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Conduction abnormalities associated with mitral valve prolapse in patients with normal coronary arteries
ABSTRACTS
CONDUCTION ABNORMALITIES ASSOCIATED V~TH MITRAL VALVE PROLAPSE IN PATIENTS WITH NORMAL CORONARY ARTERIES Ronald R. Masden, MD; Daniel E. McMartin, MD; B.Y. Pathakjee, MD; Nancy C. Flowers, MD, FACC; University of Louisville, Louisville, Kentucky In the past decade much attention has been focussed on the spectrum of mitral valve prolapse (MVP) syndromes. In certain case reports of the clinically diagnosed clickusually without angiographic confirmation murmur syndrome, conduction disturbances have been sporadof the prolapse, ically observed. The present study, however, confined itself to 356 patients evaluated for chest pain and found to have normal cardiac catheterization data, including indices of ventricular function and coronary arteriography. These patients were further divided into 203, ages 20-70 years, (115 females and 88 males) with no ventriculographic evidence of MVP, and 153 patients, ages 18-71 years, (84 females and 69 males) clearly meeting ventriculographThese two groups were compared for ic criteria for MVP. In the group without the incidence of conduction defects. MVP one subject had right bundle branch block (RBBB) and one left bundle branch block (LBBB). No other conduction In the MVP group, I3 demonabnormalities were recorded. strated multiple conduction system abnormalities including 6 with RBBB, one of whom also had left anterior hemiblock (LAHB) and two of whom also had left posterior hemiblock. Three had only LAHB. Two A seventh had incomplete RBBB. Five had LBBB and a third had LBBB alternating with RBBB. on no drugs, demonstrated PR prolongation expatients, His bundle studies done on 2 of the ceeding 210 msec. patients with RBBB showed prolonged HV intervals of 97 and We concluded that not only is there 73 msec respectively. an increased incidence of rhythm disturbances in patients with HVP, but that even against the background of normal coronary arteries and normal hemodynamic function, there is an increased incidence of abnormalities of the HisPurkinje system as well.
VALUE OF NONINVASIVELY-INDUCED VENTRICULAR PREMATURE BEATS DURING ECHOCARDfOGRAPHlC AND PHONOCARDIOGRAPHIC ASSESSMENT OF PATIENTS WITH IDIOPATHIC HYPERTROPHIC SUBAORTIC STENOS I S Gerald H. Angoff, MD; John E. Markis, MO; Laurence J. Sloss, MD; Daniel Wistran, MD; Patricia C. Come, MD; Paul 2011, MD; Peter F. Cohn, MD, FACC, Peter Bent Brigham Hospital and Beth Israel Hospital, Boston, Massachusetts. Fifteen patients (pts) with idiopathic hypertrophic subaortic stenosis (IHSS) had ventricular premature beats (VPB) induced with a new external mechanical stimulator during noninvasive evaluation of left ventricular outflow tract obstruction. Ten pts were monitored with simultaneous echocardiography (ECHO) and phonocardiography and carotid pulse tracing (PHONO-CPT) while 5 were monitored by PHONO-CPT a I one. Nine of the pts showed obstruction in the post-VP5 beat as defined by appearance of the characteristic bifid carotid pulse, prolongation of the systolic ejection time (ET), and, where recorded, increase in systolic anterior motion of the mitral valve on ECHO. Six did not show obstruction. All 9 pts with obstruction had 3 20 msec prolongation of uncorrected ET in the post-VPB beat. Change in the uncorrected ET was +38?8 msec in these 9 pts as compared with -5?4 msec for the 6 not showing obstruction (pc.01). Six pts underwent cardiac catheterization: pts without obstruction during noninvasive evaluation had none at catheterization and pts with obstruction after noninvasively-induced VPB’s demonstrated obstruction after provocative maneuvers during catheterization. No complications occurred and there were no pts in whom a VPB could not be induced noninvasively. These results indicate that the noninvasive induction of a VPB is a useful and easily performed procedure for both diagnosing and evaluating the dynamic left ventricular outflow tract obstruction of IHSS.
INDUCTION OF SARCOMEROGENESIS BY SYNCHRONOUS BIFOCAL VENTRICULAR PACING Stephen Raskin, MD; Larry F. Lemanski, Ph.D.; Jacob Abouav, MD; Hyman W. Paley, MD; Mt. Zion Hospital, and VA Hospital, San Francisco, Ca.
IDIOPATHIC HYPERTROPHIC SUBAORTIC STENOSIS: LONG-TERM MEDICAL FOLLOW-UP Roger G. Nissen, MD; Abdul J. Tajik, MD, FACC; Emilio R. Giuliani, MD, FACC; Robert 0. Brandenburg, MD, FACC, Mayo Clinic and Mayo Foundation, Rochester, Minn.
