Further investigation of the late morning peak and of precipitants of ventricular tachyarrhythmias by use of data from the implantable cardioverter/defibrillator may provide insight into the pathophysiological mechanisms causing sudden cardiac death.
The effects of a 15-week quantitated training program were evaluated in nine men, 32 to 59 years old. All had been blind for 10 years or more but were otherwise in good health. They were sedentary with a stable activity pattern. Training sessions were held three times per week and consisted of four 3-minute exercise periods on a bicycle ergometer, each followed by a rest period of equal duration. Heart rates at the end of the fourth exercise period averaged 27 beats below individual maximal heart rates.
Maximal oxygen uptake increased from 24.0 to 28.5 ml/kg x min or by 19%. Total heart volume and mean serum cholesterol decreased significantly, and psychological tests showed improvement.
Five subjects continued exercising at the same intensity but only once weekly for another 14-week period. Mean maximal oxygen uptake decreased to 6% above the control level. Four subjects who discontinued training after 15 weeks were retested at the same time and had a mean value 5% below control maximal oxygen uptake.
The effects of maximal, voluntary isometric handgrip exercise on the intensity of cardiac murmurs was evaluated in 36 patients and the results compared with the effects of amyl nitrite and phenylephrine. The isometric handgrip exercise produced immediate, reproducible, and significant increases in heart rate and blood pressure. It also increased the intensity of murmurs due to aortic and mitral regurgitation and mitral stenosis and attenuated the murmurs of left ventricular outflow tract obstruction.
Internal mammary artery (IMA) grafts were performed without optical assistance in 175 consecutive patients during a 17-month period. The predominant indications were angina pectoris and the angiographic evidence of a 70% or greater obstruction in one or more major coronary arteries. Eight patients were considered to be in New York Heart Association functional class I, 63 class II, 71 class III, and 33 class IV before the operation. Forty per cent had three major vessels obstructed, and 33% had double vessel disease. IMA grafts were constructed to the anterior descending artery in 151 patients, diagonal branch in 22, and circumflex in two. Two of the 175 and three additional patients had free IMA grafts in the aortocoronary position. Saphenous vein grafts were combined with IMA grafts in 61%. One hospital death occurred, a 0.6% operative mortality.
Late clinical results were analyzed in the first 100 patients. Eighty-four of 99 have had complete remission of angina, and 12 are improved. Repeat arteriograms in 65 patients show 65 of 67 IMA grafts open (97%) and 56 (85%) of 66 saphenous vein grafts patent after an average interval of four months.
These early clinical and angiographic results are encouraging and indicate that the higher IMA patency may result from less size discrepancy between the graft and the coronary artery. The addition of the technically more complicated IMA graft to direct revascularization does not increase morbidity or mortality.
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