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Biomedical subjects

K M Kessler

Publications and source records attributed to K M Kessler.

At least 73 records · Page 4Linked to original sources
PubMed1992

Sudden cardiac death. Structure, function, and time-dependence of risk.

Sudden cardiac death (SCD) remains a major unresolved clinical and public health problem, accounting for more than 300,000 of the deaths in the United States annually. The ability to identify potential SCD victims is limited by the large size of the population subgroups that contain the majority of SCD victims and by the apparent time dependence of risk of sudden death. The latter refers to the tendency for SCD to follow other cardiovascular events within a high-risk period of 6-18 months after a primary cardiovascular event, with risk decreasing thereafter. The combination of time dependence and denominator pool size provides a basis for future studies to identify the higher risk individuals. Pathophysiologically, SCD can be viewed as an interaction between structural abnormalities of the heart, transient functional disturbances, and the specific electrophysiological events responsible for fatal arrhythmias. Structural abnormalities provide the anatomic substrate for chronic risk and include the myocardial consequences of coronary artery disease, left ventricular hypertrophy, myopathic ventricles, and specific electrophysiological anatomic abnormalities such as bypass tracts. The functional factors responsible for destabilizing a chronic electrophysiological abnormality include transient ischemia and reperfusion, systemic factors (e.g., electrolyte disturbances, acidosis, and hemodynamic dysfunction), autonomic fluctuations (both systemic and at a tissue level), and myocardial toxic influences such as proarrhythmic effects of various drugs. Each of these changes is able to destabilize myocardial membrane integrity, some regionally and some globally, making the heart susceptible to an electrical triggering event for ventricular tachycardia or fibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1991

Abnormal left ventricular diastolic filling in eccentric left ventricular hypertrophy of obesity.

Left ventricular (LV) diastolic filling pattern of obese subjects with eccentric LV hypertrophy was studied. Findings were compared with those of normal control subjects and hypertensive patients with concentric LV hypertrophy. M-mode, 2-dimensional and Doppler echocardiograms were recorded in 11 obese (body mass index greater than 30 kg/m2) normotensive patients with eccentric LV hypertrophy, 10 normal control subjects, and 18 nonobese, hypertensive patients with concentric LV hypertrophy whose antihypertensive medications were discontinued 2 weeks before study. LV hypertrophy was defined as LV mass/height greater than 143 g/m. Hypertrophy in the obese patients was eccentric: Their LV internal dimension (61 +/- 3 mm) was greater than that of hypertensive patients (55 +/- 5 mm, p less than 0.001) and normal control subjects (55 +/- 2 mm, p less than 0.01); their septal (10.7 +/- 0.7 mm) and posterior (10.9 +/- 0.6 mm) wall thicknesses were smaller than those of the hypertensive patients (12.2 +/- 1.7 mm, p less than 0.05 and 11.7 +/- 1.2 mm, respectively, difference not significant). Pulsed-wave Doppler echocardiographic filling indexes were used to evaluate LV diastolic filling. Obese patients had a higher peak velocity of atrial filling (69 +/- 14 vs 54 +/- 15 cm/s, p less than 0.05), lower early/atrial filling velocity ratio (1.0 +/- 0.26 vs 1.32 +/- 0.21, p less than 0.05), prolonged deceleration half-time (108 +/- 9 vs 86 +/- 15 ms, p less than 0.01) and lower peak filling rate corrected to stroke volume (4.08 +/- 0.68 vs 4.96 +/- 0.88 stroke volume/s, p less than 0.05) than normal control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Usefulness of the automatic implantable cardioverter defibrillator in improving survival of patients with severely depressed left ventricular function associated with coronary artery disease.

Clinical outcome was analyzed among a group of 39 consecutive patients with coronary artery disease, left ventricular (LV) ejection fractions less than 30% and arrhythmias that required an automatic implantable cardioverter defibrillator (AICD) in an attempt to better define the role of the device in patients with severely depressed LV function. Twenty-nine (74%) were survivors of out-of-hospital cardiac arrest and 10 (26%) had ventricular tachycardia that was refractory to electrophysiologically guided antiarrhythmic therapy. The study group had the following demographic characteristics: 90% were men, mean age was 64 years (range 41 to 79) and mean LV ejection fraction was 21 +/- 4%. Concomitant pharmacotherapy included antiarrhythmic drugs 31 (79%), vasodilators in 22 (56%) and digoxin in 20 (51%). There was no statistical difference in baseline characteristics between survivors and nonsurvivors. Patients were followed for a mean of 24 months (range 2 to 72) from implantation. The difference between actuarial survival--77% at 1 year and 72% at 2 years--and projected survival without the AICD (patients who survive without appropriate device discharge)--30% at 1 year and 21% at 2 years--was significant (p less than 0.01 and less than 0.05 at 1 and 2 years, respectively). This study suggests that the AICD improves survival in patients with coronary artery disease despite severely depressed LV function.

Adult↗
PubMed1991

Percutaneous transluminal coronary angioplasty of anomalous right coronary artery.

Coronary angioplasty of tortuous anomalous coronary arteries can be technically challenging. We describe a successful percutaneous transluminal coronary angioplasty (PTCA) of an anomalous right coronary artery after a failed previous attempt. The anatomic limitations of anomalous right coronary arteries and technical considerations for PTCA are discussed.

Angioplasty, Balloon, Coronary↗
PubMed1991

Clinical, radiographic, and hemodynamic correlations in chronic congestive heart failure: conflicting results may lead to inappropriate care.

