This communication has focused on the effect of AN on QRS potential amplitudes; however, AN exert its effect proportionally on the entire QRST curve; consequently “dwarfing,” or virtual disappearance of the P waves occasionally occurs. When this happens, the clinician is presented with an ECG showing low-voltage QRS complexes and no P waves. When the prevailing heart rates are within the normal range, one can assume that the underlying rhythm is still normal sinus rhythm; however, patients with critical care illnesses are prone to both bradycardia and tachycardia, and when such complications arise, it becomes problematic to diagnose the specific rhythm or conduction disorder using the standard ECG. In such an occasion, even employment of special surface ECG leads is noncontributory, and resorting to esophageal or intracardiac electrography becomes necessary.
Why is it important for critical care Viagra in Australia physicians to be aware of the above? What are the implications for the care of patients with critical illness?
Recognizing this AN/low-voltage ECG association provides the following advantages to the physician managing a critically ill patient: (1) low-voltage ECG is not automatically connected to the presence of a pericardial effusion; (2) when a pericardial effusion is ruled out by echocardiography, the presence of low-voltage ECG can be explainable in the setting of weight gain, positive intake and output records, or visible fluid accumulation or AN; (3) in the presence of discrepancy of data pertaining to fluid status of a patient, based on weights, physical examination, or intake/output balance records, review of serial ECGs may be of great help; this issue is of importance in the bedridden patient with a critical illness where weighing by sling scales and accurate intake/output record keeping becomes problematic; (4) the puzzling disappearance of ECG evidence of left ventricular hypertrophy, in a patient known to carry such a diagnosis prior to the development of AN, finds an explanation; and (5) the absence of P waves in the ECG in a patient with AN does not necessarily imply the presence of an AV junctional rhythm or junctional tachycardia; often the rhythm is merely normal sinus or sinus tachycardia in association with “invisible” P waves. Correct identification of the rhythm can be accomplished by intracardiac or esophageal ECG, or by employing a saline solution-filled central venous catheter ECG lead, as shown recently.