Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.

Q: Abstract: Atrial pacing was performed in 16 patients with angina at rest and significant coronary artery stenosis (greater than 70%) over 2 consecutive days in the morning (10 A.M. to 1 P.M.), in the afternoon (4 to 7 P.M.), and at night (12 midnight to 3 A.M.) to assess possible circadian variations of their ischemic threshold. Overall, the incidence of resting angina was highest at night. All pacing results were positive (greater than or equal to 1.0 mm ST segment shift) and tended to be reproducible in nine patients, whereas some or all were negative in seven. Among all positive results, ischemic thresholds at night were significantly lower than those in the morning and in the afternoon (125 +/- 3 vs 138 +/- 3 and 139 +/- 2 beats/min, mean +/- SEM; p less than .005). In nine patients, 19 pacing tests produced ST segment elevation, of which 13 were performed at night (68%). We conclude that patients with resting angina and severe coronary stenosis often exhibit a nocturnal decline in their ischemic threshold, which seems to facilitate development of transmural ischemia during atrial pacing.

A: Resting angina with fixed coronary artery stenosis: nocturnal decline in ischemic threshold.
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Q: Abstract: Two cases of osteochondritis dissecans of the talar dome treated by closed percutaneous drilling are presented to illustrate a procedure for high-risk patients. The operation is performed with the aid of an image intensifier. The ostoechondral fragment is percutaneously drilled to avoid open operation and osteotomizing the medial malleolus.

A: Closed percutaneous drilling for osteochondritis dissecans of the talus. A report of two cases.
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Q: Abstract: A case is reported of fracture of the pedicles of the axis vertebra in an infant. Non-operative management in a Minerva cast resulted in union and full recovery without complications.

A:
Hangman's fracture in an infant.
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