Traumatic left ventricular papillary muscle rupture: the role of transesophageal echocardiography in diagnosis and surgical management.

We report a case of left ventricular posteromedial papillary muscle rupture caused by blunt chest trauma. Transesophageal echocardiography was used to establish the diagnosis and to assist with surgical repair of the mitral valve apparatus. Echocardiographic findings of the acutely ruptured papillary muscle are reviewed.

Theophylline--an alternative therapy for bradyarrhythmia in the elderly.

Treating elderly debilitated patients with symptomatic bradyarrhythmia may be difficult. Traditional therapy includes use of limited resources (intensive care unit monitoring) and expensive interventions (permanent pacemaker insertion). When a pacemaker is not ideal or appropriate, yet intervention is desired to improve quality of life, theophylline may be a safe and effective alternative therapy. We expanded this use of theophylline in a series of 11 patients admitted 14 consecutive times with hemodynamically compromising bradyarrhythmias, including atropine-resistant complete heart block with idioventricular rhythm. Three patients experienced deterioration of status and recurrence of bradycardia with the withdrawal or reduction of theophylline, and subsequent recovery of heart rate and conduction with its resumption.

Measurement of cardiac output using improved chromatographic analysis of sulfur hexafluoride (SF6).

A constant current variable frequency pulsed electron capture detector has been incorporated into the gas chromatographic analysis of trace amounts of sulfur hexafluoride (SF6) in water and blood. The resulting system offers a broader effective operating range than more conventional electron capture units and has been utilized for measurements of cardiac output employing constant-rate infusion of dissolved SF6. The SF6 technique has been validated against direct volumetric measurements of cardiac output in a canine right-heart bypass preparation and used subsequently for rapidly repeated measurements in conscious animals and man.

Tone-dependent waterfall behavior during venous pressure elevation in isolated canine hearts.

We examined the "vascular waterfall" hypothesis, which proposes that coronary flow is unaffected by elevations in outflow pressure until the latter reaches a critical threshold level, in 29 isolated canine hearts. In fibrillating hearts vasodilated with adenosine or carbocromen, coronary flow and the coronary pressure-flow relation were not affected by changes in great cardiac vein pressure (PGCV) below a threshold value of 11 +/- 0.9 (mean +/- SEM) mm Hg. Further elevations of PGCV reduced flow and shifted the pressure-flow relation to the right, increasing its pressure-axis intercept (Pf=0). When vasomotor tone was augmented with vasopressin, threshold PGCV increased to 25 +/- 2.7 mm Hg (p less than 0.001). Once again, the pressure-flow relation was unaffected by changes in PGCV below the threshold value and shifted to the right when this value was exceeded. The amount by which spontaneous values of Pf=0 exceeded threshold values of PGCV was greater when vasomotor tone was augmented than during vasodilation. Pf=0 continued to exceed PGCV when the latter was raised above the threshold level. Both Pf=0 and threshold values of PGCV were less during a long diastole than during ventricular fibrillation. We reached the following conclusions. 1) During changes in PGCV below a threshold value, the coronary circulation exhibits traditional waterfall behavior. 2) The threshold pressure for altering waterfall behavior is affected by vascular tone and mechanical activity. 3) Pf=0 remains above PGCV when the latter is increased above the threshold value needed to alter flow.