Electrocardiographic Predictors of Morbidity and Mortality in Patients With Acute Myocarditis: The Importance of QRS-T Angle.

BACKGROUND: Acute myocarditis carries a variable prognosis. We evaluated the morbidity and mortality rates in patients with acute myocarditis and admission electrocardiographic predictors of outcome. METHODS AND RESULTS: Patients admitted to a tertiary hospital with a clinical diagnosis of acute myocarditis were evaluated; 193 patients were included. Median follow-up was 5.7 years, 82% were male, and overal median age was 30 years (range 21-39). The most common clinical presentations were chest pain (77%) and fever (53%). The 30-day survival rate was 98.9%. Overall survival during follow-up was 94.3%. The most common abnormalities observed on electrocardiography were T-wave changes (36%) and ST-segment changes (32%). Less frequent changes included abnormal T-wave axis (>105° or < -15°; 16%), abnormal QRS axis (12%), QTc >460 ms (11%), and QRS interval ≥120 ms (5%). Wide QRS-T angle (≥100°) was demonstrated in 13% of the patients and was associated with an increased mortality rate compared with patients with a narrow QRS-T angle (20% vs 4%; P = .007). The rate of heart failure among patients with a wide QRS-T angle was significantly higher (36% vs 10%; P = .001). Cox regression analysis demonstrated that a wide QRS-T angle (≥100°) was a significant independent predictor of heart failure (hazard ratio [HR] 3.20, 95% confidence interval [CI] 1.35-7.59; P < .01) and of the combined end point of death or heart failure (HR 2.56, 95% CI 1.14-5.75; P < .05). CONCLUSIONS: QRS-T angle is a predictor of increased morbidity and mortality in acute myocarditis.

Echocardiography in the Diagnosis and Management of Hypertrophic Cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is an inherited condition present in about 1/500 individuals with more than 1500 causative mutations identified in primarily 10 sarcomeric proteins. Although HCM is inherited in an autosomal dominant way, there is often incomplete penetrance and variable phenotype even with the same genotype. It is characterized by a degree of hypertrophy (usually asymmetric), that is, not due to another identifiable cause, as well as variable degrees of myocardial fibrosis and microvascular abnormalities.

Serum Potassium Levels and Outcome in Patients With Chronic Heart Failure.

Potassium levels are often abnormal in patients with heart failure (HF) and have a detrimental effect on clinical outcome. We evaluated potassium levels in a real-world cohort of patients with HF and its effect on mortality. All patients with a diagnosis of HF at a health maintenance organization were evaluated and followed for cardiac-related hospitalizations and death. The cohort consisted of 6,073 patients with HF. Mean potassium levels were 4.57 ± 0.53 mmol/L. Most patients (68%) had potassium levels in the normal range (4.0 to 5.0 mmol/L). High-normal potassium levels (5.0 to 5.5) were present in 17% of the patients, low potassium levels (<4.0) in 11%, and hyperkalemia (K ≥5.5) in 4%. Mean follow-up was 576 days. The overall mortality rate during this period was 14%. Survival rate by Kaplan-Meier analysis demonstrated that hypokalemia (K ≤3.5) was associated with the lowest survival rate. Survival was highest in patients with high-normal potassium levels. Cox regression analysis after adjustment for significant predictors including co-morbidities and standard HF drug therapies demonstrated that high-normal potassium levels were independently associated with reduced mortality compared with normal reference levels (hazard ratio 0.78, 95 confidence interval [CI] 0.64 to 0.95, p = 0.01). Subgroup analysis showed improved outcome with high-normal potassium levels in patients with reduced renal function, spironolactone, and loop diuretic therapy. In conclusion, potassium levels in the high-normal range appear to be safe and are associated with an improved outcome in patients with HF.