August 1981 286 Brief communications American Heart Journal

from either the HRA or CS programmed into the cardiac cycle during tachycardia were able to preexcite the His bundle and advance tachycardia in proport ion to prema- tur i ty of the a t r ia l electrogram recorded at the His bundle (Fig. 4, panel A). The a t r ia l exci tat ion sequence and P wave morphology of APDs delivered from the proximal CS were strikingly similar to a t r ia l echo beats during tachycardia. A sufficiently premature A P D was able to terminate tachycardia by advancing the ventr icular elec- t rogram at the CS sufficiently to reach the re t rograde effective refractory period of the accessory pa thway (Fig. 4, panel B). Fur ther evidence for a t r ia l par t ic ipat ion in the tachycardia circuit was obtained from the observa- tions i l lustrated in Fig. 5. PVCs programmed into the cardiac cycle during tachycardia at a t ime when the His bundle was refractory were able to preexcite the atr ium, init ially at the proximal CS, and a curve relat ing subse- quent AH to prematur i ty of the advanced a t r ia l impulse was derived. This curve was v i r tua l ly superimposable on tha t derived by delivering a t r ia l s t imuli from the proximal CS. This observation is compat ible with the concept t ha t atr ial tissue in the vicinity of the CS is a link in the tachycardia circuit. If the reen t ran t circuit were confined to the AV node and subnodal structures, 1 one would expect a change in the sequential relat ionship of the low atr ia l electrogram recorded near the His bundle to the onset of AV nodal depolar izat ion tha t would result in a different AH interval for a given A1-A~ interval obtained by different pacing sites2

The normal AV conduction system is the antegrade limb of the proposed reent ran t circuit for this tachycard ia as evidenced by the normal QRS morphology and the presence of a His electrogram preceding each QRS during tachycardia. The antegrade propert ies of the AV node fulfilled our criteria for "enhanced" AV nodal conduc- t ion. ' Autonomic intervent ions showed tha t the accessory pa thway was under the influence of both sympathe t ic and vagal tone (Table I, and Fig. 3). These results are consis- tent with the physiology of the a t r ioventr icular (AV) node. The subst ra te for incessant tachycardia in this pat ient is clearly an accessory ventr iculoat r ia l pa thway with properties typical of the AV node. ~ 5-7 Fur thermore , the presence of "enhanced" conduction in the ana tomica l AV node in this patient and in others reported ~, 5. supports the suggestion of Gallagher and Sealy ~ that a developmental anomaly in such patients may result in a displaced "accessory" AV node. The preservation of normal ventricular function in our middle-aged, asympto- matic patient suggests that incessant tachycardia may be associated with a benign prognosis and appropriate man- agement in asymptomatic patients could consist of peri- odic assessment of exercise tolerance and left ventricular function.

REFERENCES 1. Coumel P, Attuel P, Leclercq JF: Permanent form of

junctional reciprocating tachycardia: Mechanism, clinical and therapeutic implications. In Narula OS, editor: Cardiac arrhythmias-electrophysiology, diagnosis, and manage-

ment. Baltimore, 1979, The Williams & Wilkins Co, pp 347-363.

2. Gallagher JJ, Sealy WC: The permanent form of junctional reciprocating tachycardia: Further elucidation of the underlying mechanism. Eur J Cardiol 8:413, 1977.

3. Batsford WP, Akhtar M, Caracta AR, Josephson ME, Seides SF, Damato AN: Effect of atrial stimulation site on the electrophysiological properties of the atrioventricular node in man. Circulation S0:283, 1974.

4. Benditt DG, Pritchett ELC, Smith WM, Wallace AG, Gallagher J J: Characteristics of atrioventricular conduction and the spectrum of arrhythmias in Lown-Ganong-Levine syndrome. Circulation 57:454, 1978.

5. Epstein ML, Stone FM, Benditt DG: Incessant atrial tachy- cardia in childhood: Association with rate-dependent con- duction in an accessory atrioventricular pathway. Am J Cardiol 44:498, 1979.

6. Farre J, Ross D, Wiener I, Bar FW, Vanagt EJ, Wellens HJJ: Reciprocal tachycarclias using accessory pathways with long conduction times. Am J Cardiol 44:1099, 1979.

7. Brugada P, Vanagt EJ, Bar FWHM, Wellens HJJ: Inces- sant reciprocating atrioventricular tachycardia: Factors playing a role in the mechanism of the arrhythmia. PACE 3:670, 1980.

