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P Varriale

Publications and source records attributed to P Varriale.

At least 37 records · Page 2Linked to original sources
PubMed1990

Single-lead VDD pacing system.

A single pass ventricular lead with a dual chamber electrode system, designed for VDD pacing, was implanted in 17 patients (11 men, 6 women, aged 53 to 86 years, mean 74) for symptomatic bradycardia due to second-or third-degree AV block and normal sinus node function. Bipolar atrial electrodes, diagonally displaced along the lead axis and positioned within the right atrial cavity, are used to detect atrial activity that is then differentially processed within the pacemaker. P wave amplitude (amp) derived from a PSA-DAA device at implant was 1.38 +/- 0.28 mV. P wave signal amp derived from telemetered atrial electrograms was 1.29 +/- 0.22 mV at predischarge (n = 17), 1.31 +/- 0.24 mV at 3 months (n = 15), 1.30 +/- 0.24 mV at 6 months (n = 8), 1.51 +/- 0.34 mV at 9 months (n = 4), and 1.35 +/- 0.35 mV at 12 months (n = 2); and the far-field QRS signal measured at predischarge was of negligible voltage (0.17 +/- 0.07 mV). The susceptibility of the atrial sensor system to interference was noted with chest wall stimulation and only at higher sensitivities (0.1 to 0.3 mV) and not with isometric arm exercise. Intact VDD pacing function at rest and during exercise was established using Holter and periodic ECG monitoring. Postoperative complications included one lead displacement and one pocket hematoma. Three patients died postimplant of causes unrelated to pacemaker function. Advantages of the single-lead VDD pacing include: (1) elimination of second atrial sensing lead; (2) superior atrial sensing performance; (3) effective resistance to myopotential and far-field signal interference; and (4) stability of postimplant atrial signal amplitude.

Aged↗
PubMed1988

Necropsy study of right atrial appendage: morphology and quantitative measurements.

The right atrial appendage (RAA) of 23 randomly selected autopsied patients was examined at necropsy, and data related to orifice size and appendicular depth measurements and features of the endocardial surface were recorded. The study included 21 men and 2 women aged 71 +/- 15 years (range, 32-91); underlying coronary artery disease was present in 16 patients. The orifice size of the RAA measured 2.0 +/- 1.0 cm (range, 0-5 cm). The orifice size was slightly, but not significantly, smaller in patients over age 70 years compared with those younger than 70. In hearts weighing more than 450 g, the orifice was significantly larger (2.6 cm) than in hearts weighing less (1.4 cm). The appendicular depth averaged 1.2 +/- 0.7 cm (range, 0-2.5 cm), and a significant difference was noted in patients older and younger than 70 years (depth of 0.9 cm vs. 1.5 cm; p less than 0.05). The RAA depth was 0.5 cm or less in 8 patients (35%), 6 of whom represented patients older than 70 years. Antemortem mural thrombi within the RAA were found in three hearts and completely filled the lumen in one. The suitability of the RAA as a site for atrial pacing and secure electrode implantation, particularly when anatomical deficiencies are identified, was also considered. Atrial lead displacement, a relatively common postoperative complication, may be related more to implantation within a shallow appendicular fossa and/or one with larger orifice than to faulty technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Short-term hemodynamic effects of intravenous methyldopa in patients with congestive heart failure.

The acute hemodynamic effects of intravenous methyldopa were studied in six patients with chronic congestive heart failure (New York Heart Association class IV) at 4-6 hours after a 750-mg bolus (period A) and 6-12 hours after a maintenance infusion of 1-2 mg/minute (period B). For period A, the most consistent and striking finding was a significant (48%) fall in pulmonary wedge pressure (33 +/- 6 to 17 +/- 2 mm Hg; p less than 0.05). Stroke volume increased 39% (23 +/- 3 to 32 +/- 4 ml/m2; p less than 0.05), while peripheral vascular resistance decreased 15% (3331 +/- 363 to 2841 +/- 241 dynes.s.cm-5; p less than 0.05). Heart rate fell from 97 +/- 7 to 76 +/- 3 beats/minute (p less than 0.05) with a nonsignificant decline in mean right atrial pressure (18 +/- 4 to 9 +/- 1 mm Hg). These hemodynamic changes were either sustained or enhanced during period B. Concomitant clinical improvement was also noted. As an agent with potent vasodilatory and antiadrenergic properties, methyldopa permitted a rise in stroke volume by virtue of unloading and possible inhibition of sympathetic activity that led to increased density of beta-adrenergic receptors of the heart (up-regulation). Significant reduction of ventricular filling pressure was attributed to venodilation and probable improved diastolic function. In selected patients with severe congestive heart failure, particularly underscored by excessive sympathetic tone, methyldopa may be considered as an alternative agent to improve cardiac performance and clinical symptomatology.

Aged↗
PubMed1984

Intravenous nitroglycerin in transfusion therapy for severe anemia. Association with congestive heart failure.

The risk of aggravated heart failure due to expanded blood volume and augmented left-ventricular filling pressure poses a challenge when transfusion is indicated by severe anemia complicating congestive heart failure. Intravenous (IV) nitroglycerin therapy produces a favorable redistribution of circulating blood volume and may be used to surmount these hemodynamic constraints during transfusion. In four patients with severe anemia and cardiac failure, IV nitroglycerin permitted rapid and large-volume blood transfusion without compromising cardiac function. In two of the four patients, recalcitrant unstable angina abated after the correction of anemia.

Aged↗
PubMed1983

Atrial flutter secondary to hypokalemia.

Electrophysiologic studies support significant hypokalemia as a cause of atrial flutter in a patient without manifest heart disease. Atrial flutter, reproducibly initiated and terminated by rapid atrial pacing during hypokalemia, was not inducible after potassium correction. In an individual with existing atrial conduction disease, hypokalemia may generate both non-uniform atrial refractoriness and atrial premature beats, and it may facilitate the development of atrial flutter as a re-entrant arrhythmia.

Aged↗
PubMed1982

The "lead tug" sign for the diagnosis of early and inapparent lead fracture.

The cause of pacemaker malfunction in a patient having intermittent pacing failure associated with diminished pacer stimuli was not determined during conventional intraoperative electrical testing. A modest manual pull on the lead, termed the "lead tug" sign, induced an inordinately high lead impedance and established lead fracture as the etiology. The "lead tug" maneuver is proposed as a useful procedure during stimulation studies for the detection of early lead fracture, not apparent from the x-ray film or usual testing protocol.

Aged↗
PubMed1978

Unipolar ventricular electrogram in the diagnosis of right ventricular ischemic injury.

Unipolar ventricular electrograms were recorded in the right ventricular apical area in five patients with clinical, hemodynamic features of the right ventricular infarction. The intracavitary potential exhibited a downward displacement of the ST segment (1.5 mV). This significant negative current of injury in the ventricular electrogram is consistent with ischemic injury of the free right ventricular wall in the area subtended by the intracavitary exploring electrode. We suggest that ventricular electrographic recordings be performed in patients who present with acute inferior wall infarction requiring temporary electrode catheter pacing for serious AV conduction disturbances. The presence of a significant downward ST segment displacement (1.5 mV) provides further support and an electrical criterion for right ventricular ischemic injury.

Action Potentials↗