Contraction induced linear stresses initiated by abnormal septal sympathetic innervation in dogs causes ultrastructural changes similar to those seen in idiopathic hypertrophic subaortic stenosis (IHSS). To isolate the role of an abnormal sequence of myocardial activation on sarcomerogenesis an altered contraction pattern was established in adult mongrel dogs. Following surgically induced heart block, nearly synchronous (0.1-0.5 msec delay) bifocal epicardial pacing was achieved with fixed rate and R-synchronous pacers. Augmented linear stresses between the electrode pairs was recorded by strain gauges at the time of implant. Sacrifice was performed at 20 weeks and morphological studies were obtained. All tissue from areas of stress submitted for electron microscopy revealed variable degrees of 2 band thickening, thin filaments transversely attached to Z bands, dilataof transverse tubules, Increased autophagic vesicles, and mitochondrial swelling with bizarre branching cristae. These changes were not present in non-stress samples in the same dogs. The ultrastructural changes suggestive of sarcomerogenesis appear to be initiated by artificially altered myocardial activation pattern and may relate to the pathogenesis of IHSS in man.
Although propranolol (P) has been used in idiopathic hypertrophic subaortic stenosis (IHSS), little is known about the long-term follow-up of large groups of patients (pts) treated with various doses of P. One hundred nineteen pts (63 males, 56 females) more than 20 years old received P. Mean age was 58 years (range 23-79). Eleven pts were in NYHA Class I, 53 Class II, 51 Class III, and 4 Class IV at onset of P. Meandose of P was 142 mg (range 40-640). Mean duration of follow-up was 40.9 mo (range 8-137). During this period, 51 pts (43%) symptomatically improved, 52 (44%) remained unchanged, and 16 (13%) deteriorated. Most improved were chest pain, dizziness, and palpitations; least improved was dyspnea on exertion. Of 119 pts, 10 (8%) eventually required surgical myotomy-myectomy because of either no improvement or deterioration of symptoms. Of the remaining 109 pts, 9 (8%) died (2 noncardiac deaths). Of the 7 cardiac deaths, 5 were sudden and occurred in pts with mean age of 61 years (range 28-78), all of whom were receiving P<160 mg daily. Of the 5 pts who died suddenly, 1 had right bundle branch block (RBBB), left axis deviation (LAD), and atria1 fibrillation; one had RBBB and LAD; and one had atria1 fibrillation without associated conduction disturbance. This study documented that, in a large group of pts, P in modest doses is effective in symptomatic improvement over long-term follow-up. However, sudden death was not prevented by P in dose $60 daily.
434
February 1979
The American Journal of CARDIOLOGY
Volume 41
CONDUCTION ABNORMALITIES ASSOCIATED V~TH MITRAL VALVE PROLAPSE IN PATIENTS WITH NORMAL CORONARY ARTERIES Ronald R. Masden, MD; Daniel E. McMartin, MD; B.Y. Pathakjee, MD; Nancy C. Flowers, MD, FACC; University of Louisville, Louisville, Kentucky In the past decade much attention has been focussed on the spectrum of mitral valve prolapse (MVP) syndromes. In certain case reports of the clinically diagnosed clickusually without angiographic confirmation murmur syndrome, conduction disturbances have been sporadof the prolapse, ically observed. The present study, however, confined itself to 356 patients evaluated for chest pain and found to have normal cardiac catheterization data, including indices of ventricular function and coronary arteriography. These patients were further divided into 203, ages 20-70 years, (115 females and 88 males) with no ventriculographic evidence of MVP, and 153 patients, ages 18-71 years, (84 females and 69 males) clearly meeting ventriculographThese two groups were compared for ic criteria for MVP. In the group without the incidence of conduction defects. MVP one subject had right bundle branch block (RBBB) and one left bundle branch block (LBBB). No other conduction In the MVP group, I3 demonabnormalities were recorded. strated multiple conduction system abnormalities including 6 with RBBB, one of whom also had left anterior hemiblock (LAHB) and two of whom also had left posterior hemiblock. Three had only LAHB. Two A seventh had incomplete RBBB. Five had LBBB and a third had LBBB alternating with RBBB. on no drugs, demonstrated PR prolongation expatients, His bundle studies done on 2 of the ceeding 210 msec. patients with RBBB showed prolonged HV intervals of 97 and We concluded that not only is there 73 msec respectively. an increased incidence of rhythm disturbances in patients with HVP, but that even against the background of normal coronary arteries and normal hemodynamic function, there is an increased incidence of abnormalities of the HisPurkinje system as well.