Dynamic left ventricular outflow tract obstruction associated with pheochrornocytorna

Clarence Shub, M.D.,* Michael D. Will iamson, M.D.,** Abdul J. Tajik, M.D.,* and Donald R. Eubanks, M.D.** Rochester, Minn., and Clearwater, Fla.

Diffuse "catecholamine myocardi t is" and left ventr icular hyper t rophy (LVH) are found in association with pheo- chromocytoma, 1 but hyper t rophic ca rd iomyopa thy (HCM), a l though reported, 2, 3 seems to be very rare. 1 In animal experiments, funct ional obstruct ion of the left ventr icular outflow t rac t (LVOT) has been produced by adminis trat ion of catecholamines, 4 and a clinical counter- par t of this phenomenon has been suggested2 We repor t two cases of pheochromocytoma in which echocardio- graphic and clinical features mimicking hyper t rophic obstructive card iomyopathy (HOCM) were present. These features either abated or disappeared following surgical removal of the tumor.

CASE 1

A 61-year-old man was referred for evaluat ion of severe, labile hypertension and "dizzy spells." On examinat ion,

From the Mayo Clinic and Mayo Foundation, and the Morton F. Plant Hospital.

Received for publication Nov. 3, 1980; accepted April 3, 1981. Reprint requests: Clarence Shub, M.D., Division of Cardiovascular Disease and Intarnal Medicine, Mayo Clinic, Rochester, MN 55905. *Mayo Clinic and Mayo Foundation. **Morton F. Plant Hospital, Clearwater.

0002-8703/81/080286 + 05500.50/0 © 1981 The C. V. Mosby Co.

Volume 102

Number 2 Brief communications 287

Fig. 1. Case 1. ECGs before (A) and 17 months after (B) surgical removal of pheochromocytoma.

supine blood pressure was 210/120 m m Hg. A sustained cardiac apical impulse was noted, along with grade 2/6 systolic murmur at left s ternal border and apex which was unaffected by Valsalva maneuver. The murmur decreased with squat t ing and increased with s tanding and during adminis trat ion of amyl nitrite. Chest roentgenogram was normal. ECG showed LVH (Fig. 1, A) and two-dimension- al echocardiography revealed symmetr ic LVH with sug- gestive systolic anterior mot ion (SAM) of the mi t ra l valve (MV). A cineventriculogram showed hyper t rophied and hyperdynamic left ventricle (LV). There was no resting LV aortic gradient; however, amyl ni tr i te pro- voked peak systolic gradient of 60 mm Hg. Biochemical parameters assessed for pheochromocytoma were abnor- mal (Table I). Computed tomographic abdominal scan

Table i. Biochemical parameters indicat ing pheochromocytoma

Parameter (urinary) Case 1 Case 2

Vanillylmandelic acid 10.9 69.8 (0.5-12)* (mg/24 hr) (~ 5.0)*

Metanephrines 4.4 (< 1.3) 18.8 (< 1) (rag/24 hr)

Total catecholamines - > 180 (< 180) (~g/24 hr)

Norepinephrine (~g/24 243 (15-80) - hr)

Epinephrine (/~g/24 hr) 599 (0-20) Dopamine (~g/24 hr) 127 (65-400) -

*Normal value for each laboratory is given in parentheses.

August 1881

288 Brief communications Am~c~n Hee~ ao~,a~

: HI oVF V 3

!i

! aYR

II

~ ' ~ - ' ~ 1 r ' ~

. . . . . . . h , . . . . oVF

Vt V4

V2 V5

! ~ ,~ , , i . ! 2 " ~ i 1

V3 V6

big. 2. Case 2. ECGs before (A) and 19 months after (B) surgical removal of pheochromocytoma.

showed a left adrenal mass. Phenoxybenzamine and pro- pranolol were administered preoperatively. At operation, a left adrenal pheochromocytoma was excised. Postopera- tively, blood pressures were normal and the hear t murmur decreased in intensity. At follow-up examinat ions 6 and 12 months after operation, the pa t ien t was asymptomat ic and normotensive without t rea tment , the cardiac murmur was no longer present, and ECG was essential ly normal (Fig. 1, B).

