Volume 129, Number 1 American Heart Journal Brooks, Jackson, and McGovern 195

:.2: J . . . . . . ~ ~ . . . . . . . . . = . . . . . - - - - - ~

Fig. 3. Transesophageal basilar short-axis view shows Amplatz catheter tip (arrow) engaged in right coronary os- tium. RA, Right atrium: SVC, superior vena cava. Other abbreviations as in Fig. 1.

0.5% of all coronary angiograms. 3,4 Various forms of anomalous coronary artery origins have been associated with acute myocardial infarction and sudden cardiac death in patients with no other structural heart disease. The os- tial location and the course of the anomalous artery is of great importance in assessing possible clinical significance. Coronary angiography has been the most commonly used diagnostic test for identifying anomalous coronary arteries. Origin of the right coronary artery from the left sinus of Valsalva is notoriously difficult to engage with coronary catheters. Our experience and the experience of others suggests that Amplatz left coronary catheters have the greatest success in engaging this type of anomalous coronary anatomy. 3 However, in the case presented, fluoroscopically guided engagement was not possible with several catheters, including Amplatz left-shaped catheters.

TEE has been shown to be a useful adjunctive method for identifying abnormal ostial locations and vessel orien- tation and course. Gaither et al. 5 used monoplane TEE and reported a series of five patients in whom various coronary anomalies were successfully imaged. In all patients but one, both the ostium and the anomalous course were identified. In the exception the patient had the same anatomy we de- scribe here. In the Gaither et al. series, the ostium was not imaged, but the course anterior to the aorta was. The use of omniplane TEE in our case likely enabled successful os- tial imaging and helped correctly define the vessel course. In addition, TEE-guided engagement made the coronary angiographic procedure simpler and safer. To our knowl- edge, this is the first report of the use of TEE to facilitate coronary angiography. The role of TEE as an aid to diag- nostic and therapeutic cardiac catheterization procedures has considerable potential in selected patients.

REFERENCES

1. Chairman BR, Lesperance J, Salties J, Bourassa MG. Clinical, angio- graphic and hemodynamic findings in patients with anomalous origin of the coronary arteries. Circulation 1976;53:122.

2. Baltaxe HA, Wixson D. The incidence of congenital anomalies of the coronary arteries in the adult population. Radiology 1977;122:47-51.

3. Douglas JS Jr, Franch RH, King SB III. Coronary artery anomalies. In: King SB III, Douglas JS Jr, eds. Coronary arteriography and angio- plasty. New York: McGraw-Hill, 1985:40-2.

4. Berdoff R, Haimowitz A, Kupersmith J. Anomalous origin of the right coronary artery from the left sinus of Valsalva. Am J Cardiol 1986;58:656-7.

5. Gaither NS, Rogan KM, Stajduhar K. Banks AK, Hull RW, Whitsztt T, Vernalis MN. Anomalous origin and course of coronary arteries in adults: identification and improved imaging utilizing transesophageal echocardiography. AM HEART J 1991;122:69-75.

Transvenous cardioverter-defibrillator implantation via persistent left superior vena cava

Ross Brooks, MD, Guy Jackson, PA, Brian A. McGovern, MD, and Jeremy N. Ruskin, MD Boston, Mass.

Persistent left superior vena cava is an uncommon venous anomaly that is usually discovered unexpectedly at the time of pacemaker-lead insertion. Successful transvenous pacemaker implantation by means of this approach has been previously reported, 1-3 but implantation of a trans- venous cardioverter-defibrillator system via this route has not heretofore been described.

A 62-year-old woman was admitted for further evalua- tion after successful resuscitation of in-hospital ventricu- lar fibrillation cardiac arrest that occurred 2 days after elective appendectomy. She had no history of cardiac anomalies or arrhythmia, and no precipitants were identi- fied. Cardiac catheterization performed via the right fem- oral artery and vein showed findings consistent with mod- erate mitral stenosis with a calculated mitral valve area of 1.1 cm 2. Aside from a 40 % stenosis involving the right cor- onary artery, coronary angiography was unremarkable. Bi- plane left ventriculography disclosed normal left ventricu- lar function without mitral regurgitation. An echocardio- gram showed no abnormalities of the right atrium or ventricle. An off-drug electrophysiologic test produced no inducible ventricular arrhythmias with up to three extra- stimuli at two right ventricular sites. An implantable car- dioverter-defibrillator (ICD) system was recommended to this patient, and an initial nonthoracotomy approach with a two-lead Medtronic (Minneapolis, Minn.) transvenous

From The Cardiac Arrhythmia Service, Massachusetts General Hospital.

Reprint requests: Ross Brooks, MD, Cardiac Unit, Massachusetts General Hospital, Boston. MA 02114.

AM HI~ART J 1995;129:195-7.

