical region of the left ventricle directed towards the apex (termed "back flow"). 2. In the cardiac cycle with "back flow", the preceding R-R interval was shorter; whereas it was longer when "back flow" was absent (591 +/- 103 vs 817 +/- 179 msec, p less than 0.01). Moreover, when a long R-R interval (PPI) followed by a short R-R interval (PI) was observed (greater PPI/PI ratios), the next beat showed distinct "back flow". 3. Left ventricular ejection fraction decreased significantly in patients with "back flow" compared to those without it (42 +/- 15 vs 66 +/- 12%, p less than 0.01). 4. On left ventriculography, the motion of the base of the heart was preserved; however, with "back flow", the motion of the apical area was abnormal, extending towards the apex along the longitudinal axis. 5. Left ventricular ejection flow at the outflow tract disappeared in 13 of the 22 cases with "back flow" in cardiac cycles with short preceding R-R intervals.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Fibrillation↗

PubMed1987

[A case of constrictive pericarditis associated with coronary artery disease].

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Aged↗

PubMed1987

[Increased anti-tumor activity of chemotherapeutic agents combined with direct current against murine transplanted tumors].

The antitumor activity of direct current was studied in mice which were transplanted fibrosarcoma (FSa) into the right thigh. Mice were inserted electrodes into tumor and normal tissue surrounding the tumor, and treated with constant current. The direct current therapy (D.C.T.) (0.6 mA, 120 min) alone was effective to regress tumor, but tumor was not eradicated by D.C.T. alone. Cyclophosphamide (CPA, 100 mg/kg) could markedly reduce the FSa tumor size, but all tumor regrew finally. When D.C.T. was combined with CPA (100 mg/kg), the therapeutic response of FSa tumor was enhanced in mice which were inserted cathode into tumor. For example, in mice receiving direct current (0.6 mA, 120 minutes), the cure rate was 70% compared with 30% by the anode in tumor. Using cure rate assay, D.C.T. and about half dose of CPA could give the similar treatment results as the full dose of CPA alone. That is, D.C.T. will be able to reduce the dose of chemotherapeutic agents. Combination of D.C.T. and doxorubicin was not so effective as CPA, but showed the similar results. The experimental results suggest that D.C.T. alters the drug distribution in the tumor and makes the drugs more effective.

Animals↗

PubMed1987