Analysis of QT interval in patients with idiopathic mitral valve prolapse.

Analysis of QT interval from repeated recordings was made in 56 patients with documented idiopathic mitral valve prolapse (IMVP). The results were compared with a control of 62 healthy volunteers in whom mitral valve prolapse was excluded by both phonocardiography and echocardiography and with two other standard populations, those of Simonson and co-workers and of Ashman. After correction for age, the maximum QT interval of the patients with IMVP exceeded the 97.5 percentile of Simonson population in 51 of 56 patients compared with only three of 62 subjects of the control group. The difference between the QT interval of patients from the upper limits of the predicted mean values of Simonson was significant (P less than 0.002). The mean QTC interval in patients with IMVP was 0.48 +/- 0.035 second compared with 0.038 +/- 0.025 second in the control subjects. The difference between the mean QTC interval in patients with IMVP and the control subjects was significant (P less than 0.005). Spontaneous prolongation in the mean QT interval was noted in 43 of 56 patients with IMVP (76.6 percent) compared with only two of 62 control subjects (3 percent). The incidence of episodic arrhythmias was 72 percent in patients with marked QTC prolongation (mean, 0.58 second) compared with 22.6 percent in patients with lesser degree of QTC prolongation (mean, 0.46 second). The results suggest that QT abnormality is common in patients with IMVP and may play an important role in the genesis of cardiac arrhythmia.

Rapid serum lidocaine determination in the coronary care unit.

Eighty-four serum lidocaine determinations were made in 33 hospitalized patients with the use of a rapid enzyme innumoassay technique. Prediction of lidocaine concentration within broad categories based on clinical assessment alone was compared with actual measurements. When serum concentrations were not considered, most episodes of lidocaine toxic reactions were obscured by associated complex clinical problems. The rapid lidocaine enzyme immunoassay is a useful tool for assisting in the detection of lidocaine toxic reactions in the coronary care unit.

Noninvasive assessment of left ventricular effects of hydralazine in heart failure.

In order to develop a noninvasive means for following left ventricular responses to hydralazine, we measured the systolic time intervals serially in 6 patients with heart failure. Without affecting heart rate or arterial pressure, hydralazine lengthened the left ventricular ejection time relative to the heart rate (LVETc) 19 +/- 7 msec (p < 0.05) and shortened the preejection period 23 +/- 3 msec (p < 0.001), restoring it to normal in 4 patients. The data suggest that preejection period shortening and LVETc lengthening provide the basis for a noninvasive method of assessing the effects of hydralazine on left ventricular performance in heart failure.

Massive coronary arterial aneurysm.

The pathologic and echocardiographic findings of a massive right coronary arterial aneurysm in a 62 year old man are presented. The thrombosed aneurysm simulated a cardiac tumor, destroying one pulmonary valve cusp. It also caused marked pulmonary stenosis with elongation and narrowing of the outflow tract of the right ventricle and fixation of half of one cusp of the tricuspid valve.

Cold water syncope.

Cardiac bradyarrhythmias upon swallowing have been reported previously and most commonly have been related to esophageal abnormalities. We have reported the case of an unusual patient who experiences bradycardia and syncope only upon swallowing cold liquids.

Drug-induced cardiovascular diseases.

A wide variety of drugs may be associated with serious cardiovascular toxicity. Toxicity due to drugs primarily used for treating cardiovascular toxicity. Toxicity due to drugs primarily used for treating cardiac disorders is the most extensively documented, especially the arrhythmias due to digitalis glycosides. Various arrhythmias are also caused by toxic levels of many antiarrhythmic agents including quinidine, procainamide and phenytotin. Myocardial depression and heart failure are serious side-effects of beta-adrenoceptor blocking agents and myocardial ischaemia due to sympathominetic amines may result from both direct and indirect mechanisms. The many toxic reactions in the cardiovascular system due to non-cardiac drugs are less widely known and for the most part less clearly understood. Many remain controversial at the current time; for example, the diathesis toward thromboembolism in women taking oral contraceptives. Potential cardiac toxicity due to drugs used in the rapidly expanding sphere of anti-neoplastic chemotherapy is exemplified by the cardiomyopathy-like toxicities of doxorubicin and daunorubicin. Many of the psychotherapeutic drugs including phenothiazine antipsychotics and tricyclic antidepressants have arrhythmogenic potential.

Acute myocardial infarction following fluorescein angiography.

A 64-year-old woman with diabetes mellitus as well as hypertensive retinopathy developed an acute myocardial infarction and hypertensive crisis following the injection of 5 ml. of 10 per cent sodium fluorescein for fundus angiography. This is the first time this complication has been documented. Possible mechanisms for such an occurrence are discussed. Recommendations for recognizing and dealing with patients at high risk for cardiovascular complications of fluorescein angiography are emphasized.