Copyright ® 1995 by Mosby-Year Book, Inc. 0002-8703/95/$3.00 + 0 4 / 4 / 5 9 1 3 5

January 1995 196 Brooks, Jackson, and McGovern American Heart Journal

Fig. 1. Poster ior-anter ior (A) and left lateral (B) chest x-ray film shows positions of t ransvenous lead and subcutaneous patch electrodes in pa t ien t with persis tent left superior vena cava.

Table h Sensing and pacing parameters measured during 2-year follow-up

Follow-up R-wave amplitude Pacing threshold time (too) (m V, base-peak) (msec)

Predischarge 13 1 10+ 3 15+ 6 13 9 13 12 13 15 15 24 13

2.8V '.12 2.8V '.18 2.8V ~.18 2.8V '.12 2.8V '.09 2.8V '.15 2.8V '.15 2.8V ~.15

system was selected. 4 During insertion of a Medtronic 10.5F t r ipolar electrode with use of the left subclavian vein, it became evident tha t the pa t ien t had a pers is tent left su- perior vena cava. However, without too much difficulty, the t r ipolar lead was inserted into the right ventricle after a loop was made in the r ight a t r ium (Fig. 1). The t ip of the active fixation electrode was screwed into the diaphrag- matic surface of the right ventricle (Fig. 1). Satisfactory R-wave ampl i tudes (25 mV), slew rates (4.20 V/sec), pac- ing thresholds (0.8V, 1.2 mA at 0.5 msec), and resistances (599 ohms) were obtained. A 8F unipolar coil electrode was inserted into the left superior vena cava as a second elec- t rode (Fig. 1). The pa t ien t underwent intraoperat ive de- fibril lation threshold test ing and pulse generator implan- tation. Wi th the right ventr icular coil electrode used as a cathode and the superior vena cava coil electrode and sub-

cutaneous patch electrode placed on the lateral left chest wall as a combined anode, ventr icular fibrillation was con- vet ted with energies as low as 12 J. A Medtronic 7217B PCD pulse generator was implanted and tested satisfacto- rily. The pa t ien t ' s postoperat ive course was uneventful, and predischarge ICD test results were normal. Two months after discharge, she was readmi t ted after two ap- propr ia te ICD discharges in response to rapid atr ial fibril- lat ion tha t exceeded the programmed rate cutoff of the ICD (180 beats/min). Because of new-onset atr ial fibrillation, we performed percutaneous mitral valvuloplasty; there were no complications. After 24 months of follow-up, non- invasive test ing of the ICD device has demonst ra ted stable sensing and pacing parameters (Table I).

To our knowledge, this case repor t represents the first t ransvenous nonthoracotomy ICD system successfully im- p lanted by means of a left superior vena cava and suggests tha t this approach need not be abandoned if it is found at the t ime of implantat ion. Pers is tent left superior vena cava is an uncommon venous anomaly with an approximate in- cidence of 1:348 in cadavers. 5 Many pat ients have associ- ated congenital abnormalities; in some pat ients a pa ten t r ight superior vena cava may also be lacking. 6 There are only scat tered reports in the l i terature of successful inser- t ion of permanent pacing electrodes with this approach. 1-3 Because the pa th of venous flow is from left subclavian--qeft superior vena cava--*coronary s inus-*r ight atrium, the un- usual entry into the right a t r ium makes it more difficult to cross the t r icuspid valve and maneuver the t ip to an opti- mal posit ion in the r ight ventricle. Looping the lead facil- i tates passage across the t r icuspid valve and may aid in the

Volume 129, Number 1

American Heart Journal Shaddy et al. 197

prevention of displacement. 1 Long-term stability of the lead tip is another potential concern, although it is report- edly less of a problem with an active rather than passive fixation lead. 2-3 Another issue specifically related to the implantable cardioverter-defibrillator is whether the un- usual locations of the transvenous coil electrodes that re- sult from this approach would adversely affect the defibril- lation energy requirements. Although this is not known, it was not a problem in this patient and is less likely to be an issue when the left ventricle is of normal size. 4 In a major- ity of cases, including our own, a persistent left superior vena cava is found unexpectedly at the time of transvenous lead insertion when a left-sided venous approach is se- lected. The case presented here suggests that a transvenous ICD system with separate superior vena cava and right ventricular electrodes and an active fixation tip can be successfully implanted with a left superior vena cava with a favorable long-term outcome. If the leads cannot be im- planted via this route, a right-sided venous approach can be tried before resorting to thoracotomy.

REFERENCES

1. Westerman GR, Baker J, Dugan WT, Van Devanter SH. Permanent pacing through a persistent left superior vena cava: an approach and report of dual-chamber lead placement. Ann Thorac Surg 1985;39:174-6.