VALUE OF NONINVASIVELY-INDUCED VENTRICULAR PREMATURE BEATS DURING ECHOCARDfOGRAPHlC AND PHONOCARDIOGRAPHIC ASSESSMENT OF PATIENTS WITH IDIOPATHIC HYPERTROPHIC SUBAORTIC STENOS I S Gerald H. Angoff, MD; John E. Markis, MO; Laurence J. Sloss, MD; Daniel Wistran, MD; Patricia C. Come, MD; Paul 2011, MD; Peter F. Cohn, MD, FACC, Peter Bent Brigham Hospital and Beth Israel Hospital, Boston, Massachusetts. Fifteen patients (pts) with idiopathic hypertrophic subaortic stenosis (IHSS) had ventricular premature beats (VPB) induced with a new external mechanical stimulator during noninvasive evaluation of left ventricular outflow tract obstruction. Ten pts were monitored with simultaneous echocardiography (ECHO) and phonocardiography and carotid pulse tracing (PHONO-CPT) while 5 were monitored by PHONO-CPT a I one. Nine of the pts showed obstruction in the post-VP5 beat as defined by appearance of the characteristic bifid carotid pulse, prolongation of the systolic ejection time (ET), and, where recorded, increase in systolic anterior motion of the mitral valve on ECHO. Six did not show obstruction. All 9 pts with obstruction had 3 20 msec prolongation of uncorrected ET in the post-VPB beat. Change in the uncorrected ET was +38?8 msec in these 9 pts as compared with -5?4 msec for the 6 not showing obstruction (pc.01). Six pts underwent cardiac catheterization: pts without obstruction during noninvasive evaluation had none at catheterization and pts with obstruction after noninvasively-induced VPB’s demonstrated obstruction after provocative maneuvers during catheterization. No complications occurred and there were no pts in whom a VPB could not be induced noninvasively. These results indicate that the noninvasive induction of a VPB is a useful and easily performed procedure for both diagnosing and evaluating the dynamic left ventricular outflow tract obstruction of IHSS.
INDUCTION OF SARCOMEROGENESIS BY SYNCHRONOUS BIFOCAL VENTRICULAR PACING Stephen Raskin, MD; Larry F. Lemanski, Ph.D.; Jacob Abouav, MD; Hyman W. Paley, MD; Mt. Zion Hospital, and VA Hospital, San Francisco, Ca.
IDIOPATHIC HYPERTROPHIC SUBAORTIC STENOSIS: LONG-TERM MEDICAL FOLLOW-UP Roger G. Nissen, MD; Abdul J. Tajik, MD, FACC; Emilio R. Giuliani, MD, FACC; Robert 0. Brandenburg, MD, FACC, Mayo Clinic and Mayo Foundation, Rochester, Minn.
Contraction induced linear stresses initiated by abnormal septal sympathetic innervation in dogs causes ultrastructural changes similar to those seen in idiopathic hypertrophic subaortic stenosis (IHSS). To isolate the role of an abnormal sequence of myocardial activation on sarcomerogenesis an altered contraction pattern was established in adult mongrel dogs. Following surgically induced heart block, nearly synchronous (0.1-0.5 msec delay) bifocal epicardial pacing was achieved with fixed rate and R-synchronous pacers. Augmented linear stresses between the electrode pairs was recorded by strain gauges at the time of implant. Sacrifice was performed at 20 weeks and morphological studies were obtained. All tissue from areas of stress submitted for electron microscopy revealed variable degrees of 2 band thickening, thin filaments transversely attached to Z bands, dilataof transverse tubules, Increased autophagic vesicles, and mitochondrial swelling with bizarre branching cristae. These changes were not present in non-stress samples in the same dogs. The ultrastructural changes suggestive of sarcomerogenesis appear to be initiated by artificially altered myocardial activation pattern and may relate to the pathogenesis of IHSS in man.
Although propranolol (P) has been used in idiopathic hypertrophic subaortic stenosis (IHSS), little is known about the long-term follow-up of large groups of patients (pts) treated with various doses of P. One hundred nineteen pts (63 males, 56 females) more than 20 years old received P. Mean age was 58 years (range 23-79). Eleven pts were in NYHA Class I, 53 Class II, 51 Class III, and 4 Class IV at onset of P. Meandose of P was 142 mg (range 40-640). Mean duration of follow-up was 40.9 mo (range 8-137). During this period, 51 pts (43%) symptomatically improved, 52 (44%) remained unchanged, and 16 (13%) deteriorated. Most improved were chest pain, dizziness, and palpitations; least improved was dyspnea on exertion. Of 119 pts, 10 (8%) eventually required surgical myotomy-myectomy because of either no improvement or deterioration of symptoms. Of the remaining 109 pts, 9 (8%) died (2 noncardiac deaths). Of the 7 cardiac deaths, 5 were sudden and occurred in pts with mean age of 61 years (range 28-78), all of whom were receiving P<160 mg daily. Of the 5 pts who died suddenly, 1 had right bundle branch block (RBBB), left axis deviation (LAD), and atria1 fibrillation; one had RBBB and LAD; and one had atria1 fibrillation without associated conduction disturbance. This study documented that, in a large group of pts, P in modest doses is effective in symptomatic improvement over long-term follow-up. However, sudden death was not prevented by P in dose $60 daily.
434
February 1979
The American Journal of CARDIOLOGY
Volume 41