CASE 2

A diabetic, hypertensive 65-year-old woman was ad- mi t ted to her local hospital because of suspected hypoglycemia. She complained of weakness, nonspecific chest pain, fatigue, and episodes of headaches, dizziness and sweating, along with palp i ta t ions and pal lor asso- ciated with emotional stress. On examination, blood pres- sure was 130/100 mm Hg supine but was unobta inable in the upright position. The cardiac apical impulse was

Volume 102

Numb~r 2 Brief communications 2 8 9

sustained, S, gallop sound was present, and grade 2/6 systolic murmur was heard along the left sternal border which did not increase wi th Valsalva maneuver. Chest roentgenogram was normal. ECG showed LVH (Fig. 2, A). Bolus nephrotomogram and computed tomographic abdominal scan revealed a right adrenal mass. Urinary catecholamines were abnormal (Table I). An M-mode echocardiogram (Fig. 3, A) showed increased septal thick- ness, hyperdynamic LV posterior wall, and SAM of the MV. Propranolol, phenoxybenzamine, and saline were administered preoperatively. At operation, the pheochro- mocytoma was excised without complication. Follow-up M-mode echocardiogram obtained 3 weeks later demon- strated less dynamic motion of the LV posterior wall and no SAM of the MV {Fig. 3, B). The patient has been normotensive with only a trivial systolic murmur along the left sternal border. ECG obtained 19 months after operation no longer showed LVH (Fig. 2, B).

In experimental animals, repeated injections of cate- cholamines can induce LVH' and hemodynamic abnor- malities suggesting LVOT obstruction2 LVH and myocar- dial damage have been described as sequelae to increased catecholamine exposure. 6 The patients in this report had a variety of symptoms alleviated following pheochromocy- toma removal. Postoperatively, their cardiac abnormali- ties abated or disappeared. In Case 1, the murmur disap- peared and ECG showed resolution of LVH. In Case 2, MV SAM was absent postoperatively and ECG was normal. Others have reported disappearance of echocar- diographic MV SAM after pheochromocytoma removal/ Thus it appears that decrease in functional subaortic obstruction occurs following removal of pheochromocyto- ma. In addition, diffuse catecholamine cardiomyopathy has been reported to resolve clinically ~ and by ECG 9 after pheochromocytoma removal.

Both patients in this report had only a mild degree of LVOT obstruction. It is possible that the hypertension caused by the pheochromocytoma, despite concomitant increased contractility, may have masked the typical expressions of dynamic LVOT obstruction. It can be expected that the net cardiovascular effect of the physio- logic variables associated with pheochromocytom a (in- creased catecholamines, relative hypovolemia, increased LV afterload, and tachycardia) on the dynamics of LVOT obstruction in a hypertrophied, hypercontractile LV would be complex, variable, and unpredictable. In the patients reported herein, the salutary clinical course, the improvements seen on ECG and echocardiogram, and the virtual disappearance of murmurs after removal of pheochromocytoma imply dynamic obstruction secondary to LV hypercontractile state rather than HOCM. ~°

REFERENCES

1. Van Vliet PD, BurcheU HB, Titus JL: Focal myocarditis associated with pheochromocytoma. N Engl J Med 274:1102, 1966.

2. Warembourg H, Bertrand ME, Ginestet A, Vallet PM, Lefebvre JM, Lemaire P, Filleul P: Relations entre ph~o-

• Ibo,-'v~

, , i , l ........ . . . . i - . - ~ ,,+i - • 1 . . . . . . . . . . . i l _

Fig. 3. Case 2. A, Preoperative M-mode echocardiogram showing mild septal hypertrophy, hyperdynamic LV pos- terior wall, and SAM (arrow) of mitral valve (MV). B, Tracing 3 weeks postoperatively shows that posterior wall is less dynamic and MV SAM is absent.

chromocytome et myocardiopathie obstructive: A propos d'une observation. Arch Mal Coeur 69:553, 1976.

3. Oakley CM: Clinical recognition of the cardiopathies. Circ Res 35(suppl 2):152, 1974.

4. De Bono AH, Proctor E, Brock R: Dynamic obstruction of the left ventricle: Its production and abolition by drugs in normal animals. Guy Hosp Rep 114:4, 1965.

5. Krasnow N, Rolett E, Hood WB Jr, Yurchak PM, Gorlin R:

August 1981

290 Brief communications American Hurt Journal

Reversible obstruction of the ventricular outflow tract. Am J Cardiol 11:1, 1963.

6. Raah W: The pathogenic significance of adrenalin and related substances in the heart muscle. Exp Med Surg 1:188, 1943.

7. Cueto L, Arriaga J, Zinser J: Echocardiographic changes in pheochromocytoma. Chest 7§:600, 1979.

8. Engelman K, Sjoerdsma A: Chronic medical therapy for pheochromocytoma: A report of four cases. Ann Intern Med 61:229, 1964.

