How many electrocardiographic leads are required for exercise treadmill tests?

Forty-four consecutive patients who had perfusion defects on thallium-201 scanning and positive exercise treadmill tests were prospectively studied. Thirty-eight (86%) subjects had diagnostic ST segment changes in lead V5, 37 (84%) in lead V4, and 44 (100%) in either lead V4, V5 or both. Thirty patients had ST segment changes in the inferior leads, 20 in lead aVR, and only four in lead I and/or aVL. All of these latter subjects had diagnostic ST segments in lead V4 and/or V5. It is concluded that: combined electrocardiographic leads V4 and V5 detect the vast majority of ischemic changes during exercise treadmill testing, regardless of the site of perfusion defects detected by thallium-201 scanning; and monitoring the inferior and lateral leads rarely provides more diagnostic information.

Two-dimensional echocardiographic recognition of an aortic intimal flap prolapsing into the left ventricular outflow tract.

A 59 year old man presented with dyspnea and a new murmur of aortic regurgitation. Two-dimensional echocardiography demonstrated a to and fro motion of the intimal flap as it prolapsed into the left ventricle and was thrust into the aorta during diastole and systole, respectively. At surgery, the echocardiographic and angiographic findings were confirmed and a proximal aortic dissection was identified. Prolapse of an intimal flap from the aorta into the left ventricular outflow tract represents a new two-dimensional echocardiographic sign of aortic dissection.

Phonocardiographic profile of the porcine bioprosthesis in the aortic position.

The phonocardiographic characteristics of the porcine bioprosthesis in the aortic position were evaluated in 24 asymptomatic patients. A medium to high frequency early systolic sound (AO) was present in 16 of 24 patients; abrupt "halting" of the stiff cusps of the porcine bioprosthesis during early left ventricular ejection seems to be the likely mechanism for the genesis of this sound. An unusually high amplitude aortic closing sound (AC) was present in all patients. A high frequency crescendo-decrescendo systolic murmur in early to mid systole was present in 22 patients. Possible mechanisms for the systolic murmur include: 1) altered resonating properties of the cusps, 2) functional bioprosthetic stenosis, and 3) the presence of a flexible stent. An early systolic opening sound preceding a short systolic murmur and a loud closing sound are common phonocardiographic findings of an uncomplicated porcine bioprosthesis in the aortic position. Therefore, absence of the aortic opening sound, alterations in the amplitude of the aortic closing sound, or an increase in the length of the systolic murmur may suggest bioprosthetic malfunction.