Roland Werres

Studies on left ventricular function during sustained ventricular tachycardia

The acute effects of rapid ventricular pacing and sustained ventricular tachycardia on left ventricular function were examined in patients with recurrent sustained ventricular tachycardia. Programmed electrical stimulation and left ventricular hemodynamic measurements were performed in 20 patients (19 men and 1 woman), with an age range of 49 to 79 years (mean 63 +/- 9). Indexes of left ventricular function that were analyzed included left ventricular peak systolic pressure, end-diastolic pressure, first derivative of peak left ventricular pressure (dP/dt) and negative left ventricular dP/dt. Measurements were obtained during sinus rhythm, after paced premature ventricular depolarizations, during rapid ventricular pacing (cycle lengths 600 to 250 ms) and immediately after induction of sustained ventricular tachycardia. Mean left ventricular peak systolic blood pressure was 123 +/- 19 mm Hg during sinus rhythm, decreased to 77 +/- 23 mm Hg (p less than 0.05) at the induction of ventricular tachycardia and remained decreased during arrhythmia (p less than 0.01). Mean left ventricular end-diastolic pressure was 22 +/- 5 mm Hg during sinus rhythm, did not change after arrhythmia induction (22 +/- 9 mm Hg, p greater than 0.2) and remained unchanged during sustained ventricular tachycardia (p greater than 0.2). Mean peak left ventricular dP/dt was 1,400 +/- 620 mm Hg/s in sinus rhythm, decreased to 810 +/- 580 mm Hg/s (p less than 0.05) at ventricular tachycardia induction and remained decreased during sustained ventricular tachycardia (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Electrical Alternans of the ST Segment in Non-PrinzmetaPs Angina

Elevated electrical alternans of the elevated ST segment (STEA) was documented in a patient with non‐Prinzmetals or classical angina and severe atherosclerotic coronary artery disease. STEA was precipitated during graded exercise testing. The disappearance of this phenomenon after aortocoronary bypass surgery suggests that the coronary obstructions were the etiologic factors. These findings emphasize that the STEA may occur in myocardial ischemia caused by conditions other than Prinzmetals angina.

Two‐dimensional Echocardiographic Studies during Sustained Ventricular Tachycardia

We evaluated left ventricular function in patients with recurrent sustained ventricular tachycardia (VT) using two‐dimensional echocardiography (2DE). Thirteen patients, 11 men and 2 women, age range 42–77 (mean 62 ± 12) years were studied in sinus rhythm (SR) and immediately after VT induction. 2DE parameters analyzed included wall motion, mitral valve leaflet motion, and ejection fraction (EF). In SR, 21 segments/walls in 12 patients showed wall motion abnormalities (WMA) ranging from hypokinesis to dyskinesis and one patient had generalized LV hypokinesis. In VT, new WMA were noted in 2 patients. Thirteen segments/walls in 8 patients showed further worsening of pre‐existing WMA. In 1 patient there was worsening of generalized LV hypokinesis. Three patients showed apparent improvement in pre‐existing WMA during VT. In 2 patients large apical aneurysms showed a reduction of dyskinesis in VT. Mitral valve opening was intermittent in patients with shorter VT cycle lengths and was maximal when atrial systole preceded or coincided with ventricular depolarization. Doppler echocardiography in 1 patient confirmed the pattern of intermittent mitral flow, with greatest flow occurring when mitral valve opening occurred well before the QRS peak. In 5 patients, 2DE permitted EF measurements. EF in SR ranged from 24–56% (mean 36 ± 13), decreased to 6–33% (mean 21 ± 11) within the first ten beats of VT and 6–25% (mean 19 ± 8) after twenty beats of VT. EF decreased more in patients with shorter VT cycles as compared to those with longer VT cycle lengths. We conclude: 1) 2DE is feasible during clinical electrophysiologic studies for sustained VT and may be a useful adjunct in studying the physiologic impact of VT; 2) WMA generally worsens during VT but can appear less evident due to declining systolic function in adjacent viable myocardium; 3) VT cycle length is a major determinant of hemodynamic compromise and atrial systole may contribute to cardiac output at slow VT rates.

A Decade of Nuclear Pacing

In April, 1973, a decade‐long study was begun on nuclear‐powered pacemakers. The first 15 of these were designed by the Numec Corporation under a contract from the United States Atomic Energy Commission. Altogether 151 units powered by the isotope Plutonium 238 were implanted in 131 patients; the pacemakers of 4 different manufacturers were used. The last nuclear pacemaker was implanted in January, 1983. The actuarial survival at 10 years was 92%, meeting the original performance goal of the Commission of 90%. Ninety pulse generators are still in service today; 25 patients have died and 36 pulse generators have been replaced with non‐nuclear units. The most common indication for replacement was an inappropriate pacing mode. This high reliability and superior performance suggest that continued use of a radioisotopic power source is justified, particularly if combined with the electronic circuits of todays dual‐chambered, multiprogrammable, and multifunctional pacemakers.

Spontaneous migration of a catheter embolus from the left inferior to the right inferior pulmonary artery

This is the first reported case of a spontaneous migration of an embolized catheter fragment from the left side of the pulmonary arterial system to the right side.