9. Wiswell JG, Crago RM: Reversible cardiomyopathy with pheochromocytoma. Trans Am Clin Climatol Assoc 80:185, 1968.

10. Come PC, Bulkley BH, Goodman ZD, Hutchins GM, Pitt B, Fortuin NJ: Hypercontractile cardiac states simulating hypertrophic cardiomyopathy. Circulation 55:901, 1977.

Triple ventricular fusion due to intermittent ventricular parasystole in the Wolfl.Parkinson-White syndrome

Shinji Kinoshita, M.D., Masayuki Sakurai, M.D., and Taro Yasukouchi, M.D. Sapporo, Japan

Recently, Kinoshita "3 showed the presence of second- degree entrance block of Mobitz type I in patients with intermittent ventricular parasystole. The present commu- nication is the first report of triple ventricular fusion due to the coexistence of such intermittent ventricular para- systole with the Wolff-Parkinson-White (WPW) syn- drome.

ECGs were recorded from a 21-year-old asymptomatic man without otherwise apparent heart disease. Figs. 1 to 3 present parts of a long continuous recording. In Fig. 1 the configuration of sinus beats shows type A WPW pattern, and the configuration of ectopic beats resembles left bundle branch block pattern. This indicates that the preexcitation area of the sinus impulse is situated in the left ventricle (LV), while the ectopic focus is in the right ventricle (RV). The ectopic beats show intermittent ven- tricular parasystole due to second-degree entrance block of Mobitz type I. 1-3 Diagrams below the strips of Fig. 2 illustrate such second-degree entrance block. In the dia- grams, shaded bars represent the long absolute refractory period in the pathway containing the parasystolic focus. The diagrams show that when a sinus impulse conducted to the RV (e.g., DS3 in the top strip) falls in the absolute refractory period of the pathway, the parasystolic focus is protected from this sinus impulse: On the other hand,

From the Second Department of Medicine and the Department of Cardiovascular Medicine, Hokkaido University School of Medicine; and the Department of Medicine, Higashi Nippon Gakuen University School of Dentistry.

Supported in part by a grant-in-aid for scientific research from the Ministry of Education, Science and Culture of the Japanese Govern- ment.

Received for publication Oct. 17, 1980; revision received March 6, 1981; accepted March 30, 1981.

Reprint requests: Shinji Kinoshita, M.D., the Second Department of Medicine, Hokkaido University School of Medicine, Sapporo, Japan.

0002-8703/81/080290 + 03500.30/0 © 1981 The C. V. Mosby Co.

Fig. 1. Sinus beats showing type A Wolff-Parkinson- White (WPW) pattern and parasystolic beats resembling left bundle branch block pattern. Time intervals are expressed in hundredths of a second. DS = sinus beat; E = ectopic (parasystolic) beat.

when a conducted sinus impulse (e.g., DSll in the top strip) falls after the absolute refractory period of the pathway, it reaches and discharges the parasystolic focus after some delay, and then becomes a concealed reentrant ventricular extrasystole. After that, concealed reentrant bigeminal rhythm 3.4 continues until a parasystolic beat reappears.

In Figs. 2 and 3, triple ventricular fusion beats are seen. In these fusion beats, the ventricles are simultaneously stimulated by three impulses of different origins: (1) an impulse coming through the accessory pathway and pro- ducing the delta wave (D), (2) a sinus impulse coming through the normal AV junction (S), and (3) an impulse coming from the ectopic (parasystolic) focus (E). The triple ventricular fusion beats have various configurations. These fusion beats can be classified into several groups. In the fusion beat EDS (the bottom strip of Fig, 3), impulse E invades the ventricles earlier than impulse D. In the fusion beat D/E S (Fig. 3), the impulses D and E invade the ventricles simultaneously, in which case the fusion beat shows a narrow QRS complex because the parasystolic focus and the preexcitation area of impulse D are situated in different ventricles. In the fusion beat DES (the bottom strip of Fig. 2), impulse E invades the ventricles later than impulse D, but earlier than impulse S. In the fusion beat DSE (the middle strip of Fig. 2), impulse E invades the ventricles later than impulse S. Prior to the present report, triple ventricular fusion in the WPW syndrome was noted in only a few patients with ventricular escape beats ~' or continuous ventricular parasystole." However, this is the initial report of triple ventricular fusion due to coexistence of the WPW syndrome with intermittent ventricular parasystole.