No abstract

No abstract

The ST segment electrical axis in the frontal plane was calculated in 20 patients with an acute inferior myocardial infarction (AIMI) and another 20 patients with the acute phase of pericarditis (AP). The ST segment axis of patients with AIMI ranged from 100 degrees-120 degrees (mean 114 degrees). The ST segment axis of patients with AP ranged from 30 degrees-60 degrees (mean 45 degrees). Thus, the ST segment axis can be used for the differential diagnosis in the early acute phase, especially when there are no other important distinguishing factors between these two conditions.

The new terminology "Q and non-Q wave myocardial infarction" (MI) tends to replace the traditional terms "transmural" and "subendocardial" MI since the anatomy cannot be accurately predicted by electrocardiography. Although some subtypes of non-QMI display a favorable early or in-hospital prognosis, the long-term outlook seems less benign, particularly when early or late recurrence of MI occurs. Coronary arteriograms show an equal number of diseased vessels in both types of MI, but complete coronary artery occlusion is less frequent in non-QMI. The management of patients with non-QMI should be mainly directed to preventing extension or recurrence of MI by using either drugs such as thrombolytic agents and drugs against coronary artery spasm or invasive techniques like percutaneous transluminal coronary angioplasty.

The effect of nifedipine (N) on sinus node (SN) function was studied in 15 patients (9 males, 6 females) sixty-two to seventy-six (mean 68.1 +/- 11) years old, with sick sinus syndrome (SSS). SSS was characterized electrophysiologically by a prolonged corrected sinus node recovery time (CSNRT greater than 535 msec) and/or prolonged sinoatrial conduction time (SACT greater than 125 msec), assessed by applying premature atrial stimulation. Ten mg N was given sublingually, and CSNRT and SACT were again evaluated sixty minutes after N administration, and again ten minutes after 1.5 mg atropine (A) was given IV. Heart rate increased significantly after N (p less than 0.005), systolic blood pressure (SBP) diminished significantly (p less than 0.005), and CSNRT and SACT shortened significantly (p less than 0.005, p less than 0.005) and became normal in 7 and 5 patients respectively. After A administration, a further significant increase of heart rate (p less than 0.005) and decrease of CSNRT (p less than 0.005) and SACT (p less than 0.005) were observed. CSNRT and SACT became normal in 8 and 7 patients respectively. SBP remained stable.