A Prototype Coronary Electrode Catheter for Intracoronary Electrogram Recording Lawrence T. Weston, MD. Robert W. Hull. MD. John R. Laird, MD, Yem Chin, and Dale C. Wortham, biD uccessfulcatheter ablation of accessorypathways is critically dependenton precisepathway localization.l S Rapid and precisepathway localization can alsodramatically shorten proceduretimes. Mapping of left-sided accessorypathways is facilitated by use of the coronary sinus which provides a stable conduit for catheter map ping along the left atrioventricular groove. Mapping of right-sided accessorypathways is technically more difficult and requires an appreciation of the radiographic anatomy of the right atrioventricular groove.2The right coronary artery coursesthrough the right atrioventricular groove and can provide a means to record right-sided epicardial electrograms. Localization of right-sided accessorypathways using the right coronary artery was first reported in 1990 by Swartz et a1.3In 1991 Lesh et al4 reported their experiencewith thii technique.In both of theseinvestigations,a 2.2Fr wire manufactured for pacing purposeswas modified to record unipolar electrograms.The initial experiencein a combinedtotal of 10patients suggestedthat this techniquewassafeand effective.The particular technology used in these cases,however, has several disadvantages. First, the recording wire is stiff and subjectspatients to the risks of intimal dissection, perforation or coronary artery spasm. Second, repeated mapping requires that the wire traverse the coronary artery each time. Finally, only unipolar electrogram recordings are possible. We have developed a coronary electrode catheter (CEC) for use in recording epicardial electrograms via the coronary artery tree (Figure 1). A standard 3-lumen 4SFr coronary angioplasty catheter was modified (Boston Scientific Corporation, Watertown, Massachusetts) by mounting tantalum ring electrodes to the catheter shaft and cold-soldering them to wire conductors located in the intation and vent lumens. These conductors were then connected to pin electrodes for use with a recording system. This CEC permits mapping of the coronary artery over 0.014- and 0.018~inch guidewires. It was believed that this system would allow for safer manipulation within the coronary artery, facilitate repeated mapping since the catheter tracks over a guidewire, and allow for both untplar and bipolar electrogram recording. As an initial test of this system’s safety and efficacy we performed coronary arterial mapping during sinus rhythm and right ventricular pacing in 5 swine (protocol approved by the Department of Clinical Znvestigations). While under general anesthesia, the swine underwent cutdown and cannulation of the internal jugular vein and From the Cardiology Service, Walter Reed Army Medical Center, Washington, D.C. 20307-5001.Manuscript received April 23, 1992; revisedmanuscript receivedJune l&1992, and acceptedJune 22. The opinionsand assertionscontainedherein are the private views of the authorsand are not to be construedasoffkial or as reflecting the views of the Department of the Army or the Department of Defense.
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THE AMERICAN JOURNAL OF CARDIOLOGY VOLUME 70
carotid artery. After 10,000 U of heparin sulfate was administered intravenously, a quadripolar electrode catheter was advanced through a 6Fr internal jugular sheath to the right ventricular apex. Through an 8Fr arterial sheath, a standard 4Fr angioplasty guiding catheter was used for intubation of the coronary arterial ostia. After administration of 200 pg of intracoronary nitroglycerin and baseline angiography, a 0.014~inch jloppy-tipped guidewire was advanced down a major epicardial coronary artery. The CEC was then advanced over the guide-wire to the most distal segments of the vessel. While maintaining the distal guidewire position, the CEC was withdrawn in 1 cm increments. At each location, tracings from surface leads Z and aVF and bipolar electrograms from the right ventricular apex and CEC were recorded during sinus rhythm and right ventricular pacing. Cine radiography was performed in 2 orthogonal views at each site of electrogram recording. The mapping procedure lasted approximately 10 minutesper artery. At the conclusion of the recording, angiography was repeated. This procedural sequence was repeated for each major epicardial vessel. At the end of the study the swine were killed and the hearts harvested for gross pathologic examination. Each major epicardial coronary artery (anterior descending, circumflex ana’ right) and adequate-sized branches of these vessels (diagonals, marginals, posterior descending) were successfully cannulated in every animal so that a total of 23 arterial segments were studied. Zntimal disruption or dissection was not observed angiographically or on gross pathologic examination. One swine had diffuse right coronary artery spasm after catheter mapping, but angiography performed after a second dose of intracoronary nitroglycerin documented complete resolution of spasm. High-quality bipolar electrograms were recorded from all sites (Figure 2). Both atria1 and ventricular electrograms were recorded from the right and left circumjlex coronary arteries during sinus rhythm and ventricular pacing.
