Cardiovascular

Cardiovascular deterioration usually declares itself through one of three linked failures: inadequate coronary blood flow, inadequate forward pump function, or electrical instability. The nurse’s first task is not to name an isolated abnormality but to decide whether the patient is maintaining tissue perfusion. Chest discomfort with autonomic symptoms and new ECG changes points toward myocardial ischemia. Breathlessness, crackles, orthopnea, raised jugular venous pressure, and falling oxygen saturation suggest congestion from impaired pump function. A rapid irregular rhythm may be tolerated briefly in one patient but cause hypotension, ischemia, or pulmonary edema in another because the clinical effect depends on ventricular filling, contractility, and baseline reserve. A 12-lead ECG supplies a map of electrical activity and myocardial injury. The P wave represents atrial depolarization, the PR interval reflects atrioventricular conduction, and the QRS complex represents ventricular depolarization. A widened QRS suggests delayed intraventricular conduction; a prolonged PR interval suggests slowed AV conduction. ST-segment elevation in anatomically contiguous leads raises immediate concern for STEMI and should trigger a reperfusion pathway rather than a leisurely diagnostic work-up. ST depression or T-wave inversion may...