2. Hellesttrand KJ, Ward DE, Bexton RS. The use of active fixation elec- trodes for permanent endocardial pacing via a left superior vena cava. PACE 1982;5:180.

3. Zardo F, Nicolosi GL, Burelli C, Zanu~tini D. Dual-chamber trans- venous pacemaker implantation via anomalous left superior vena cava. AM HEART J 1986;112:621-2.

4. Brooks R, Garan H, Torchiana D, Vlahakes G, Jackson ,G, Newell J, McGovern B, Ruskin JN. Determinants of successful nonthoracotomy cardioverter-defibrillator implantation: experience in 101 patients us- ing two different lead systems. J Am Coll Cardiol 1993;22:1835~42.

5. Sanders JH. Bilateral superior vena cava. Anat Rec 1946;94:657. 6. Steinberg I, Dubilier W, Lukas DS. Persistence of left superior vena

cava Dis Chest 1953;24:479.

Efficacy and safety of metoprolol in the treatment of doxorubicin-induced cardiomyopathy in pediatric patients

Robert E. Shaddy, MD, Stephanie L. Olsen, MD, Michael R. Bristow, MD, PhD, David O. Taylor, MD, Emily A. Bullock, RN, BSN, Lloyd Y. Tani, MD, and Date G. Renlund, MD Salt Lake City, Utah

From the Departments of Pediatrics and Medicine, Primary Children's Medical Center and the University of Utah.

Reprint requests: Robert E. Shaddy, MD, Divimon of Cardiology, Primary Children's Medical Center, 100 North Medical Dr., Salt Lake City, UT 84113.

AM HEART J 1995;129:197-9.

Copyright © 1995 by Mosby-Year Book, Inc. 0002-8703/95/$3.00 + 0 4/4 /59133

Doxorubicin is an anthracycline used widely in the treat- ment of childhood cancer. The most serious long-term side effect of doxorubicin is cardiac toxicity, which can lead to dilated cardiomyopathy and congestive heart failure. The degree of cardiac toxicity is dose-dependent, and the inci- dance of echocardiographic abnormalities and congestive failure in children after doxorubicin is significant, l-3 Meto- prolol, a selective ill-receptor blocker without intrinsic sympathomimetic activity, has been shown to be effective in the treatment of adults with dilated cardiomyopathy through reversal of the adverse myocardial effects of car- diac adrenergic drive, including down-regulation of myo- cardial fl-receptors, direct and indirect toxic myocardial effects mediated by intracellular Ca 2+ overload, and effects on macromolecular synthesis. 4, 5 This report examines the efficacy and safety of metoprolol in three pediatric patients with congestive heart failure from doxorubicin-indueed cardiomyopathy who were referred for heart transplanta- tion.

Three patients who were 14.3 _+ 2 years old (mean _+ SD) had symptoms of severe congestive heart failure after receiving doxorubicin, 437 _+ 32 mg/m 2, as cancer chemo- therapy starting at age 4.3 _+ 2.8 years (Table I). The on- set of symptoms ranged from 2 to 13 years after completion of doxorubicin. Patients 1 and 2 had no symptoms for 13 and 11 years, respectively, before suddenly having syrup- toms of severe congestive heart failure. Patient 3 had symptoms of heart failure 2 years after doxorubicin ther- apy that persisted with intermittent Symptoms during the next 3 years before metoprolol therapy was started. All pa- tients had been receiving heart failure medications for at least 5 months without significant improvement in symp- toms or noninvasive estimates of cardiac performance before starting metoprolol. Patient i received digoxin, di- uretics, and captopril for 5 months before starting meto- prolol. Patient 2 received digoxin, diuretics, and hydra- lazine for 8 months before being seen at our institution. This patient's hydralazine was discontinued, and the patient was started on metoprolol nearly simultaneously with starting enalapril. Patient 3 received digoxin and di- uretics for 18 months before being seen at our institution. He was initially started on captopril for I month without significant improvement before starting metoprolol. Right ventricular endomyocardial biopsies showed evidence of cardiomyopathy caused by doxorubicin and no evidence of inflammation to suggest myocarditis.

Before starting metoprolol, all patients underwent echo- cardiography, radionuclide angiography to determine ejec- tion fraction, and cardiac catheterization (Table I). MeW- prolol was instituted in all patients at an initial oral dose of 6.25 mg twice daily. Initial symptoms of fatigue and de- creased exercise tolerance after starting metoprolol were short-lived, and metoprolol was gradually increased to a maximum dose of 92 _+ 52 rag/day. The method of increas- ing metoprolol was individualized to each patient, depend- ing on their evaluations, performed approximately weekly in the outpatient clinic. In the absence of evidence of wors- ening congestive heart failure or significant bradycardia, the metoprolol dosage was increased initially to 12.5 mg