FIGURE 1. Coronmy DECEMBER 1, 1992
ebcbode
cathe&.
In this report we describe a newly developedCEC designedfor intracoronary mapping of accessorypathways. Intracoronary catheter manipulation over a guidewire appearssafe,and high-quality bipolar electrograms can be recorded.Since its initial development,the CEC has been further relined to include reduction to 2.7Fr. Further testing in a patient population is required but, if proved safe and effective, the CEC has obvious applications to electrophysiologicstudies.
FlGUREZlnbWOWYW rioht-~Mnl~mu3hm.~c=-
tmadedfromuse
eleddeccheteqRv=fight-.
1. Hung S. Advances in applications of radiofrequency current to catheter ablation therapy. PACE 1991;14:28-42. 2. Szabo T’S, Klein GJ, Guiraudon GM, Yee R, Arjun DS. Localization of accessorypathways in the Wolff-Parkinson-White syndrome. PACE 1989;12: 1691-1705. 3. Swartz J, Fletcher R, CohenA, WestonL, Wish M, JonesJ. Endccardialatria1 catheter ablation of accessorypathway after intravascular localization (abstr). PACE 1990.13527. 4. LeschMD, Van Hare GF, Chien WW, ScheinmanMM. Mapping in the right coronary artery as an aid to radiofrequency ablation of right-sided accessory pathways (abstr). PACE 1991;14(supplII):II-671.
Effects of Acute Expure to Altit+e (3,460 F) on SlOpa Pressure ~~n~;nDynamlc and lsometrw Exercise In Men wth Systemic I Stefano Savonitto, MD, Giovanni Cardellino, MD, Giulio Doveri, MD, Silvia Pernpruner, MD, Roberto Bronzini, MD, Nicole Milloz, MD, M. Delia Colombo, MD, Marco Sardina, MD, Guido Nassi, and Paolo Marraccini, MD he effects of the acute exposure to altitude on the cardiovascular system have been extensively studied.1-4In normal subjects,reports on blood pressure(BP) changesassociatedwith initial exposureto altitude lack generalagreement:someinvestigatorshavefound a small increase,5v6others a small reduction7*8and others no change.9-11Two articles have recently reported BP reactivity at altitude in patients with systemicarterial hypertension,showing that the exposureto an altitude between 2,500 and 3,000 m induces a small increase in systolic BP6or no changeat all.12Neither study investigatedthe BP responseto exerciseduring acute exposureto altitude. The subject is of practical relevancesince many uncomplicated hypertensivesubjectsare discouragedfrom hiking or skiing at altitudes for fear that acute hypoxia may produce excessivehypertension. In this study we investigated the effectsof an acute changein altitude of 2,090m on BP and heart rate responsivenessto dynamic and isometric exercise in untreated hypertensive patients.
