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M Minella

Publications and source records attributed to M Minella.

12 recordsLinked to original sources
PubMed1985

Respiration-dependent ventricular pacing compared with fixed ventricular and atrial-ventricular synchronous pacing: aerobic and hemodynamic variables.

A pacemaker that adapts heart rate in response to the patient's metabolic requirements has been developed. The pacemaker uses breathing frequency and tidal volume as the indicators of physiologic demand. Maximal physical work capacity, anaerobic threshold, oxygen uptake (16 patients) and hemodynamic variables (9 patients) were assessed with fixed rate (VVI), atrial synchronous (VDT/I) and respiration-dependent ventricular (VVI-RD) pacing. All subjects attained their anaerobic threshold in stress tests with VVI pacing. The maximal physical capacity (p less than 0.001), work time to attain the anaerobic threshold (p less than 0.01) and oxygen uptake (p less than 0.001) were significantly greater with VVI-RD than with VVI pacing. The transition from the supine to the standing position was characterized by a significant increase of cardiac index at rest with both VDT/I and VVI-RD pacing as compared with VVI pacing. Progressive increments in the cardiac index and average left ventricular stroke work index were significantly different at submaximal and maximal exercise when VVI and VVI-RD were compared. At maximal exercise, mean cardiac output was also significantly different: 10.21 +/- 2.5 (SD) liters/min with VVI, 11.2 +/- 0.8 liters/min with VDT/I (p less than 0.05) and 12.65 +/- 3.1 liters/min with VVI-RD (p less than 0.05) pacing. Maximal oxygen extraction values were greater with VVI and VVI-RD pacing than with VDT/I pacing. Pulmonary artery end-diastolic pressures at maximal exercise were within the normal range with the three different modes of pacing. In conclusion, there is a significant (25%) improvement in exercise performance with VVI-RD pacing as compared with VVI pacing.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

[Non-invasive recording of the His bundle electrogram: choice of leads and reliability of the "averaging" technic].

An improvement in detecting His bundle activity using a Marquette high resolution Mac unit, without pharmacologic depression of AV node conduction, was obtained with two surface lead systems, which were selected on the basis of the His bundle anatomical position and its electrostimulation axis. In 8 patients the direction of the His bundle bipolar stimulation vector was evaluated in the frontal plane, on the orthogonal leads and with map of the chest potential. In 39 patients the surface recording, using high-gain amplification, filtering between 50-300 Hz and an averaging of 256-512 cycles, was obtained by positioning the electrodes in the following sites: manubrium sterni-xiphisternum-V4. When this lead system failed, it was replaced by another one, which included V4-right sternal and right vertebral border at the level of the 3rd intercostal space. In 24 patients (PR less than 0.16" in 4 cases) intracavitary and surface H-V recording were compared. The surface interval was measured between the apex of the surface "blip" and onset of the QRS. Sensitivity was 86% with a good correlation (r = 0.94) between invasive and non-invasive measurements. The surface leads, in which the His bundle activity was best detected, were the manubrium-xiphisternum (on the midsternal line) and V4-right vertebral border at the 3rd intercostal space level. Our external measurement technique avoids subjective misinterpretations; the surface H-V interval was on an average 6 msec. shorter than the invasive one. The upper normal value of non-invasive H-V interval is therefore 50 msec in our measurement method.

Aged↗
PubMed1979

[Automatic method for the evaluation of the extent of myocardial infarct from the serum of CPK curve].

An off-line system for calculating the extent of infarct from serial serum CPK determinations based on Sobel et al.'s compartmental model is presented. Results in 40 patients with acute infarct in a coronary unit showed that the index of infarct extent had an appreciable prognostic significance. Employment of the MB isoenzyme in the calculation could, it is felt improve the sensitivity of the method.

Adult↗