Alternation of the Mitral Opening Click Time in a Patient with the Beall Mitral Valve Prosthesis

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GRAPHIC TECHNIQUES IN CARDIOLOGY

Alternation of the Mitral Opening Click Time in a Patient with the Beall Mitral Valve Prosthesis* Alberto Benchimol, M.D., F.C.C.P., Charles L. Harris, M.D., and Kenneth B. Desser, M.D. The Beall mitral valve is a low profile caged lens prosthesis.' We recently observed a patient with a Beall valve in the mitral position, who demonstrated an unusual alternation of the aortic closingmitral opening click interval. CASE REPORT

In 1965, this 49-year-old man with aortic stenosis underwent aortic valve replacement with a Starr-Edwards prosThe Institute for Cardiovascular Diseases, Good Samaritan Hospital, Phoenix, Ariz. Supported in part by the Nichols' Memorial Fund. Reprint requests: Dr. Benchimol, Good Samaritan Hospital, Phoenix 85062 o From

thesis. The patient did well until 1972 when he experienced the onset of atrial fibrillation with a rapid ventricular response. He was subsequently referred for investigation of the arrhythmia. At that time a phonocardiogram confirmed the auscultatory impression of a mitral area opening snap and an aortic arterial diastolic decrescendo murmur. In addition, there was an aortic systolic ejection murmur, which is commonly heard in patients with aortic prostheses. An ascending aortic angiogram revealed aortic insufficiency of a moderate degree. The patient was subsequently subjected to an open heart operation, and the aortic prosthesis was replaced with another Starr-Edwards valve prosthesis. In addition, a severely stenotic mitral valve was excised and a medium size Beall valve prosthesis implanted in the mitral position. Prior to discharge from the hospital, it was noted that the patient had a varying aortic closing-mitral opening click (AC-MO) in-

49 M. - PROSTH. AO. AND MITR. VALVES 50-500cps.

FIGURE 1. Simultaneous mitral (MA), tricuspid (TA), pulmonic (PA), and aortic area (AA) phonocardiograms recorded in 49-year-old man with Starr-Edwards aortic prosthesis and Beall mitral prosthesis. There is an aortic ejection systolic murmur, commonly seen in patients with prosthetic aortic valves. CT = external carotid pulse tracing; MC, AO, AC, MO = mitral closing, aortic opening, aortic closing and mitral opening sounds respectively; L II lead II of .eleetrocardiogram. AC-MO intervals are indicated. (See discussion)

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49 M. - PROSTHETIC AORTIC & MITRAL VALVES

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FIGURE 2. Simultaneous tricuspid area (TA) phonocardiogram, apexcardiogram (ACG) and lead II of the electrocardiogram recorded from same patient one month later. Aortic closingmitral opening interval is constant at 0.11 second. Note that mitral opening click occurs in conjunction with apexcardiographic "0" point. (See discussion) terval which was intermittently present in an alternating cadence during regular sinus rhythm. Figure 1 shows the simultaneous mitral, tricuspid, pulmonic and aortic area phonocardiograms which were recorded during this alternation. The basic AC-MO interval is constant at 0.11 second. Longer AC-MO periods range from 0.18 to 0.24 second and occur in an alternating fashion. Note the constant relationship of the aortic closing click to the dicrotic notch of the external carotid pulse recording. Although the carotid pulse upstroke and ejection times were constant, there was a greater peak pulse plateau during beats preceding the longer AC-MO intervals. Subsequent follow-up phonocardiograms revealed a constant AC-MO interval at 0.11 second. Each mitral opening click was inscribed in conjunction with the "0" point of a simultaneously recorded apexcardiogram (Fig 2). COMMENT

Definitive values for the normal medium Beall valve AC-MO time have not been set forth. In our experience this interval is usually about O.lOS second and does not vary significantly during sinus rhythm or atrial fibrillation. It is generally accepted that the interval between aortic valve closure and mitral valve opening represents left ventricular isovolumic relaxation.f Since aortic ball valve and mitral disk valve traveling times must be taken into account in subjects with prosthetic valves, it is likely that isovolumic relaxation may vary from the normal value of 0.10 second," depending on the types of prostheses implanted. The marked alternating prolonga-

tion of the AC-MO time described here can be ascribed to either varying left ventricular diastolic pressure or some form of intrinsic mechanical obstruction to disk motion." The subsequent uncomplicated clinical course and normalization of the AC-MO time in this patient suggests that if transient obstruction to disk movement occurred, it was of a temporary nature. In conclusion, it appears that further investigation based on simultaneous recording of external pulse wave-forms and phonocardiograms must be performed in subjects with different types of prosthetic valves in order to determine what constitutes graphic evidence of mitral disk valve malfunction. ACKNOWLEDGMENT: We wish to acknowledge the technical assistance of Nancy Copeland, R.N., Carole Crevier, Larry Kuriger, Sydney Peebles, Sharon Squire and Les Zendle. REFERENCES

1 Beall AC Ir, Brickler DL, Messmer BJ: Results of mitral valve replacement with Dacron velour-covered Teflon-disc prosthesis. Ann Thorac Surg 9: 195-202, 1970 2 Benchimol A, Ellis JG: A study of the period of isovolumic relaxation in normal subjects and in patients with heart disease. Am J Cardiol19: 196-206, 1967 3 Wise JR Jr, Webb-Peploe M, Oakley CM: Detection of prosthetic mitral valve obstruction by phonocardiography. Am J Cardiol28:107-110, 1971

CHEST, VOL. 64, NO.3, SEPTEMBER, 1973