graphic abnormalities suggesting coronary artery diseaseor a previous cerebrovascular accident, chronic lung disease and any metabolic or hematologic disorder. Six patients had a normal resting electrocardiogram, whereas 6 had left ventricular hypertrophy by voltage criteria. Ten were being treated with antihypertensive medications which were withdrawn 12 weeks before the study was performed. The study was performed on 2 consecutive days, in Courmayeur, on the Italian side of Mont Blanc. Two comfortable rooms were prepared for the study, 1 at the lower station of the ‘%univie de1 Monte Bianco” cable car, at 1,370 m (4,5OOfeet), and 1 at the upper station, at 3,460 m (11,350 feet). The temperature of both rooms was kept between 20 and 24°C. On each study day, 6 patients drove by car to the lower station of the cable car, where their baseline BP values were recorded and they were randomized to 1 of 2 alternative experimental sequences: those randomized to sequence A performed Eleven men aged 31 to 69 years with mild and moder- their exercise tests first at 3,460 m and then at 1,370 m, ate essential hypertension who hiked regularly at mod- while those randomized to sequence B first exercised at erate altitudes were selected among those referred to the 1,370 m and then at 3,460 m. All the exercise tests were performed between 9 A.M. Hypertension Clinic of the General Hospital of Aosta. None of these men lived at an altitude of >1,500 m. and 1 P.M. 20 to 90 minutes after having reached the test altitude. During the tests, BP was measured by a cuff Exclusion criteria were severe hypertension (>200/115 mercury sphygmomanometer placed on the nondomimm Hg while untreated), a history or electrocardionant arm, and heart rate from the electrocardiogram. The patients first performed the isometric test by From the Servizio di Cardiologia, Policlinico San Marco, 24040 Zin- squeezing with their dominant arm a graduated digital gonia (BG), Italy; and Centro IpertensioneOspedaleRegionale Aosta; Istituto di Fisiologia Clinica C.N.R., Pisa, Italy. Manuscript received dynamometer for 2 minutes at 50% of their maximal April 1.1992; revisedmanuscript receivedand acceptedJune 15,1992. hand strength, which was measured at both altitudes. T
BRIEF REPORTS 1493
1492
THE AMERICAN JOURNAL OF CARDIOLOGY VOLUME 70
carotid artery. After 10,000 U of heparin sulfate was administered intravenously, a quadripolar electrode catheter was advanced through a 6Fr internal jugular sheath to the right ventricular apex. Through an 8Fr arterial sheath, a standard 4Fr angioplasty guiding catheter was used for intubation of the coronary arterial ostia. After administration of 200 pg of intracoronary nitroglycerin and baseline angiography, a 0.014~inch jloppy-tipped guidewire was advanced down a major epicardial coronary artery. The CEC was then advanced over the guide-wire to the most distal segments of the vessel. While maintaining the distal guidewire position, the CEC was withdrawn in 1 cm increments. At each location, tracings from surface leads Z and aVF and bipolar electrograms from the right ventricular apex and CEC were recorded during sinus rhythm and right ventricular pacing. Cine radiography was performed in 2 orthogonal views at each site of electrogram recording. The mapping procedure lasted approximately 10 minutesper artery. At the conclusion of the recording, angiography was repeated. This procedural sequence was repeated for each major epicardial vessel. At the end of the study the swine were killed and the hearts harvested for gross pathologic examination. Each major epicardial coronary artery (anterior descending, circumflex ana’ right) and adequate-sized branches of these vessels (diagonals, marginals, posterior descending) were successfully cannulated in every animal so that a total of 23 arterial segments were studied. Zntimal disruption or dissection was not observed angiographically or on gross pathologic examination. One swine had diffuse right coronary artery spasm after catheter mapping, but angiography performed after a second dose of intracoronary nitroglycerin documented complete resolution of spasm. High-quality bipolar electrograms were recorded from all sites (Figure 2). Both atria1 and ventricular electrograms were recorded from the right and left circumjlex coronary arteries during sinus rhythm and ventricular pacing.
FIGURE 1. Coronmy DECEMBER 1, 1992
ebcbode
cathe&.
In this report we describe a newly developedCEC designedfor intracoronary mapping of accessorypathways. Intracoronary catheter manipulation over a guidewire appearssafe,and high-quality bipolar electrograms can be recorded.Since its initial development,the CEC has been further relined to include reduction to 2.7Fr. Further testing in a patient population is required but, if proved safe and effective, the CEC has obvious applications to electrophysiologicstudies.
FlGUREZlnbWOWYW rioht-~Mnl~mu3hm.~c=-
tmadedfromuse
eleddeccheteqRv=fight-.