PURPOSE: Clinical and radiographic examinations are commonly used for estimating severity and titrating therapy of chronic congestive heart failure. The purpose of this study was to establish the relationship between findings on history, physical examination, chest roentgenogram, and pulmonary capillary wedge pressure (PCWP). PATIENTS AND METHODS: Fifty-two consecutive patients with chronic congestive heart failure, referred for evaluation for heart transplantation, were studied; all patients underwent history, physical examination, upright chest roentgenogram, and cardiac catheterization. The mean left ventricular ejection fraction was 0.19 +/- 0.06. Patients were divided into three groups according to their PCWP: Group 1, normal PCWP (less than or equal to 15 mm Hg, n = 19); Group 2, mild to moderately elevated PCWP (16 to 29 mm Hg, n = 15); Group 3, markedly elevated PCWP (greater than or equal to 30 mm Hg, n = 18). RESULTS: Physical and radiographic signs of congestion were more common in the groups with higher PCWP, but they could not be used to reliably separate patients with different filling pressures. Physical findings (orthopnea, edema, rales, third heart sound, elevated jugular venous pressure) or radiographic signs (cardiomegaly, vascular redistribution, and interstitial and alveolar edema) had poor predictive value for identifying patients with PCWP values greater than or equal to 30 mm Hg. These findings had poor negative predictive value to exclude significantly elevated PCWP (greater than 20 mm Hg). Radiographic pulmonary congestion was absent in eight (53%) patients in Group 2 and seven (39%) in Group 3. In patients in Group 2 and 3, those without radiographic congestion were in a better New York Heart Association functional class (3.5 +/- 0.5 versus 2.8 +/- 0.6, p less than 0.01). There was good correlation between right atrial pressure and PCWP (r = 0.64, p less than 0.001). A normal right atrial pressure had no predictive value, but a pressure greater than 10 mm Hg was seen in all but one patient with a PCWP value greater than 20 mm Hg. CONCLUSION: Clinical, radiographic, and hemodynamic evaluations of chronic congestive heart failure yield conflicting results. Absence of radiographic or physical signs of congestion does not ensure normal PCWP values and may lead to inaccurate diagnosis and inadequate therapy. It is not known whether therapy aimed at normalizing PCWP is superior to relieving clinical and radiographic signs of congestion.

Adult↗
PubMed1990

Right ventricular diastolic function in systemic hypertension.

Right (RV) and left ventricular (LV) diastolic function was evaluated in 50 patients with mild, uncomplicated essential hypertension using pulsed-wave Doppler echocardiography. Patients with pulmonary, valvular or coronary artery disease were excluded and antihypertensive drugs were discontinued for the 2 weeks preceding the study. Ten normotensive patients without heart disease acted as control subjects. In the hypertensive patients, RV peak velocity of atrial filling was higher (42 +/- 10 vs 31 +/- 7 cm/s, p less than 0.01) and deceleration half-time was prolonged (96 +/- 20 vs 83 +/- 10 ms, difference not significant); ratio of early/atrial filling velocity (1.1 +/- 0.3 vs 1.7 +/- 0.4, p less than 0.001) and peak filling rate corrected to stroke volume (3.6 +/- 0.7 vs 5.3 +/- 0.9 SV/s, p less than 0.001) were lower. LV filling parameters showed similar changes. RV filling parameters did not correlate with age, LV mass or septal thickness but correlated weakly with LV radius/thickness ratio. There was good correlation between RV and the following corresponding LV filling parameters: peak filling rate, r = 0.68, p less than 0.001; ratio of early/atrial filling, r = 0.88, p less than 0.0001; and deceleration half-time, r = 0.62, p less than 0.001. Data indicate that RV diastolic function is abnormal in essential hypertension and these abnormalities are closely related to those of LV diastolic function.

Adult↗
PubMed1990

Iatrogenic aorto-sinus of valsalva fistula: angiographic and cine computerized tomography delineation.

A patient is reported who underwent cardiac catheterization 4 years following coronary artery bypass grafting. Cardiac catheterization revealed the presence of a fistulous tract in the wall of the ascending aorta, originating at the site of aortic anastomosis of a saphenous vein bypass graft and ending in the superior aspect of the right sinus of Valsalva. This complication was felt to have resulted from a inadvertent localized dissection of the aorta during bypass surgery. The fistula was also imaged by ultrafast cine computerized tomography which proved a useful non-invasive method for follow-up examination.

Aortic Diseases↗
PubMed1990

Interrelationship of variable coupling, multiformity and repetitive forms: implications for classification of ventricular arrhythmias.

One hundred 24-hour ambulatory electrocardiograms were prospectively examined to determine the relationship of variable coupling and multiformity of single premature ventricular complexes to repetitive forms. Premature ventricular complexes were present in 86 patients and were categorized by a three-tier decision-making tree using (1) multiformity confirmed in two channels, (2) variable coupling of greater than 80 msec of premature ventricular complexes of similar QRS morphologies, and (3) repetitive forms of greater than or equal to 2 premature ventricular complexes. Variable coupling was present in 51 patients, among whom 35 (69%) had repetitive forms; multiformity was present in 46 patients, among whom 37 (80%) had repetitive forms; repetitive forms were present in 41 patients, among whom only one patient (2%) did not demonstrate multiformity or variable coupling. Variable coupling, multiformity, or either were significantly associated with the occurrence of repetitive forms (chi square = 34, 15, 29, respectively, each p less than 0.005). There was a bimodal distribution between patients with uniform, fixed coupled premature ventricular complexes who had rare repetitive forms (1 of 26) and patients with multiformity and variable coupling of premature ventricular complexes who had significantly more repetitive forms (30 of 37; p less than 0.001). The frequency distribution of repetitive form length suggested a natural break point between five and six consecutive complexes.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