1. Hung S. Advances in applications of radiofrequency current to catheter ablation therapy. PACE 1991;14:28-42. 2. Szabo T’S, Klein GJ, Guiraudon GM, Yee R, Arjun DS. Localization of accessorypathways in the Wolff-Parkinson-White syndrome. PACE 1989;12: 1691-1705. 3. Swartz J, Fletcher R, CohenA, WestonL, Wish M, JonesJ. Endccardialatria1 catheter ablation of accessorypathway after intravascular localization (abstr). PACE 1990.13527. 4. LeschMD, Van Hare GF, Chien WW, ScheinmanMM. Mapping in the right coronary artery as an aid to radiofrequency ablation of right-sided accessory pathways (abstr). PACE 1991;14(supplII):II-671.
Effects of Acute Expure to Altit+e (3,460 F) on SlOpa Pressure ~~n~;nDynamlc and lsometrw Exercise In Men wth Systemic I Stefano Savonitto, MD, Giovanni Cardellino, MD, Giulio Doveri, MD, Silvia Pernpruner, MD, Roberto Bronzini, MD, Nicole Milloz, MD, M. Delia Colombo, MD, Marco Sardina, MD, Guido Nassi, and Paolo Marraccini, MD he effects of the acute exposure to altitude on the cardiovascular system have been extensively studied.1-4In normal subjects,reports on blood pressure(BP) changesassociatedwith initial exposureto altitude lack generalagreement:someinvestigatorshavefound a small increase,5v6others a small reduction7*8and others no change.9-11Two articles have recently reported BP reactivity at altitude in patients with systemicarterial hypertension,showing that the exposureto an altitude between 2,500 and 3,000 m induces a small increase in systolic BP6or no changeat all.12Neither study investigatedthe BP responseto exerciseduring acute exposureto altitude. The subject is of practical relevancesince many uncomplicated hypertensivesubjectsare discouragedfrom hiking or skiing at altitudes for fear that acute hypoxia may produce excessivehypertension. In this study we investigated the effectsof an acute changein altitude of 2,090m on BP and heart rate responsivenessto dynamic and isometric exercise in untreated hypertensive patients.
graphic abnormalities suggesting coronary artery diseaseor a previous cerebrovascular accident, chronic lung disease and any metabolic or hematologic disorder. Six patients had a normal resting electrocardiogram, whereas 6 had left ventricular hypertrophy by voltage criteria. Ten were being treated with antihypertensive medications which were withdrawn 12 weeks before the study was performed. The study was performed on 2 consecutive days, in Courmayeur, on the Italian side of Mont Blanc. Two comfortable rooms were prepared for the study, 1 at the lower station of the ‘%univie de1 Monte Bianco” cable car, at 1,370 m (4,5OOfeet), and 1 at the upper station, at 3,460 m (11,350 feet). The temperature of both rooms was kept between 20 and 24°C. On each study day, 6 patients drove by car to the lower station of the cable car, where their baseline BP values were recorded and they were randomized to 1 of 2 alternative experimental sequences: those randomized to sequence A performed Eleven men aged 31 to 69 years with mild and moder- their exercise tests first at 3,460 m and then at 1,370 m, ate essential hypertension who hiked regularly at mod- while those randomized to sequence B first exercised at erate altitudes were selected among those referred to the 1,370 m and then at 3,460 m. All the exercise tests were performed between 9 A.M. Hypertension Clinic of the General Hospital of Aosta. None of these men lived at an altitude of >1,500 m. and 1 P.M. 20 to 90 minutes after having reached the test altitude. During the tests, BP was measured by a cuff Exclusion criteria were severe hypertension (>200/115 mercury sphygmomanometer placed on the nondomimm Hg while untreated), a history or electrocardionant arm, and heart rate from the electrocardiogram. The patients first performed the isometric test by From the Servizio di Cardiologia, Policlinico San Marco, 24040 Zin- squeezing with their dominant arm a graduated digital gonia (BG), Italy; and Centro IpertensioneOspedaleRegionale Aosta; Istituto di Fisiologia Clinica C.N.R., Pisa, Italy. Manuscript received dynamometer for 2 minutes at 50% of their maximal April 1.1992; revisedmanuscript receivedand acceptedJune 15,1992. hand strength, which was measured at both altitudes. T
BRIEF REPORTS 1493
